Introduction to renewables


Renewable energy use is not an invention of the 20th or 21st century. In fact, wind and water have been used to produce mechanical energy through mills, while the sun was used to dry food, for centuries.

The sun is the most abundant and reliable source of energy supplying the earth and strictly speaking indirectly responsible for wind, wave, biomass and hydro resources as well. Renewable energy resource base consists mainly of solar, wind, hydro and biomass energy with other minor resources being tidal, wave and ocean thermal energy conversion. South Africa is in the fortunate position that it has a high level of renewable energy sources, especially solar when compared to European countries.

Unlike the nature of traditional fossil fuel generation plants, the wind and the sun only provide power when the energy source is available, apart from other forms of renewable energy, such as biomass, pumped hydropower and geothermal.

For that reason smart decision making for the use of renewable sources would be needed such as the more recent study by the Centre of Scientific and Industrial Research (CSIR) that reinforced earlier studies that a low-cost and resilient power generation system can be achieved by using a high share of renewable based energy [Forder, 2016]. Give the countries climatic conditions a complementary generation profile for solar and wind would be needed, since the solar PhotoVoltaic (PV) supply peaks at mid-day and the wind supply generally peaks in the evening, along with the use of bio-energy, these sources can be complementary to one another. This would off course only be achievable with the right geographical distribution of solar and wind generation plants, the right use of bio-energy technologies, along with the installation of storage and flexible peaking plants to power up at short notice when the need arises [Gauchè et al., 2015].

The depletion of fossil oil reserves on a global scale, constant uncertainties as far as price is concerned, unsecured supplies and environmental pollution, are amongst the many global energy problems, when the use of fossil fuels are considered [Peres et al, 2013], which helps with the business case for cleaner technology sources and is clearly illustrated through the deployment of renewable energy sources exceeding the net new capacity of fossil fuel generation plants [REN21, 2017].

Several other distinct, modern applications of re­newable energy are gaining importance and yet, due to their stand-alone nature, do not necessar­ily appear in energy statistics. These are desalina­tion, heat pumps, water pumps and communica­tion towers powered by renewable sources.

Figure: Cumulative renewable power generation capacity

Assumptions:

Energy Demand Forecast: A 1,5% annual increase from 2018

IPP: Successful commissioning of first 3 rounds of the REIPPPP

IPP: Successful implementation of a 5th REIPPPP round

Continuous growth of 3.5% per annum for solar thermal

Conservative growth of 3.6GW for embedded generation (rooftop PV) for 2035 based on baseline study

Coal fired plants: Decommissioning of plants according to Eskom’s projections

References

Forder, S. (2016) ‘There are grounds for optimism about South Africa’s energy future – 2050’. Paper developed for WWF Internal Strategy Process. (Unpublished).

Gauchè, P., Rudman, C. & Silinga, C. (2015) ‘Feasibility of the WWF Renewable Energy Vision 2030 – South Africa: A spatial-temporal analysis, A WWF Technical Report’.

Peres, A.P.G., Lunelli, B.H., Fllho, R.M. (2013) ‘Application of Biomass to Hydrogen and Syngas production’, The Italian Association of Chemical Engineering

Renewable Energy Policy Network for the 21st century (2017) ‘Advancing the Global Renewable Energy Transition’.