The ever increasing and unpredictable costs of electricity in South Africa is placingsignificant financial strain on the economy. Coupled with a global emphasis on environmental awareness, consumers must consider alternative sources of energy. Luckily, renewable energy provides the opportunity to save costs and turn the tide on globalclimate change.
A number of options are available in configuring the new‘renewables centred’energy-mix of a building. Popular choices include solar water heaters, heat pumps or gas geysers for water heating; solar photo-voltaic (PV) for electricity generation, and battery banks or generators for back-up power.To find which options are best suited to your needs, factors such as grid availability, cost of grid power, building occupation, usage patterns andenergy usage ratio need to be considered.
To get started, consumers can follow this three-step approach:
Step 1 – Reduce
Reduce the energy consumption of your facility through energy-efficient lighting and appliances. Compact fluorescent lamps (CFLs) and LED lamps provide the same amount of light, using about 80% less energy than a conventional incandescent lamp. When replacing appliances, check the energy ratings and opt for more energy efficient models.
Step 2 – Energy Switching
The most environmentally friendly and cost-effective approach when transforming your building’s energy mix is to use primary fuels for primary heating. This means using solar,heat pumps or gas for water heating, space heating and cooking.Once this step has been implemented, all that remains on grid power is high-efficiency lighting and appliances within the building. At this point the consumer would be realising significant savings in energy consumption and carbon footprint.
Step 3 – Solar PV
A solar PV system harnesses energy from the sun and converts it to electricity. The system provides electricity at the same voltage and frequency as grid-power and feeds into the existing wiring network of a building. Therefore, no additional wiring or special appliances are required.
Depending on the available space, and objectives of the consumer, the PV system can be designed to partially supplement the electricity needs of the building or to generate the full electricity requirement, taking the building “off-grid”.
In an off-grid arrangement, provisions must be made for night-time usage and rainy days. This is achieved through battery storage and/or a generator. To be effective, these need to be sized, specified and installed correctly.
A third option is to use the municipal grid to "store" the electricity. To do this, a system capable of generating excess energy during the day is required. The excess energy is fed into the municipal grid during the day and draws it back out during the night. This option relies on a favourable feed-in tariff from the municipality and the installation of a bi-directional energy meter. This measures energy supplied to-,and exported fromthe building. Municipalities set different tariffs for energy sold and energy purchased, therefore the economic viability of such an arrangement must be considered.