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•	financial performance;

•	cash flows;

•	capital expenditures;

•	dividends;

•	capital structure;

•	other financial items;

•	strategic goals and objectives;

•	business environment; and

•	plans for operations.

•	weather conditions (temperatures, precipitation levels and wind patterns), which affect both energy demand and electric generating capability, including the effect of precipitation and temperature on hydroelectric resources, the effect of wind patterns on wind-generated power, weather-sensitive customer demand, and similar effects on supply and demand in the wholesale energy markets;

•	our ability to obtain financing through the issuance of debt and/or equity securities, which can be affected by various factors including our credit ratings, interest rates and other capital market conditions and the global economy;

•	changes in interest rates that affect borrowing costs, our ability to effectively hedge interest rates for anticipated debt issuances, variable interest rate borrowing and the extent to which we recover interest costs through retail rates collected from customers;

•	changes in actuarial assumptions, interest rates and the actual return on plan assets for our pension and other postretirement benefit plans, which can affect future funding obligations, pension and other postretirement benefit expense and the related liabilities;

•	deterioration in the creditworthiness of our customers;

•	the outcome of legal proceedings and other contingencies;

•	economic conditions in our service areas, including the economy's effects on customer demand for utility services;

•	declining energy demand related to customer energy efficiency and/or conservation measures;

•	changes in long-term climates, both globally and within our utilities' service areas, which can affect, among other things, customer demand patterns and the volume and timing of streamflows to our hydroelectric resources;

•	state and federal regulatory decisions or related judicial decisions that affect our ability to recover costs and earn a reasonable return including, but not limited to, disallowance or delay in the recovery of capital investments, operating costs, commodity costs, interest rate swap derivatives and discretion over allowed return on investment;

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•	possibility that our integrated resource plans for electric and natural gas will not be acknowledged by the state commissions, which could result in future resource acquisitions based on the integrated resource plans that are later deemed imprudent;

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volatility and illiquidity in wholesale energy markets, including the availability of willing buyers and sellers, changes in wholesale energy prices that can affect operating income, cash requirements to purchase electricity and natural gas, value received for wholesale sales, collateral required of us by counterparties in wholesale energy transactions and credit risk to us from such transactions, and the market value of derivative assets and liabilities;

•	default or nonperformance on the part of any parties from whom we purchase and/or sell capacity or energy;

•	potential environmental regulations affecting our ability to utilize or resulting in the obsolescence of our power supply resources;

•	severe weather or natural disasters, including, but not limited to, avalanches, wind storms, wildfires, earthquakes, snow and ice storms, that can disrupt energy generation, transmission and distribution, as well as the availability and costs of materials, equipment, supplies and support services;

•	explosions, fires, accidents, mechanical breakdowns or other incidents that may impair assets and may disrupt operations of any of our generation facilities, transmission, and electric and natural gas distribution systems or other operations and may require us to purchase replacement power;

•	explosions, fires, accidents or other incidents arising from or allegedly arising from our operations that may cause wildfires, injuries to the public or property damage;

•	blackouts or disruptions of interconnected transmission systems (the regional power grid);

•	terrorist attacks, cyber attacks or other malicious acts that may disrupt or cause damage to our utility assets or to the national or regional economy in general, including any effects of terrorism, cyber attacks or vandalism that damage or disrupt information technology systems;

•	work force issues, including changes in collective bargaining unit agreements, strikes, work stoppages, the loss of key executives, availability of workers in a variety of skill areas, and our ability to recruit and retain employees;

•	increasing costs of insurance, more restrictive coverage terms and our ability to obtain insurance;

•	delays or changes in construction costs, and/or our ability to obtain required permits and materials for present or prospective facilities;

•	increasing health care costs and cost of health insurance provided to our employees and retirees;

•	third party construction of buildings, billboard signs, towers or other structures within our rights of way, or placement of fuel receptacles within close proximity to our transformers or other equipment, including overbuild atop natural gas distribution lines;

•	the loss of key suppliers for materials or services or disruptions to the supply chain;

•	adverse impacts to our Alaska operations that could result from an extended outage of its hydroelectric generating resources or their inability to deliver energy, due to their lack of interconnectivity to any other electrical grids and the extensive cost of replacement power (diesel);

•	changing river regulation at hydroelectric facilities not owned by us, which could impact our hydroelectric facilities downstream;

•	compliance with extensive federal, state and local legislation and regulation, including numerous environmental, health, safety, infrastructure protection, reliability and other laws and regulations that affect our operations and costs;

•	the ability to comply with the terms of the licenses and permits for our hydroelectric or thermal generating facilities at cost-effective levels;

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•	cyber attacks on us or our vendors or other potential lapses that result in unauthorized disclosure of private information, which could result in liabilities against us, costs to investigate, remediate and defend, and damage to our reputation;

•	disruption to or breakdowns of information systems, automated controls and other technologies that we rely on for our operations, communications and customer service;

•	changes in costs that impede our ability to effectively implement new information technology systems or to operate and maintain current production technology;

•	changes in technologies, possibly making some of the current technology we utilize obsolete or introducing new cyber security risks;

•	insufficient technology skills, which could lead to the inability to develop, modify or maintain our information systems;

•	growth or decline of our customer base and the extent to which new uses for our services may materialize or existing uses may decline, including, but not limited to, the effect of the trend toward distributed generation at customer sites;

•	the potential effects of negative publicity regarding our business practices, whether true or not, which could hurt our reputation and result in litigation or a decline in our common stock price;

•	changes in our strategic business plans, which may be affected by any or all of the foregoing, including the entry into new businesses and/or the exit from existing businesses and the extent of our business development efforts where potential future business is uncertain;

•	non-regulated activities may increase earnings volatility;

•	failure to complete the proposed acquisition of the Company by Hydro One, which would negatively impact the market price of Avista Corp.'s common stock and could result in termination fees that would have a material adverse effect on our results of operations, financial condition, and cash flows;

•	changes in environmental laws, regulations, decisions and policies, including present and potential environmental remediation costs and our compliance with these matters;

•	the potential effects of initiatives, legislation or administrative rulemaking at the federal, state or local levels, including possible effects on our generating resources of restrictions on greenhouse gas emissions to mitigate concerns over global climate changes;

•	political pressures or regulatory practices that could constrain or place additional cost burdens on our distribution systems through accelerated adoption of distributed generation or electric-powered transportation or on our energy supply sources, such as campaigns to halt coal-fired power generation and opposition to other thermal generation, wind turbines or hydroelectric facilities;

•	wholesale and retail competition including alternative energy sources, growth in customer-owned power resource technologies that displace utility-supplied energy or that may be sold back to the utility, and alternative energy suppliers and delivery arrangements;

•	failure to identify changes in legislation, taxation and regulatory issues which are detrimental or beneficial to our overall business;

•	the new federal income tax law and its intended and unintended consequences on financial results and future cash flows, including the potential impact to credit ratings, which may affect our ability to borrow funds or increase the cost of borrowing in the future;

•	policy and/or legislative changes resulting from the current presidential administration in various regulated areas, including, but not limited to, environmental regulation and healthcare regulations; and

•	the risk of municipalization in any of our service territories.

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•

Avista Utilities – an operating division of Avista Corp., comprising the regulated utility operations in the Pacific Northwest. Avista Utilities provides electric distribution and transmission, and natural gas distribution services in parts of eastern Washington and northern Idaho. Avista Utilities also provides natural gas distribution service in parts of northeastern and southwestern Oregon. Avista Utilities has electric generating facilities in Washington, Idaho, Oregon and Montana. Avista Utilities also supplies electricity to a small number of customers in Montana, most of whom are employees who operate Avista Utilities' Noxon Rapids generating facility. Avista Utilities also engages in wholesale purchases and sales of electricity and natural gas as an integral part of energy resource management and its load-serving obligation.

•	AEL&P - a utility providing electric services in Juneau, Alaska that is a wholly-owned subsidiary and the primary operating subsidiary of AERC.

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•	electric loads at various points in time (ranging from intra-hour to multiple years) based on, among other things, estimates of customer usage and weather, historical data and contract terms, and

•	resource availability at these points in time based on, among other things, fuel choices and fuel markets, estimates of streamflows, availability of generating units, historic and forward market information, contract terms and experience.

