US DOE 10 CFR 436.19: Federal Solar Life Cycle Cost Guide
Updated 6 September 2026 · By SolarNevs Research Desk, Dealer surveys + verified sources · 1 source · Method ↗
Key Takeaways
- Title 10 CFR Part 436 Subpart A (§ 436.19) codifies the statutory formula for determining Total Life Cycle Costs (LCC) for federal solar projects.
- Calculates LCC as the sum of the present values across 5 distinct cost categories.
- Mandates deducting salvage values from initial investment costs at the end of the study period.
- Requires present value accounting for non-fuel operation and maintenance (O&M) and replacement expenditures.
- Administered by the US Department of Energy (DOE) under the Federal Energy Management Program (FEMP).
Statutory Mathematical Framework of Section 436.19
Under Title 10 of the Code of Federal Regulations, Chapter II (Department of Energy), Section 436.19 defines the exact accounting formula for project life cycle evaluation.
To qualify for federal financing or Energy Savings Performance Contracts (ESPC), solar energy systems must demonstrate life cycle cost reductions relative to baseline energy supply.
Five Components of Total Life Cycle Cost (LCC)
Section 436.19 structures the LCC equation into five discrete present value elements:
LCC Component | Statutory Definition | Accounting Treatment |
|---|---|---|
Category (a) | Investment costs, less salvage values at the end of the study period | Initial turnkey solar hardware, design, and commissioning costs |
Category (b) | Non-fuel operation and maintenance costs | Preventative maintenance, panel washing, monitoring subscriptions |
Category (c) | Replacement costs, less salvage value of replaced building systems | Mid-life inverter replacements and battery module swaps |
Category (d) | Energy costs | Net grid electricity purchases under residual solar offset |
Category (e) | Water costs | Water consumption and utility charges, if applicable |
Present Value Accounting & Project Approval
Under 10 CFR Part 436, federal energy managers apply discounted cash flow methodologies:
- Salvage Value Offsets: Equipment retaining market or scrap value at the conclusion of the study period directly reduces initial and replacement capital burdens.
- O&M Discounting: Recurring annual operations costs are discounted back to the base date using FEMP real discount rates.
- Comprehensive Project Comparison: Comparing the total LCC of a solar-equipped building against a non-solar baseline yields the Net Savings (NS) and Savings-to-Investment Ratio (SIR).
Frequently asked questions
What is the statutory definition of Life Cycle Costs under 10 CFR 436.19?
Under 10 CFR § 436.19, Life Cycle Costs are defined as the sum of the present values of investment costs (less salvage), non-fuel O&M costs, replacement costs (less salvage), energy costs, and water costs (August 2026).
How are investment costs accounted for in the federal solar LCC formula?
Investment costs are evaluated at present value less terminal salvage values realized at the end of the study period (August 2026).
How are solar inverter and hardware replacements handled under § 436.19(c)?
Replacement costs are entered as present values less the salvage value of the replaced building systems or components (August 2026).
What role does water cost play in federal energy LCCA calculations?
Under § 436.19(e), water costs (if any) must be included in the total life cycle cost summation when evaluating systems that consume or conserve water (August 2026).
References
- LII / Legal Information Institute: 10 CFR § 436.19 — accessed 31 August 2026
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