NNSA Pantex Plant ESPC Audit Reveals Savings Issues

DOE OIG Reports

Filed March 24th, 2026

Detected March 31st, 2026

Summary

The DOE Office of Inspector General issued Audit DOE-OIG-26-24 finding that the National Nuclear Security Administration failed to realize $21,187,829 in guaranteed savings from its Energy Savings Performance Contract with Siemens Government Technologies at Pantex Plant. The audit identified that NNSA based savings estimates on wholesale power rates that decreased after the project became operational, sold excess power back to the utility at a loss, allowed wind turbine maintenance contracts to expire, and made payments exceeding verified savings over a 10-year period.

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What changed

The DOE OIG audit (DOE-OIG-26-24) examined NNSA's Energy Savings Performance Contract No. DE-NA0001628 with Siemens Government Technologies for the Pantex Renewable Energy Project. The investigation found that NNSA's original savings estimates relied on escalating wholesale power rates, but rates declined after project operationalization. Additionally, NNSA could not utilize all generated power and sold excess electricity back to the utility at times at a loss, while allowing wind turbine maintenance contracts to lapse. These failures resulted in $21,187,829 in payments over 10 years for savings that could not be verified.\n\nFederal agencies and contractors holding ESPCs should review the three recommendations to improve ESPC management practices. Specifically, NNSA and similar entities should verify that energy savings projections are based on realistic rate assumptions, implement controls to prevent maintenance contract lapses, and establish procedures to reconcile payments against documented savings. While no formal compliance deadline was specified, agencies should proactively address these control weaknesses to avoid questioned costs in future audits.

What to do next

Review energy savings projections to ensure they are based on realistic rate assumptions rather than optimistic forecasts
Implement controls to prevent lapses in critical equipment maintenance contracts
Establish procedures to reconcile payments against verified documented savings

Source document (simplified)

Audit: DOE-OIG-26-24

Additional Actions Will Help the National Nuclear Security Administration Realize Guaranteed Savings Through Its Energy Savings Performance Contract With Siemens Government Technologies Inc. at Pantex Plant

Office of Inspector General

March 30, 2026

March 24, 2026

Energy Savings Performance Contracts (ESPCs) are contracts between a Federal agency and an energy service company that allow the agency to improve energy efficiency at no direct cost to the U.S. Treasury. ESPCs include energy conservation measures, which are upgrades to equipment intended to save energy and associated costs.

In 2013, the National Nuclear Security Administration (NNSA) awarded an ESPC to Siemens Government Technologies, Inc. (Siemens) to construct the Pantex Renewable Energy Project in Amarillo, Texas. The Office of Inspector General has issued several audit reports identifying weaknesses in the Department of Energy’s oversight of ESPCs.

We conducted this audit to determine whether NNSA’s Pantex Plant realized the guaranteed savings with Siemens under contract No. DE-NA0001628.

We found that NNSA did not realize its planned guaranteed savings from the ESPC with Siemens. Specifically, we found that NNSA’s original estimated savings were based on escalating wholesale rates for exported power; however, the rates decreased substantially shortly after the Pantex Renewable Energy Project became operational. Additionally, NNSA could not fully use the power generated by Pantex Renewable Energy Project throughout the Pantex Plant and instead sold power back to the local utility provider, sometimes at a loss.

Finally, NNSA permitted the maintenance contracts for the wind turbines to expire and made payments to Siemens that exceeded reported savings. As a result, the Federal Government paid a total of $21,187,829 for a 10-year period of guaranteed savings that it could not verify it received.

To address the issues identified in this report, we have made three recommendations that, if fully implemented, should help improve NNSA’s management of ESPCs.