Tailpipe emissions
from Compressed Natural Gas (CNG)-powered vehicles may be relatively clean
and you may live longer surrounded by vehicles that run on it. But if CNG
doesn’t kill you, waiting in those endless queues to get this new clean
fuel, probably would.
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| CNG
not practical alternative |
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| Modern
diesels gaining popularity in Europe thanks to improved refinement,
power and lower emissions. |
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Directives from the Supreme Court have forced CNG down the engines of buses,
taxis and autorickshaws in Delhi but there just isn’t enough of the
gas to go around. And that’s the snag. The severe supply shortage,
insufficient outlets and safety issues highlighted by dubious retro-fitters
has put CNG under a cloud. It’s becoming increasingly clear that CNG
is not a practical alternative to conventional fuel. Firstly, CNG outlets
are still far and few between and it will be years before the fuel is as
easily available as petrol or diesel. The volumetric efficiency of CNG is
poor, much lower than that of a liquid fuel which means you have to carry
more of it for a given range. This is why all CNG-powered cars have to cart
around huge cylinders which at best can give 200km between fill-ups. Besides,
these geyser-sized cylinders when fitted into a small car fill the entire
boot, leaving not much space for even a toothbrush. Performance is also
compromised and a gas-powered vehicle just doesn’t drive as well as
a car that runs on petrol or diesel.
From
a long term perspective, CNG, LPG, or for that matter any fossil fuel,
are not the fuel of the future. Car makers are spending billions of dollars
on developing fuel cells to power electric cars. This new energy source
is an environmentalist’s dream as cars powered by it drip drinkable
water as the only byproduct. The huge resources global giants are putting
into fuel cell technology will ensure that one day cars powered by them
eventually become a showroom reality. But that day will take time. Perhaps
even 15-20 years.
In the interim, the trend is moving towards diesel-powered cars, especially
in Europe. In India, the D-word is a dirty one in the eyes of environment
regulators and the courts. The reasons are understandable. The vast majority
of old diesel vehicles roaming our streets are a menace to human health,
spewing smoke and particulates that you could literally chew. The worn-out
engines of most of this ageing diesel fleet and the bad fuel they use
is the reason for their filthy exhaust.
The fact is that diesel hasn’t been given a fair chance in India.
Not many people know how clean diesel engines can be until you’ve
spent time in Europe. There the latest diesel engines are the antithesis
of India’s pollution-belching monsters. Diesel technology is so advanced
in Europe that the latest engines can honestly be called ‘clean’
and their emissions are comparable to CNG engines. European car companies
have invested heavily in refining diesel engines and they are so good
that you don’t hear, see or smell them. Don’t believe it? Hail
a taxi in Frankfurt.
So if diesel engines can be so clean, why can’t we have them? There
are two issues both of which are inter-linked. Firstly, you need the latest
in diesel technology which would add considerable cost to the vehicles
and to make it all work you need the cleanest diesel fuel in the world
which has next to no sulphur content. Impossible? All you need to do is
look back a little more than two years to see what’s changed on petrol
engines. With the introduction of Bharat Stage II norms, four-valve heads,
multi-point-fuel injection and eight to 32-bit microprocessors, once deemed
as costly exotica, are now standard fare. Even the Maruti 800 has this
technology! The lesson here is that if industry is forced to apply its
resources, it can get the results.
Providing ultra-clean diesel is more of a challenge but is not impossible.
We import regular diesel anyway so there’s no problem to import Ultra
Low Sulphur Diesel (ULSD). The tricky part is that ULSD cannot be contaminated
nor adulterated if it is to work wonders in high-tech diesel engines.
What is needed is strict monitoring of ULSD filling stations to ensure
that the fuel remains pure when it enters the fuel tank. Besides, wouldn’t
all this be cheaper than setting up a CNG infrastructure?
The truth is that the diesel engine is the most efficient internal combustion
engine in the world, more so than a CNG or LPG-powered one and there is
no good reason to try and keep it out of the consumer’s hands.
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October 2001 