Renewable Energy uses in Nepal
Renewable Energy Technologies (RETs) is a synonym for new, renewable and non-conventional forms of energy i.e. the technologies, which use local energy resources (other than commercial fuels) and biomass fuel (firewood, agricultural residues and animal wastes) in traditional forms. The main sources of these alternatives are biomass, water, sun and air.
The biomass fuel contributes an overwhelming share of the energy consumption in the rural areas. About 90 percent of the energy demand of the country are met by biomass, of which about 78 percent come from fuel wood. This huge dependence on fuel wood has been a cause for depletion of forests and degradation of environment.
Biomass as a source of energy mainly consists of fuel wood, agricultural residue and animal dung. Fuel wood and other biomass fuels are burnt in traditional stoves of various kinds. Agricultural residue can be converted into briquettes or brunt directly for energy purpose. Conversion of biomass technology into other efficient and convenient energy forms include biogas, improved cooking stoves and briquettes.
Biogas technology was introduced in Nepal some 30 years ago. About 60 companies are being involved in the construction of biogas plants these days. More than 12,000 people who have been directly involved in biogas promotion of the companies in 67 districts. By the end of March 2007 about 171,000 family sized biogas plants (mostly 4 to 10 cubic meter total volume capacity) have been installed in the country. This has been made possible due to standardization of design as well as biogas appliances, an extensive system of quality control and financial incentive provided to potential users for the installation of biogas plants.
Typical biogas plant consists of an inlet, outlet, dome, digester, turret, water drain pit, compost pit, pipe fittings and biogas appliances such as stove, lamp etc.
Since biogas is a high quality fuel, it can be used for many purposes besides cooking and lighting, such as fuel for running dual fuel engine, for agro-processing, pumping water and for generating electricity. The application of the slurry from the biogas plants and their impact on agricultural production both on cereal and vegetables could not be quantified. However, it is estimated about 10 - 15% agricultural production could be increased with proper composting and application of the slurry in the field. It also helps in improving the texture and structure of soil condition. On top of that it reduces the consumption of chemical fertilizer.
Improved Cooking Stoves (ICSs) with efficiency of 18 to 28 percent have been developed in Nepal over some time. Research and Development (R&D) have been carried out in these devices since the early eighties. As a result, different types of ICSs have been designed and developed. So far more than 140,000 ICSs have been distributed to the people in about 55 districts. However, their actual uses vary considerably from place to place.
ICS consists of combustion chamber, baffle, pothole, flue exist hole, raised pothole, chimney pipe, grate, lug, shoot cleaning hole, chimney hood, and primary and secondary holes. So far eight types of ICS (mud, metal, brick and five ceramic insert stoves) have been developed in the country.
ICS are slowly gaining popularity among rural housewives due to the reduction in fuelwood use as well as the improvement of health and sanitation.
Briquetting technology was introduced in Nepal in 1982 using rice-husk and sawdust as the main raw materials. It is a pyrolyzing technology and relies on partial pyrolysis of rice husk, which is mixed with binder and then made into pellets by casting and pressing. Another form of briquette making is beehive briquette made out of biomass char such as wood, leaves, twigs and other agricultural residues. Biomass is converted into char by carbonizing in a charring drum, which is a simple drum fitted with a conical shaped grate; a chimney and water sealed arrangement. The biomass char is grind into powder and mixed with 20 to 30 percent by its weight bentonite clay by adding required amount of water. It is then filled completely into the mould and made into briquettes. After drying in the sun for about two days these are ready to use in briquette stove.
The history of waterpower in Nepal begins with the traditional water mills or ghatta used for grinding flour. However, there are a variety of technologies already available or being developed, which come under the mini and micro hydropower category. The improved ghatta i.e. Multi Purpose Power Unit (MPPU) is an innovation on the traditional ghatta. This uses a metal runner to increase efficiency higher than that of traditional ghatta.
Turbine for milling purpose accounts for about 60 percent of the existing micro-hydro schemes in Nepal at present. These schemes are used to run a range of agro-processing machines such as rice huller, grinder and oil expeller. However, in the present days, more focus is on rural electrification and other end use applications.
