Hawaii utility proposes storage options for NEM customers


On March 9, the HECO Companies submitted a revised proposal to allow NEM customers to add energy storage or other non-export technology to their solar facilities, provided they update their NEM system with advanced inverters. HECO proposed that this policy be effective for one year, at which point it will be reviewed to address any unforeseen negative impacts.

The objectives of the policy are to 1) provide NEM customers an option to add energy storage to their existing NEM system and keep their entire NEM system grid-connected and 2) provide an opportunity to upgrade “legacy” NEM systems with advanced inverters, which will help to enable the utilities to integrate higher levels of DERs. The HECO proposal provides three options: 1) Residential Option 1, which limits exports to 3 kW; 2) Residential Option 2, which limits exports to the original NEM size; and 3) Larger Systems/Commercial Option, which limits the kW capacity of the non-export add-on such that the total technical size does not exceed 100 kW. These options do not apply in cases where NEM customers request to add storage for emergency back-up only, which are not subject to interconnection review.

The PUC directed HECO to revise its initial proposal from November 2017 because it was unclear in the whether the addition of non-export technology would add to the NEM program size or how the HECO Companies proposed to measure kWh exports. The utilities’ proposed compliance procedures and interconnection reviews also required further clarification. Lastly, there was no description of how HECO would ensure that customers complied with the legacy inverter upgrade requirement.