Deploying more variable generating resources, such as wind and solar, will increase the need for power-system flexibility, but, historically, flexibility has not been systematically evaluated in utility planning studies, says a new report from Lawrence Berkeley National Laboratory.
Analysts at Lawrence Berkeley have developed a high-level, year-to-year model that tracks the flexibility supply and demand based on utility integrated resource plans (IRPs). They apply the flexibility model to western IRPs from the Resource Planning Portal database.
Lawrence Berkeley defines flexibility supply as the capability of generation and demand to change in response to system conditions. Flexibility demand is largely determined by the amount that the net demand changes over different timescales and the degree to which those changes can be predicted.
According to the report, flexibility demand is largest over long time intervals – greater than six hours. However, flexibility supply is also large over these intervals based on the ability to ramp resources fully and turn units on or off.
Flexibility supply is most limited relative to flexibility demand over shorter intervals (e.g., 15 minutes) when the ability to ramp resources is much more limited. In the regions covered in the report,Â the analysts find that the ratio of flexibility supply to demand is largely expected to decrease over the next decade, though the change is expected to be slow.
The report and summary slides can be downloaded here.
A webinar presentation summarizing the report will be held on Nov. 3 from 10 a.m. to 11 a.m. Pacific Time. To receive log-in instructions for the webinar, register here.