Nepal has over 6,000 rivers of length over 2 km. Therefore the total theoretical potential of micro-hydropower is very large. Mini and micro- hydro technology has enormous potential to promote environmentally sound sustainable development in hilly region of Nepal. At present about 16 companies manufacture and install micro-hydro plants in Nepal. So far about 17.6 MW of power has been generated from about 2500 micro-hydro plants including peltric sets. Most of these turbines are installed solely for agro- processing. Some of the units are also coupled with electric generators.
Micro-hydro plant consists of civil and electro-mechanical components. Civil structure consists of intake, canal, desilting basin, forebay tank, support piers, anchorblocks and powerhouse. Similarly electrical components consist of generator, control panel, ballast heater, transmission distribution system, earthing, poles, stay sets, insulators and load limiting devices. Likewise, mechanical components of a micro-hydro scheme consists of penstock pipe, turbine, valve, drive system and expansion joints.
Today there are about 30 manufacturers of solar water heaters and the total installed capacity in the country is estimated at 10,000 sq. meters of solar panels.
Mainly, two types of solar energy technologies (solar thermal and solar photovoltaic systems) are available in the country. Solar thermal systems include solar water heaters, solar dryers, and solar cookers. Similarly solar PV systems include solar communication systems, solar electrification systems, and solar pumping systems.
Solar photovoltaic (PV) is not a new technology to Nepal. It is estimated that about 14 companies have installed more than 60,000 units of PV in about 61 out of 75 districts of the country. Solar cookers and dryers were also developed and propagated some time back in the country. Various experts and institutions are also studying white lead lamps.
Wind is still one of the unharnessed energy sources in Nepal. Its countrywide potential has not been assessed yet. Some studies have indicated that wind potential for power generation is favorable in Tansen of Palpa, Lomangthang of Mustang and Khumbu regions of Nepal. However, wind monitoring and mapping data are not available for many places. A few studies that have been conducted so far have been indicated some potential for wind energy in Nepal. Nevertheless, due to difference in topography and consequent variation in meteorological conditions it is difficult to generalize the wind condition in Nepal. However, specific areas have been identified as favorable for viable wind generation.
The importance / advantages of RETs on rural development are of many folds. These:
- help in reducing the drudgery of rural population;
- provide cleaner cooking environment especially to rural women;
- save foreign currency by substituting imported fuel;
- conserve environmental protection;
- have potentials to create rural employment and to increase productivity; and
- contributes towards the sustainable economic development of the country.
The present strategy of the government in renewable energy technology include:
- provision of subsidies;
- provision of bank loans;
- encouragement to private sectors;
- insuring quality construction;
- training and extension activities; and
- monitoring and evaluation studies.
- Nepal’s energy scenario is dominated by forestry sector as it supplies more than 78 percent of total energy demand. Improved cooking stoves are being used in the places where access to fuel wood is limited.
- The micro-hydro and biogas technologies have been proved to be viable alternative energy technologies in Nepal. These technologies have developed awareness among the rural people, made the life of rural people more comfortable, improved educational status of rural children and has promoted some industrial activities, which have to some extent generated employment opportunities. The solar energy technology has been promoted gradually in the country while the wind energy technology has yet to be harnessed.
- Several government agencies as well as private organizations have been involved in the development and dissemination of renewable energy technology especially biogas and micro-hydro during the past three decades where as the dissemination of other renewable energy technologies such as solar and wind were initiated only some years back.
- Renewable energy technologies have not being massively disseminated in Nepal as compared to their technical potentialities. For commercialization of the technology, various promotional and marketing activities study to be conducted. Integration of renewable energy with agriculture, livestock, irrigation and health sectors might create a good market of the technology in the country.
- Solar PV systems are associated with storage system such as lead acid battery, the disposal of which is a serious environmental concern. Similarly, standardization is another issue to be addressed.
- Govinda Prasad Devkota, Universal Consultancy Services P. Ltd.,Banasthali, Kathmandu.
- User:Dr Karabi Dutta 16 April 2008