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What is a solar electric or photovoltaic system?
Photovoltaic (PV) systems convert sunlight directly into electricity. They work any time the sun is shining, but produce more electricity when intense sunlight strikes the PV modules directly. When sunlight interacts with semiconductor materials in the PV cells, electrons are freed and subsequently captured to create an electric current.
PV systems are made up of solar cells; multiple solar cells are connected to form a PV module. A PV system connected to the utility grid includes these components:
- One or more PV modules
- An inverter, which converts the system's direct current (DC) electricity into alternating current (AC) electricity
- Batteries for energy storage or backup power in case of a power interruption or outage (optional)
AC electricity is compatible with the utility grid and is used to power our lights, appliances, computers, and televisions. Appliances that run directly on DC power are available, but can be expensive.
Things to Consider Before You Buy a PV System
- PV systems produce power intermittently because they only work when the sun is shining.
- Photovoltaic systems connected to the grid get additional electricity automatically from the utility; non-grid or stand-alone PV systems require batteries to store energy for later use
- If you live near existing power lines, PV-generated electricity is usually more expensive than conventional utility-supplied electricity
- PV power requires a high initial investment; you can lower the cost of your system by taking advantage of State of Hawaii and federal tax credits and incentives
In October 2015, the Hawaii Utilities Commission (PUC) announced the Distributed Energy Resources (DER) program will replace the Net Energy Metering (NEM) program for new PV customers. The DER program includes a Grid Supply program, which allows rooftop PV customers to send extra energy to the grid in return for energy credits on their monthly electric bills, as well as a Self-Supply program, which allows rooftop PV customers with energy stroage, such as our Home Energy Storage Site (HESS), to capture excess solar power for their home and business.
Existing NEM customers and those who filed applications for the program before October 13, 2015 are unaffected by these changes. However, if these customers want to modify their PV systems they will be required to adopt the Grid Supply or Self-Supply program.
For more information on the DER program, see Your Guide to PUC's Energy Program Reform.