The California Independent System Operator Corp. proposed amendments to broaden options for energy storage and customer-sited generation to earn revenue in wholesale power markets, according to an Aug. 20 filing with the Federal Energy Regulatory Commission, as the grid manager looks to break down barriers for the emerging technology. The proposal would add three new evaluation methods for demand response, which is one of the most common ways for distributed resources, including energy storage, to participate in the wholesale markets. CAISO said that the two existing evaluation methods, one for pure load resources and another to include behind-the-meter generation, may be inadequate to capture the performance of various resources. The new methods for evaluating performance are intended to improve accuracy and reduce bias and variability. The grid operator seeks to have the rules take effect Nov. 1.