•	purchasing fuel for generation,

•	when economical, selling fuel and substituting wholesale electric purchases, and

•	other wholesale transactions to capture the value of generating resources, transmission contract rights and fuel delivery (transport) capacity contracts.

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(1)

Normal hydroelectric generation is determined by reference to the effect of upstream dam regulation on median natural water flow. Natural water flow is the flow of the rivers without the influence of dams, whereas regulated water flow takes into account any water flow changes from upstream dams due to releasing or holding back water. The calculation of normal varies annually due to the timing of upstream dam regulation throughout the year.

•	the combined cycle CT natural gas-fired Coyote Springs 2 located near Boardman, Oregon,

•	a 15 percent interest in a twin-unit, coal-fired boiler generating facility, Colstrip 3 & 4, located in southeastern Montana,

•	a wood waste-fired boiler generating facility known as the Kettle Falls Generating Station (Kettle Falls GS) in northeastern Washington,

•	a two-unit natural gas-fired CT generating facility, located in northeastern Spokane (Northeast CT),

•	a two-unit natural gas-fired CT generating facility in northern Idaho (Rathdrum CT), and

•	two small natural gas-fired generating facilities (Boulder Park GS and Kettle Falls CT).

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(1)	The contracts for power sales decrease due to certain contracts expiring in each of these years. We are evaluating the future plan for the additional resources made available due to the expiration of these contracts.

(2)	The forecast assumes near normal hydroelectric generation.

(3)	Includes the Lancaster Plant PPA. Excludes Boulder Park GS, Kettle Falls CT, Northeast CT and Rathdrum CT, as these are considered peaking facilities and are generally not used to meet our base load requirements.

(4)	The combined maximum capacity of Boulder Park GS, Kettle Falls CT, Northeast CT and Rathdrum CT is 278 MW, with estimated available energy production as indicated for each year.

•	Our current generation resources will remain cost effective and reliable sources of power to meet future customer needs over the next 20 years.

•	Energy storage costs are significantly lower than those assumed in the 2015 IRP, which, for the first time, makes the energy storage technology operationally attractive in meeting energy needs in the 20-year timeframe of the 2017 IRP.

•	A power purchase agreement for a solar facility of at least 15 MW for our new Solar Select Program for commercial and industrial customers.

•	Conservation will effectively provide 53 percent of the requirements of future load growth.

•	Colstrip will remain a cost effective and reliable source of power to meet future customer needs.

•	If Colstrip were retired in 2030, total customer bills would increase approximately $50.0 million in the first year following retirement.

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The 2017 Expected Case energy forecast will grow at 0.47 percent per year, replacing the 0.6 percent annual growth rate in the 2015 IRP. See "Item 7. Management Discussion and Analysis – Economic Conditions and Utility Load Growth" for further discussion regarding utility customer growth, load growth, and the general economic conditions in our service territory. The estimates of future load growth in the IRP and at "Item 7. Management Discussion and Analysis – Economic Conditions and Utility Load Growth" differ slightly due to the timing of when the two estimates were prepared and due to the time period that each estimate is focused on.

•	Peak load growth will be lower than energy growth, at 0.42 percent for the winter and 0.46 percent for the summer.

•	Lower expected load growth combined with recent Mid-Columbia hydroelectric contracts, energy efficiency, and demand response will delay the need for additional resources from the end of 2020 until 2026.

•	Demand response (temporarily reducing the demand for energy) is a viable strategy for meeting future energy needs and energy storage and solar have been added as future resources.

•	We expect lower emissions from Avista Corp. owned and controlled resources due to lower utilization of natural-gas fired peaking plants and no new combined-cycle plants.

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•	wholesale market sales of surplus natural gas supplies,

•	purchases and sales of natural gas to optimize use of pipeline and storage capacity, and

•	participation in the transportation capacity release market.

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•	We will have sufficient natural gas transportation resources well into the future with resource needs not occurring during the 20-year planning horizon in Washington, Idaho, or Oregon.

•	Natural gas commodity prices will continue to be relatively stable due to robust North American supplies led by shale gas development.

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Future customer growth in our service territory will increase slightly compared to the 2014 IRP. There will be increasing interest from customers to utilize natural gas due to its abundant supply and subsequent low cost. We anticipate that any increased demand in the region will primarily come from power generation as natural gas is increasingly being used to back up solar and wind technology, as well as replace retired coal plants. There is also potential for increased usage in other markets, such as transportation and as an industrial feedstock.

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The availability of natural gas in North America will continue to change global LNG dynamics. Existing and new LNG facilities will look to export low cost North American natural gas to the higher priced Asian and European markets. This could alter the price of natural gas and/or transportation, constrain existing pipeline networks, stimulate development of new pipeline resources, and change flows of natural gas across North America.

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(1)

Cooling degree days are the measure of the warmness of weather experienced, based on the extent to which the average of high and low temperatures for a day exceeds 65 degrees Fahrenheit (annual degree days above historic indicate warmer than average temperatures). During 2017, we modified the calculation for historical average cooling degree days. We have recalculated 2016 and 2015 using the updated methodology to be consistent with 2017.

(2)

Heating degree days are the measure of the coldness of weather experienced, based on the extent to which the average of high and low temperatures for a day falls below 65 degrees Fahrenheit (annual degree days below historic indicate warmer than average temperatures). During 2017, we modified the calculation for historical average heating degree days. We have recalculated 2016 and 2015 using the updated methodology to be consistent with 2017.

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(1)

Heating degree days are the measure of the coldness of weather experienced, based on the extent to which the average of high and low temperatures for a day falls below 65 degrees Fahrenheit (annual degree days below historic indicate warmer than average temperatures). During 2017, we modified the calculation for historical average heating degree days. We have recalculated 2016 and 2015 using the updated methodology to be consistent with 2017.

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(1)	Normal hydroelectric generation is defined as the energy output of the plant during a year with average inflows to the reservoir.

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(1)	Heating degree days are the measure of the coldness of weather experienced, based on the extent to which the average of high and low temperatures for a day falls below 65 degrees Fahrenheit (annual heating degree days below historical average indicate warmer than average temperatures).

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•	Salix is a wholly-owned subsidiary of Avista Capital that explores markets that could be served with LNG.

•	Equity investments are primarily in an emerging technology venture capital fund.

•	Equity investments are primarily in emerging technology venture capital funds and companies, including an investment in a technology company that delivers scalable smart grid solutions to global partners and customers, and a predictive data science company.

•	Real estate consists primarily of mixed use commercial and retail office space.

•	Notes receivable and other assets are primarily long-term notes receivable made to a company focused on spurring economic development throughout Washington State and to a smart grid solutions company.

•	AM&D, doing business as METALfx, performs custom sheet metal fabrication of electronic enclosures, parts and systems for the computer, construction, telecom, renewable energy and medical industries. The asset balance above excludes an intercompany loan from METALfx to Avista Corp. The loan balance was $5.6 million as of December 31, 2017 and $4.0 million as of December 31, 2016.

•	Includes AERC and AJT Mining, which is a wholly-owned subsidiary of AERC and is an inactive mining company holding certain real estate.

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•	certain retail electricity and natural gas sales,

•	the cost of natural gas supply, and

•	the cost of power supply.

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•	electric and natural gas utilities,

•	electric generators and transmission providers,

•	oil and natural gas producers and pipelines,

•	financial institutions including commodity clearing exchanges and related parties, and

•	energy marketing and trading companies.

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•	required to write off our regulatory assets, and

•	precluded from the future deferral of costs or decoupled revenues not recovered through rates at the time such amounts are incurred, even if we are expected to recover these amounts from customers in the future.

•	our obligation to serve our retail customers at rates set through the regulatory process - we cannot decline to serve our customers and we cannot change retail rates to reflect current energy prices unless and until we receive regulatory approval,

•	customer demand, which is beyond our control because of weather, customer choices, prevailing economic conditions and other factors,

•	some of our energy supply cost is fixed by the nature of the energy-producing assets or through contractual arrangements (however, a significant portion of our energy resource costs are not fixed), and

•	the potential non-performance by commodity counterparties, which could lead to replacement of the scheduled energy or natural gas at higher prices.

