Note: Given the unprecedented level of distributed solar generation that has raised substantial grid reliability concerns, the Hawaii Public Utilities Commission (PUC) is undergoing a major interconnection & reliability standards review in Docket No. 2011-0206. To address reliability concerns, the PUC has authorized Hawaii's largest utility, Hawaii electric (HECO), to require additional solar interconnection studies on some circuits. For more information on locations where solar might take additional study, visit the HECO Locational Value Maps page or visit HECO’s website.

Hawaii has established simplified interconnection rules for small renewables and separate rules for all other distributed generation (DG). For inverter-based systems up to 10 kilowatts (kW) in capacity (and inverter-based DG under 250 kW on islands other than Kauai), there is a simple application process for interconnection. Systems must use inverters compliant with IEEE 1547 and UL 1741.  For other smaller systems, there are simplified interconnection procedures for net metered systems powered by solar, wind, biomass and hydroelectric up to 50 kW on Kauai and 100 kW in capacity on the other islands. 

The state's largest electric utility, Hawaiian Electric Company (HECO), which owns Hawaii Electric Light Company (HELCO) and Maui Electric Company (MECO), uses a set of simple interconnection guidelines. HECO also uses a simple, net-metering agreement. A manual, lockable disconnect switch is required for net-metered systems, and mutual indemnification is required. The state's only other utility, Kauai Island Utility Cooperative (KIUC), has a similar set of rules for net metering and interconnection.  In May 2010, A Public Utilities Commission (PUC) decision and order created a standard three-party interconnection agreement.

Two dockets were opened in 2006 to streamline interconnection procedures: (1) PUC Docket No. 2006-0497 (Hawaiian Electric Co., Hawaii Electric Light Co., and Maui Electric Co.,); and (2) PUC Docket No. 2006-0498 (KIUC). The PUC issued a decision and order for each of these dockets in April and May 2008, and more streamlined procedures for interconnection were adopted. KIUC provides a fast-track process for small generating facilities under two megawatts (MW), while larger systems must undergo more extensive review.

In November 2011, the Public Utilities Commission issued a decision and order to improve Hawaii's interconnection standards. The order approved a supplemental review process and other measures to limit the scope of systems that must conduct an Interconnection Requirements Study (IRS).  In the past, a system would automatically have to conduct an IRS if the project did not meet certain technical screening criteria. In particular, the 15% circuit penetration threshold often triggered an IRS.  In the new approach by the HECO Companies, if certain technical screening criteria are not met, the utility will conduct a supplemental review if a customer chooses to proceed with interconnection.  The supplemental review will determine if simplified interconnection can take place, if interconnection requirements beyond simplified interconnection are needed, or if an IRS is needed.  The new rules have set timelines in the interconnection process, including a timeline for dispute resolution.  Under the new rules, a meeting to resolve a dispute must be scheduled within 15 days of a written request being submitted.