On-Peak Energy 2 topics · 2 sources ScienceEnergyEnergy supplied during periods of relatively high system demands as specified by the supplier.US DOE Office of Energy Efficiency & Renewable Energy — Glossary of Energy-Related Terms retrieved 2014-05-26 Cite ScienceWaterElectric energy supplied during periods of relatively high system demand. Bureau of Reclamation — Bureau of Reclamation Glossary Cite