Renewable energy-present and future outlooks
Energy is the prime property of an object which can take one form or the other. It can neither be created nor can be destroyed. The total energy of the universe is conserved and thus everything that happens in the world is due to the flow of energy from one of its forms to another.
There are a variety of energy sources. Available. They can be divided on the basis of different measures. Broadly, the energy sources available can be divided into four types.
1. Primary energy source:
They are the sources which are not subjected to any transformation or conversion. They can be of renewable as well as of non renewable kind. The examples are coal, uranium, natural gas (non renewable) and solar energy, wind energy, biomass (renewable energy).
The energy required to obtain these fuels is much less than what they can produce by combustion hence there energy yield ratio is very high.
2. Secondary energy sources:
They are the energy sources which are transformed or converted from other primary energy sources. Though they are the demand of the economy, these may not yield net energy. Intensive agriculture is an example where in terms of energy the yield is less than the input.
3. Supplementary energy sources:
They are the energy sources whose net energy yield is zero. They need a high investment to protect them. Biogas digesters and destructive distillation of wood are the examples of this kind.
4. Intermittent energy source:
They are the sources which are not continuously available in the specific regions. This is because their availability is not in direct control and is quite unpredictable. The energy source such as tidal power comes into this category.
Today, every country draws its energy needs from a variety of sources. The other way to divide these energy sources is as commercial and noncommercial.
1. Commercial energy sources:
They are the energy sources which are being used to meet day to day energy requirements on a commercial scale. They can further be categorized as renewable (conventional) energy sources such as solar energy, wind energy and biomass and non renewable (non conventional) energy sources such as coal, petroleum and natural gas.
2. Noncommercial energy sources:
They are the energy sources which are mainly used in the rural areas for domestic purposes such as heating and cooking. The examples of this type are firewood and agricultural waste.
In an industrialized country like USA most of the energy requirements are met from commercial sources while in an industrially less developed country, the use of commercial and noncommercial sources are about equal. The use of non commercial energy sources as well as non renewable energy sources pollutes the environment. This can be overcome by the use of renewable energy sources which are pollution free when used.
Furthermore the renewable energy sources are limited on the earth and will get exhausted in the next century or so. Attempts are being made to conserve the natural energy sources and to find some alternate way to meet the energy requirements by the use of renewable energy sources.The sources of renewable energy could be
1. Solar energy:
It is the energy coming from the sun in the form of either light or heat. Both of the forms can be trapped and utilized with the help of current growing technologies. The solar power is of so much potential that it could be used for the energy requirements of whole the world or more. The problem arises with the lack of technologies to trap and store this energy. Currently the solar energy is used in the form of thermal or photovoltaic. The former is currently being used for steam and hot water production.
2. Wind energy
It uses the high wind velocity available in certain parts. Wind energy is used for pumping the water or power generation.
3. Geothermal energy
This derives the heat in the center of the earth and it is stated that the potential to the extent of 3400MW exist in new Zeeland, USA, Japan and Iceland.
4. Energy from seas
It can be utilized as wave, tide or ocean thermal energy. Japan and UK are developed in this era.
It is another renewable source of energy in the form of wood, agriculture residues etc. The agricultural residues can be burnt directly to generate steam for use in steam turbine for power generation or they can be gasified and the gas used in an internal combustion engine for agricultural pumping or power generation. Power generation is being tried on a small scale up to 1MW or so. But large scale application is yet to be shown. The main problem with agricultural residues is its collection. One way to overcome this is to grow a large no of trees.
As per the current technologies and difficulties in using the renewable energy sources, the question arises to why is it advantageous to use them as an energy source. Here is a list of some of its advantages.
1. They are easily available and are in abundance though are difficult to be utilized. Though not enough, the developing nations are capable of developing significant energy with the renewable resources at regional or national levels.
2. The use of renewable energy could help to conserve foreign exchange and generate local employment if conservation technologies are designed, manufactured, assembled and installed locally.
3. several renewable options are financially and economically competitive for certain applications such as in remote location where the cost of transmitting electrical power or transporting conventional fuels are high, or in those well endowed with biomass, hydro or geothermal sources.
4. Rapid scientific and technological advantages are expected to expand the economic range of renewable energy applications over the next decade.
Experience with renewable energy projects in the developing countries indicates that there are a number of barriers to the effective development and widespread diffusion of these systems. Among these are
1. Inadequate documentation and evaluation of past experiences, a rare set of validated field performance data and a lack of clear priorities for future work.
2. The current technologies also fail in producing enough amount of energy especially in developing countries.
3. With regard to energy planning, separate and completely uncoordinated organizations are often responsible for petroleum, electricity, coal, forestry, fuel wood, renewable resources and conservation.
4. Technical and economic uncertainties in many renewable energy systems, high economic and financial cost for some systems in comparison with conventional supply options and energy efficiency measures.
5.Inadequate donor coordination in renewable energy assistance activities, with little or no information exchange on successful and unsuccessful projects.
With the above current advantages and limitations of the projects using renewable energy sources, the future is bright though not near. Given a considerable attention by the governing bodies, the goals may be achieved earlier.