Two systems, one smart choice.Thinking of “going solar”? There are two main types of solar energy systems to choose from. The first, solar water heating, is a solar thermal system; that is, it collects heat. The second, photovoltaics, is a solar electric system. It makes electricity from sunshine. Often, people will talk about a “solar system” or “solar panels” without being clear on whether they mean a thermal or electrical system. The two are very different, so it helps to be clear what you’re talking about.
A solar water heating system consists of a few (usually two) collectors, a water storage tank, and pipes (with the appropriate valves) connecting the collectors and the tank. While some systems move the water passively, using natural convection, many use a pump. A pumped system has a few additional components, such as sensors and a controller to turn the pump on and off. Some pumped systems use a photovoltaic module to run a DC pump.
Essentially, what a solar water heating system does is collect the sun’s heat in a metal plate and pipes (that’s what’s in the panels), run water through the pipes so it picks up the collected heat and then store that hot water in an insulated tank. Purely and simply, it heats water with sunlight, and it is by far the most cost-effective method of heating water that you can buy in Hawai‘i.
A solar electric, or photovoltaic, system consists of a number of modules, an inverter to change the DC electricity that the solar cells make to AC so you can use it in your home, and wires and other equipment. If you are a MECO customer, your home might be “net energy metered,” meaning MECO will give you credit for any extra electricity your system makes. If you are not connected to the utility, you will probably need a battery bank to store the electricity for the times (such as evenings) when you want to use it.
Basically, a photovoltaic system makes electricity from sunlight and converts it to a form that you can use in your house. It will either be connected to the utility or have a storage system. It is clean, quiet, and becoming increasingly popular because the electricity it generates can be cheaper over the life of the system than today’s utility rates.
In partnership with the state’s energy office, the Maui Weekly provides this feature to help Valley Isle homeowners reduce their utility bills and increase their environmental awareness.