RENEWABLE ENERGY RESOURCES IN PAKISTAN
SAIMA IBRAHIM (Saima_virgo1@hotmail.com)
Aug 31 - Sep 06, 2009
Pakistan has a wide spectrum of high potential renewable energy resources - conventional and non-conventional, which have not been adequately explored, exploited, or developed.
Current primary energy supplies in Pakistan are not enough to meet even the present demand. Moreover, a very large part of the rural areas does not have the electrification facilities because they are either too remote and/or too expensive to for it to connect to the national grid.
Therefore, Pakistan, like other developing countries of the region, is facing a serious challenge of energy deficit. The development of the renewable energy sources can play an important role in meeting this challenge.
Considering the geological setup, geographical position, climatologic cycles and the agricultural activities, various renewable resources are technologically viable and have bright prospects to be exploited commercially in Pakistan. The resources include Solar (PV, thermal), Water (mega & macro-micro-hydel, and sea wave & tide),Wind, Wastes (solid waste, waste from local chicken farms, forestry waste, wood waste from furniture factories, agricultural waste, hospital waste, and animal slurry from farms), geothermal, and others.
Pakistan can be benefited from these substitute energy resources in areas where they are available.
POTENTIAL OF WATER ENERGY
Hydropower source of energy is well known in Pakistan and there is ever growing experience in this sector to develop the hydropower potential indigenously in the country.
The hydro potential was estimated at about 50,000 MW out of which about 4,800 MW has been developed over the past 50 years through mega hydro plants and the remaining has yet to be exploited. The northern areas of the country are rich with hydropower resources.
The canal system has a huge hydropower potential at numerous sites/locations, ranging from 1MW to more than 10MW, which can be utilized for developing small hydropower stations using low head high discharge water turbines in Punjab and Sindh provinces.
Pakistan is ideally located on the sunny belt to take advantage of the solar energy technologies. During last twenty years, Pakistan has shown quite encouraging developments in photovoltaic (PV). Currently, solar technology is used in Pakistan for stand-alone rural telephone exchanges, repeater stations, highway emergency telephones, cathodic protection, refrigeration for vaccine and medicines in the hospitals etc.
The public health department has installed many solar water pumps for drinking purposes in different parts of the country. A number of companies are not only involved in trading photovoltaic products and appliances but also manufacturing different components of PV systems. They are selling PV modules, batteries, regulators, invertors, as well as practical low power gadgets for load shedding such as photovoltaic lamps, battery chargers, garden lights etc.
In many countries, wind power to produce electricity on a commercial scale has become the fastest growing energy technology. Pakistan has 1000 km long coastline, which could be utilized for the installation of wind farms, as found in UK, Netherlands and other countries.
Although Pakistan has tremendous wind potential, at present the facilities for generating electricity from wind are virtually nonexistent in the country.
Considering the significance of the wind resource model, Ministry of Science & Technology has provided funds to Pakistan Meteorological Department to establish a network of wind masts along the coastal areas to conduct an extensive wind survey of the coastal areas to assess wind power potential.
ENERGY FROM WASTES
Every day, we produce a lot of waste - in our homes, offices and factories, farms, and hospitals, and so on. The domestic solid waste in Pakistan has not been managed in a satisfactory and adequate manner as far as its collection, transportation & disposal or dumping are concerned regardless of the size of the city. It is estimated that the urban areas of Pakistan generate over 55,000 tonnes of solid wastes daily.
In Karachi alone, more than 7,000 tons of solid waste is generated every day. There are thousands of auxiliary mismanaged collection dumps all over the city called "kutchra kundis" causing noticeable environmental degradation and large-scale pollution.
In Karachi, the solid waste management services are inadequate and unsatisfactory. About 20% of the waste is picked up by the waste scavengers as the salable items. Almost 20% waste is most often burned openly to ashes. About 60% of the garbage is transported to the uphill areas located 30-35 km away from the city and disposed in open air.
Such huge amount of solid wastes can be used as a fuel. Heat and electric power can be generated either by incineration of the solid wastes or by anaerobic composting of solid wastes through proper landfill techniques. The heat can then be used to generate electricity. In Pakistan no "energy-from-municipal waste" facility has been built while advanced technologies have been developed in world to ensure that the wastes' gases emitted from these facilities would not be harmful to the environment.
Most of the waste we produce is disposed of in "landfill sites". The waster is dumped on surface without any soil cover. In case of proper landfill sites, as the waste decomposes in the oxygen-free environment below the surface, it gives off a gas that is rich in methane through a process known as "anaerobic digestion". This biogas or landfill gas as it is called, can be collected through a system of wells, drilled into the waste, and pipelines.
It is then used to fuel an electricity generator or to provide heat. Greengairs is Scotland's largest landfill site. It handles around 750,000 tonnes/year of waste. The power plant uses landfill gas to produce almost 8MW of power.
ENERGY FROM MISCELLANEOUS WASTES
Waste from local chicken farms (poultry litter), forestry waste, wood waste from furniture factories, agricultural waste, hospital waste and animal slurry from farms are just some of the kinds of waste that can be used as fuel.
