26 Alternative technology
Going‘ green’— solar water heaters are best option
For those who care about climate change or about the future of this planet from an environmental perspective, solar water heaters are simply the best option for saving carbons.
By
James Green
This is not an argument as to whether climate change is happening— it is. It is also not a debate about whether carbon emissions are the contributing factor to the world heating up— whether it is in the oceans or in the highest temperatures ever recorded worldwide in July 2016.
South Africa’ s reliance on coal and cheap electricity, combined with a lack of alternatives from gas or hydroelectricity, has resulted in the heating of water being done by electricity. Whether it is lower income households using kettles and hot plates, or middle and upper income households using electric geysers( approximately seven million of them), with the addition of commercial water heating, up to 25 % of Eskom’ s power is used for heating. Depending on the formulas used, approximately 1kg of carbon is emitted for every kilowatt-hour used in heating water.
Solar water heating can, in theory, replace close to 100 % of the electricity used in heating water and save the equivalent in carbon emissions.
In contrast, alternative heating technologies of heat pumps save, theoretically, 65 % on electricity— most don’ t, by definition, save less. Gas boilers or oil heating boilers emit less harmful emissions than coal, but still not as much as solar water heaters. Solar PV for heating water is not an economically viable option, but in theory, it could save 100 % of carbon emissions.
Utility scale renewables such as commercial solar PV farms and concentrated solar thermal( CSP) wind farms are clean energy, but are basically additional energy rather than the substitution of coal. Bioenergy is currently very small in South Africa, but again, burning gas emits carbons. In comparison with end user renewables( solar water heaters and solar PV), they are all less efficient per kilowatt-hour in that REIPPPs( Renewable Energy Independent Power Producer Procurement) suffer transmission losses.
When the financial argument is brought into the carbon equation, solar water heaters again are the cheapest solution per kilowatt-hour saved. PA
James Green is the CEO of Ubersolar and Pay As You Go Solar.
February 2017 Volume 22 I Number 12 www. plumbingafrica. co. za