Renewable energy for the 21st century

Dr. Kshirode C Roy

Per capita consumption of electricity is an indicator of quality of life. In this regard, Bangladesh is one of the poorest country of the world. Present per capita consumption of energy is only 85 kWh/yr whereas that of USA is 12,711 kWh/yr. Twenty-first century is the century of great expectation for the mankind. People are eager to see what technological advancement takes place in this century. Based on the past experience it can be said that technological advancement in all the fields will take place in a geometrical progression in the coming years. And it will also be true for the renewable energy (RE).Solar, wind, bio gas, biomass, hydro and tidal energy are called renewable energy. Its supply is not exhausted like commercial energy, that is, coal, gas and fossil fuel. RE does not create any environmental hazards and the most important RE, the solar energy is more or less evenly distributed. Today's worldwide problem of environmental pollution can largely be attributed to the widespread use of commercial energy. On the other hand, as RE is a clean, environment friendly energy, its use would reduce carbon di oxide emission significantly, which will, in turn, reduce the greenhouse gas emissions.In developed countries, electricity is available to almost all the people. Yet government is spending a huge amount of money to develop RE so that its price can be reduced to compete with the commercial energy. In future, the supply of fossil fuel, coal and natural gas may be exhausted. Therefore, scientists are trying to develop clean and environment friendly RE.At present, the installed electricity generation capacity of all the plants of Bangladesh is 3603 MW though the maximum production is about 2200 MW. Only 15 per cent people have access to electricity. It has been estimated that the investment cost for one kilometre of rural electric distribution line is, on an average, Tk five lakhs. Low consumer density makes it quite uneconomical to extend electricity in rural areas. RE can be ideal for this situation. Also it will be appropriate for small islands and coastal areas because extending national grid lines in those areas will be uneconomical.Being a tropical country, Bangladesh is endowed with abandoned supply of solar energy one of the most important renewable energy. Annually about 1.9 MWh energy is received per square metre of horizontal area in Bangladesh. Even during the monsoon season when sky is almost always cloudy, the incidence of solar radiation is as good as the annual average.Bangladesh has about one hundred seventy kilometres coastal area where wind speed is sufficient for wind turbines from February to September. So is true for hilly areas. The demand for electricity is higher during this period. Therefore, wind turbines may be installed to augment the power generation capacity during the summer and rainy seasons. Also the intensity of solar radiation is more during this time. If solar thermal power station could be installed, that would also increase the power generation capacity.Bio gas technology can fulfill the demand of energy of rural as well as urban areas to a great extent. More than two thousand bio gas plants have been set up country wide and the installations of new plants are in progress. Night soil based bio gas plants have been set up at Muslim Mission, Faridpur and at Ganaktuli slum in Dhaka City. Both of them are working well. Successful operation of these two plants has inspired to construct more such plants in other areas.Though RE is very attractive apparently and technology is available, it has not become popular yet. Present cost of photovoltaic (PV) cell is expensive which is the main reason for its low acceptance. But with the advancement of technology, its price has decreased remarkably in the recent past. For example, in 1983 the electricity cost of solar thermal power stations was US $ 0.54/kWh, which was reduced to $ 0.12 to 0.14/kWh in 1997. This cost will continue to reduce further in future.In Bangladesh, a few NGOs and private entrepreneurs have ventured to popularise the solar PV cell technology. It is claimed that even with present price, the cost of electricity is competitive with commercial energy and the pay back period for the initial investment is 5-7 years. If appropriate measures were taken to create awareness among the people of rural areas, especially in char areas, coastal areas, islands and hill tracts, PV technology would have been popular, as installation of transmission line is very expensive and difficult in those areas.At present, pricing of conventional energy (e.g. electricity) is done based on direct and indirect subsidies. Also the cost of environmental hazards is not considered properly. If the subsidies were withdrawn and the environmental cost were considered, the cost of RE would have edge over the commercial energy by now.Worldwide wind power installation is 8000 MW. Forecasts for Europe alone for 2010 is 20,000 MW and for 2030 is 100,000 MW. As wind velocity is not sufficient all the year round, wind-solar-diesel hybrid plant would be most appropriate for the generation of electricity.World production of commercial energy may be exhausted in future, but supply of RE is almost constant. With the advancement of technology, RE has become cheaper and will continue to be so in future. Government should formulate policy to popularize the RE so that per capita consumption of electricity would increase which will in turn raise the quality of life.

Source: The Observer, 23 February 2000

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