In the present scenario of world's depleting energy pool, green technologies are getting more and more attention the world over.

Depleting reserves of fossil fuels and environmental concerns associated with them and nuclear power are beginning to drive the energy sector worldwide to strive towards development of renewable energy sources. Renewable energy sources (including biomass, solar, wind, geothermal, and hydropower) that use indigenous resources have the potential to provide energy services with zero or almost no emissions of both air pollutants and greenhouse gases. They have been acknowledged as a vital source of plentiful energy that can meet entire world's demand.

Renewable energy sector at present is meeting 13.5 per cent of global energy demand. This sector is growing faster than the growth in overall energy market. Some long-term scenarios postulate a rapidly increasing share of renewable technologies.

Under these circumstances, renewable energy could reach up to 50 per cent of the total share of mid-twenty-first century with appropriate policies and new technology developments.

Renewable energy sources have enormous potential and can meet many times the country's present energy demand as Pakistan has a lot of valuable energy resources. These resources have the potential to enhance diversity in energy supply markets, secure long-term sustainable energy supplies and reduce local as well as global atmospheric emissions. They can also provide commercially attractive options to meet specific needs for energy services (particularly in rural areas), create employment opportunities and offer potential for local manufacturing of equipment.

The three provinces NWFP, Balochistan and Sindh provide vast untapped resources for hydropower, wind and solar energy. The geographical location, topography and local climate favour the exploitation of these resources. Besides renewable resources, green technologies particularly use of biofuels have opened a new horizon in energy sector.

We are agriculture-based country with arable land and water as principal natural resources. Agriculture with livestock as its sub-sector accounts for about 23 per cent of country's GDP. This share can possibly be increased with recycling of both animal and crop wastes for energy production.

Biogas production is increasing rapidly all over the world because fuel costs have been rising steadily for a number of years. Attempts are now being made to improve the use of renewable energy sources.

The production is also possible in small scale sites, obviating the need to supply energy to outlying areas. Even a very basic construction using mostly used materials will produce gas if a few simple design rules are followed.

Biomass (raw material for biofuel production) is material derived from living organisms. This includes plants, animals and their by-products. For example, manure, garden waste and crop residues are all sources of biomass. It is a renewable energy source based on carbon cycle, unlike other natural resources such as petroleum, coal and nuclear fuels.

Agricultural products specifically grown for biofuel production include corn and soybeans, primarily in the United States, rapeseed, wheat and sugar-beet in Europe, sugarcane in Brazil, palm oil in South-East Asia and Jatropha in Pakistan, India and Bangladesh.

Biodegradable outputs from livestock, industry, agriculture, forestry and households can be used for biofuel production, either using anaerobic digestion to produce biogas or using second generation biofuel processes; examples include straw, timber, animal manure, rice husks, sewage and food waste. The use of biomass fuels can therefore contribute to waste management as well as fuel security and help prevent climate changes.

Using a biological treatment process called anaerobic digestion, biogas can be produced as a by-product.Biogas typically contains between 60 and 70 per cent of methane gas. This high methane content makes biogas an excellent source of renewable energy to replace natural gas and other fossil fuels.

Biogas is typically used in factory boilers and in engine generator sets to produce electricity and heat. If internal combustion engines are fuelled with biogas to produce electricity, the facility can use the electricity or export it to power grid.

Gober gas is a biogas generated out of animal dung. The gas plant is basically an airtight circular pit made of concrete with a pipe connection. The manure is directed to the pit (usually directed from the animal shed). The pit is then filled with a required quantity of water (usually waste water). The gas pipe is connected to kitchen fire place through control valves. The flammable methane gas generated out of this is practically odorless and smokeless. The residue left after the extraction of gas is used as bio-fertiliser. Owing to its simplicity in implementation and use of cheap raw materials in villages, it is often quoted as one of the most environmentally sound energy source for rural needs.

Recycling of both animal and agricultural wastes for energy production is gaining more and more attention all over the world. All the developed nations are now focusing on these resources as they are environment-friendly and have more public acceptance. Further these resources are cost effective and their implementation in almost all energy driven fields is easy.

Developing countries like that of ours should adopt these resources on promptly.There is a dire need to initiate collaboration with other countries for feedback of such techniques. The government should take initiative by bringing together the local educational institutions, the scientific community, private industry and international institutions dealing with biofuel production.