How to make electricity from rice husk

“When you travel through Bihar at night,” says Ratnesh Kumar, co-founder of Husk Power Systems, “every place you see is dark. You don’t see anything.

“But if you travel during the day, no matter where you go you’ll find roads full of people in the remotest of places. Houses just next to the highway.” His voice is slow and steady, like his manner. “But people won’t light their lanterns for a moment longer than they need, as they are so poor.”

Bihar is one of the poorest states in India, in the north-eastern center of the country. In such lean conditions as in its villages, people waste very little. When Ratnesh and Gyanesh Pandey, Ratnesh’s childhood friend and the other co-founder of Husk Power Systems, first began to research the living conditions in these villages, they found that even the garbage gathered in the evenings was used in some way. “Villagers live in complete harmony with nature,” explains Ratnesh. In these stretches of darkened countryside, they found only one substance that was going to waste: the leftover husks of rice grains. Ratnesh and Gyanesh decided to use this one stray link to produce what the villagers most needed.

Their company, Husk Power Systems, now provides electricity for six to seven hours each evening, to about 100,000 people across 125 villages, using only rice husk.

The power plants that have achieved this impressive task are modest in appearance. A typical Husk Power Systems (HPS) compound is only 5000-6000 square foot of rented land with a small biomass gasifier on it, one storey tall and slim enough that two men could encircle it with their arms. Biomass gasification is a simple and relatively old process, in which biomass is heated to very high temperatures in an atmosphere of less than 1% oxygen. Under these conditions, it does not burn in flames, but turns into a ‘producer gas.’ In the HPS compound, there are large piles of biscuit-coloured rice husk for feeding the machine, and smaller piles of black rice husk char, which is the small amount of solid waste the gasification process generates in addition to the gas. Next to the gasifier are four filters for cleaning tar and dust from the gas, and a generator in which the producer gas is used to drive a turbine and create electricity. That’s it. From the compound run the HPS wires that carry electricity to houses within a maximum distance of two to three kilometres, because, beyond that, there begins to be a drop in voltage. To further increase efficiency, HPS also insist that customers may use only energy-saving CFL bulbs.

India’s rural electrification programme focuses on extending a main electricity grid, but there are many places it hasn’t reached yet, and it’s estimated 40 million people in the country still have no electricity connection. HPS focuses its attention primarily on villages that are off-grid, but will set up anywhere there is rice husk and a demand for electricity. To date, they have 35 power plants in operation; four of 52kW and the rest 32kW installed capacity. Once the 25 plants currently under installation are complete, HPS will have a total installed capacity of about 2MW.

Some more figures: HPS pays under one rupee per kilo for rice husk, and by loading 50kg per hour into one of their 32kW power plants, can produce enough power to sustain a load of 700 typical rural households at the same time. The model seems unstoppable: this year, Bihar will produce 1.8 billion kilograms of rice husk. If you extend the model to all of India, as HPS plan to do, they say it is possible to generate 27GW of power from just the waste rice husk that is produced in the country. That’s one sixth of the total installed generating capacity of the nation.

Part of the beauty of the model is that it’s built on a resource that costs, as Ratnesh describes it, “not that much.” When the company first began buying rice husk for their pilot plant, local millers noticed the commodity had become valuable and started hoarding it, driving prices up accordingly. Ratnesh and Gyanesh responded by setting up their own rice mill, dehusking villagers’ rice for free. All the other rice mills went out of business. Ratnesh and Gyanesh signed a contract with them, guaranteeing that they could buy rice husks at an affordable price for the next six to eight years, and then shut down their free mill to direct the business back to the other mills. They have a similarly inclusive approach to the diesel merchants, as many of the villages they’ve set up in have private micro-grids already in place, distributing electricity generated by enterprising individuals from burning diesel. “First we offer them work at our plant. If they choose not to work with us, there’s enough business that we can both set up there. We don’t want to completely take over somebody else’s business.” Ratnesh laughs a little. “We do take some share of their market, though.”

Climate change and pollution doesn’t really feature on the radar of the rural poor, but diesel fuel presents other problems due to its expense. Incomparison, the HPS electricity is an excellent deal for a customer. Anush Kumar, 25, runs a hostel for schoolboys in Sariswa, a village in West Champaran District in the west of the state. He previously paid 1700 rupees per month for a diesel generator to light the hostel for three hours every evening, but now pays 1200 rupees a month to HPS for a power supply for seven hours from their nearby plant. The students can study later, and a saving of 500 rupees can really make a difference when you have 125 boys to take care of. “I’d be happy to pay for full, 24-hour access,” he says. “We have a grid connection but it only gives us power for one or two days a month. It’s useless.” Scant power supply is a common bane for the rural population of India, who too often lose out to the cities in the scrabble for electricity from the large power plants.

Photo: Harikrishna Katragadda/Greenpeace

Madi Devi, 50, sits in the marketplace down the street with a two-year-old child asleep in her lap. The 32kW Sariswa plant is already operating at full capacity, and so Madi has not been able to take a connection. She’d like to, and says she would pay for it. The HPS connection would be cheaper than the kerosene she buys at the moment, and her household could save 150 rupees per month. What would they spend it on? “Food,” she says simply. The family of seven have a monthly income of 1500 rupees.

