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Cover Story | June 2017

Pay Dirt

Waste-to-energy conversion can help India deal with not only the increasing garbage disposal problem, but also address health and economic issues. It provides a largely unexplored potential for the country's development.

The humongous amounts of garbage generated in India can very well entitle the waste management sector to claim being an industry. Add to this, people's 'not in my backyard' syndrome and lack of initiative from civic authorities, which have exacerbated the garbage disposal problem, and we're left with an ever increasing and undealt with stink.

But, what if the very cause of the problem could be the solution as well? Waste-to-energy (WtE) or refuse driven energy is the process of generating energy in the form of electricity and/or heat from the incineration of waste. It is a form of energy recovery that the European countries are utilising very successfully, as are Japan, Korea and Singapore.

In fact, Japan is an almost 'zero' waste producing and 'zero' landfill using country, where 90 per cent of the electricity produced is clean and green. Meanwhile, Norway imports garbage from other European countries to feed their WtE generation plants. The 'Eurotrash Business' has been flourishing and how! While it sounds like an unpromising enterprise, it is indeed increasingly profitable. Case in point: the UK paid to send 45,000 tonnes of household waste from Bristol and Leeds to Norway between October 2012 and April 2013 alone.

And Norway is not alone. WtE has become a preferred method of rubbish disposal in the EU, and there are now 420 plants in Europe equipped to provide heat and electricity to more than 20 million people. Imagine this replicated in India! While people talk about investment in other renewable energy sectors, one major advantage in favour of WtE is the fact that it does not need to be connected to the grid.

Ground realities
According to the Ministry of Urban Development (MoUD), urban India alone generates around 70 million tonnes of municipal solid waste each year, which does not include either wastes picked up by kabadiwalas from households and from the streets by rag pickers or biomedical, biochemical, agricultural and industrial wastes.

There is no public concept of segregation and almost all waste is either dumped in land or water. Veritably, landfills account for an overwhelming 94 per cent of garbage disposal. This, despite early school education, extolling the monetary and environmental benefits of biogas. Further, efforts into turning these gasses into electricity, which can be distributed for use while tackling the garbage problem and providing employment and revenue, remains largely unapproached and unheard of. However, if the requisite practices are promoted across the country, WtE could help turn around sanitation problem and provide three-fold benefits in the economic, infrastructural and health fields. Ideally, the concept should not have a problem being widely promoted and adopted in a country like India, where collecting bhangar and re-using plastic bottles and bags are as innate as breathing.

Another challenge to be taken into account is that in India even if a government project gets approved, is commissioned and then successfully completed after overcoming various hurdles, maintenance and quality checks are still the stuff that legends are made. Even other official reports concur that quite a few of the processing plants set up as mentioned earlier are currently non-operational.

Meanwhile, a report prepared by the 'Task Force' of the MoUD which critically looked at failure or under performance of the processing facilities set-up, observed:
1) Lack of due diligence on the part of investors as well as public sector,
2) Non-supply of committed quantity and quality of waste to the plant by the municipal authority,
3) Presence of inerts - dust & C and D waste in MSW delivered for processing, making the operations difficult and very expensive,
4) Inadequate market for sale of compost and RDF,
5) Public outcry against the location of a plant, and
6) Lack of financial viability of projects, were major reasons.

Cash from trash - a concept
According to Cédric Philibert, Energy and Climate Change Analyst, International Energy Agency (IEA), traditional energy alternatives pose a threat to power plant operators and end users: volatility and insecurity of price, while renewable energy prices on the contrary have been continually decreasing.

'Renewables are an infinite source of power with long-term certainty. While majority of oil & gas sources are concentrated in certain regions, many of which are getting more technically challenging and expensive to reach, renewables are domestic. It provides security of supply, helping a nation reduce its dependence on imported sources in favour of clean and reliable home-grown electricity with the added bonus of fantastic local economic opportunities.

With revision of tariff in many states such as Bihar, Haryana, Punjab, Rajasthan, Maharashtra etc., many developers are finding it attractive to go ahead with setting up of biomass based power plants in various states. Furthermore WtE can help in rural employment and revenue generation.

