Hawaii to use residential batteries, energy management to relieve solar grid congestion

The small island of Molokai in Hawaii has a colorful past, including hosting a leper colony until 1969. However, it is now going to be home to a very different kind of experiment. Last Friday Hawaiian Electric Companies (HECO) announced a new pilot program to utilize energy management and storage to allow more customers to interconnect solar PV systems on Molokai.

HECO notes that the level of solar PV systems already installed or approved for installation on Molokai is among the highest in Hawaii. Further, as the island has only 7,000 inhabitants and occupies 670 square kilometers, its small grid poses additional technical challenges.

The company’s search for solutions to the technical issues raised in reviews has led it to contract with local Hawaiian company E-Gear for the installation of its Energy Management Control (EMC) and storage technology, which it says will enable up to 10 PV systems stuck in the interconnection queue to move forward.

E-Grid says that its EMC is designed to minimize the impact of rooftop PV systems on small, saturated grids like the one in Molokai, and the company is currently evaluating EMC-equipped PV systems with the Electric Power Research Institute.

"Our advanced edge-of-grid solutions have been developed and tested over the past two years to bridge a gap between Hawaii’s 100 percent renewables goal and a grid designed in a pre-PV era,” explained E-Gear Co-Founder and Managing Partner Chris DeBone in a press statement.

HECO will have the ability to remotely monitor and control these distributed EMC systems, and will pay for them. The utility will also evaluate the project to determine if this is a suitable solution for other islands.

?Canadian battery storage company Eguana Technologies, which will supply its AC Battery product for the project, says that this is the first deployment of residential energy storage systems by a U.S. utility for the purpose of allowing more rooftop solar on saturated feeders.

However, GTM Research Energy Storage Senior Analyst Ravi Manghani sees this move in light of HECO and other utilities’ increasing interaction with energy storage technologies. He cites other examples of utilities using residential energy storage to understand how to facilitate more renewable energy, such as public utility Sacramento Municipal Utility District’s (SMUD) 2500 R Midtown project.

“In this particular instance, however, the utility will pay for residential energy storage as a prerequisite to clear the interconnection queue on particular saturated feeders,” Manghani told pv magazine. “I’m sure this won’t be the last instance of a utility using, and paying for storage as a means to improve grid reliability in such locations.”

It is not only utilities that are deploying energy storage, and the market for battery storage is growing very rapidly in the United States. A recent GTM Research report estimates that the U.S. distributed energy storage market grew more than 400% to 35 MW deployed in 2015, with Hawaii leading residential installations.