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•	severe weather or natural disasters, including, but not limited to, avalanches, wind storms, wildfires, earthquakes, snow and ice storms, which can disrupt energy generation, transmission and distribution, as well as the availability and costs of materials, equipment, supplies support services and general business operations,

•	blackouts or disruptions of interconnected transmission systems (the regional power grid),

•	unplanned outages at generating plants,

•	fuel cost and availability, including delivery constraints,

•	explosions, fires, accidents, or mechanical breakdowns that may occur while operating and maintaining our generation, transmission and distribution systems,

•	damage or injuries to third parties caused by our generation, transmission and distribution systems,

•	natural disasters that can disrupt energy generation, transmission and distribution, and general business operations,

•	terrorist attacks or other malicious acts that may disrupt or cause damage to our utility assets or the vendors we utilize, and

•	work force issues, including changes in collective bargaining unit agreements, strikes, work stoppages, the loss of key executives, availability of workers in a variety of skill areas, and our ability to recruit and retain employees.

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•	increase the operating costs of generating plants,

•	increase the lead time and capital costs for the construction of new generating plants,

•	require modification of our existing generating plants,

•	require existing generating plant operations to be curtailed or shut down,

•	reduce the amount of energy available from our generating plants,

•	restrict the types of generating plants that can be built or contracted with,

•	require construction of specific types of generation plants at higher cost, and

•	increase the cost of distributing natural gas to customers.

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•	disruptive innovations in the marketplace may outpace our ability to compete or manage our risk,

•	potential difficulties in integrating acquired operations and in realizing expected opportunities, diversions of management resources and losses of key employees, challenges with respect to operating new businesses and other unanticipated risks and liabilities,

•	market or other conditions may adversely affect our operations or require changes to our business strategy, which could result in a non-cash goodwill impairment charge that would reduce assets and reduce our net income, and

•	potential reputational risk arising from repeated general rate case filings, degradation in the quality of service, or from failed strategic investments and opportunities, which could erode shareholder, customer and community satisfaction with our Company.

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(1)	Nameplate rating, also referred to as “installed capacity,” is the manufacturer’s assigned power capability under specified conditions.

(2)	Present capability is the maximum capacity of the plant under standard test conditions without exceeding specified limits of temperature, stress and environmental conditions. Information is provided as of December 31, 2017.

(3)

For Cabinet Gorge, we have water rights permitting generation up to 265 MW. However, if natural stream flows will allow for generation above our water rights, we are able to generate above our water rights. If natural stream flows only allow for generation at or below 265 MW, we are limited to generation of 265 MW. The present capability disclosed above represents the capability based on maximum stream flow conditions when we are allowed to generate above our water rights.

(4)	These generating stations can operate as separate single-cycle plants or combined-cycle with the natural gas plant providing exhaust heat to the wood boiler to increase efficiency.

(5)	Jointly owned; data refers to our 15 percent interest.

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(1)	Nameplate rating, also referred to as “installed capacity,” is the manufacturer’s assigned power capability under specified conditions.

(2)	Present capability is the maximum capacity of the plant under standard test conditions without exceeding specified limits of temperature, stress and environmental conditions. Information is provided as of December 31, 2017.

(3)	AEL&P does not own this generating facility but has a PPA under which it has the right to purchase, and the obligation to pay for (whether or not energy is received), all of the capacity and energy of this facility. See further information at "Part 1. Item 1. Business – Alaska Electric Light and Power Company."

•	our results of operations, cash flows and financial condition,

•	the success of our business strategies, and

•	general economic and competitive conditions.

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•	certain covenants applicable to the Company's outstanding long-term debt and committed line of credit agreements (see "Item 7. Management's Discussion and Analysis - Capital Resources" for compliance with these covenants),

•	the hydroelectric licensing requirements of section 10(d) of the FPA (see “Note 1 of Notes to Consolidated Financial Statements”),

•	certain requirements under the OPUC approval of the AERC acquisition in 2014. The OPUC's AERC acquisition order requires Avista Utilities to maintain a capital structure of no less than 40 percent common equity (inclusive of short-term debt). This limitation may be revised upon request by the Company with approval from the OPUC,

•	certain covenants applicable to preferred stock (when outstanding) contained in the Company’s Restated Articles of Incorporation, as amended (currently there are no preferred shares outstanding), and

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the Merger Agreement with Hydro One, which states Avista Corp. cannot (A) declare, authorize, set aside for payment or pay any dividend on, or make any other distribution in respect of, any shares of its capital stock, other than (1) dividends paid by any Subsidiary of the Company to the Company or to any wholly owned subsidiary of the Company, (2) quarterly cash dividends with respect to the Company common stock not to exceed the 2017 annual per share dividend rate by more than $0.06 per year, with record dates and payment dates consistent with the Company’s current dividend practice, or (3) a “stub period” dividend to holders of record of Company common stock as of immediately prior to the effective time of the merger equal to the product of (x) the number of days from the record date for payment of the last quarterly dividend paid by the Company prior to the effective time of the merger, multiplied by (y) a daily dividend rate determined by dividing the amount of the last quarterly dividend prior to the effective time of the merger by ninety-one or (B) adjust, split, combine, subdivide or reclassify any shares of its capital stock (see "Note 4 of the Notes to Consolidated Financial Statements" for additional information regarding the merger).

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(1)	The total assets at year-end for the year 2013 exclude the total assets associated with Ecova of $339.6 million.

(2)	See Exhibit 12 for computations.

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•	A permanent reduction in the statutory corporate tax rate from 35 percent to 21 percent, beginning with tax years after 2017;

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Statutory provisions requiring that excess deferred taxes associated with public utility property be normalized using the average rate assumption method (ARAM) for determining the timing of the return of excess deferred taxes to customers. Excess deferred taxes result from revaluing deferred tax assets and liabilities based on the newly enacted tax rate instead of the previous tax rate, which, for most rate-regulated utilities like Avista Utilities and AEL&P, results

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•	Repeal of the corporate alternative minimum tax (AMT);

•	Bonus depreciation (expensing of capital investment on an accelerated basis) was removed as a deduction for property predominantly used in certain rate-regulated businesses (like Avista Utilities and AEL&P), but is still allowed for our non-regulated businesses;

•	The deduction for interest expense that is properly allocable to certain rate-regulated trades or businesses is still allowed under the new law, but the deduction is now limited for our non-regulated businesses; and

•	Net operating loss (NOL) carryback deductions were eliminated, but carryforward deductions are allowed indefinitely with some annual limitations versus the previous 20-year limitation.

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Because of accelerated depreciation, including bonus depreciation, and other tax deductions, we have paid less in actual cash taxes than what was being collected from customers. The temporary timing differences between cash paid as income taxes and tax expense recorded for GAAP resulted in the recording of a net deferred tax liability. This temporary timing difference from prior years will ultimately reverse with taxable income and corresponding income taxes increasing in future years;

•	Lowering the corporate tax rate to 21 percent resulted in excess deferred taxes, which must be returned to customers using the ARAM discussed above. This will result in a reduction of future revenue as we refund the excess deferred taxes to customers;

•	Lowering the tax rate to 21 percent will result in customers' future rates having an embedded 21 percent tax rate rather than the 35 percent tax rate, which will result in lower future revenue (which will be offset by lower actual tax expenses); and

•	The loss of the bonus depreciation tax deduction for 2018 and 2019 results in less depreciation as a tax deduction in those years, which will increase our taxable income and result in us having to pay taxes earlier than we had projected under the old tax law.

•	seek recovery of operating costs and capital investments, and

•	seek the opportunity to earn reasonable returns as allowed by regulators.

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(2)	As a part of the electric rate plan, we have proposed to update power supply costs through a Power Supply Update, the effects of which would also go into effect on May 1, 2019 and May 1, 2020. The requested revenue increases for 2019 and 2020 do not include any power supply adjustments.

•	Major hydroelectric investments at the Little Falls and Nine Mile hydroelectric plants.

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•	Generator maintenance at the Kettle Falls biomass plant that will ensure efficient generation and operations.

