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Boom time for biogas

Despite economic improvements over the last decade, Nepal remains one of the poorest countries in the world. Less than three per cent of the rural population have access to electricity, and fuel for cooking and heating is provided predominantly by firewood, with some use of dung and kerosene. Increasing demand for firewood has resulted in soil degradation, erosion, landslides and flooding. But livestock make a substantial contribution to the livelihoods of rural households, and making greater use of biogas technology suits the social, economic and geographical conditions not only of Nepal but of several other countries, including Rwanda and China.

Biogas installation at Haixi Village of Yulong County (Winrock International)
Biogas installation at Haixi Village of Yulong County
Winrock International

A biogas plant consists of an airtight underground container where livestock manure or household toilet waste is stirred with water. The anaerobic bacteria in the manure convert residual plant material into gas containing up to 70 per cent methane, which is piped to the family's cooking stove to be used on demand. Families thus reduce their need to collect firewood and escape the toxic effects of inhaling smoke from burning wood. In addition, the slurry that remains in the digester makes an excellent odourless fertiliser.

Biogas technology is not new to Nepal, having been available for around 35 years. Large-scale use began in 1992 with the creation of the Biogas Support Program (BSP) funded by the governments of Nepal, Holland and Germany and assisted by the local business community. The committed collaboration of these partners has resulted in rapid progress for the Program. The use of local financial institutions and local people to install, maintain and test biogas plants means that "everyone is involved and they all have a sense of ownership," says BSP executive director, Sundar Bajgain. Local companies guarantee each plant for at least three years following installation and BSP provides training to all households on day-to-day maintenance and minor repairs. As a result, operation of Nepal's plants remains above 97 per cent.

Biogas progress

This simple and reliable technology is now used in 70 of the nation's 75 districts. By mid-2005, over 100,000 plants had been installed and the BSP aims to double this number by 2009. The benefits are clearly evident: use of digesters has reduced Nepal's CO2 emissions by an estimated 890,000 tonnes, has provided over 20,000 jobs, and has improved rural sanitation by incorporating waste from 95,000 household toilets.

A typical plant costs US$300 but government subsidies reduce the cost by about one third. However, the majority of rural users are still unable to afford to pay for the plants up front. In the long-term, the initial outlay is recouped within three years by savings in fuel costs, but to promote the use of biogas plants, more than 100 micro-finance institutions located in rural areas provide loans, which are obtained through a simple application procedure. Winrock International*, in collaboration with BSP, is actively involved in training micro-finance institutions and studying biogas as a solution to reducing indoor air pollution.

Besides overseeing biogas plant installation, BSP advises government policy, conducts research, protects forests, and networks with other organisations to enable more rural poor to boost their crop yields through the use of the residual fertiliser in their crop and vegetable production. In 2005, BSP won two internationally recognised awards: the Japenese Global 100 Eco-Tech Award and the UK Ashden Award for Sustainable Energy. Bajgain reports that the prize money will enable the Program to investigate the use of biogas plants in 400 households in high altitude areas of Nepal where water is scarce.

Biogas taking off in Rwanda and China

Cooking with biogas (Winrock International)
Cooking with biogas
Winrock International

Another winner of the 2005 UK Ashden Awards was the Kigali Institute of Science and Technology (KIST), which has successfully implemented biogas plants in Rwanda's congested prisons. Some 120,000 inmates currently await trial for war crimes committed during the 1994 genocide, which has led to overcrowding and sanitation problems from leaking septic tanks, as well as overuse of forest resources to fuel the prison stoves. However, half of the country's largest prisons have now installed biogas plants with assistance from KIST. Cost return on saved fuel is estimated to take seven years or less, but the biogas plants have also eliminated the health hazards from seeping sewage and have cut firewood use by half. The odour-free fertiliser is used by prisoners to grow crops such as maize and tomatoes.

Biogas plants are also being used in the mountainous Yunnan Province in Southern China, where extensive deforestation is threatening the environment and the livelihoods of 3.2 million poor rural people. The "four-in-one" biogas plant, developed by Chinese scientists, incorporates a pigpen and a household latrine to provide waste, and an underground biogas digester, which also heats a greenhouse for growing vegetables. Building on a pilot project testing plant prototypes, The Nature Conservancy (TNC) is currently partnering with other organisations to scale up the delivery of sustainable energy to half a million households in the region. Alternative Energy Program Manager (TNC China) Dr. Wang Shuwen notes that his organisation often conducts pilots and demonstrations of alternative energy technologies "first in the central school of the community, with the aim of proving the adaptability of the new technology, and also to attract the local farmers to invest." TNC then offers households a 10-30 per cent grant, with the other portion of the investment shared more or less equally between farmers and local government.

With continued commitment from government and organisations, increasing numbers of biogas digesters will provide convenient and clean energy to farmers in developing countries. New developments in technology are expected to lead to cheaper and more efficient biogas plants, as well as to their expansion into areas where water resources are scarce.

*Winrock International is a nonprofit organisation that works with people in the United States and around the world to increase economic opportunity, sustain natural resources, and protect the environment.

Written by: Treena Hein

Date published: November 2006

 

Have your say

simple biogass plant is very cool. (posted by: syyeda naghma hasan zaidi)

 

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