What Centre’s push to power plant biomass co-firing means to farmers, air quality

Finance Minister Nirmala Sitharaman’s Budget speech declaring a scheme to push for use of biomass in coal-fired thermal power plants is just one step towards addressing the ever-evolving challenge of environmental hazards posed by coal-based power generation plants.

Termed SAMARTH (Sustainable Agrarian Mission on use of Agro Residue in Thermal Power Plants), the scheme entails blending 5 per cent biomass pellets with coal while gradually increasing the blend to 7 per cent within two years.

Also called thermal power plants, the coal-based units are known to be world’s most resource-intensive and polluting industries. Nevertheless, they remain the mainstay of India’s energy sources with roughly 75% of electricity coming from thermal power plants.

The FM said in her speech that about 5-7% biomass pellets will be used in thermal power plants, which will cut carbon dioxide emissions by 38 million tonnes annually. “This will also provide extra income to farmers, give job opportunities to locals and help avoid stubble burning in agricultural fields,” the minister added.

What is biomass co-firing?

Blending agriculture residue or urban waste (in the form of pellets) with coal in older power stations is called biomass co-firing. It is a practice followed by several old power plants across the globe and also in India of late. Till December 2021, about 59,000 metric tonnes of biomass has been co-fired in thermal power plants in India, while tenders for 12 million metric tonnes are in the pipeline.

Need for biomass in power plants

Emissions from thermal power plants don’t just give out CO2, but also release heavy amounts of sulphur dioxide, nitrogen oxides, particulate matter, mercury among other pollutants in the form of coal ash also called fly ash.

Areas around power plants report piling ash in the form of slurry in ash ponds and in the dry form in open fields. Several studies have confirmed contamination of drinking water in areas around Koradi and Khaparkheda power plants in Nagpur (Maharashtra). Delhi has for long paid the price for fly ash disposed of unscientifically by power plants located in close vicinity to the national capital. Scientists say that long-term exposure to fly ash in the air can lead to serious pulmonary illnesses and even cancer.

Despite several legislations and litigations in the past, the utilisation of fly ash has not gained momentum mainly because power plants have been lax in disposing off such toxic waste in an environment-friendly way. The National Green Tribunal (NGT) has ordered the Central Pollution Control Board (CPCB) to ensure all thermal power plants in India make 100% ash utilisation. Yet, 21 years after the first notification was issued, almost 50% power plants are yet to comply with the 100% ash utilisation order. Many plants do not even have a 50% annual ash utilisation rate.

Meanwhile, despite strong commitments at the Paris Climate Change summit in 2015 and at COP-26 in Glasgow last year, India’s reliance on coal energy has only increased. As per ‘State of India’s Environment Report 2021’, about 64 per cent (132 GW) coal power capacity has been added in the last decade. Annual fly ash generation rose from 123 million tonnes to 217 million tonnes during the same period, the report adds.

What is equally concerning is the amount of residual or legacy ash that has accumulated over the years due to low utilisation of existing ash.

A recent report from Centre for Science and Environment found that the unused ash stock from coal power plants of India in the last 10 years is 627 million tonnes. This is three times the current annual ash generation of 200 million tonnes.

Also read: Power ministry revises policy to use biomass pellets in coal plants

It is unfortunate that despite a well-defined policy and regulatory framework for 100 per cent utilisation of fly ash, thermal power plants have failed to achieve the targets for one reason or the other. Hence, the blending of biomass (made from crop residue and organic waste) with coal will go a long way in minimising the harmful effects of coal-based energy.

Centre’s efforts so far

The National Mission on Use of Biomass in Thermal Power Plants has been promoting use of biomass in power plants by way of ad campaigns, awareness missions and extensive training programmes. Aggressive promotion in Haryana, Punjab and Uttar Pradesh is showing results. Power plants in the NCR region (around Delhi) have used 21,000 tonnes of biomass so far and have issued tenders for procuring 5.5 million tonnes more.

State-owned power generator NTPC has alone co-fired 58,000 tonnes of biomass, while issuing tenders for 10.7 million tonnes recently.

Benefit to farmers

Stubble burning by farmers of Punjab, Haryana and Uttar Pradesh and the consequent air pollution in the entire north India hits the headlines every winter. A resident of Daryaganj in Delhi may whine about the “bad agriculture practices” of farmers which causes health hazards to his family, but farmers over the years have been constrained by labour shortage and excess production (rice and wheat) aided by mechanisation, which has only added to stubble load. They are left with no viable option but to burn the agriculture waste, which increases air pollution.

Also read: Better use of waste biomass critical to meet 20% ethanol blending target

This farm residue can be converted into biomass pellets, which can then be supplied to power plants for biomass co-firing, which reduces CO2 emissions significantly while offering an alternative to stubble burning and mitigating harmful effects of coal burning like fly ash generation.

Soundaram Ramanatham of Centre for Science and Environment quotes power ministry data to say that about 0.25 million tonnes of biomass pellets are needed to produce one gigawatt capacity at the rate of seven per cent co-firing. Thus, for 100 GW capacity, nearly 25-30 million tonnes of biomass pellets will be required. This is a huge opportunity for farmers to increase their income while cutting down on air pollution.

Biomass use – an answer to coal shortage

An unprecedented coal shortage in September-October last year resulted in power cuts across the country and intense competition among state power utilities to secure enough energy from the grid to keep its industry and cities working.

Blending biomass pellets (5-7 per cent) with coal can cut the need for coal and aid India’s gradual transition towards clean and renewable energy sources like solar and wind.

There are ample examples of successful biomass co-firing reducing carbon footprint of coal power plants in Europe and the US.

The International Energy Agency (IEA) has documented evidence to prove that biomass pellets made from agricultural residue have calorific value equal to that of coal.

So, increasing use of biomass in coal-based power plants will not only help the country reduce its carbon emissions, but also meet its Nationally Determined Contributions (NDCs) for net zero emissions target in 2070.

Thus, increasing use of biomass in electricity generation is a win-win for farmers, coal-based power plants and citizens who have the right to clean and ambient air.