Dive Brief:

• Hawaiian Electric is testing two types of water heaters as possible grid resources on Oahu, part of a pilot program looking for ways to help smooth the state's problems integrating renewable power, Greentech Media reports.
• The new water heaters were installed in September as part of the utility's Grid Interactive Water Heater (GIWH) demonstration project. The new technology calls for high-speed, two-way communication between the water heater and the utility. 
• The scope of Hawaiian Electric's pilot is unclear, but the utility is working with small and medium-sized businesses and expects to conclude the test in July 2015.

Dive Insight:

The explosion of rooftop solar on Oahu has created integration problems for utilities and built interest in storage and distributed resources that can help smooth out power flowing into the grid. Now Hawaiian Electric has launched a pilot program that would use water heaters — which make up most of a typical customer's monthly power use on the island — as a resource capable of helping support the utility grid.

The GIWHs would becomes a thermal battery for storing energy, with the ability to follow locational marginal pricing, provide fast regulation service and better integrate renewable energy, Greentech reports. A conventional storage water heater for a family of four uses an estimated 240 to 400 kWh/month, according to Hawaiian Electric.

In September, Hawaiian Electric selected Stem Inc. to provide 1 megawatt of behind-the-meter energy storage in a demonstration project with the utility.