Renewable Energy
Are solar cells new technology?
Modern solar cells were invented in the early 1950s and were used to power satellites. In the 1970s, they were used for remote telecommunications and navigational aids. In the 1980s, they were used for roadside emergency telephones and traffic signs. Now in the 21st century, they help power your home.
Are solar electric systems good for the environment?
Energy created through the SunPower system produces no pollutants. By offsetting peak electricity demand, SunPower systems reduce the need for coal-fired power plants. Over a thirty-year period, a 2.3 kWp system typically offsets the same amount of greenhouse gases as close to 30 acres of trees.
What are solar cells and solar panels?
A solar, or photovoltaic (PV), cell is the smallest element of a system that converts sunlight into electricity. Each cell is made of silicon, which is the same material found in computer chips. Silicon in photovoltaic cells is treated so that it generates a flow of electricity whenever it is exposed to light. A series of solar cells are wired and manufactured together to form solar panels.
Can the system produce enough energy to meet all of my electricity needs?
Not usually, but solar electric systems do not need to provide all of a home’s electricity to be of significant value to homeowners. Cutting electricity usage by 40 to 60 percent is typically the most cost-effective approach for home solar power.
What is a kilowatt-hour (kWh)? How many kWh does my home consume?
A kilowatt-hour is a measure of electricity. It is the amount of power (kilowatts) used over a period of time (hours). A 60-watt light bulb that is illuminated for one hour uses 60 watt-hours of electricity, or .060 kilowatt-hours. If it is illuminated for a half-hour, the bulb will consume .030 kWh of electricity, or half as much. The average home consumes about 20 kilowatt-hours of electricity per day, or 600 kWh per month.
Here’s an example of how Net Metering works:
On a particular day in Perth, depending on weather conditions and time of year, a 3kW SunPower solar system may generate 15 kilowatt hours. If your home uses 11 kilowatt-hours during this time, 4 kilowatt-hours are sent back into the grid. At night the solar system is off and does not generate power. And if at night your home uses 10 kilowatt-hours, all of that power is supplied by the utility. The utility will charge you only for the net amount purchased—that is, the amount the home received from the utility minus what it delivered to the utility. Using the example above, this would be:
| Solar System energy generated | 15 kWh |
| Day time energy used | -11 kWh |
| Total sold during the day | 4 kWh |
| Night time energy used | -10 kWh |
| Net amount billed for 24 hrs | 6 kWh |
Your utility will calculate these net charges on a monthly basis, charging you for the difference between what they have delivered to you and what you have delivered to them in the month.
