IT WAS once the hero of the oil industry. The fuel additive MTBE was supposed
to be the answer to air pollution. Instead, it turned out to be a villain,
causing groundwater pollution that has left aquifers from New England to
California reeking. Now, with the US on the brink of banning MTBE, the question
is what will come next.
American farmers are hoping it will be alcohol. Like MTBE (methyl
tertiary-butyl ether), ethanol can reduce emissions from cars. Unlike MTBE,
any ethanol that leaks into the environment quickly breaks down. And farmers
love it because most ethanol is produced from maize, so it promises a lucrative
new market for their crops. 鈥淒epending on how it鈥檚 handled, the MTBE phase-out
could be a huge boost for the ethanol industry,鈥� says Monte Shaw of the
Renewable Fuels Association in Washington DC. 鈥淭his is the year.鈥�
Once seen as a potential fuel in its own right, ethanol proved too expensive
to compete with petrol. There are exceptions, such as Brazil, where fuel is up
to 24 per cent ethanol made from sugar cane鈥攂ut only with the help of
government subsidies.
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In the US, ethanol鈥檚 first hope of hitting the big time came with the Clean
Air Act of 1990, which required petrol sold in polluted cities to contain at
least 2 per cent of oxygen by weight. This means petrol must be around 6 per
cent ethanol by volume, or 11 per cent MTBE鈥攁 huge market.
By releasing oxygen when the fuel is burnt, these 鈥渙xygenates鈥� ensure
complete combustion, particularly when engines are cold. This reduces levels of
pollutants such as carbon monoxide.
The fledgling ethanol industry, however, lost out to cheaper MTBE. Then
MTBE began to turn up in wells, lakes and aquifers around the country. 鈥淪anta
Monica has lost its entire groundwater supply,鈥� says Bill Magavern of the
environmental group Sierra Club California. 鈥淢TBE is wreaking havoc on this
蝉迟补迟别.鈥�
The trouble is that MTBE is water-soluble, so leaks from underground
tanks can spread through water supplies
(快猫短视频, 22 November 1997, p 24).
It has an unpleasant smell and taste, and may also be a carcinogen.
鈥淲e鈥檙e the damn skunk at the picnic,鈥� complains Thomas Adams, whose Oxygenated
Fuels Association near Washington DC represents MTBE producers.
Apart from the US, few countries make much use of MTBE. But in Europe its
future could be boosted by plans to remove benzene from petrol. The European
Union intends to cut the level of this potent carcinogen in fuel by 75 per cent
by 2005, which could lead to a big increase in the use of MTBE.
In the US, however, its prospects look bleak. Some oil companies, including
Chevron, support a ban and a handful of states are already moving to outlaw it.
Now Congress looks likely to rule against it.
The crucial questions are whether the 2 per cent oxygen requirement will
survive an MTBE ban, and whether the law will stipulate that renewable fuels
should be gradually introduced. Either would be a boost for ethanol鈥攂ut
both would be fiercely opposed by oil companies.
Citing ethanol鈥檚 already heavy subsidies, Senate power brokers John Breaux of
Louisiana and John McCain of Arizona are formidable opponents. Yet the ethanol
lobby is confident, listing Senators Bob Smith, head of the Environment and
Public Works Committee, and Democratic leader Tom Daschle as allies. Even
oilman-turned-president George W. Bush has made overtures to the ethanol
industries. The biggest hurdle is likely to be fears that imposing ethanol on
the fuel industry could increase prices at the pumps.
Bill Bush of the American Petroleum Institute, which lobbies for the oil
companies, says that the 2 per cent requirement is too rigid. There are other
ways of making clean-burning fuels. 鈥淭ell us what the emission goals are,鈥� says
Bush, 鈥渁nd we鈥檒l figure out the best way to get there.鈥�
Some scientists agree. They argue that the drop in pollution in the US in
recent years is due to the introduction of catalytic converters rather than
the use of oxygenated fuels
(快猫短视频, 22 May 1999, p 20
and 15 July 1995, p 24).
Ethanol鈥檚 supporters counter that oxygenates are essential for maintaining
good engine performance, and that maize farmers depend on the market. 鈥淒on鈥檛
throw out the oxygenate standard with the MTBE-polluted bathwater,鈥� says Eric
Vaughn of the Renewable Fuels Association. 鈥淕eorge W. Bush has pushed
`domestic鈥� sources of fuel,鈥� adds his colleague Shaw. 鈥淲hat could be more
domestic than ethanol, which comes from corn?鈥�
Industry sources predict that the ethanol industry will continue to grow
slowly even if left to itself. But legislation that calls for ethanol could help
kick-start biomass fuels (see 鈥淔rom barrels to biomass鈥�). 鈥淚t would create a 2 billion-bushel demand
for grain to be used towards the production of ethanol,鈥� says Vaughn. 鈥淭hat鈥檚
丑耻驳别.鈥�
Laws specifying the use of ethanol as an additive, or the introduction of
renewable fuels (main story), aren鈥檛 the only ways biofuels are gaining ground.
鈥淲e鈥檙e at the forefront of the renewable fuels movement,鈥� said Bruce Knight of
the National Corn Growers Association.
Mountains of potential fuel鈥攆rom wood chips to forest brush and farm
refuse, for example鈥攇o to waste because there鈥檚 no easy way to turn them
into usable fuels. Cellulose, one of the main components of plants, is
particularly hard to exploit.
鈥淲e don鈥檛 know yet how to produce the bugs to make ethanol from cellulose on
a large scale,鈥� says Eric Vaughn of the Renewable Fuels Association. 快猫短视频s
have grown bacteria that break down cellulose, but the process is uneconomic on
an industrial scale.
This is where the biotech boys come in. Companies are investing millions of
dollars in the race to come up with commercially viable processes. Diversa of
San Diego has trawled the hot pools of Yellowstone National Park for suitable
heat-resistant enzymes. Others are trying to engineer bacteria for the job by
giving them cellulose-munching genes from fungi. 鈥淲e find cellulases in nature,鈥�
says John Carroll of Novo Nordisk BioChem, 鈥渁nd we also develop our enzymes by
actual protein engineering.鈥�
The US government has been encouraging: in 1999 Congress passed laws
authorising some $300 million for research into biofuels, and President
Clinton signed an executive order the same year to stimulate bio-based products
and energy.
Some foresee a world powered by green 鈥渂iorefineries鈥�, where whole crops
would be converted to plastics, chemical intermediates and fuels. 鈥淲e鈥檙e a lot
closer to that than you might think,鈥� says Dan Reicher, the outgoing assistant
secretary for energy efficiency at the Department of Energy. He points at the
factory built in Blair, Nebraska, by grain giant Cargill, which is set to open
this year. 鈥淏iomass goes in the front door and a whole host of products come out
the back.鈥� The factory鈥檚 main product, polyactic acid, is an ingredient in
plastics for clothing, food containers and films.
Other uses for biomaterials abound. Cargill and chemicals giant Dow recently
teamed up to produce 鈥済reen plastics鈥� from corn and wheat. Soybean farmers hope
their crops could be used to make biodiesel.
For some optimists, this is only the beginning. 鈥淭he ethanol plants of today
will be the biorefineries of tomorrow,鈥� says Jim Evangelow of the New York-based
consulting firm Chemical Strategies. 鈥淭he days of big oil are coming to an
别苍诲.鈥