Introduction

Solar energy is used to power equipment such as watches, calculators, cookers, water heaters, lighting, water pumping, communication, transportation, power generation, and many more. Solar energy, like all other renewable energies, is very safe and environmentally friendly. There are no emissions as the source of fuel is the sun, unlike coal-powered stations.

Most areas in South Africa average more than 2 500 hours of sunshine per year, and average solar-radiation levels range between 4.5 and 6.5kWh/m2 in one day.

The southern African region, and in fact the whole of Africa, has sunshine all year round. The annual 24-hour global solar radiation average is about 220 W/m2 for South Africa, compared with about 150 W/m2 for parts of the USA, and about 100 W/m2 for Europe and the United Kingdom. This makes South Africa's local resource one of the highest in the world.

The use of solar energy is the most readily accessible resource in South Africa. It lends itself to a number of potential uses and the country's solar-equipment industry is developing. Annual photovoltaic (PV) panel-assembly capacity totals 5MW, and a number of companies in South Africa manufacture solar water-heaters.

The White Paper on Energy Policy (1998) [PDF, 592KB] identifies universal access to electricity as one of the primary goals of South Africa's energy policy. To achieve this goal, it was decided to integrate non-grid technologies into the Integrated National Energy Planning (INEP) as complementary supply-technologies to grid extension.

A pilot programme has been launched to establish a limited number of public-private sector institutions in conjunction with the relevant municipalities to provide electricity services on an integrated basis. The service-provider will own and maintain the systems, allowing longer-term financing to ameliorate monthly payments. It will provide the service against a monthly fee.

Once the underlying managerial and funding issues have been resolved, the process will be expanded to cover all rural areas. Solar power is increasingly being used for water-pumping through the rural water-provision and sanitation programme of the Department of Water Affairs and Forestry.

Solar water-heating is used to a certain extent. Current installed capacity installed domestic 330 000 m2 and swimming pools 327 000 m² (middle- to high-income), commerce and industry 45 000 m² and agriculture 4 000 m2.

Three co-operatives with more than 10 permanent employees each have been started in the Eastern Cape to maintain 8 000 solar home systems installed under the previous electrification programme.

Solar-passive building design

Houses and buildings in South Africa are seldom designed from an energy consumption or energy-efficiency perspective. The energy characteristics of low-cost housing are particularly poor, resulting in high levels of energy consumption for space heating in winter. The net result is dangerously high levels of indoor and outdoor air pollution in townships, due mainly to coal burning.

Research has shown that low-cost housing could be rendered 'energy smart' through the utilisation of elementary solar-passive building design practice. This can result in fuel savings of as much as 65%. Such savings on energy expenditure will have a major beneficial impact on the household costs.

Energy-efficient homes may be constructed at the same direct cost (and lower life-cycle cost) as energy-wasteful houses. The challenge is to develop awareness and to ensure implementation of basic energy-efficiency principles.

Stirling dish demonstration project

This system consists of a mirror collector that follows the sun during the day and a Stirling engine mounted at the focal point of the mirror collector. As the collector follows the sun, the working gas inside the engine is heated, which is converted to mechanical energy and drives a generator to generate electricity. Eskom's Research, Development and Demonstration Division Project is assessing the technical and economic feasibility of this new technology.

To achieve these objectives, a 25kW unit was installed at the Development Bank of Southern Africa in Midrand, Johannesburg, in 2002.

National solar water-heating programme

Water-heating accounts for a third to half of the energy consumption in the average household. In South Africa, this derives mainly from electricity, being the most common energy-carrier employed. Removing this expenditure could lead to significant improvements in the disposable incomes of the lower-income sector.

The equivalent of a large coal-fired power station (2 000MW+) is used to provide hot water on tap to the domestic sector alone. Since the inception of the accelerated domestic electrification programme through grid extension, a major distortion of the national load curve has emerged, with the early evening load peak growing significantly.

Modelling indicates that the introduction of solar water-heating can ameliorate the situation substantially.

Switching from electrical to solar water-heating can, therefore, have significant economic and environmental benefits.

There are economic benefits for home owners in reducing their energy bills. Expensive generation capacity to address load peaks will be obviated, and the introduction of new base-load capacity will be postponed. Benefits for the country include reducing greenhouse gas (GHG) emissions, and the release of scarce capital for other pressing needs.

A roll-out programme of solar heaters has commenced, with the focus on middle- to high-income households in Gauteng, the Western Cape and KwaZulu-Natal. The initiative is spearheaded by the Central Energy Fund (CEF).

The DME is investigating the use of solar water heaters as part of the government's plan to increase the use of renewable energy within the current generation mix, and Eskom's Demand Side Management (DSM) - the process whereby an electricity supplier influences the way electricity is used by customers - strategy.

Solar water heaters have many benefits both for the customer and for South Africa. The customer benefits by having a reduced electricity bill and the country benefits because less power has to be generated by Eskom and so less pollution is generated.

A solar water heater normally has a panel with a tank mounted on the roof and sometimes an element too, ensuring that hot water is available whenever needed. Solar water heaters can be used both at residential and commercial/industrial buildings.

The DME has embarked on a project run by the CEF to:

• Produce national standards for solar water heaters;
• Write a code of practice;
• Market awareness to determine savings when using a solar water heater;
• Buy a test rig to allow the South African Bureau of Standards (SABS) to certify the systems; and
• Determine models for financial aid in helping this industry in South Africa.

To date, the South African National Standards (SANS) are now available (SANS 1307) and the code of practise has been finalised at SABS (SANS 10106). The project will see in total 500 SABS certified systems installed in Cape Town, Durban and Johannesburg. The systems will be monitored for one year and thereafter the DME will determine which financial aid model to adopt.

Solar water heating by-laws

The City of Cape Town is busy drafting of by-laws to support the drive for solar water heating. According to these by-laws, the City will enforce the installation of these solar heaters to all newly built houses to help manage peak demand on the national Eskom grid. The by-law should be enforced later in 2006.