DEPRECIATION AND EARLY PLANT RETIREMENTS

This briefing by Energy Innovation examines how utility depreciation accounting and regulatory asset management influence the transition from coal-fired power plants to clean energy in the United States. It details the mechanisms regulators use to handle 'stranded assets'—plants that become uneconomic before their useful life ends—and the trade-offs between accelerated and extended depreciation schedules regarding consumer rates and investor returns.

• The declining cost of renewable energy has made the operational cost of coal generation higher than the total cost of replacing it with wind and solar in various U.S. regions, leading to a reconsideration of the prudency of continuing coal operations for regulated investor-owned utilities.
• In regulated utility markets, depreciation is an allocation method rather than a valuation method, determining how a plant's book value changes over time. Assets are considered 'impaired' or 'stranded' when their expected cash flow is lower than their remaining book value.
• When power plants retire early, regulators may move remaining book values from 'plant in service' accounts into 'regulatory asset' accounts. These accounts allow utilities to continue recovering investments and earning equity returns through consumer rates, though the justification for high equity returns may decrease once the operational risks of the plant are gone.
• Regulators have two primary options for adjusting depreciation schedules during early retirement: accelerated depreciation, which recovers capital faster and increases current consumer rates to avoid burdening future users, and extended depreciation, which reduces immediate rate impacts and may benefit future consumers who gain access to lower-cost clean energy sooner.
• Stakeholders hold conflicting views on asset recovery: utilities seek full return 'of and on' capital investments; consumers may argue for disallowance based on faulty management or the fact that equity risk premiums already compensated for early retirement; and clean energy advocates prioritize whether depreciation policies facilitate or hinder the transition speed.
• Beyond depreciation, the financial transition can be optimized by refinancing undepreciated balances with lower-cost debt—such as corporate debt, ratepayer-backed bonds, or green bonds—and reinvesting the resulting savings into energy efficiency, demand management, or grid-scale clean energy.

APA

LEHR, R., & O’BOYLE, M. (2018). DEPRECIATION AND EARLY PLANT RETIREMENTS. Energy Innovation. https://energyinnovation.org/wp-content/uploads/Depreciation-and-Early-Plant-Retirements-Brief_12.3.2018-2.pdf

Chicago

LEHR, RON, and MIKE O’BOYLE. DEPRECIATION AND EARLY PLANT RETIREMENTS. Energy Innovation, 2018. https://energyinnovation.org/wp-content/uploads/Depreciation-and-Early-Plant-Retirements-Brief_12.3.2018-2.pdf.

Wikipedia

{{cite report |last1=LEHR |first1=RON |last2=O’BOYLE |first2=MIKE |title=DEPRECIATION AND EARLY PLANT RETIREMENTS |publisher=Energy Innovation |date=December 2018 |url=https://energyinnovation.org/wp-content/uploads/Depreciation-and-Early-Plant-Retirements-Brief_12.3.2018-2.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{lehr2018depreciation, author = {LEHR, RON and O’BOYLE, MIKE}, title = {{DEPRECIATION AND EARLY PLANT RETIREMENTS}}, institution = {Energy Innovation}, year = {2018}, month = dec, url = {https://energyinnovation.org/wp-content/uploads/Depreciation-and-Early-Plant-Retirements-Brief_12.3.2018-2.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }