A lifecycle economic metric defined as the net present value of all costs (capital, operation & maintenance, fuel, and decommissioning where applicable) over a generation asset's operational life divided by the discounted sum of its expected energy output, yielding a single average unit cost of electricity under the adopted assumptions.

Principle

LCOE provides an average cost per energy unit under uniform discounting and assumed production profile; it is comparable across technologies only when discount rate, lifetime, capacity factor, fuel and fixed cost treatments, and treatment of taxes/subsidies are aligned.

Demonstration

Illustrative scenario → Two hypothetical plants: Plant A capital‑intensive with low marginal cost, Plant B low capital and high fuel cost. Recognition → assemble capital, O&M, fuel schedules and assumed capacity factors; discount costs and energy to present value. Action → divide total discounted costs by total discounted energy to obtain each LCOE. Consequence → the metric ranks per‑unit average cost but is sensitive to capacity factor and discount rate assumptions.

Misapplication

Using LCOE as a sole decision criterion for resource selection while ignoring system integration costs (flexibility, curtailment, transmission, locational value) or comparing LCOEs computed with inconsistent assumptions; the semantic error is treating LCOE as an intrinsic, context‑free measure of value rather than an assumption‑dependent accounting average.

Consequence

Appropriately used, LCOE enables transparent cost accounting and sensitivity analysis for project comparison; misused, it can bias procurement and policy toward resources that appear cheap on average but impose hidden system costs or deliver value at times of low market price.

Reversal

For resources whose value depends strongly on timing, location, or dispatchability (e.g., intermittent renewables, storage), value‑based metrics (market revenue, LACE, value‑adjusted LCOE) or system‑level cost‑benefit analysis may be more appropriate than raw LCOE.

Boundary

Clearly within: generation‑level comparisons under explicit, aligned assumptions about discounting, life, and output. Boundary case: inclusion of carbon costs or subsidies—valid only if consistently applied. Clearly outside: measures of system‑level cost, market revenue, or socioeconomic welfare unless explicitly expanded to include those elements.

Semantic Tension

Cost (LCOE) ↔ Value (market/dispatch value): low average cost does not guarantee high system value at relevant times or locations; procurement decisions must reconcile the two.

Synthesis

LCOE is a transparent accounting tool for average unit cost conditional on specific assumptions; it is most useful for scenario and sensitivity comparisons, not as a standalone measure of a generator's system value.