Diesel is normally used in automobiles, tractors and trucks and is considered a dirty fuel since these vehicles emit smoke and particulates. Recently, the high pollution levels in Delhi's air have been blamed on diesel-powered vehicles. It has a bad rap. However, recent work done by the Nimbkar Agricultural Research Institute (NARI), a rural NGO in Maharashtra, has shown that it can be an excellent and clean fuel for cooking and lighting in rural households when used in a newly invented device called the "Lanstove" (lantern plus stove). So far, diesel has not been considered for use as a household fuel primarily because of its cost and also because of the unavailability of devices that can run on it.
What the Lanstove can do
NARI's diesel-powered Lanstove simultaneously provides excellent light (equivalent to that from a 200 W electric bulb) and cooks a complete meal (including chapatti and bhakari) for a family of five. Besides it can make 10l of water potable. Thus, one device provides excellent light, clean cooking energy and drinking water.
"The carbon monoxide (CO) levels from regular chulhas are between 250-400 ppm-- or 80 to 130 times more than that from the Lanstove. Thus, this is an extremely clean device for cooking."
The diesel Lanstove has been tested for the last few months in five unelectrified rural huts in western Maharashtra. It has shown excellent results, with users commenting that it does not produce smoke or smell like their existing biomass-powered chulhas. In addition, they say it gives excellent light compared to the presently used hurricane lanterns, tin wick lamps and even solar lamps.
Why the device is 'clean'
The carbon monoxide (CO) levels (measure of how good the combustion is) from Lanstoves are less than 3 parts per million (ppm), whereas those from regular chulhas are between 250-400 ppm-- or 80 to 130 times more than that from the Lanstove. Thus, this is an extremely clean device for cooking, equivalent to an LPG stove.
Previously, NARI had developed this stove to run on kerosene and had tested it in 23 unelectrified huts for one year. However, the unavailability of kerosene for the rural poor (it is normally diverted on a large scale for adulteration of diesel) hampered its growth. Hence NARI thought it prudent to run it on diesel which is available in plenty everywhere.
Normally, both kerosene and diesel are considered to be dirty fuels. Hence their use for rural households has not been looked at favourably. But here's the thing: every fuel is dirty. It is the way it is burnt that makes the fuel clean or dirty. Thus liquid petroleum gas (LPG), compressed natural gas (CNG) or ethanol become clean fuels only because of excellent combustion technologies available for them. The Lanstove allows diesel to burn very cleanly.
"The poor cannot wait indefinitely to get cheap renewable energy technologies for lighting and cooking. They need devices now to improve their quality of life."
The Lanstove has been designed so that diesel is stored in a slightly pressurised (4 kg/cm squared) 7l cylinder from where it flows into the combustor and burns very cleanly. This detachable cylinder can be filled up and pressurised in diesel pump stations. This filling of diesel in a cylinder will be similar to getting an LPG cylinder changed.
Our data shows that for a family of five, the Lanstove will require about 20l of diesel per month and one full cylinder will last for 10 days. Our research also shows that on large scale manufacturing, the Lanstove (including the cooking utensils) will cost only Rs 4000 or so.
Subsidies for better reach
However, for the Lanstove to be adopted on a large scale in rural areas, we need an enlightened government to come on board and make it available at cheaper rates to poor people. Our data shows that it should be made available to BPL families through their UID (Aadhaar) card at the subsidised rate of Rs. 30/litre.
With this diesel subsidy the Lanstove's running cost will be equivalent to having subsidised LPG for cooking and subsidised electricity for lighting.
According to the latest census figures (2011) there are about 35,000 villages in India which have never been electrified. These villages should be the first to be given the Lanstove so as to improve the quality of life of their inhabitants.
With a selling price to rural poor at Rs 30/litre the total subsidy bill for diesel for 35,000 villages will come to be about Rs 12,600 crores. This is less than one-third of the subsidy given presently for LPG (Rs 40,000 crores/year) and which mostly goes to middle- and upper-class Indians. With a diesel subsidy given to the rural poor, around 21 million rural households (10.5 crore people) will immediately benefit with excellent light and clean cooking technology.
The poor cannot wait any longer
Electricity-based lighting is the most efficient but it is difficult to see how it can be made available throughout rural India. According to the 2011 census around 300 million people are without electricity even after 65 years of independence. Various NGOs, foreign agencies and even GOI departments are therefore promoting solar-powered LED lanterns. These lanterns are costly, produce light equivalent to that from a 40W bulb, are difficult to maintain because the lead acid battery in them fails easily and are energy guzzlers in their production (solar cells consume more energy in their manufacture than they will ever produce in their lifetime). Besides solar lanterns cannot cook!
Recently it has also been shown that LED light is harmful to the eyes and produces irreparable damage to the retina. On the other hand, light from the Lanstove has a continuous visible spectrum and is easy on the eyes.
The critics of diesel or other fossil fuel-based lanterns contend they contribute to harmful earth-warming greenhouse gases. However, a recent scientific study suggests that earth-warming is caused mostly by Chlorofluorocarbons (CFCs) emissions rather than those of carbon dioxide.
The poor cannot wait indefinitely to get cheap renewable energy technologies for lighting and cooking. They need devices now to improve their quality of life. The best strategy, therefore, is to rapidly develop technologies which make the existing fuels burn efficiently and in an environmentally safe manner. I believe that the Lanstove does exactly that.