Green and sustainable: Waste-to-energy route17 January 2015, The Hindu | |
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Effective waste treatment and finding an ideal source of non-polluting energy hold the key to transition to green and clean cities. By M. A. Siraj Green cities are often misunderstood as cities having high densities of trees. It is time this myth is debunked and the term is understood with reference to eco-friendly practices the civic authorities and the citizens must adopt. Green cities are ones that make efficient use of energy; are high on use of renewable energy; cut down emission of toxic gases; plan open spaces; conserve the greenery, hills, water bodies and heritage (artistic, historical as well as architectural); groom citizens to adopt consumer habits aimed at reducing pollution; and, have waste disposal that is safe and adds to sustainability of resources. Going by this wish-list, people, transporters, nature, energy, economy, resources and authorities all are essential stakeholders in the process. The top ten ‘green cities’ in the world are Reykjavik (Iceland), Portland (Oregon-U.S.), Curitiba (Brazil), Malmo (Sweden); Vancouver (Canada), Copenhagen (Denmark), London (U.K.), San Francisco (California-U.S.), Bahia de Caraquez (Ecuador) and Sydney (Australia). Looked from this angle, we Indians have a tall order as WHO statistics have listed 13 of the 20 dirtiest cities to be from India. Our cities depend on energy infrastructure that is outdated and polluting. Dirty fossil fuel-based power plants which emit greenhouse gases into the atmosphere are contributing to climate change. The most critical step that we need to take should be small-scale renewable energy sources that would replace huge and centralised plants that guzzle up fossil fuels. Transition to solar energy India is fast urbanising and by 2050, our cities are likely to take nearly two-thirds of the population. Going by the current rate of polluting emissions, transition to renewable energy sources would be inevitable. Says S.K. Gupta, Dean, Civil Engineering at K.L. University, Vijayawada, the first choice must be solar energy. He says, “Converting sunlight into electricity is a fast-growing technology, doubling its capacity every couple of years. India is densely populated and has high solar ray incidence, ideal for using this technology. Large solar power projects in the Thar Desert occupying an area of 35,000 sq. km are sufficient to generate 700 to 2,100 GW of electricity.” At the end of 2013, worldwide photovoltaic capacity reached 139 Giga Watt (GW). Germany remains the world’s largest overall producer of photovoltaic power with 35 GW. Other significant contributors are Italy, China, Japan and the U.S. But Gupta suggests emulation of the Kenyan model. Kenya has emerged the world leader in the number of solar power systems installed per capita. More than 30,000 small solar panels are being installed in Kenyan homes annually. India’s Jawaharlal Nehru National Solar Mission launched in 2009 has set a target of 22 GW of solar power by 2020 but the current installed capacity is merely 2.6 GW. The gap is yawning and the pace needs to be expedited. Heating model from China In matters of Concentrated Solar Power (CSP), the alternative route to tapping solar power, China is cited as the model where this technology is used to heat water in 50 to 60 million households. CSP is stated to be ideal for apartment, housing colonies and large establishments requiring hot water or steam. Waste-to-energy route Treatment of solid waste and raw sewage could also be a route to renewable energy. Every year, about 55 million tonnes of municipal solid waste (MSW) and 38 billion litres of sewage are generated in the urban areas of India. In addition, large quantities of solid and liquid wastes are generated by industries. Only 12 of the 497 cities with one lakh plus population have anything like adequate infrastructure to deal with garbage and human and organic waste. Gupta says the amount of waste generated in urban India will increase at approximately 1 to 1.33% annually. It will demand more land for disposal and also the economic cost for collection and transportation of the waste. The new state of residual Andhra Pradesh has planned one waste-to-energy plan for every district. Ranipet Hafeez Basha, an Indian scientist who teaches Renewable Engineering at Kumamoto University in Japan and who is vice-president of BRCORP, a Singapore-based conglomerate, says, “The first priority should be zero waste mission, where combustible waste should be used for electricity generation and non-combustible waste as a potential construction material for cost-efficient dwelling units”. Abdul Razak, Dean, Department of Planning, School of Planning and Architecture, Vijayawada, says, “In the national capital Delhi itself, 3.6 million litres of sewage, 40% of the total generated in the city, is let out into the Yamuna. Forty five per cent of the capital’s households is not covered by the sewerage system. Gupta says India had a long involvement with anaerobic digestion and biogas technologies. A waste-water treatment plant could produce renewable energy from raw sewage which has significant untapped potential”. Harvesting wind power Prof. Basha points out that cities on the long coastline of India and on and around the hills can look for tapping wind power. As of December 2013 the installed capacity of wind power in India was 20 GW, mainly spread across the coastal States of Tamil Nadu, Maharashtra, Gujarat, and Karnataka and the desert State of Rajasthan. Wind power accounts for 6% of India’s total installed power capacity, and it generates 1.6% of the country’s power. In its 12th Five Year Plan (2012-17), the nation has set for itself a target of 11 GW of power through this source. (The author can be reached at [email protected]) |
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