The Value of Efficiency: Renewable Ramp Challenge

As the electricity grid increasingly accommodates solar electricity, a problem is emerging: At sunset, non-solar sources of electricity must quickly ramp up. This limits choices for power plants providing the post-sunset electricity and is difficult for traditional power grids to accommodate. In this study, Efficiency Vermont analyzed the effectiveness of specific energy-efficient equipment upgrades in flattening the loads of Vermont businesses and residences. These measures and results were: 1) clothes washers and dryers—minimal effect; 2) refrigerators—slight positive effect; 3) freezers—an excellent vehicle for alleviating the curve; 4) LED lighting—consistent alleviation of the system coincident peak, especially during the coldest weather; 5) cold climate heat pumps—while calculated to improve curve scores on the whole, this measure added to the morning ramp in warm weather (because water heaters have a nearly flat load shape) and improved scores by increasing usage in the early morning hours.

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