In recent years, biogas has attracted considerable attention as a promising approach to rural development. Prior to it, developed and developing countries and several international organizations have been showing interest in biogas with respect to several other objectives like a promising renewable energy source, biofertilizer, waste recycling, public health and hygiene, pollution control and environmental management.

Basically biogas is a fuel produced through anaerobic fermentation of agricultural and animal waste in digester at a temperature of 35-40 degree centigrade. It is a mixture of methane, carbon dioxide, hydrogen sulfide and other trace gases. Alike any other combustible gas, it can be burnt in stoves, lamps and motors, or used to produce electric power or pump water.

Biogas is a cheap source of energy because it is manufactured from natural products like animal dung and human waste. In countries, such as China, India and Nepal, biogas is used widely as a source of energy. A biogas digester offers many benefits: it provides a good form of sanitation, it generates a useful fuel product and it produces a regular supply of nitrogen-enriched fertilizer for farms.

A simple biogas plant consists of an air tight compartment called digester, a gas holder, a gas distribution system and a mixer. A digester can be constructed with variety of materials such as bricks, concrete, fibre glass, steel etc. Size of the digester depends upon quantity of input substrate (feedstock and water).

A two-cubic meter digester normally produces 1000 liters of biogas per day. Gas production, however, depends upon digester temperature, fermentation or retention time, controlled pH (acidification) and the feedstock material.

Biogas is an economical and environmental friendly way of disposing off the municipal waste that is collected in tonnes every day in our cities. It is estimated that one cubic meter of biogas generates 5500 kcal of energy, corresponding to the thermal power of 0.6 liters of diesel fuel.

In our remote areas, where people are economically or geographically disadvantaged to get electricity or fossil fuels for cooking and lighting, biogas seems to be the most logical source of cheap energy. There is quite potential of using biogas as rural energy throughout the country by network of community-based biogas generation plants.

Pakistan, being an agriculture-based country, breeds sufficient live stock to produce enough animal waste for the production of biogas. Currently all such animal waste is burned in dry form as a domestic source of energy. However, the processing of cattle dung in a biogas digester provides a better quality gas and liquid manure than raw dung. Biogas provides nearly three times more useful energy than dung directly burnt besides producing nutrient-rich manure.

It has been proved by many scientific studies that nitrogen fertilizer value of the proposed manure makes it worthwhile as a biogas source rather than burning it as a primary fuel cakes.

The potential for biogas technology is particularly attractive for agricultural areas where the organic feedstock and water are readily available, since regular supply of water is essential for the operation of biogas plants. To get a steady biogas supply, you need to feed your biogas digester every day with fresh cow dung and water. The mixture must be two parts water to one part dung. (25 kg of dung a day will need 50 litres of water).

In 1974 a comprehensive biogas scheme was launched in our country during which around 5000 biogas units were installed through out the country. But unfortunately, all these units ceased to exist after the withdrawal of the government financial support.

The failure of this biogas scheme in our country was largely attributed to; lack of a proper authority to design, install and operate such plants; high initial investment costs compounded with lacking credit schemes; negative image caused by failed biogas plants and limited private sector involvement.

Apart from general hurdles of cost effectiveness, collection, conversion and production of biogas the other potential bottleneck in promotion of biogas is lack of trained technicians to design and install biogas generation system particularly in country-wide remote areas.

Under our current national energy scenario, renewable sources of energy have been fast projected as an attractive option for Pakistan. The role of biogas has been negligible in the total energy picture of Pakistan. Biogas technology has so far been used in our country only for demonstration purposes. The experiments in the past in this area were not so successful due to variety of reasons including lack of understanding and handling of this technology.

In order to revive the biogas generation in our country it is required that:

a. sufficient resources are directed to promote the technology in high potential areas; b. private sector involvement in promotion and dissemination for successful adoption of the technology is encouraged;

c. proven designs and post installation support is provided to counter the already negative image of the technology;

d. cheaper low costs designs are developed to lower the cost-entry barrier;and

e. access to credit for end-users and small enterprises promoting biogas is ensured

The biogas technology has not been exploited on a large scale for lack of motivation and inadequate demonstration of effective use of the technology. Recently there is a realization in government circles, about the necessity of using biogas for the purpose of saving the environment and socio-economic uplift of the peoples living in the remote areas. Keeping in view the importance of renewable energy sources, the government has done well to establish an Alternative Energy Development Board (AEDB) but surprisingly biogas generation has not been included in the scope of AEDB despite of its promising prospects for the rural development.

It is therefore required that government develop appropriate medium and long-term national plans and policies for alternative/renewable sources of energy including biogas generation and also to oversee their implementation closely.