The Peak Load Management Alliance (PLMA) has published a study on the market potential for water heater demand management.
The study, entitled "Market Potential Study for Water Heater Demand Management," was produced by Frontier Associates LLC.
According to the study, between 13% and 17% of residential energy consumption nationwide is for heating water, and that over 53 million homes have water heaters. It says that with such a high saturation of electric water heating across the country, direct load control for water heaters has a lot of potential for reducing peak demand—particularly to help offset summer peak demand periods caused by heavy air conditioning use.
Controlling demand could be accomplished by not only shutting water heaters off during high demand periods, but also by allowing them to operate during off-peak hours only.
PLMA study (pdf)
Demand Side resources on SGN