Net Energy Metering (or NEM) is one way to lessen Hawaii's dependence on imported oil by encouraging the greater use of eligible renewable energy sources like solar (photovoltaic, PV), wind, biomass, or hydroelectric power for electrical generation by residential and commercial customers. Hawaiian Electric Company (Hawaiian Electric), Maui Electric Company (MECO), and Hawaii Electric Light Company (HELCO) support Net Energy Metering and recognize our roles to help Hawaii transition from fossil fuels to more renewable energy resources. Below is information for HELCO's customers and contractors that we hope will be helpful. NEM application processes for Hawaiian Electric and Maui Electric may differ. For information on NEM for MECO, visit www.mauielectric.com; and for Hawaiian Electric, nem.heco.com.
Distributed Generation (DG), including NEM, has changed how electricity is produced and delivered. NEM has become very popular and many of HELCO’s customers have participated in the program. Unfortunately, there is a limit to the amount of distributed generation (DG), including generation from NEM systems, that can interconnect with our distribution circuits before power quality and reliability may be negatively impacted. Traditionally, electrical transmission and distribution systems, commonly referred to as networks or grids, were designed for the flow of electricity in only one direction, from central power plants to the customer. Today, in addition to central power plants, customer sited DG from solar (PV), wind, hydro, and biomass, are increasingly being used to generate electricity resulting in the flow of electricity in two directions. In addition, the amount of power generated from PV (or wind or hydro systems) on the grid is variable because the generation output changes with cloud (or wind or water-flow) conditions. This two-way and variable flow of electricity may cause the power to fluctuate on the distribution feeder, impacting every customer connected to it and the reliability of power provided by HELCO. If there are already high levels of DG on a feeder, or if there is a relatively light load, further study may be needed to determine the impact of interconnecting additional DG. HELCO’s vision for the future includes an increased reliance on renewable energy generation resources, including electricity produced by customer-sited distributed generation, and we are working with the national labs and others to analyze and overcome the associated technical issues.
Ensuring reliability is an essential step in the interconnection of DG. As the penetration of distributed generation increases on the utility distribution feeder (the power line that brings electricity to your home or business), there is increased risk of voltage regulation problems, along with adverse interactions with the utility’s system. Therefore, interconnections of distributed generation systems to HELCO’s grid go through a technical screening process. Currently, to protect our customers and HELCO’s grid, when the aggregate distributed generation generating capacity per distribution feeder of installed and planned systems exceeds 15% of the peak KVA load of the line section, the technical screening process may indicate that Supplemental Review of the application is required. If the 15% penetration on the line section has not been reached, the system may qualify for Simplified Interconnection. The level of DG circuit penetration before Supplemental Review may be required is approved by the State of Hawaii Public Utilities Commission and the need for review is identified by HELCO.
Supplemental Review may result in one of the following: a) approval of interconnection; b) approval of interconnection with additional requirements; or c) the need for an Interconnection Requirements Study (IRS). Payment for an IRS and the installation of any additional equipment identified as a result of Supplemental Review or an IRS is the responsibility of the customer applying for the interconnection. HELCO continues to support NEM, however we must ensure the reliability and quality of electricity that we provide to all of our customers.
The DG queuing process allows customers to reserve capacity for their NEM system. To facilitate customers applying for NEM and to make the application process as equitable as possible, HELCO has created a circuit reservation queue for customers planning to install their own qualifying renewable energy generation systems. The queue allows customers to apply for NEM and to reserve capacity on the circuit for the size of system they are planning to install if circuit capacity for DG is available (DG penetration <15% and no Supplemental Review or Interconnection Requirements Study is needed) or following Supplemental Review the system qualifies for Simplified Interconnection. Placement in the queue is on a first-come, first-served basis. Deadlines for system installation are placed on customers admitted to the queue so that space may open up for others if projects do not move forward. Please be aware that the NEM application processes, including the queuing process, are subject to change without notice. Additional information is provided below.