In order to develop biomass supply chain to power plants, rural youth can be identified and trained to develop them as Village Level Entrepreneurs (VLEs). These VLEs are then provided with the necessary machinery and given responsibility of operating and maintaining these power plants. They thus have stable income and leads to the whole rural chain involving VLEs, farmers and rural youth.

The biomass energy sector has the biggest potential in helping India's rural growth as it utilises rural logistics and manpower for its operation and can be a big employment provider to villagers. A 1 MW plant provides direct employment to 50 rural people in the fuel and logistic management fields alone, while many others are also employed indirectly. It also provides additional income to farmers, who get value to their agricultural waste.

Way forward
To realise the untapped potential of more than 2 GW from WtE projects, road blocks on structural, policy and regulatory aspects need to be removed. Standardisation of bidding documents, capacity building of ULBs and expediting approvals will help in faster PPP implementation.

Inter-ministerial coordination between the Urban Development and Power Ministries is the key. Policy driven push for creating separate market for WTE power through RPO and timely tariff visibility will protect viability of WTE projects. Distribution utilities and regulators need to recognise the larger purpose of WTE projects and encourage commercial sale of power from them.

Thermal Conversion:
Involves thermal degradation of waste through complete oxidation under high temperature.
Incineration is the major technological option. Either mixed MSW is combusted directly, or dry high organic component is segregated from it and given the form of briquette/pellets/fluff to combust and generate energy.

Thermo-chemical conversion:
Entails high temperature driven decomposition of organic matter to produce either heat energy/ fuel oil/ gas. It is useful for waste with high share of organic non-biodegradable matter and low moisture content.
Pyrolysis and Gasification produces gas to be used purely as heat energy

Bio-chemical conversion:
Enzymatic decomposition of organic matter by microbial action produces methane gas, and alcohol etc. It is preferred for wastes having high share of organic, bio-degradable (putrescible) matter and high level of moisture/ water content, which aids microbial activity. Bio-methanation is used for WtE frequently.

Source: PwC
1Tipping fee is the charge ULB pays to the project developer for processing MSW 2If tipping fees are in negative, they are termed as Royalty fees. Local authority earns it for supplying MSW

Case study on use of cane trash in sugar mill in Karnataka
A sugar mill in Belgaum district of Karnataka has been making use of cane trash in their co-generation plant for almost one and a half decades. The company has taken up lead in introducing several improvements and innovation in the sugar industry. The economics of a high efficiency co-generation system as well as other factors which were conducive, prompted the mill owners to install the high efficiency co-generation system. Use of cane trash was the next step in maximising the benefits from the co-generation system.

Power requirement of the entire unit is met through power generated at the co-generation plant with surplus power being fed to the grid. Steam is generated through multiple high-pressure boilers each having a capacity of 60 tph and having pressure and temperature ratings of 61 kg/cm2 and 480°C. Two turbines are installed for the co-generation system out of which one is a back pressure extraction turbine while the other is extraction cum condensing turbine.

During the trial period, the quantity of trash fired along with bagasse was about 24.5 per cent on an average on weight basis. The maximum quantity of trash fired was 25.5 per cent on weight basis. On heat basis, the percentage of trash utilisation was 37.1 per cent. These trials were conducted for a total of 12 hours utilising about 80 tonne of cane trash. The boiler performance was satisfactory and there was not much change in the boiler parameters.

After trials, the management gained confidence of firing cane trash up to 25 per cent of the total quantity of fuel on weight basis. The total quantity of trash available per day is about 600 tonne which amounts to about 125,000 tonne per season. The bagasse, thus saved as a result of the use of the trash, will be stored for use in off-season. Also, the moisture content in the bagasse reduced from 50 per cent to a considerable low limit when stored for a considerably longer period.

The use of cane trash has resulted in several benefits for the sugar mill:

  • Increase in operation period of the co-generation plant,
  • Increased steam generation and power generation,
  • Increase in revenue as a result of more power exported to the grid,
  • No extra man power requirement for operation of the boiler or power plant,
  • Reduction in greenhouse gas emission to the extent of 6,000 kg CO2 per TCD capacity of the sugar mill.

Author: R Rajmohan, CEO, Development Environergy Serviced Ltd (DESL) - A group company of Veolia, France.

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