The thought of going green and installing solar panels on your roof is exciting for most of us, but do you really understand how solar works? Hopefully this page will give you a better understanding of the ins and outs of solar energy.
How it works
Photovoltaic (PV) or solar cells convert sunlight into electricity. When light strikes the semiconductor material of a solar cell, it releases electrons that generate electric current.
A solar panel or PV panel is a frame with several connected solar cells. The more solar panels are connected together, the more electricity is produced.
Solar panels produce direct current (DC), not alternating current (AC) electricity. We connect the solar panels to an inverter, which changes the current from DC to AC electricity.
This clean electricity from the sun can replace power from the national grid or a generator and eliminates all the harm of power from fossil fuels.
What you need to know
The grid is the electricity supplied nationally by Municipalities in South Africa and by various utility companies elsewhere.
A kilowatt (kW) equals 1 000 watt (W) and is a unit of power.
A kilowatt hour (kWh) is a unit of energy. It is not the number of kW used per hour – it is the amount of energy used to keep a 1 000 W appliance running for an hour. For example, a 100 W light bulb would use 1 kWh in 10 hours; a 2 000 W appliance would use 1 kWh in half an hour; a 50 W item would use 1 kWh in 20 hours.
Renewable energy comes from sources that cannot run out (such as the sun) or can be easily replaced (such as new vegetation being planted). Renewable energy is carbon neutral and does not produce carbon compounds and greenhouse gases when consumed. Renewable energy therefore does not pollute the environment: it causes no air, land or water pollution.
A grid-interactive PV system is still connected to the national grid, although it draws clean energy from solar panels. This system can feed clean energy directly into the grid, lowering your dependence on the grid and decreasing your electricity bill. It also charges solar batteries for use during power failures.
Deep-cycle batteries store energy from the sun for use when the sun is not shining. They are called “deep cycle” because they can survive long periods of being repeatedly and deeply discharged to almost their entire capacity.