Distributed Energy Resources (DER) including rooftop PV, batteries, and electric vehicles, are changing the way that distribution networks operate. Instead of the traditional power flow from network to customer, the power now often flows from the customer to the network. This reversal challenges the traditional design of the distribution networks, but also provides opportunities to run the networks more reliably and efficiently.

DER challenges include coping with network overloads, increased voltage fluctuations due to varying DER power output, and failure of protection systems. On the other hand, DER also presents opportunities to defer or avoid expenditure on network assets by providing alternative power supplies to the grid.

Electricity regulatory authorities in several states are trying to encourage distribution utilities to actively consider DER as a viable option when planning for network growth. Regulatory guidance is often necessary to handle the potential conflict of interest that arises because making use of customer owned DER does not expand the asset base and overall value of the distribution utility.

In California, PSC worked with the Regulatory Assistance Project to advise the California Public Utilities Commission on 2015 distribution resource plans and DER integrated capacity analysis submitted by Pacific Gas and Electric, Southern California Edison, and San Diego Gas and Electric.

In Minnesota, PSC worked with Lawrence Berkeley National Laboratory to advise the Minnesota Public Utilities Commission to review Xcel Energy’s 2017 report on DER Hosting Capacity.

In both California and Minnesota, PSC helped the regulators with their understanding of the current DER technology and associated challenges and benefits. We were able to provide a view on global issues and trends on DER, and an independent and well informed opinion on the DER plans of the state distribution utilities.