Renewable Portfolio Standard (RPS):
RPS Calculator



The RPS Calculator has an integral role in planning for Renewables procurement at both the CPUC and the California Independent System Operator CAISO. The RPS Calculator is a modeling tool that develops and evaluates portfolios of renewable resources including:

  • Resource cost and performance
  • Transmission needs
  • Environmental impacts and potential permitting hurdles
  • The value of different types of renewable resources 

The RPS calculator, utilizing data originally developed as part of the Renewable Energy Transmission Initiative (RETI), has been widely used for scenario analysis of renewable resources that achieve the state’s RPS targets. 

On October 10, 2014, the CPUC issued a Ruling requesting comments on its Staff’s Proposal to revise components of the RPS calculator, which informs the CPUC’s long-term procurement planningprocess.  Long-term planning develops various scenarios of future demand and supply over a 10-year horizon, including incorporating the renewables portfolios. The CAISO then uses these scenarios in its Transmission Planning Process studies.  

On August 28, 2015, the CPUC issued a Ruling soliciting proposals from parties on a methodology for incorporating land use and environmental information into the RPS calculator. The CPUC subsequently held a workshop to discuss interim approaches for 2016 on land use and environmental information.



ORA Position

ORA supports the RPS Calculator provides accurate and timely information to the CPUC’s long-term procurement planning process in order to promote transmission planning that provides safe and reliable capacity at the least cost to ratepayers. Additionally, the RPS Calculator is useful in providing necessary information to the CAISO’s Transmission Planning Process to identify transmission that is needed to access the most cost-effective and environmentally preferred renewable resources in California.                                 

Efforts to update the RPS Calculator should be coordinated with other proceedings at the CPUC proceedings including Resource Adequacy, the Distributed Resources Plan, Interconnection, and the Long Term Procurement Plan so that  costs are equally captured across all proceedings.



See ORA’s: 

September 28, 2015 Opening Comments on the CPUC’s Ruling regarding methodology.    

April 27, 2015 Comments on the RPS Calculator Post workshop.


ORA Opening Comments from December 3, 2014.

ORA Reply Comments from December 22, 2014.   




CPUC Docket

See the Proceeding docket.




Other Resources

CPUC's Webpage on the Renewables Portfolio Standard

CAISO Transmission Planning Process