|
|
|
|
Photovoltaic systems
For many homes, a photovoltaic or solar electric system is a way of generating electricity for use in your home and reducing or even eliminating your reliance on the electricity network.
A household photovoltaic (PV) system consists of solar panels mounted on the roof that produce DC electricity. This electricity is then converted into AC electricity for use in your home by means of an inverter, which is part of the system package.
If your home is “off the grid” you can store electricity in a battery bank for use at night or when the sun is not shining. If you are “on the grid” then you don’t need a battery bank – you simply use the grid as a battery bank when you require electricity. You can also export any electricity that you are generating from your PV system but not using at the time (say you are away at work on a sunny day) back into the local network. Some electricity retailers will pay you for this exported electricity. Rates of purchase vary from just a few cents per kWh to the full retail price. Contact Energy is a retailer that pays the full retail price for surplus electricity exported into the local network by owners of small PV systems.
PV systems are still quite expensive in New Zealand. As a rule of thumb, a quality grid-connected home PV system presently costs about $20 per watt installed. Thus, a 2 kW system will cost about $40,000 (say the cost of a new SUV). A 2 kW system will provide an energy efficient home with a solar water heater and energy efficient appliances with enough electricity to supply its needs for most or all of the time. However, prices for PV systems are set to decline in New Zealand as more suppliers enter the market with innovative system packages.
Although PV systems may not yet be generally cost effective for homes already connected to the local network, the story is different for homes in more remote areas. If your house is presently off the grid, or you are planning to a build a house that is not presently connected to the grid, then a PV system could be a very good investment at this time. This is because a PV system avoids the cost of connecting a property to the grid, which can be between $18,000 and $24,000 per kilometre. Given this investment, it becomes cost effective to consider using PV panels for homes, farms or lodges in remote areas more than a kilometre or so from the closest point on the network.
If you are interested in learning more about PV systems, EECA has put out an excellent fact sheet:
http://www.eeca.govt.nz/renewable-energy/solar/solar-electricity.html
|
|
|
|