ENERGY FROM POULTRY LITTER
Poultry farms and animal processing operations create birds-wastes that constitute a complex source of organic materials with environmental consequences. These wastes can be used to make many products, including the energy generation.
In Britain, the Thetford Power Station in Norfolk burns chicken litter of about 400,000 tonnes/year to produce 38.5 MW of electricity.
Pakistan has broad-based poultry farms network mainly in private sector in different cities and as such significant potential for power generation from chicken litter exists, but so far there is no such facility for its use to generate electricity around the country.
ENERGY FROM ANIMAL SLURRY
Pakistan is an agriculture country. About 70% of the population resides in rural areas that meet 95% of its domestic fuel needs by burning bio-fuels, but people in urban areas use mainly kerosene oil, LPG, and natural gases in addition to fuel wood to meet their domestic fuel needs.
As per livestock census 2000, there are 46.69 million of animals (buffaloes, cows, bullocks) in Pakistan. On the average, this would yield a total of 700 million kg dung per day. Assuming 50% collect ability the availability of fresh dung comes to be 350 million kg per day. Thus, 17.5 million M3 biogas per day can be produced through the biomethanation.
With the effective efforts of PCRET, COMSATS and other organizations such cattle waste is utilized to generate biogas at the local level in many parts of the country. But, the serious environmental problems are faced in urban areas, where large cattle farms exist.
Biogas, one of the most significant types of biomass energy, makes optimal utilization of the valuable natural resource of dung. It provides (soot-free) clean gas for meeting cooking and energy needs as well as enriched bio-fertilizer for improvement of fertility/productivity of agricultural lands.
Moreover, being clean and renewable, it also contributes towards environment protection, sustenance of ecosystem and conservation of biodiversity.
Pakistan is rich in biogas potential; it provides nearly three times more useful energy than that when dung directly burnt, and also produces nutrient-rich manure.
1. Biomass and waste to energy plants conserve fossil fuels by generating electricity. One ton of MSW combusted reduces oil use by about 45 gallons; or coal use by about 0.28 tons.
2. It has been estimated that one ton of MSW combusted rather than land filled reduces greenhouse gas emissions by 1.2 tons of carbon dioxide.
3. Biomass and waste to energy plants save the space required for land filling.
Biomass/Waste to Energy projects are considered to be most environmental friendly technologies which are very much supportive in reducing emissions and developing healthy environment.
They have the benefits over conventional energy resources projects as they do not emit any effluents, pollutants, and residues.
Biogas units turn human and animal waste into a mixture of methane and carbon dioxide gases that can be used for lighting and cooking. Household can build its own plant to channel waste from the domestic toilet and nearby shelters for animals into a sealed tank. Similarly, a large amount of agricultural residues, instead of being burnt, can be put into biogas tanks to undergo fermentation. The process converts the wastes into gas and compost. This reduces air pollution and helps produce high-quality organic fertilizer.
BIOGAS PRODUCTION PROCESS
To start the process, shredded plant materials and animal wastes are mixed with water in the biogas generator. Many kinds of naturally occurring bacteria arrive with the shredded plant material. The tank is then sealed so no air can get in. Within days, a special kind of bacteria in the tank begins to produce biogas. These bacteria are known as "methanogenic", because they produce methane, the main ingredient in biogas. The biogas forms bubbles in the mixture, and collects at the top of the tank.
It is piped to a large balloon-like bag where it is stored until needed. Eventually, the production of biogas in the generator starts to slow down. The mixture of water and manure is replaced with a fresh supply to start the process again. The old material is unable to produce any more biogas, but still contains large amounts of plant material and other organic matter. It is dried to form a rich black soil, and is spread on fields as a fertilizer. The fertilizer obtained from the dung was of fine quality consisting five times more nitrogen.
Another source of biogas is landfills. At the landfill site, large mounds of garbage are buried under the surface. Bacteria break some of the garbage down and can produce large amounts of biogas. This is sometimes collected and burned to heat buildings near the landfill. Biogas can contain traces of hydrogen sulfide (H2S) gas, particularly in the case of landfill gas. Care must be taken to deal safely with this gas because H2S can be fatal.
BIOMASS/WASTE TO ENERGY PLANT
In recent years, waste-to-energy technologies have been developed to produce clean energy through the combustion of municipal solid waste in specially designed power plants equipped with the most modern pollution control equipment to clean emissions.
Biomass and waste to energy plants are used not only to generate sufficient power but also used to cleanup the environment as well by conserving non-renewable fossil fuel resources and reducing the environmental impacts of trash disposal.
In Pakistan, about 450 biogas units, based on dung of buffaloes and cows have been installed.
The biogas programme of the PDDC is allowing farmers to reduce expenditure on LPG purchases, deforestation, providing health benefits, which over the time would have a major impact on the country.
All over the world, renewable energy projects have been implemented to avoid dependency over the conventional resources, which have been a source of effluent emissions and endangered environment. International organizations and institutes including financing organizations are encouraging such projects, which utilize renewable energy technologies for the generation of power.