The dim tarry light from Madi’s kerosene lamp is one of three grades of light in Sariswa village at night time. Those doorways with a connection are pooled in the white light of a CFL bulb, and above each connected household hang a bunch of low wattage yellow bulbs like balloons. These filament bulbs are HPS’s field method of monitoring current: a customer can have as much electricity as they want and would want to pay for, but there has been a problem with people stealing by using more than agreed. The filament bulbs work as fuses because they burn out when too much current is drawn. Ratnesh blames the theft on the rural Bihari’s “inertia to change”, and a sense of entitlement borne of an intractable caste system. He tells us about a story of one village, where an HPS electrician fitting a fuse outside an upper-caste man’s house had a gun held to his head by the furious customer, who felt his caste gave him the right to free electricity. When the electrician did not demur, the man “broke his head” with a stick. A police complaint went nowhere. “This man would spend 50,000 rupees fighting the case, but he wouldn’t pay 50 rupees a month because he had to show his supremacy in the village,” explains Ratnesh. In the face of such brutality, HPS shut the plant and 500 villagers lost their electricity connection. “The whole village suffered, but no one came forward to say anything.” Ratnesh shakes his head.

The stubborn caste system is something that HPS is striving to challenge through their power as an employer as well as a supplier. On one of the days we visit, Ratnesh has driven the eight hours from Patna to play a game of football with the HPS employees of West Champaran District. The managers play next to the husk-loaders in the pouring rain, distinguished only by their shirt or lack of it to demark the two teams. HPS insists that all employees refer to each other respectfully, with the ji suffix that balances respect and affection in India to every name, but creating a sense of equality is a slow process.

“Sir! Sir! Shall I kick the goal now, sir!” shouts one employee to his managers, pausing in front of the makeshift goalposts. “Just kick it!” They shout back.

The exemplary HPS model has won accolades, both social and financial. Yet if they hadn’t won their first monetary awards in the US, accessing start-up finance could have posed a problem, and banks do not consider such projects in Bihar a worthwhile investment: too much corruption, too many problems. Instead, HPS now has thousands of paying customers in both domestic (80-90%) and commercial sectors across Bihar, and have just built their first plant in Uttar Pradesh, a neighbouring state. There are plans to expand to states in the south (Tamil Nadu), east (West Bengal) and north-east (Assam), as well as across the border to Nepal. “Anywhere there is rice husk, it can work,” says Ratnesh. They’ve now discovered that silicon can be extracted from the rice husk char, and plan to start selling this to solar panel manufacturers, creating in-house employment for rural women in Bihar in the process. They’re also seriously contemplating registering HPS’s power plants under the Clean Development Mechanism (CDM) , which would bring them an extra income of around 100,000 rupees per plant per annum, based on the calculation that an electricity connection will save a villager from burning ten litres of kerosene per month.

They have no interest in patenting their model. The secret lies not in the biomass gasification system, which is “so simple that even a person who cannot read and write can operate it with a little bit of training,” sniffs Ratnesh, but in their social blueprint. Most of the managerial staff trained at India’s best business schools, and have left jobs with higher salaries both at home and abroad to work long hours in villages with no connectivity and no toilets. “But they work very well,” says Ratnesh, “because they also want to make a difference.” Some other employees previously led lives of drugs or crime, and now work for HPS on the straight and narrow. The unifying factor is “passion. If you don’t have that, you can’t work with us.”

One suspects there must be some negative externalities to the model. Every method of power generation has them. “To be honest,” Ratnesh says, “of this plant, I haven’t seen any. We have analysed noise level pollution, quality of gas, the effect the plant is having on the surrounding area…” In fact, there have been many positive effects witnessed in the villages where HPS has set up plants. Villagers say that burglaries have reduced because of better lighting at night, and the number of snakebites in each village suddenly dropped to zero when the electricity came. Quality of life for women improves as they can at least see the insects that swarm as they’re cooking, and shopkeepers make more money, as they can stay open for more hours. Electricity to power one 30W CFL bulb costs 80 rupees a month, and most plants operate for six to seven hours every evening. “They wouldn’t have got a better deal than this in their whole life,” says Ratnesh. Initially customers were paying after using the electricity, but there were problems with some people refusing to pay. Payments are now collected in advance by an HPS employee.

On the final day we meet, he shares some news. It’s a small piece of news, but it holds a wonderful potential. Five residents from the village where the upper caste man beat an electrician, and HPS had to shut their plant, came to see Ratnesh in the morning. They told him they wanted electricity, and were prepared to put in the work to start up a plant themselves. HPS decided that these five villagers will be their first production franchisees.

When Ratnesh and Gyanesh were children, they used to chant a sanskrit prayer in the mornings at school. Aum, the children said.

Asato ma sad gamaya,
tamaso ma jyotir gamaya,
mrityor ma aamritaam gamaya

Line for line, it means

lead me from ignorance to truth,
from darkness to light,
from death to immortality.

Today, tamaso ma jyotir gamaya – ‘from darkness to light’ – is the motto of Husk Power Systems.

The above is adapted from a case study conducted on behalf of Greenpeace India into renewable energy in Bihar. The full release can be found here.