Solar Energy

Solar energy in Southern Africa

In Africa today fossil fuels are still very much being used. Fossil fuels are oil, natural gas, and coal. Fossil fuels are the remains of plant and animals buried below the earth’s surface. When these plants and animals were alive and growing, they absorbed the energy of the sunlight, and they have retained it as chemical storage. Unfortunately, energy from fossils is now depleting. Fossil fuels also produce carbon-dioxide. When this gas builds up in the atmosphere, it can cause ‘greenhouse effect’. Carbon-dioxide allows sunlight to warm the earth but prevents heat from escaping back into space. The greenhouse effect raises temperatures on earth. This causes polar ice caps to melt, causing floods, droughts and other climatic changes. As fossils become scarce, their prices go up, and poor people around the world find it difficult to get access to them. This is the reason why there is a search for alternative forms of energy which are sustainable. They are called ‘renewable energy’ forms.

The sun is the source of all forms of energy which is radiated in form of light and heat energy. Heat from the sun causes moisture to rise into the atmosphere. The moisture turns into rain that provides water for the fields and forests. Water and air that falls as acid rains polluting lakes and rivers cause skin irritation and cancer. It is estimated that Africa experiences, on average, 15 hours of sunshine each day, in a year  with about 300 days are days of sunshine. This is because most African countries are close to the equator and the tropics. The sun’s rays can be harnessed to effectively supply energy. In traditional societies Africans trap and store heat energy by placing the containers of water in sunlight, the heat energy is absorbed in the water and its temperature rises. The warm water is then used to infuse herbs for medical purposes.

Advantages of solar energy

Solar energy has the following advantages:

  • Clean and non-polluting
  • It is safe
  • Does not depend on a large energy network
  • Can be used in conjunction with other systems like wind power and hydrogen.
  • Sunlight is the only energy source used
  • Renewable, endless supplies that do not belong to anyone

 

Disadvantages of solar energy

  • Cannot be used as the only system on cloudy days.
  • Electricity generated from solar systems cannot be produced in large quantities.
  • Solar energy has to be stored in batteries, hydrogen, water and other matter.
  • The initial investment for the electricity produced from solar energy is relatively high.

Solar Energy in Zimbabwe 

Solar energy is free and abundant in Zimbabwe and can be harnessed to provide sustainable energy sources to meet part of the energy requirements for the growing population of Zimbabwe, the majority of who are in the rural areas and may not have access to conventional sources of energy in the foreseeable future.


Solar Applications 

Solar power can be used for the following applications:
•    Lighting, TV and Radio. 
•    Refrigeration 
•    Solar water pumping 
•    Telecommunications 
•    Traffics Signs 
•    Small – scale industrial applications

Free and renewable source of energy 

Solar energy is free and abundant in Zimbabwe, with an average radiation of 2,100 kWh/m2/year and 3,000 hours of sunshine per year. It is renewable as long as the sun exists. Solar energy is environmentally friendly and a clean source of energy. It does not pollute the environment like fossil energy. The electricity produced from solar energy is clean and the electricity generation process does not produce hazardous substances such as smoke and other dangerous gases.  

Solar power is the conversion of sunlight into electricity, either directly using photovoltaic (PV), or indirectly using concentrated solar power. Concentrated solar power systems use lenses or mirrors and tracking systems to focus on a large area of sunlight into a small beam. Photovoltaic convert light into electric current using the photoelectric effect. Solar are relatively inexpensive source of electrical energy where grid power is inconvenient, unreasonably expensive to connect, or simply unavailable.

Solar energy use in Zimbabwe

The country’s solar energy potential of 16–20 MJ/m2/day is greatly under exploited (Zimbabwe Energy Policy). At 3,000 hours a year, this can produce 10,000 GWh of electrical energy per year. Donor-funded solar PV (photovoltaic) installations have been installed in many homes, businesses, schools and health centres since the launch of the Global Environment Fund initiative in the early 1990s. In addition to the Rural Electrification Agency, there are a lot of small and medium enterprises now involved in importing and installing these systems.

Solar lanterns have a great potential in improving lighting for rural households and institutions; prices range from US$10 to US$25, depending on their size. With local assembly, these prices can be reduced even further. Solar water heating for urban households and businesses could save significant amounts of fossil-fuel electricity. Its potential is greatly under-exploited because, so far, only a few private-sector businesses are in the market. It is estimated that there are 250,000 to 300,000 geysers in households. If all these are retrofitted with solar collectors, the saving in peak demand could be as much as 350MW to 500MW (Zimbabwe Energy Policy). Industries could also save a lot of power by using solar for pre-heating water.

The major challenge with solar is the high up-front cost, which many users cannot afford. Several innovative solutions for subsidizing access costs have been used elsewhere and can be tried here. Penalties for energy inefficiency can assist in funding subsidies for a solar geyser roll-out programme.