Utility microgrid: Lessons learnt from California’s SDG&E

The Association for Demand Response and Smart Grid has carried out a study on how SDG&E is incorporating distributed energy resources and IT to ensure microgrid reliability

In the US, the Association for Demand Response & Smart Grid (ADS) and the Demand Response Coordinating Committee last week released a new case study that examines how San Diego Gas & Electric’s Borrego Springs microgrid was developed.

The study ‘San Diego Gas & Electric: A Utility-Owned Microgrid is the sixth analysis carried out by the association in line with the National Action Plan on Demand Response published in Q2 of 2010 by the Federal Energy Regulatory Commission.

The plan calls for stakeholders in the energy sector to develop and disseminate case studies as an action to support demand response practitioners and policymakers.

According to a statement, the ADS research demonstrates the viability of utilities’ integrating consumers in developmental plans and tweaking services to fit consumer needs to improve service delivery.

The demand response and smart grid association utilised interviews to provide an inside view of implementing a smart grid project including how various state and federal stakeholders collaborated, said Dan Delurey, CEO of ADS.

Mr Delurey added that the SDG&E’s microgrid was chosen as the subject of the case study due to “its innovative approaches and its applicability to jurisdictions for utilities of any size or governance structure”.

The research findings highlight SDG&E’s learnings over the course of the microgrid project. These include:

1. Being sure to include a technical evaluation on all plug and play technology to ensure everything works in your specific environment.

2. Making sure that the community is involved and has buy-in to the project.

3. Incorporating simulations and modelling before putting everything together.

4. Being aware of all regulations (siting, emissions, etc.) before launching a project.

SDG&E’s microgrid

The California utility’s microgrid is being upgraded under the project to provide a proof-of-concept as to how IT and distributed energy resources can increase utility asset utilisation and reliability for the 2,800 customers of Borrego Springs , Metering and Smart Energy International has learnt.

In terms of control systems, the project incorporates SCADA on all circuit breakers and capacitor banks, feeder automation system technologies, OMS and price-driven load management at the customer level.

Upon completion, the total microgrid installed capacity is expected to be 4 MW, with the main technologies being two 1.8 MW diesel generators, a large 500 kW/1500 kWh battery at the substation, three smaller 50 kWh batteries, six 4 kW/8 kWh home energy storage units, about 700 kW of rooftop solar PV, and 125 residential home area network systems.