Wholesale Distributed Generation (WDG) Solar
Want to learn more about wholesale distributed generation (WDG) solar? Check out Vote Solar’s WDG solar guide. The guide is a ‘how-to’ for stakeholders interested in competitive mechanisms for procuring WDG solar.Note: There are other procurement options that can be utilized to procure WDG solar, including feed-in-tariffs and utility-owned generation. Every approach has its strengths and weaknesses. For simplicity’s sake, this guide covers only competitive programs for procuring power from independent producers. We plan future guidance for other types of programs–or, feel free to reach out and ask us.
What is WDG solar?
Wholesale distributed generation (WDG) refers to solar projects that sell electricity to a utility (as opposed to generation principally for on-site consumption), and are sited close to demand–usually interconnected on a distribution network (as opposed to high-voltage transmission line). While there is no official size parameter, WDG systems are usually under 20 MW.
What are the benefits of WDG solar?
WDG solar provide numerous environmental and economic benefits to utilities and their customers. Because WDG solar is sited close to load, line losses (which can be up to 8-9%) are reduced, and in certain instances, WDG can reduce or defer investment in transmission and distribution systems. Since WDG systems utilize existing networks, they can be brought online in relatively short timeframes, helping meet RPS goals quickly. By spreading generation over a wide geographic area, the aggregate weather-related impacts to generation are smoothed out, thereby potentially reducing grid integration issues. Finally, a robust WDG program with best-practice guidelines, can build a strong local solar industry and deliver low-cost and high-value power to ratepayers.
Where do WDG solar programs exist?
WDG solar programs are being pursued in numerous countries. In the US, Arizona and California have the most well-developed programs; see: Arizona Public Service’s Small Generator Standard Offer Program, and the California Reverse Auction Mechanism.