Seasonal relationship of peak demand and energy impacts of energy efficiency measures—a review of evidence in the electric energy efficiency programmes

While energy efficiency programmes traditionally focus on energy savings, there is also a policy interest in their impact on system peak demand. Examples include demand-side management, integrated resource planning and recent developments to integrate energy efficiency into forward capacity markets. However, there is only limited research on the relationship between peak demand impacts and overall energy savings from efficiency measures, although this relationship can have important bearings on efficiency programmes. This paper reviews utility efficiency programmes in nine jurisdictions in North America and analyses how the seasonal peak-energy relationship differs between commercial and industrial (C&I) and residential sectors, among efficiency measures. In terms of the seasonal difference in peak demand impacts, these programmes show that residential lighting and residential water heating can deliver greater peak savings in weekday early evening winter peak periods. By contrast, C&I lighting and residential appliances make higher peak savings in weekday afternoon summer peak periods. A seasonal difference is more significant in lighting, especially residential lighting, than other measures. The evidence from North America also suggests that space cooling in both sectors and C&I lighting may well make greater peak savings relative to non-peak impacts than other measures during summer peak periods, while in winter peak periods, residential lighting can achieve greater peak savings relative to non-peak impacts. This review highlights the significance of regional electricity use patterns along with climatic and regulatory conditions and indicates how further research may contribute to appropriate electricity demand reduction programme design and monitoring regimes in particular regions.