Rooftop solar electricity — what is it truly worth?
A search for answers by California utility regulators is generating some prickly computer challenges.
An intricate computer model was commissioned last year by the California Public Utilities Commission to analyze the cost-effectiveness of new solar policy proposals. A recent test run of the giant equation found it to be painfully slow, with answers and forecasts that look strange or unreliable.
“We have this very complicated modeling exercise that is built into Excel and takes four-and-a-half hours to run,” observed Alison Seel of the Sierra Club, which wants greater consideration given to the societal benefits of rooftop solar. “It doesn’t matter how big your computer is. They’ve kind of created this whole universe in Excel.”
California is looking for new solutions as it phases out a generous credit for excess rooftop solar electricity (at the full retail rate) streaming from homes and stores. A rough version of the computer model was released to gather feedback.
At stake is the future trajectory of the nation’s largest solar market, California. Solar policy changes hold major implications for the state’s big investor-owned utilities, as disruptive consumer technologies make incursions into traditional monopoly territory.
Before solar tariff proposals are unveiled by utilities and the solar industry, the state wants an unbiased way to evaluate them using the big computer app developed through an outside contractor.
The utilities commission is urging patience after a beta version of the model elicited some stinging reviews.
Pacific Gas and Electric, the state’s largest utility, said the computer tool “currently generates illogical and counter-intuitive outputs, which if taken as the basis for policy making, would result in poorly designed policy.”
The solar industry has described the tool as “complex, difficult to understand and time-consuming.”
“We are skeptical that the public (computer) tool can serve as a fair analytic frame for analyzing the issues,” at attorney for the industry wrote.
Analysts at the California Public Utilities Commission are standing their ground as they work toward a final version of the computer tool with a San Francisco- and Vancouver-based consultant Energy + Environmental Economics, or E3.
The agency says the recent test run produced unreliable results because some data fields had to be filled out temporarily with hypothetical numbers.
http://www.utsandiego.com/news/2015/may/27/computer-mega-program/