Punjab Chief Minister Mian Shahbaz Sharif has said that negotiations are in progress with China and France for generation of energy from solid waste, and that a solid waste energy project would soon be started at Faisalabad. This is indeed a good news for our mismanaged and cash-strapped energy sector. Such projects should in fact be started in all the provinces to ease the growing energy crunch.
Municipal solid waste has come to be increasingly employed as a handy raw material for producing inexpensive power, and many advanced countries of the world are currently engaged in developing new techniques and technologies to tap this rich source of energy.
Municipal solid waste or MSW includes trash or garbage produced by households, commercial establishments, industries and institutions, which would ensure its abundant availability. The waste consists of everyday items such as discarded packing material, furniture, clothing, plastic bottles, food scraps, newspapers etc. It is managed through a combination of disposal in landfill sites, recycling as well as incineration processes.
Scientists believe that the most environmentally sound management of MSW can be achieved through the use of three-tier process involving source reduction, recycling and disposal in landfills or waste combustors, in which the burning of waste converts water into steam, which drives turbines connected to power generators.
The pre-combustion process varies from facility to facility, though it generally involves shredding of solid waste and removal of metals etc. The shredded MSW is then used as fuel in the same manner as at mass burn plants. MSW is categorised as a renewable source of energy because it is abundant, and contains significant amounts of biomass.
It has been estimated that the burning of MSW can generate energy while reducing the volume of waste by up to 90 percent, which represents an additional environmental benefit. As MSW contains different waste materials, with some of them benign and others highly toxic, meticulous separation of the two is of critical importance.
Effective environmental management of MSW plants aims at excluding toxic from MSW-fuel and to control emissions of air pollutants from waste-to-energy (WTE) plants. Secondly, the burning of WTE plants produces comparatively high carbon dioxide emissions. However, the impact of these emissions is reduced because a major part of the trash is wood, paper or food waste, which would decompose anyway, if not burned.
If left to decompose in a solid waste landfill, the material produces methane, a toxic gas. As far as the quantum of air pollution is concerned, the on-site land use impacts are generally equal to those of coal or oil-fired plants. Incineration converts municipal solid waste into incinerator bottom ash, particles and heat, which can in turn be used to generate power.
Pelletization of municipal waste, an important pre-incarceration process, involves segregation, crushing, mixing high and low heat volume organic waste material, and solidifying it to produce fuel pellets. The process is essentially a method that condenses waste or changes its physical form and enriches its organic content through removal of inorganic materials and moisture.
According to one estimate, on an average about 15-20 tons of fuel pellets can be produced after treatment of 100 tons of raw garbage. Since pelletization enriches the organic content of the waste through removal of inorganic materials and moisture, it can be a very effective method for preparing enriched fuel.
We have discussed here the broad outlines of some of the MSW management techniques employed in advanced countries of the world for producing inexpensive energy. There is a need for the government to generate public awareness that solid waste can be used as an inexpensive source of energy.
We propose that the scope of talks being held with China and France should be enlarged to include all the provinces. After success of the project, energy obtained from MSW can be made a part of the overall national energy mix. Power co-generation is another option, along with numerous other alternative energy sources, which the government must expeditiously tap to keep the widening gap between power supply and demand within manageable limits.
While all these diverse methodologies need to be employed to ensure energy security in the country, long-term benefit to the country can only come from tapping our immense hydropower and coal energy potential. (It is said that the share of coal in the US energy mix is as high as 50 percent.) The government should simultaneously undertake fast-track implementation of water and power projects to rid the economy of the crippling power shortages.