•	The ongoing project to systematically replace portions of natural gas distribution pipe in our service area that were installed prior to 1987, as well as replacement of other natural gas service equipment.

•	Transmission and distribution system and asset maintenance, such as wood pole replacements, feeder upgrades, and substation and transmission line rebuilds to maintain reliability for our customers.

•	Technology upgrades that support necessary business processes and operational efficiencies that allow us to effectively manage the utility and serve customers.

•	A refresh of the customer-facing website, providing relevant information, greater accessibility on mobile devices, easier navigation, and a streamlined payment experience.

•	the discontinuation of the after-the-fact earnings test (provision for earnings sharing) that was originally agreed to as part of the settlement of our 2012 electric and natural gas general rate cases, and

•	the implementation of electric and natural gas Fixed Cost Adjustment mechanisms.

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(1)	Due to declining wholesale natural gas prices that have occurred since the 2017 PGAs were filed and went into effect, we filed, and the respective commissions approved, out of cycle PGAs to reduce customer rates and pass through expected lower costs during the winter heating months, rather than waiting until the next regular PGA cycle.

•	short-term wholesale market prices and sales and purchase volumes,

•	the level, availability and optimization of hydroelectric generation,

•	the level and availability of thermal generation (including changes in fuel prices),

•	retail loads, and

•	sales of surplus transmission capacity.

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(1)	This balance includes public street and highway lighting, which is considered part of retail electric revenues and it also includes revenues and rebates from decoupling.

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(1)

The provision for earnings sharing in Washington for 2017 represents a $0.2 million adjustment for the 2016 provision for earnings sharing and $1.0 million relating to 2017 earnings. The provision for earnings sharing in Washington in 2016 resulted from a $2.5 million reduction in the 2015 provision for earnings sharing (which increased 2016 revenues) offset by a $2.3 million provision for earnings sharing for 2016 electric operations.

(2)	The provision for earnings sharing in Idaho in 2016 resulted from a reduction in the 2015 provision for earnings sharing (which increased 2016 revenues). Beginning in 2016 there is no longer an earnings sharing mechanism in Idaho.

(n/a)	This mechanism did not exist during this time period.

•	a $52.0 million increase in retail electric revenues due to an increase in total MWhs sold (increased revenues $36.6 million) and an increase in revenue per MWh (increased revenues $15.4 million).

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The increase in total retail MWhs sold was the result of weather that was cooler than the prior year during the heating season (which increased electric heating loads) and warmer than the prior year during the cooling season (which increased electric cooling loads), as well as customer growth. Compared to 2016, residential electric use per customer increased 8 percent and commercial use per customer did not change materially. Heating degree days in Spokane were 3 percent above normal and 17 percent above 2016. Cooling degree days in Spokane were 40 percent above normal and 57 percent above the prior year.

◦	The increase in revenue per MWh was primarily due to a general rate increase in Idaho and a greater portion of retail revenues from residential customers in 2017.

•	a $30.6 million decrease in wholesale electric revenues due to a decrease in sales prices (decreased revenues $27.3 million) and a decrease in sales volumes (decreased revenues $3.3 million). The fluctuation in volumes and prices was primarily the result of our optimization activities.

•	a $13.4 million decrease in sales of fuel due to a decrease in sales of natural gas fuel as part of thermal generation resource optimization activities. For 2017, $35.3 million of these sales were made to our natural gas operations and are included as intracompany revenues and resource costs. For 2016, $44.0 million of these sales were made to our natural gas operations.

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a $25.6 million decrease in electric revenue due to decoupling. Weather was cooler than normal during the heating season and warmer than normal during the cooling season in 2017, which resulted in decoupling rebates for 2017. Weather was warmer than normal during the heating season in 2016, which resulted in significant decoupling surcharges. Decoupling mechanisms are not affected by fluctuations in weather compared to prior year; rather, they are only affected by weather fluctuations as compared to normal weather.

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(1)	This balance includes interruptible and industrial revenues, which are considered part of retail natural gas revenues and it also includes revenues and rebates from decoupling.

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•	a $36.3 million increase in retail natural gas revenues due to an increase in volumes (increased revenues $51.2 million), partially offset by lower retail rates (decreased revenues $14.9 million).

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We sold more retail natural gas in 2017 as compared to 2016 primarily due to cooler weather in the first and fourth quarters, as well as customer growth. Compared to 2016, residential use per customer increased 16 percent and commercial use per customer increased 17 percent. Heating degree days in Spokane were 3 percent above normal for 2017, and 17 percent above 2016. Heating degree days in Medford were 1 percent below normal for 2017, and 17 percent above 2016.

◦	Lower retail rates were due to PGAs, partially offset by a general rate increase in Oregon.

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a $10.7 million decrease in wholesale natural gas revenues due to a decrease in volumes (decreased revenues $36.4 million), partially offset by an increase in prices (increased revenues $25.7 million). In 2017, $49.3 million of these sales were made to our electric generation operations and are included as intracompany revenues and resource costs. In 2016, $51.2 million of these sales were made to our electric generation operations. Differences between revenues and costs from sales of resources in excess of retail load requirements and from resource optimization are accounted for through the PGA mechanisms.

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a $23.7 million decrease in natural gas revenue due to decoupling. Weather was overall cooler than normal during the heating season in 2017, which resulted in decoupling rebates. Weather was warmer than normal during the heating season in 2016, which resulted in decoupling surcharges. Decoupling mechanisms are not impacted by fluctuations in weather compared to prior year; rather, they are only impacted by weather fluctuations as compared to normal weather.

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•	a $17.1 million decrease in power purchased due to a decrease in wholesale prices (decreased costs $22.5 million), partially offset by an increase in the volume of power purchases (increased costs $5.4 million). The fluctuation in volumes and prices was primarily the result of our optimization activities.

•	a $10.2 million decrease in fuel for generation primarily due to a decrease in thermal generation (due in part to increased hydroelectric generation) as well as a decrease in fuel prices.

•	a $6.0 million decrease in other fuel costs.

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•	a $1.5 million increase from amortizations and deferrals of power costs.

•	a $0.5 million decrease in other electric resource costs.

•	a $3.0 million increase in other regulatory amortizations.

•	a $5.4 million decrease in natural gas purchased due to a decrease in total therms purchased (decreased costs $22.1 million), partially offset by an increase in the price of natural gas (increased costs $16.7 million). Total therms purchased decreased due to a decrease in wholesale sales, partially offset by an increase in retail sales.

•	a $6.6 million decrease from amortizations and deferrals of natural gas costs.

•	a $2.6 million increase in other regulatory amortizations.

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(1)	This balance includes public street and highway lighting, which is considered part of retail electric revenues and it also includes revenues and rebates from decoupling.

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(1)	The provision for earnings sharing in Washington in 2016 resulted from a $2.5 million reduction in the 2015 provision for earnings sharing (which increased 2016 revenues) offset by a $2.3 million provision for earnings sharing for 2016 electric operations.

(2)	The provision for earnings sharing in Idaho in 2016 resulted from a reduction in the 2015 provision for earnings sharing (which increased 2016 revenues). Beginning in 2016 there is no longer an earnings sharing mechanism in Idaho.

(n/a)	This mechanism did not exist during this time period.

•	a $3.0 million decrease in retail electric revenues due to a decrease in total MWhs sold (decreased revenues $9.5 million), partially offset by an increase in revenue per MWh (increased revenues $6.5 million).

◦	The increase in revenue per MWh was primarily due to a general rate increase in Idaho and the expiration of the ERM rebate to customers in Washington, partially offset by a general rate decrease in Washington.

◦

The decrease in total retail MWhs sold was the result of weather that was cooler in the first quarter (higher electric heating loads), warmer in April and May (lower electric heating loads), cooler June through August (lower electric cooling loads) and cooler in the fourth quarter (higher electric heating loads) as compared to the prior year (which overall decreased electric loads). Compared to 2015, residential electric use per customer decreased 1 percent and commercial use per customer decreased 1 percent. Heating degree days in Spokane were 13 percent below normal and 3 percent above 2015. The impact from increased heating loads was offset by decreased cooling loads in the summer. 2016 cooling degree days were 13 percent below normal and 41 percent below the prior year. The overall decrease in use per customer was partially offset by growth in the number of customers.

