THE discovery and control of various forms of energy is one of the greatest achievements of man as energy is a strategic input necessary for socio-economic development. We want energy supply at the flick of a switch to turn on a light, fan or any utility device. In fact our way of life now depends upon instant access to energy. The demand for energy is increasing day by day.
Worldwide, 80% of all energy used by humans comes from fossil fuels (coal, oil, natural gas). Massive exploitation is leading to exhaustion of theses resources within a few decades and we all know that this growing demand is having a detrimental effect on the environment. A lot of discussions have already been made about the present energy crisis as well as the environmental impact of increased energy use leading to 'climate change'. Therefore scientists all over the world are trying to tap the sources of energy that are inexhaustible, cheap, absolutely pollution free or green and specially suited to isolated places where extension of grid system is expensive and sometimes impossible.
After the OPEC oil embargo in 1973, interest in alternative fuels, mainly renewable energy sources, has increased rapidly. At present, environmental impact is the major driving factor influencing the growth of renewable or green energy generation. As a part of the Kyoto Protocol, both the EU and UK are supposed to reduce carbon dioxide emissions to 12.5 % of 1990 levels by 2010. Now the question is, how is this going to be achieved?
One of the important initiatives to reduce CO2 emissions includes replacement of fossil fuel base with renewable energy sources. Therefore, governments of most of the countries are trying to actively support renewable energy based embedded generation (EG) system. A recent study conducted by Ofgem (the office of gas and electricity markets) shows that in UK the capacity of the renewable Small-Scale Embedded Generation (SSEG) could reach as much as 8 GW by 2015. Similarly, Danish Government has been continuously encouraging onshore and offshore wind farms. In the summer of 2002, Elsam constructed the world's largest offshore wind farm Horns Rev (total output 160 MW; Vestas V80 - 2MW Wind Turbines) at the Danish west coast. They have planned for wind turbines with a total capacity of 4000 MW in Danish waters before 2030. Similarly, other renewable energy sources i.e. hydro, solar, biomass, tidal, wave etc are also well supported by the governments.
Now let us see our own energy situation. At present total installed capacity of Bangladesh is around 5000 MW and peak hour generation remains around 3600 MW. But the demand for electricity is always much above our generation. As a result we are suffering from a huge load shedding which is considered as the main obstruction to our development. Again, our electricity generation is mostly natural gas based which has made this sector very much insecured -- 95% of our electricity comes from conventional thermal power plants (85% natural gas, 4.0% coal 5.1% furnace oil and 0.9% diesel) and the remaining 5% from hydroelectric projects. The reserves of these fossil fuels will get exhausted within few decades. This condition will get worse if we could not find alternatives.
Time has come for us to be more serious about renewable energy sources as we are the biggest victim of climate change. We, however, have come to know that the government will go for installation of a 100-200 MW offshore wind-based independent power plant (IPP) in the Bay of Bengal. No doubt, it is a highly appreciable attempt but not enough. We need more and more solar, onshore/offshore wind, biomass, micro hydro based embedded generation. To do so we must have a very good renewable energy policy and plan as we have limited resources.
The term Embedded Generation (EG) or Distributed Generation (DG) is used to reflect the idea that the generation is embedded in the distribution network, while 'Distribution Network' is defined as that to which customers are connected directly and which has a typical voltage rage from 230/400 V to 145 kV. Main attributes of EG include -- generation is not centrally planned and despatched, it is normally smaller than 100 MW and connected to the distribution network. Connection to the network is one of the biggest challenge for the growth of the renewable energy based DG. Modern power systems were designed to deal with unidirectional power flows from the higher to the lower voltage levels (large central generation to transmission network to distribution network to consumers). However, with significant levels of embedded generation (say, renewable energy generators) distribution network is no longer a passive circuit supplying loads as the power flows may become reversed.
Therefore, approaches have been changed in many countries in order to ensure that the embedded generation does not reduce the quality of supply offered to the customers. Again if the potential benefits of using green energy are to be realized, the development of renewable energy must be escorted by a phased decommissioning of large centralized fossil fuel plant without hampering the security of supply to customers. Therefore, in order to accommodate significant level of DGs distribution networks need to become active with real time controllers.
Another challenge for the growth of DG is insufficient financial incentives. Per kW installation cost could be several times of the conventional power generation. As we have no other choice than to support our renewable energy sector, we have to develop a fund. In the recent Copenhagen Summit Bangladesh delegation demanded allocation from any climate change adaptation fund, which must be ensured. In parallel we have to develop our own climate change fund. We can gather experience from examples. In 1990 UK government set up Non-Fossil Fuel Obligation (NFFO) to force electricity suppliers to purchase a minimum amount of energy from renewable at a premium price. They also introduced Climate Change Levy in 2001 at the rate of 0.43p/kWh on business. Levy funds were to be used to support renewable. Again in 2002 UK government launched 'Renewable Obligation', requiring electricity suppliers in England and Wales to source some of their electricity from renewable. This obligation on DNOs (Distribution Network Operators) has created a whole new market in 'ROCS' (Renewable Obligation Certificates) sector.
Again, before developing any renewable energy based DG project, there must be good environmental audits to ensure minimum negative impact on the environment. Environmental Impact Assessment (EIA) is a rigorous, lengthy and comprehensive process requiring experts in the fields of ecology, landscape, noise, aviation, archaeology, transportation and construction. We have to ensure that the renewable energy project will not create any ecological problem. Finally we want that the government must develop a very good renewable energy policy to overcome the entire technical, economical and environmental barrier towards the growth of green energy sector.
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