The Hawaiʻi Natural Energy Institute ( HNEI ) at the University of Hawaiʻi at Mānoa and Maui Electric Co. ( MECO ) have collaborated to demonstrate a cost-effective solution that is allowing more rooftop photovoltaic ( PV ) systems to be added to the Molokaʻi grid.

Thanks to U.S. Office of Naval Research funding, HNEI and MECO have installed a practical and effective solution that removes one of the barriers to the integration of additional rooftop PV on Molokaʻi. In this work, a 750 kW dynamic load bank connected to the island’s electrical grid can rapidly absorb excess energy that might occur during periods of high solar generation or unplanned system disruptions, such as a sudden loss of load on the grid. This easy-to-control dynamic “safety valve,” much lower in cost than battery storage, is providing the ability for the utility to accept up to an additional 725 kW of rooftop PV .

“A small island power system like Molokaʻi is very dynamic, and the high PV penetration adds another level of complexity to managing those dynamics,” said Rick Rocheleau, HNEI director. “This makes Molokaʻi the perfect location to demonstrate advanced solutions for reliable operations of grids, in a state with some of the highest penetration levels of distributed solar generation in the world.”

Added Chris Reynolds, director of system operations at MECO , “Such partnerships with HNEI are critical as we continue to work together to integrate more renewable energy on small stand-alone systems like on Molokaʻi.

More on the project

The dynamic load bank complements the HNEI / MECO two-megawatt battery energy storage system commissioned at the utility’s Palaʻau power plant in 2016.

These projects are helping the utility to improve reliable operations on an island grid that has a large amount of renewable energy coming from rooftop solar systems. The installations are part of multi-pronged approach MECO is taking to help Molokaʻi reach the state’s 100 percent clean energy goal.

The approach includes continuous outreach and discussions with the community; alternative financing possibilities through available tax credits and third-party grants or partnerships; innovative utility-sited solutions; and new customer options to prepare the Molokaʻi grid to take on more renewable energy.