•	a $15.2 million decrease in wholesale electric revenues due to a decrease in sales volumes (decreased revenues $5.5 million) and a decrease in sales prices (decreased revenues $9.7 million). The fluctuation in volumes and prices was primarily the result of our optimization activities.

•	a $4.6 million decrease in sales of fuel due to a decrease in sales of natural gas fuel as part of thermal generation resource optimization activities. For 2016, $44.0 million of these sales were made to our natural gas operations and are included as intracompany revenues and resource costs. For 2015, $50.0 million of these sales were made to our natural gas operations.

•	a $12.6 million increase in electric revenue due to decoupling, which reflected the implementation of a decoupling mechanism in Idaho effective January 1, 2016 and lower retail revenues in 2016 as compared to 2015.

•	a $6.6 million decrease in the electric provision for earnings sharing (which increases revenues) due to a $2.5 million reduction in the 2015 provision for earnings sharing in Washington and a $0.7 million reduction in the 2015 provision for earnings sharing in Idaho recorded in 2016. For 2016 electric operations, we recorded a $2.3 million provision for earnings sharing.

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(1)	This balance includes interruptible and industrial revenues, which are considered part of retail natural gas revenues and it also includes revenues and rebates from decoupling.

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•	a $3.4 million decrease in retail natural gas revenues due to lower retail rates (decreased revenues $18.4 million), partially offset by an increase in volumes (increased revenues $15.0 million).

◦	Lower retail rates were due to PGAs, which passed through lower costs of natural gas, partially offset by general rate increases.

◦

We sold more retail natural gas in 2016 as compared to 2015 primarily due to cooler weather in the first and fourth quarters, as well as customer growth. Compared to 2015, residential use per customer increased 5 percent and commercial use per customer increased 3 percent. Heating degree days in Spokane were 13 percent below historical average for 2016, and 3 percent above 2015. Heating degree days in Medford were 16 percent below historical average for 2016, and 3 percent above 2015.

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a $50.8 million decrease in wholesale natural gas revenues due to a decrease in prices (decreased revenues $22.8 million) and a decrease in volumes (decreased revenues $28.0 million). In 2016, $51.2 million of these sales were made to our electric generation operations and are included as intracompany revenues and resource costs. In 2015, $57.0 million of these sales were made to our electric generation operations. Differences between revenues and costs from sales of resources in excess of retail load requirements and from resource optimization are accounted for through the PGA mechanisms.

•	a $6.3 million increase in natural gas revenues due to decoupling, which reflected the implementation of decoupling mechanisms in Idaho and Oregon, as well as an increase in the decoupling surcharge in Washington.

•	a $2.8 million increase in the provision for earnings sharing (which decreases revenues) representing the 2016 provision for Washington natural gas operations.

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•	a $26.1 million decrease in power purchased due to a decrease in the volume of power purchases (decreased costs $9.3 million) and a decrease in wholesale prices (decreased costs $16.8 million). The fluctuation in volumes and prices was primarily the result of our optimization activities.

•	a $14.8 million decrease in fuel for generation primarily due to a decrease in thermal generation (due in part to increased hydroelectric generation) and a decrease in natural gas fuel prices.

•	a $7.5 million decrease in other fuel costs.

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•	a $3.0 million decrease from amortizations and deferrals of power costs.

•	a $5.6 million increase in other electric resource costs primarily due to a benefit that was recorded during 2015 related to a capacity contract of Spokane Energy. This benefit was mostly deferred for probable future benefit to customers through the ERM and PCA.

•	a $5.4 million increase in other regulatory amortizations.

•	an $80.1 million decrease in natural gas purchased due to a decrease in the price of natural gas (decreased costs $52.6 million) and a decrease in total therms purchased (decreased costs $27.5 million). Total therms purchased decreased due to a decrease in wholesale sales, partially offset by an increase in retail sales.

•	a $1.6 million decrease from amortizations and deferrals of natural gas costs. This reflects lower natural gas prices and the deferral of lower costs for future rebate to customers, as well as current rebates to customers through PGAs.

•	a $4.6 million increase in other regulatory amortizations.

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Regulatory accounting, which requires that certain costs and/or obligations be reflected as deferred charges on our Consolidated Balance Sheets and are not reflected in our Consolidated Statements of Income until the period during which matching revenues are recognized. We also have decoupling revenue deferrals. As opposed to cost deferrals which are not recognized in the Consolidated Statements of Income until they are included in rates, decoupling revenue is recognized in the Consolidated Statements of Income during the period in which it occurs (i.e. during the

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Utility energy commodity derivative asset and liability accounting, where we estimate the fair value of outstanding commodity derivatives and we offset energy commodity derivative assets or liabilities with a regulatory asset or liability. This accounting treatment is intended to defer the recognition of mark-to-market gains and losses on energy commodity transactions until the period of delivery. This accounting treatment is supported by accounting orders issued by the WUTC and the IPUC. If we were no longer allowed to apply regulatory accounting or no longer allowed recovery of these costs, we could be required to recognize significant changes in fair value of these energy commodity derivatives on a regular basis in the Consolidated Statements of Income, which could lead to significant fluctuations in net income. See "Notes 1 and 6 of the Notes to Consolidated Financial Statements" for further discussion of our energy commodity derivative accounting policy and amounts recorded in the financial statements.

•

Interest rate swap derivative asset and liability accounting, where we estimate the fair value of outstanding interest rate swap derivatives, and U.S. Treasury lock agreements and offset the derivative asset or liability with a regulatory asset or liability. This is similar to the treatment of energy commodity derivatives described above. Upon settlement of interest rate swap derivatives, the regulatory asset or liability is amortized as a component of interest expense over the term of the associated debt.

•	Pension Plans and Other Postretirement Benefit Plans, discussed in further detail below.

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Contingencies, related to unresolved regulatory, legal and tax issues for which there is inherent uncertainty for the ultimate outcome of the respective matter. We accrue a loss contingency if it is probable that an asset is impaired or a liability has been incurred and the amount of the loss or impairment can be reasonably estimated. We also disclose losses that do not meet these conditions for accrual, if there is a reasonable possibility that a potential loss may be incurred. For all material contingencies, we have made a judgment as to the probability of a loss occurring and as to whether or not the amount of the loss can be reasonably estimated. If the loss recognition criteria are met, liabilities are accrued or assets are reduced. However, no assurance can be given to the ultimate outcome of any particular contingency. See "Notes 1 and 19 of the Notes to Consolidated Financial Statements" for further discussion of our commitments and contingencies.

•	employee demographics (including age, compensation and length of service by employees),

•	the amount of cash contributions we make to the pension plan,

•	the actual return on pension plan assets,

•	expected return on pension plan assets,

•	discount rate used in determining the projected benefit obligation and pension costs,

•	assumed rate of increase in employee compensation,

•	life expectancy of participants and other beneficiaries, and

•	expected method of payment (lump sum or annuity) of pension benefits.

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*	Changes in the expected return on plan assets would not affect our projected benefit obligation.

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•	increases in demand (due to either weather or customer growth),

•	low availability of streamflows for hydroelectric generation,

•	unplanned outages at generating facilities, and

•	failure of third parties to deliver on energy or capacity contracts.

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•	issuance and sale of $90.0 million of Avista Corp. first mortgage bonds in December 2017, the proceeds of which were used to pay down a portion of our committed line of credit,

•	payment of $3.3 million for the maturity of long-term debt,

•	increase in cash dividends paid to $92.5 million (or $1.43 per share) for 2017 from $87.2 million (or $1.37 per share) for 2016,

•	$15.0 million net decrease in the balance of our committed line of credit, and

•	issuance of $56.4 million of common stock (net of issuance costs).

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•	borrowing of $70.0 million pursuant to a term loan agreement in August, which was used to repay a portion of the $90.0 million in first mortgage bonds that matured in August 2016,

•	issuance and sale of $175.0 million of Avista Corp. first mortgage bonds in December 2016, the proceeds of which were used to repay the $70.0 million term loan, with the remainder being used to pay down a portion of our committed line of credit,

•	payment of $163.2 million for the maturity of long-term debt (including the $70.0 million term loan),

•	increase in cash dividends paid to $87.2 million (or $1.37 per share) for 2016 from $82.4 million (or $1.32 per share) for 2015,

•	$15.0 million net increase in the balance of our committed line of credit, and

•	issuance of $67.0 million of common stock (net of issuance costs).

