On December 20, 2011, the Hawaii Public Utilities Commission issued a decision that addresses several disputed issues from the recent Interconnection Rule 14H proceeding. This decision resulted in a favorable outcome for distributed renewables, particularly those in the small to medium size range.
The three main decisions in this order mandate the following:
Utilities prohibited from requiring SCADA equipment on systems under 250 kW
Facilities with an aggregate capacity of greater than 250 kW in HELCO and MECO territories, and greater than 1 MW in HECO territories, will be required to install supervisory (SCADA) controls. In HECO territories, the utility will have the discretion to require SCADA on facilities larger than 250 kW, up to 1 MW. This result is consistent with IEEE standards. However, for facilities with an aggregate capacity of 250 kW or less for all three utilities SCADA controls are not required. This is significant because SCADA controls can be costly and have the ability to upend an otherwise positive financial outlook for small and medium-sized systems.
Utilities required to use voltage set points consistent with IEEE and national standards
In the event of a voltage disturbance that deviates from utility normal operating ranges, facilities equipped with UL-certified inverters will automatically disconnect the utility system. The utilities requested the ability to require voltage set points and clearing times outside of IEEE-specified limits. Parties objected that this would allow utilities to establish set points and clearing times outside the already broad ranges currently specified in the rule (and allowed by IEEE) and raised questions as to the potential impact on inverter warranties. The utilities were denied the ability to adjust the set points outside of IEEE-specified ranges.
Denials of interconnection request for reasons other than safety or reliability prohibited
The HECO Companies requested the ability to reject interconnection requests for a broad range of reasons, many of which went well beyond relevant considerations of facility impacts on safety and reliability. Safety and reliability concerns are already factored in to the interconnection review process and this additional language would allow the electric utilities to reject interconnection requests for economic reasons that are not well defined and are better left to the Commission’s determination as a matter of public policy. This request was denied.
This order establishes even further precedents in Hawaii’s new cutting-edge interconnection policy, hopefully paving the way for other states to follow in its path. See Hawaii PUC order 30027 for more information.