| Abstrakt: |
The drivers for electric utilities to promote solar water heating (SWH) have included benefits related to load management, efforts toward renewable energy goals, and sometimes toward efficiency goals. Drivers also have included utility interest in promoting electric backup water heating, job impacts, and offering an affordable customer solar option. From 2007-12, the authors completed four impact studies of utility solar water heating programs in the Western US, using field monitoring and/or advanced modeling, as well as economic analysis. The research assessed each driver and identified new potential drivers for utility SWH programs. The studies were completed separately; however, they were compared to see if popular thinking about SWH programs needs to be updated. All the utilities studied showed coincident winter peak demand reduction (0.4 kW or more per system), with less dramatic summer demand benefits. Some utilities also could use SWH toward renewable energy goals, or if preferred, energy-efficiency goals. However, utility economics are not necessarily aligned with these and other benefits. Wholesale cost structures, as well as regional climate, mains inlet temperatures, competing water-heater options, and other factors affect outcomes. SWH impact modeling can estimate the economics for specific drivers under specific conditions, with results that are sometimes counter-intuitive. Of note, the research suggested SWH might have particular benefits for utilities in a booming PV market. Those benefits include the complementary load characteristics of PV and SWH, the benefits of SWH storage capabilities, and significant avoided interconnection and integration costs. [ABSTRACT FROM AUTHOR] |