•	issuance and sale of $100.0 million of Avista Corp. first mortgage bonds in December 2015,

•	payment of $2.9 million for the maturity of long-term debt,

•	cash dividends paid were $82.4 million (or $1.32 per share) for 2015,

•	issuance of $1.6 million of common stock (net of issuance costs), and

•	repurchase of $2.9 million of our common stock.

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•	66-2/3 percent of the cost or fair value (whichever is lower) of property additions of that entity which have not previously been made the basis of any application under that entity's Mortgage, or

•	an equal principal amount of retired first mortgage bonds of that entity which have not previously been made the basis of any application under that entity's Mortgage, or

•	deposit of cash.

(1)	Actual annual capital expenditures per the Consolidated Statement of Cash Flows may differ from our expected annual accrual-basis capital expenditures due to the timing of cash payments, the capital expenditure amounts accrued in accounts payable at the end of each period and the inclusion of AFUDC in our expected amounts, but excluded from the cash flow amounts.

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(1)	Standard & Poor’s lowest “investment grade” credit rating is BBB-.

(2)	Moody’s lowest “investment grade” credit rating is Baa3.

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(1)	Represents our estimate of interest payments on long-term debt, which is calculated based on the assumption that all debt is outstanding until maturity. Interest on variable rate debt is calculated using the rate in effect at December 31, 2017.

(2)	Energy purchase contracts were entered into as part of the obligation to serve our retail electric and natural gas customers’ energy requirements. As a result, costs are generally recovered either through base retail rates or adjustments to retail rates as part of the power and natural gas cost deferral and recovery mechanisms.

(3)	Includes the interest component of the lease obligation.

(4)	Represents operational agreements, settlements and other contractual obligations for our generation, transmission and distribution facilities. These costs are generally recovered through base retail rates.

(5)	Includes information service contracts which are recorded to other operating expenses in the Consolidated Statements of Income.

(6)	Represents our estimated cash contributions to pension plans and other postretirement benefit plans through 2022. We cannot reasonably estimate pension plan contributions beyond 2022 at this time and have excluded them from the table above.

(7)

Represents the net mark-to-market fair value of outstanding unsettled interest rate swap derivatives as of December 31, 2017. Negative values in the table above represent contractual amounts that are owed to Avista Corp. by the counterparties. The values in the table above will change each period depending on fluctuations in market interest rates and could become either assets or liabilities. Also, the amounts in the table above are not reflective of cash collateral of $35.0 million and letters of credit of $5.0 million that are already posted with counterparties against the outstanding interest rate swap derivatives.

(8)	Primarily relates to long-term debt and capital lease maturities and the related interest. AEL&P contractual commitments also include contractually required capital project funding and operating and maintenance costs associated with the Snettisham hydroelectric project. These costs are generally recovered through base retail rates.

(9)	Primarily relates to operating lease commitments, venture fund commitments, and a commitment to fund a limited liability company in exchange for equity ownership, made by a subsidiary of Avista Capital. Also, there is a long-term debt maturity and the related interest associated with AERC.

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•	localized and system-wide demand for energy,

•	type, capacity, location and availability of generation resources, and

•	variety and circumstances of market participants.

•	transmit power and energy to or for wholesale purchasers and sellers,

•	enlarge or construct additional transmission capacity for the purpose of providing these services, and

•	transparently price and offer transmission services without favor to any party, including the merchant functions of the utility.

•	other utilities,

•	federal power marketing agencies,

•	energy marketing and trading companies,

•	independent power producers,

•	financial institutions, and

•	commodity brokers.

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•	assumptions relating to weather and economic and competitive conditions,

•	internal analysis of company-specific data, such as energy consumption patterns,

•	internal business plans,

•	an assumption that we will incur no material loss of retail customers due to self-generation or retail wheeling, and

•	an assumption that demand for electricity and natural gas as a fuel for mobility will for now be immaterial.

•	increase the operating costs of generating plants;

•	increase the lead time and capital costs for the construction of new generating plants;

•	require modification of our existing generating plants;

•	require existing generating plant operations to be curtailed or shut down;

•	reduce the amount of energy available from our generating plants;

•	restrict the types of generating plants that can be built or contracted with;

•	require construction of specific types of generation plants at higher cost; and

•	increase costs of distributing natural gas.

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•	facilitates internal and external communications regarding climate change issues,

•	analyzes policy effects, anticipates opportunities and evaluates strategies for Avista Corp., and

•	develops recommendations on climate related policy positions and action plans.

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(1)	There are offsetting regulatory assets and liabilities for these items on the Consolidated Balance Sheets in accordance with regulatory accounting practices.

(2)	The balance as of December 31, 2017 and December 31, 2016 reflects the offsetting of $35.0 million and $34.9 million, respectively, of cash collateral against the net derivative positions where a legal right of offset exists.

(1)	These balances include the fixed rate long-term debt of Avista Corp., AEL&P and AERC.

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•	transacting through clearinghouse exchanges,

•	entering into bilateral contracts that specify credit terms and protections against default,

•	applying credit limits and duration criteria to existing and prospective counterparties,

•	actively monitoring current credit exposures,

•	asserting our collateral rights with counterparties, and

•	carrying out transaction settlements timely and effectively.

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(1)	Physical transactions represent commodity transactions where we will take or make delivery of either electricity or natural gas; financial transactions represent derivative instruments with delivery of cash in the amount of the benefit or cost but with no physical delivery of the commodity, such as futures, swap derivatives, options, or forward contracts.

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•	communication and involvement with local business leaders and community organizations,

•	providing customers with a multitude of limited income initiatives, including energy fairs, senior outreach and low income workshops, mobile outreach strategy and a Low Income Rate Assistance Plan,

•	tailoring our internal company initiatives to focus on choices for our customers, to increase their overall satisfaction with the Company, and

•	engaging in the legislative process in a manner that fosters the interests of our customers and the communities we serve.

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•	determining the market value of energy commodity derivative assets and liabilities,

•	pension and other postretirement benefit plan obligations,

•	contingent liabilities,

•	goodwill impairment testing,

•	recoverability of regulatory assets, and

•	unbilled revenues.

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•	the number of customers,

•	current rates,

•	meter reading dates,

•	actual native load for electricity,

•	actual throughput for natural gas, and

•	electric line losses and natural gas system losses.

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(1)	Income tax benefits were calculated using a 35 percent income tax rate; however, as of December 31, 2017, due to the TCJA enactment, deferred tax assets associated with stock compensation were revalued to 21 percent. Beginning on January 1, 2018 income tax benefits will be calculated using the new 21 percent tax rate.

(2)	Beginning in 2016, excess tax benefits associated with the settlement of share-based employee payments are recognized in the Statements of Income due to the adoption of ASU 2016-09, effective January 1, 2016. See Note 2 for further discussion.

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•	rates for regulated services are established by or subject to approval by independent third-party regulators,

•	the regulated rates are designed to recover the cost of providing the regulated services, and

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•	in view of demand for the regulated services and the level of competition, it is reasonable to assume that rates can be charged to and collected from customers at levels that will recover costs.

•	required to write off its regulatory assets, and

•	precluded from the future deferral of costs or decoupled revenues not recovered through rates at the time such amounts are incurred, even if the Company expected to recover these amounts from customers in the future.

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(a)	These accumulated other comprehensive loss components are included in the computation of net periodic pension cost (see Note 10 for additional details).

(b)	The adjustment for the effects of regulation during the year ended December 31, 2016 includes approximately $2.1 million related to the reclassification of a pension regulatory asset associated with one of our jurisdictions into accumulated other comprehensive loss.

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•	allowing excess tax benefits or tax deficiencies to be recognized as income tax benefits or expenses in the Consolidated Statements of Income rather than in Additional Paid in Capital (APIC),

•	excess tax benefits no longer represent a financing cash inflow on the Consolidated Statements of Cash Flows and instead will be included as an operating activity,

•	requiring excess tax benefits and tax deficiencies to be excluded from the calculation of diluted earnings per share, whereas under previous accounting guidance, these amounts had to be estimated and included in the calculation,

•	allowing forfeitures to be accounted for as they occur, instead of estimating forfeitures, and

•	changing the statutory tax withholding requirements for share-based payments.

