High Electric Demand Day Initiative
On the hot, hazy days of summer, higher demand for electricity results in a dramatic increase in ozone-forming air pollution. These are called “high electric demand days” or HEDD. The emission peaks occurring on HEDD are not usually accounted for in the seasonal based emissions inventories developed for SIPs, so they are an obstacle to the continued progress in attaining and maintaining air quality improvements in the Ozone Transport Region (OTR). The OTR consists of the Northeast region extending from Maine to northern Virginia.
Although the states in the Ozone Transport Region have made significant progress in improving the Northeast region’s air quality over the past 30 years (for example, the number of ozone exceedance days in Connecticut has significantly decreased since 1975), in recent years it appears that the decreasing ozone trend has leveled off and ozone levels are no longer decreasing at a sufficient rate to meet attainment requirements in a timely fashion. More information on Connecticut’s planning efforts for ozone attainment.
States and the Ozone Transport Commission are working together on a High Electric Demand Day Initiative incorporating various strategies to address the added pollution of peak electricity demand. As part of the HEDD Initiative, Connecticut has committed to reducing NOx emissions by 25% on high electric demand days by the 2009 ozone season, or as soon as feasible, but no later than 2012. Challenges and opportunities surround the HEDD Initiative. Electricity demand on HEDDs is growing two to three times faster than base load demand. Electric generating units (EGUs) currently used to meet peak electricity demand on HEDDs are often among the oldest and most polluting of all EGUs. Although they operate relatively infrequently, they have a large emissions impact, especially compared to the emissions of newer, more efficient and cleaner burning units. This may make them good candidates for technology-based control measures. Additionally, neither the federal CAIR NOx Ozone Season Trading Program nor the Cross-State Air Pollution Rule take into consideration the increased electric demand over short time periods. Energy efficiency, energy conservation, demand side resources and increasing the efficiency of the current system will be essential elements of the wide-range strategy needed to help the OTR states address HEDD and plan for ozone attainment and improved air quality.
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Content Last Updated on December 28, 2011