Sugar mills are helping solve India's energy crisis

Posted: 16 June 2009

There is heartening news from an unexpected quarter in India. There sugar mills are helping to ease the country's energy crisis by generating biomass- based 'green' energy from bagasse, a waste product that comes from sugarcane cultivation.

Sugar mills in the five major sugarcane growing states of Andhra Pradesh, Karnataka, Maharashtra, Tamil Nadu and Uttar Pradesh are contributing 2,000 megawatt (mw) of power to the national electricity grid. This is enough to meet the energy needs of a big business centre, such as Gurgaon, in Haryana, says a report in the latest issue of Down To Earth magazine, published by the Centre for Science and Environment (CSE).

However, says the study, India has no policy framework in place to strengthen this green energy source. Sunita Narain, director, CSE, points out. "This energy source is an important win-win solution, as it adds value and funds to agricultural resources, which in turn will give better payments to farmers and improve productivity. The question is what can be done to increase this energy source for the future."

Bagasse Co-Generation Plant
Bagasse Co-Generation Plant
Bagasse Co-Generation Plant at Sakthi Sugar Mill, in Tamilnadu. Photo: Government of India: Ministry of New & Renewable Energy
The process by which sugar mills are generating this power is called cogeneration - producing both electricity and heat.

"When we researched efforts to move towards modern biomass-based energy technologies we were amazed to find that cogeneration just by sugar mills was generating such an immense amount of energy" said Narain.

Today, out of the 650-odd sugar mills in India, 107 have cogeneration plants which are managing to bail out sugar mills reeling from the falling price of sugar. The Dhampur Sugar Mills in Uttar Pradesh, which has the largest cogeneration capacity in the country, made Rs 42 crore (£5.3m)from its cogeneration unit in 2007-08, compared to Rs 11 crore (£1.4m) from its sugar units. It sold about 177 million units of power to the state. The third largest sugar maker in India, Triveni, based in Deoband, Uttar Pradesh, is selling 16-17 MW of power to the state.

Big potential

The International Energy Agency says that the sugar sector has a potential to produce 5,100 mw of power through cogeneration, which is 69 per cent of the total cogeneration capacity. If the resources and technology are improved, cogeneration can produce almost 10,000 MW or 40 per cent of the country's 2008 power deficit.

The system works by burning bagasse in a boiler to superheat water and produce high pressure steam. The steam is sent to a turbo generator, where it rotates the generator blades producing electric current.

Bagasse
Bagasse
Bagasse, once a worthless residue, is now an important co-product used for the generation of energy and production of ethanol. It can yield 1850 kcal PCI per kg.
The report points out that bagasse generates nearly the same amount of power as the wind energy sector. Wind produces almost 2,000 MW - most of which remains unused most of the time.

Bagasse-based cogeneration plants also earn carbon credits as the carbon dioxide absorbed by sugarcane plants while growing is more than the carbon dioxide produced in burning bagasse. The cogeneration plant of Triveni earned about 186,000 certified emission reductions worth over Rs 3 crore (£382,000) between March 2004 and December 2007.

Policy changes

India launched its biomass power policy in 1990 and revised it in 2006 to provide a capital subsidy and tax rebates. The 2003 Amendment to the Electricity Act also provided the necessary framework for promoting renewable energy sources - asking states to fix a minimum limit for energy utilities to buy green energy.

However, the country still has a long way to go, says CSE. In the absence of a strong policy framework, feed-in tariffs (the premium cost of green power) differ from state to state and are based on scarcity (not policy). While in some states such as Tamil Nadu, the tariff is as high as Rs 7 per unit, others like Uttar Pradesh pay only Rs 3 per unit. Low feed-in tariffs have begun to hurt cogeneration, says the study.

Narain says: "The policy must incentivise the generation of power, not capital investment." The capital cost of biomass energy is roughly half the cost of installing wind energy. But unlike wind, the raw material - bagasse or other agricultural residues - has competing uses and value. Narain says this price must be paid, as it helps local farmers to improve their returns and encourages production of biomass.

Narain also recommends making the renewable purchase obligation (RPO) mandatory, so that it becomes a tool to push for preferential markets for green energy. "To do this", she points out, "the policy must allow for inter-state sale so that green power-deficit states can purchase from others. In addition, we should consider how biomass-based energy can be used to feed local grids for local and decentralized distribution. Local energy supply should be given preferential tariffs so that villages that do not have power, get it."

To see the complete Down To Earth story visit www.downtoearth.org