SolarCity And NREL Team Up On Voltage Regulation

NREL - SolarCity

SolarCity and the USA’s National Renewable Energy Laboratory (NREL) have partnered to solve the growing challenge of voltage regulation on the Hawaiian electricity network caused by the proliferation of grid-connected rooftop solar systems.

Scientists and engineers from SolarCity and Hawaiian Electric Company, the island state’s utility provider, are utilising NREL’s Energy Systems Integration Facility (ESIF) to study the effects of high solar penetration on the behaviour of power grids. Spikes and rapid variations in voltage can potentially endanger customers and damage utility hardware and home appliances.

The ESIF lab allows researchers to test advanced power systems before interconnection with the electric network. The recent tests involved the dynamics between grid-connected solar panels, voltage regulation, and bi-directional power flows – vital issues surrounding the deployment of solar power on Hawaii, where voltage overload issues have forced Hawaiian Electric to delay thousands of rooftop solar installations.

“This capability will be used to help utilities evaluate the impact of distributed energy resources like solar technologies on distribution systems and help them find solutions to utilising these technologies in a safe, reliable, and cost-effective manner at scale,” said Martha Symko-Davies, NREL Director of Energy Systems Integration.

Over 48,000 Hawaiian Electric customers – roughly 10 per cent of homes – have installed rooftop solar power. This compares to a national average of 0.5 per cent as of December 2013, according to the Solar Electric Power Association. The unprecedented rise in PV has caused a crisis for the company, with a backlog of households forced to meet strict technical requirements before being allowed to connect solar to the grid.

“We know how important the option of solar is for our customers. Solving these issues takes everyone – utilities, the solar industry and other leading technical experts like NREL-working together. That’s what this work is all about,” Hawaiian Electric Vice President for Energy Delivery Colton Ching said. “With the highest amount of solar in the nation, our utilities are facing potential reliability and safety issues before anywhere else.”

NREL will also test SolarCity’s newest PV curtailment equipment; a system capable of regulating the amount of solar used in the grid.

“We’re pleased that Hawaiian Electric agreed to partner on these important tests and commend them for taking early test results and instituting policy changes that will help Hawai’i’s solar industry. Our collaboration has been fruitful and we look forward to continuing our work together,” said Jon Yoshimura, SolarCity’s Director of Policy and Electricity Markets.