Solar systems still connected to the grid - grid-tied and hybrid systems were explained in the previous article. We also shared the curves of actual energy output during different weather conditions. You don’t need to have an in-depth understanding of how solar panels work. But, with technology changing so fast, it’s worth knowing the basics.
Photovoltaics (PV) directly convert solar energy into electricity. When certain materials are exposed to light, they absorb photons and release free electrons.
Solar irradiance tells us how much energy can be obtained from the sun per area. In SA, there are better levels in the West (Northern Cape) which decrease toward the East Coast.
A rough guide for installing PV panels is 10 m2 for every 1 kW of power required.
North-facing roofs are ideal in South Africa and if you can have a tilt of 25-30 degrees, that would be even better. Northeast and Northwest facing panels will also work.
On a grid-tied system, the solar energy generated during the day can only be used during that period. If you look at Figure 2, the green line and area under the curve represent the energy generated from the panels. The red line and area show the load of a domestic user for an average day.
Energy demand represented by the red area from 17:00 onwards cannot be sourced from the sun and will have to come from the municipality. To optimize the solar energy, some activities using washing machines, geyser/heat pumps, and hair dryers, could be used between 06:00 and 08:00 to improve the overlay of the energy load profile (red) and the power generated (green).
Are you still on board for solar? Cost estimates in our final post in this section give you an indication of what budget you might need. But don’t worry, we explain a few financing options too.
Ready to invest in a power or water saving solution for your home? If you’re an SA Home Loans client, we'll help you finance it through your home loan.
Our full guide to SUSTAINABLE ENERGY & WATER is available for you to download, absolutely free
Cost estimates provided in the Sustainable Living in South Africa series of articles are approximate and valid at the time of publication.