A great deal of gas to harness
Wednesday, 6 March 2013 – 8:33am IST | Place: Mumbai | Agency: dna
India has an unbelievable advantage in methane generation. Not just from bullshit, as this column explained last week, but also from food waste, agricultural waste, and even human solid waste.
This is what Vadodara-based Deepak Gadhia has been promoting for the past two decades. Gadhia helped set up the cooking facilities for the temple complex of Tirupati, which uses a combination of solar power and food waste to generate enough energy to cook 50,000 meals involving 140 varies of dishes every day.
He has done the same at Shirdi, which today cooks 50,000 meals x 40 varieties daily.
His digester takes all food waste and converts it into methane for meeting any cooking or power generation requirement. He then takes the slurry, dries it, pelletises and packages it, and sells it as first grade manure for organic farming.
India has many temples, gurudwaras and dargahs – not to count the restaurants that dot every village, town and city – which dispense food and inevitably generate food waste by way of leftovers, peels, and unwanted parts of vegetable and fruit. There has been no organised attempt to harness this – either by way of incentives or policy. That is a crying shame.
Vinay Kore, chairman, Warana Co-operative in Maharashtra, has built the largest agro-waste digester in the country to generate 10,000 cubic metres of biogas (65% methane) daily. He wants to double this capacity soon. He uses something called ‘bedmass’ – a thick noxious slurry from sugarcane juice, generated while making sugar, which used to be burnt away.
The digestor has a desulphonation plant as well, because once sulphur is removed, all odious smells disappear. Interestingly, the extracted sulphur can be sold in the market.
This, technically, can be done with both dung and human solid waste. Just as India has the world’s largest cattle population, it also has the world’s second largest human population, which could add to methane generation if all solid waste could be channelled into appropriately located digesters.
As with dung, the residual slurry (after methane extraction) is good manure. So the digester could money from methane, from pelletised odourless manure, and even from sulphur.
Thus municipalities, instead of paying money to get solid waste treated, could actually earn money by auctioning digestor rights for urban centres.
They would not need land-fills for dumping garbage, which pollute land, ground-water and the atmosphere.
Moreover, landfills only help the land mafia get land at throwaway prices.
Kore has discovered something even more interesting. When he uses methane for generating electricity, the state pays him just Rs5 per kWh, which uses one cubic metre of methane.
But when he sells the same volume as CNG to the transport sector, or as cooking fuel, he gets `45. In other words, there is more money in methane than people imagine.