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(1)	This represents the gross gain recorded to discontinued operations. The total gain net of taxes and transactions expenses was $74.8 million, of which $69.7 million was recognized during 2014.

(2)	The tax benefit during 2015 primarily resulted from the reversal of a valuation allowance against net operating losses at Ecova because the net operating losses were deemed realizable after further evaluation.

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(1)	Physical transactions represent commodity transactions in which Avista Corp. will take or make delivery of either electricity or natural gas; financial transactions represent derivative instruments with delivery of cash in the amount of the benefit or cost but with no physical delivery of the commodity, such as futures, swap derivatives, options, or forward contracts.

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(1)	Included in other property and investments-net and other non-current assets on the Consolidated Balance Sheets. Accumulated depreciation was $11.6 million as of December 31, 2017 and $11.2 million as of December 31, 2016 for the other businesses.

•	restore coal ash containment ponds at Colstrip,

•	cap a landfill at the Kettle Falls Plant,

•	remove plant and restore the land at the Coyote Springs 2 site at the termination of the land lease, and

•	dispose of PCBs in certain transformers.

•	removal and disposal of certain transmission and distribution assets, and

•	abandonment and decommissioning of certain hydroelectric generation and natural gas storage facilities.

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•	properties are externally appraised on an annual basis by independent appraisers, additional appraisals may be performed as warranted by specific asset or market conditions,

•	property valuations are reviewed quarterly and adjusted as necessary, and

•	loans are reflected at fair value.

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(1)	This category invests in multiple strategies to diversify risk and reduce volatility. The strategies include: (a) event driven, relative value, convertible, and fixed income arbitrage, (b) distressed investments, (c) long/short equity and fixed income, and (d) market neutral strategies.

(2)	This category includes private equity funds that invest primarily in U.S. companies.

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(1)	The balanced index fund for 2017 and 2016 is a single mutual fund that includes a percentage of U.S. equity and fixed income securities and International equity and fixed income securities.

•	A permanent reduction in the statutory corporate tax rate from 35 percent to 21 percent, beginning with tax years after 2017;

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Statutory provisions requiring that excess deferred taxes associated with public utility property be normalized using the ARAM for determining the timing of the return of excess deferred taxes to customers. Excess deferred taxes result from revaluing deferred tax assets and liabilities based on the newly enacted tax rate instead of the previous tax rate, which, for most rate-regulated utilities like Avista Utilities and AEL&P, results in a net benefit to customers that will be deferred as a regulatory liability and passed through to customers over future periods;

•	Repeal of the corporate AMT;

•	Bonus depreciation (expensing of capital investment on an accelerated basis) was removed as a deduction for property predominantly used in certain rate-regulated businesses (like Avista Utilities and AEL&P), but is still allowed for the Company's non-regulated businesses;

•	The deduction for interest expense that is properly allocable to certain rate-regulated trade or businesses is still allowed under the new law, but the deduction is now limited for the Company's non-regulated businesses; and

•	NOL carryback deductions were eliminated, but carryforward deductions are allowed indefinitely with some annual limitations versus the previous 20-year limitation.

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(1)

In December 2010, $66.7 million and $17.0 million of the City of Forsyth, Montana Pollution Control Revenue Refunding Bonds (Avista Corporation Colstrip Project) due in 2032 and 2034, respectively, which had been held by Avista Corp. since 2008 and 2009, respectively, were refunded by new variable rate bond issues (Series 2010A and Series 2010B). The new bonds were not offered to the public and were purchased by Avista Corp. due to market conditions. The Company expects that at a later date, subject to market conditions, these bonds may be remarketed to unaffiliated investors. So long as Avista Corp. is the holder of these bonds, the bonds will not be reflected as an asset or a liability on Avista Corp.'s Consolidated Balance Sheets.

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(2)

In December 2017, Avista Corp. issued and sold $90.0 million of 3.91 percent first mortgage bonds due in 2047 pursuant to a bond purchase agreement with institutional investors in the private placement market. The total net proceeds from the sale of the bonds were used to repay a portion of the borrowings outstanding under Avista Corp.’s $400.0 million committed line of credit. In connection with the execution of the bond purchase agreement, Avista Corp. cash-settled five interest rate swap derivatives (notional aggregate amount of $60.0 million) and paid a total of $8.8 million.

•	66-2/3 percent of the cost or fair value (whichever is lower) of property additions of that entity which have not previously been made the basis of any application under that entity's Mortgage, or

•	an equal principal amount of retired first mortgage bonds of that entity which have not previously been made the basis of any application under that entity's Mortgage, or

•	deposit of cash.

(1)	The capital lease obligation amount is equal to the amount of AIDEA's revenue bonds outstanding.

(2)	These amounts are included in utility plant in service on the Consolidated Balance Sheets.

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(1)	The Company is permitted to net derivative assets and derivative liabilities with the same counterparty when a legally enforceable master netting agreement exists. In addition, the Company nets derivative assets and derivative liabilities against any payables and receivables for cash collateral held or placed with these same counterparties.

(2)	These assets are trading securities and are included in other property and investments-net and other non-current assets on the Consolidated Balance Sheets.

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(1)	All gains and losses are included in other regulatory assets and liabilities. There were no gains and losses included in either net income or other comprehensive income during any of the periods presented in the table above.

(2)	There were no purchases, issuances or transfers from other categories of any derivatives instruments during the periods presented in the table above.

•	certain covenants applicable to preferred stock (when outstanding) contained in the Company’s Restated Articles of Incorporation, as amended (currently there are no preferred shares outstanding),

•	certain covenants applicable to the Company's outstanding long-term debt and committed line of credit agreements,

•	the hydroelectric licensing requirements of section 10(d) of the FPA (see Note 1),

•	certain requirements under the OPUC approval of the AERC acquisition in 2014. The OPUC's AERC acquisition order requires Avista Utilities to maintain a capital structure of no less than 40 percent common equity (inclusive of short-term debt). This limitation may be revised upon request by the Company with approval from the OPUC, and

•

the Merger Agreement with Hydro One, which states Avista Corp. cannot (A) declare, authorize, set aside for payment or pay any dividend on, or make any other distribution in respect of, any shares of its capital stock, other than (1) dividends paid by any subsidiary of the Company to the Company or to any wholly owned subsidiary of the Company, (2) quarterly cash dividends with respect to the Company common stock not to exceed the 2017 annual per share dividend rate by more than $0.06 per year, with record dates and payment dates consistent with the Company’s current dividend practice, or (3) a “stub period” dividend to holders of record of Company common stock as of immediately prior to the effective time of the merger equal to the product of (x) the number of days from the record date for payment of the last quarterly dividend paid by the Company prior to the effective time of the merger, multiplied by (y) a daily dividend rate determined by

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•	Jenβ v. Avista Corporation., et al., No. 2:17-cv-00333 (E.D. Wash.) (filed September 25, 2017);

•	Samuel v. Avista Corporation, et al., No. 2:17-cv-00334 (E.D. Wash.) (filed September 26, 2017); and

•	Sharpenter v. Avista Corporation., et al., No. 2:17-cv-00336 (E.D. Wash.) (filed September 26, 2017)

•	Fink v. Morris, et al., No. 17203616-6 (filed September 15, 2017, amended complaint filed October 25, 2017).

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(1)	Earning a return includes either interest on the regulatory asset/liability or a return on the investment as a component of rate base at the allowed rate of return.

(2)	Expected recovery is pending regulatory treatment including regulatory assets and liabilities with prior regulatory precedence.

(3)	Remaining amortization period varies depending on timing of underlying transactions.

(4)	As the Company has historically recovered and currently recovers its pension and other postretirement benefit costs related to its regulated operations in retail rates, the Company records a regulatory asset for that portion of its pension and other postretirement benefit funding deficiency.

(5)	The WUTC and the IPUC issued accounting orders authorizing Avista Corp. to offset energy commodity derivative assets or liabilities with a regulatory asset or liability. This accounting treatment is intended to defer the recognition of

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(6)

For the Company’s Washington jurisdiction and for any debt repurchases beginning in 2007 in all jurisdictions, premiums paid to repurchase debt are amortized over the remaining life of the original debt that was repurchased or, if new debt is issued in connection with the repurchase, these costs are amortized over the life of the new debt. In the Company’s other regulatory jurisdictions, premiums paid to repurchase debt prior to 2007 are being amortized over the average remaining maturity of outstanding debt when no new debt was issued in connection with the debt repurchase. These costs are recovered through retail rates as a component of interest expense.

(7)

In March 2016, the WUTC granted the Company's Petition for an Accounting Order to defer and include in a regulatory asset the undepreciated value of its existing Washington electric meters and natural gas ERTs for the opportunity for later recovery. This accounting treatment is related to the Company's plan to replace approximately 253,000 of its existing electric meters with new two-way digital meters and the related software and support services through its AMI project in Washington State. Replacement of the meters is expected to begin in the second half of 2018.

(8)

For interest rate swap derivatives, Avista Corp. records all mark-to-market gains and losses in each accounting period as assets and liabilities and records offsetting regulatory assets and liabilities, such that there is no income statement impact. The interest rate swap derivatives are risk management tools similar to energy commodity derivatives. Upon settlement of interest rate swap derivatives, the regulatory asset or liability is amortized as a component of interest expense over the term of the associated debt. The Company records an offset of interest rate swap derivative assets and liabilities with regulatory assets and liabilities, based on the prior practice of the commissions to provide recovery through the ratemaking process. Settled interest rate swap derivatives which have been through a general rate case proceeding are classified as earning a return in the table above, whereas all unsettled interest rate swap derivatives and settled interest rate swap derivatives which have not been included in a general rate case are classified as expected recovery. See below for additional information regarding the Company's 2016 settled interest rate swaps in the Washington general rate cases. The Idaho and Oregon portion of the 2016 settled interest rate swaps are included in earning a return because they were approved for recovery in those respective states.

(9)	This amount is dependent upon the cost of removal of underlying utility plant assets and the life of utility plant.

(10)

The amount pending recovery represents amounts due back to customers and resulted from the new federal income tax law and changing the federal income tax rate from 35 percent to 21 percent and revaluing all deferred income taxes as of December 31, 2017. The Company currently expects the amounts for utility plant items for Avista Utilities to be returned to customers over a period of approximately 36 years using the ARAM. The Company expects the AEL&P amounts to be returned to customers over a period of approximately 40 years. The Company does not currently have an estimate for non-plant items included in this balance as the Company is waiting for additional implementation guidance from various regulatory agencies. In addition, none of the excess deferred tax amounts have been through a regulatory proceeding as of this filing; therefore, a definitive amortization period has not been established. See Note 11 for additional discussion regarding the new federal income tax law.

•	short-term wholesale market prices and sales and purchase volumes,

•	the level, availability and optimization of hydroelectric generation,

•	the level and availability of thermal generation (including changes in fuel prices),

•	retail loads, and

•	sales of surplus transmission capacity.

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(1)

Intersegment eliminations reported as interest expense represent intercompany interest. Intersegment eliminations reported as operating revenues and other operating expenses for 2015 represent intercompany purchases and sales of electric capacity and energy between Avista Utilities and Spokane Energy (included in other). Intersegment eliminations reported as assets represent intersegment accounts receivable.

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(2)	Other operating expenses for Avista Utilities for 2017 includes acquisition costs of $14.6 million which are separately disclosed on the Consolidated Statements of Income.

(3)	Including interest expense to affiliated trusts.

(4)	The capital expenditures for the other businesses are included in other investing activities on the Consolidated Statements of Cash Flows.

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•	on and after the date of filing with the SEC the Registrant's definitive Proxy Statement relating to its Annual Meeting of Shareholders scheduled to be held on May 10, 2018, from such Proxy Statement; and

•	prior to such date, from the Registrant's definitive Proxy Statement, dated March 31, 2017, relating to its Annual Meeting of Shareholders held on May 11, 2017.

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•	on and after the date of filing with the SEC the Registrant's definitive Proxy Statement relating to its Annual Meeting of Shareholders scheduled to be held on May 10, 2018, from such Proxy Statement; and

•	prior to such date, from the Registrant's definitive Proxy Statement, dated March 31, 2017, relating to its Annual Meeting of Shareholders held on May 11, 2017.

(a)	Security ownership of certain beneficial owners (owning 5 percent or more of Registrant’s voting securities):

•	on and after the date of filing with the SEC the Registrant's definitive Proxy Statement relating to its Annual Meeting of Shareholders scheduled to be held on May 10, 2018, from such Proxy Statement; and

•	prior to such date, from the Registrant's definitive Proxy Statement, dated March 31, 2017, relating to its Annual Meeting of Shareholders held on May 11, 2017; reference also being made to Schedules 13G, as amended, on file with the SEC with respect to the Registrant's voting securities (the information contained in such schedules 13G, as amended, not being incorporated herein by reference).

(b)	Security ownership of management:

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•	on and after the date of filing with the SEC the Registrant's definitive Proxy Statement relating to its Annual Meeting of Shareholders scheduled to be held on May 10, 2018, from such Proxy Statement; and

•	prior to such date, from the Registrant's definitive Proxy Statement, dated March 31, 2017, relating to its Annual Meeting of Shareholders held on May 11, 2017.

(c)	Changes in control:

(d)	Securities authorized for issuance under equity compensation plans as of December 31, 2017:

(1)

Excludes unvested restricted shares and performance share awards granted under Avista Corp.’s Long-Term Incentive Plan. At December 31, 2017, 106,053 Restricted Share awards were outstanding. Performance and market-based share awards may be paid out at zero shares at a minimum achievement level; 327,088 shares at target level; or 654,176 shares at a maximum level. Because there is no exercise price associated with restricted shares or performance and market-based share awards, such shares are not included in the weighted-average price calculation.

(2)	Includes the Long-Term Incentive Plan approved by shareholders in 1998 and the Non-Employee Director Stock Plan approved by shareholders in 1996. In February 2005, the Board of Directors elected to terminate the Non-Employee Director Stock Plan.

•	on and after the date of filing with the SEC the Registrant's definitive Proxy Statement relating to its Annual Meeting of Shareholders scheduled to be held on May 10, 2018, from such Proxy Statement; and

•	prior to such date, from the Registrant's definitive Proxy Statement, dated March 31, 2017, relating to its Annual Meeting of Shareholders held on May 11, 2017.

•	on and after the date of filing with the SEC the Registrant's definitive Proxy Statement relating to its Annual Meeting of Shareholders scheduled to be held on May 10, 2018, from such Proxy Statement; and

•	prior to such date, from the Registrant's definitive Proxy Statement, dated March 31, 2017, relating to its Annual Meeting of Shareholders held on May 11, 2017.

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(a)	1. Financial Statements (Included in Part II of this report):

(a)	2. Financial Statement Schedules:

(a)	3. Exhibits:

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(1)	Incorporated herein by reference.

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(2)	Filed herewith.

(3)	Management contracts or compensatory plans filed as exhibits to this Form 10-K pursuant to Item 15(b).

(4)	Furnished herewith.

(5)	Applies to Marian M. Durkin, Karen S. Feltes, James M. Kensok, Scott L. Morris, Jason R. Thackston, Mark T. Thies and Dennis P. Vermillion.

(6)	Applies to Kevin J. Christie, Ryan L. Krasselt and Heather L. Rosentrater.

(7)	Applies to Edward D. Schlect.

(8)	Applies to James M. Kensok, David J. Meyer, Jason R. Thackston and Dennis P. Vermillion.

(9)	Applies to Marian M. Durkin, Karen S. Feltes, Scott L. Morris, and Mark T. Thies.

(10)	Applies to Kevin J. Christie, Ryan L. Krasselt, Heather L. Rosentrater and Edward D. Schlect.

(11)	This agreement currently does not apply to any executives; however, it could apply to any new Senior Vice Presidents appointed after November 13, 2009 if they chose to be under this agreement.

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