Peak oil theory and the ethanol alternative to gasoline



By John Ray

The recent big rise in crude oil prices and hence gasoline prices has really sharpened what has long been a concern across the political spectrum -- the fear that oil is running out. There are probably even libertarians who share that fear. The main concern for libertarians however is that the idea seems to be a fertile source of schemes for government intervention in all our lives -- from making air travel more expensive to herding us all onto buses instead of cars. Any oil supply problems are in fact greatly exaggerated but here I simply want to show why ethanol is in any case a viable alternative to gasoline.

There is an article here that surveys the arguments for and against using ethanol (industrial alcohol) as a motor spirit from a Greenie viewpoint. But what he says is largely irrelevant to how ethanol would be used if its usage was market-driven rather than Greenie driven. Under free trade and under conditions of higher oil prices, ethanol could be produced much more efficiently than it is. For a start, the basic feedstock used for production of ethanol in the USA is sugar extracted from corn. This is lunacy in economic terms as free-market sugar produced from sugarcane is only about a quarter of the price that Americans are forced to pay for their sugar by their government's trade controls. There would be no corn-sugar industry under free trade.

And traditional sugar-mills in countries like Australia and Brazil are powered almost entirely by burning bagasse -- the pulpy waste that is left over when the cane is crushed to extract the sugar-laden juice. So little or no fossil fuel is needed to drive the process of sugar production. The sugarcane in effect crushes itself. And after the sugar is produced, little bugs (yeast) turn it into alcohol. That's how the alcohol in beer gets there. And the bugs are not powered by fossil fuel either. They do it for us for free, all by their little selves -- as they have been doing for thousands of years. You could in fact feed the cane-juice fresh out of the crusher directly to the bugs if you wanted to be really energy-efficient about it. There is no need for an intermediate stage of sugar production. And you could get good hooch out of doing that as well. If I remember rightly, that is how rum originated

I should add that sugar production (and hence ethanol production) could be ramped up very quickly. Most sugar-producing countries are so restrained by EU, U.S. and Japanese import policy that they are producing way below capacity. Australia, for instance, could double its production within a year just by being allowed to. The crushing mills are so under-used these days that a lot have shut up shop. And there is a huge area in Western Australia (the Ord) that is suitable for cane that could be brought into production as soon as mills were built. It takes only one year for a cane crop to go from planting to maturity. .

Some background

Sugarcane is a huge grass that grows like mad in the tropics and somewhat less insanely in the subtropics. It is thus growable on a huge slice of the earth's surface. One year after planting it has huge stems which are absolutely full of sugary juice. And the technology for getting the juice out is prehistoric. You just crush the stems and the juice flows out. In most of the tropics (though not in Australia) there are vendors who will sell you for a few rupees (or whatever the local currency is) a fresh drink of very palatable cane juice which they produce by feeding cane stems through a little hand-powered crusher. So a sugar mill is a very simple thing. The only complexity arises out of the need to extract granular sugar out of the juice.

If however cane-sugar were to be used solely for ethanol production, the sugar-production step would not be needed. You could just feed the freshly-crushed juice to yeast bugs in a nice warm environment (and the tropics ARE warm) and they will excrete alcohol as a waste product of their metabolism. And since alcohol has a different specific gravity from water, it is very easily separated out. And that alcohol can go straight into an internal combustion motor and will make the motor roar like a lion -- which is why racing cars use it.

And in Brazil they do precisely that: the cane goes straight from the fields to a distillery which crushes out the juice and then ferments it. So I am not talking blue sky there.

The only reason ethanol is not widely used is cost. When crude oil was $30 a barrel, ethanol cost about twice as much to produce as gasoline. All those cane-farmers had to be paid. But crude is now around $60 a barrel so if that price stays there fairly permanently, I suspect that you are going to see ethanol-compliant engines going into mass-production worldwide. They already have them in Brazil, of course. Depending on your car, you drive up to either the ethanol or the gasoline pump. There ARE a few adjustments needed to run a car on pure ethanol for any length of time -- mostly to do with corrosion control if I remember rightly.

Because they are such a big producer of cane-sugar, Brazil long ago set in train moves to run everything on ethanol rather than gasoline. They were rightly criticized at the time for making motor fuel more costly than it needed to be (when crude was at $30 a barrel) but they seem to be having the last laugh now.

And producing ethanol from cane is extremely "sustainable". It needs no complex inputs or technology and cane can be grown on the same soil year after year as long as there is a suitable input of nitrates. And the nitrates can come either from superphosphate application or from rotating the crop with legumes (beans and peas). Australian sugar farmers do both -- and have been doing so for around 150 years. So there are no mysteries or significant problems with it.

More on the Brazilian experience

Brazil is not these days as keen on ethanol as it once was as they have now discovered oil -- which is cheaper than ethanol -- but their big experiment with ethanol does show how it would work for everybody if that became needful. I reproduce below some extracts from an excellent summary in Wikipedia -- which tells you all you never wanted to know about ethanol. The excerpt gives some real-life facts on how gasoline could over time be replaced by ethanol with little disruption and with a number of beneficial side-effects. I have highlighted some of the secondary advantages in red.

"In Brazil, ethanol is produced from sugar cane which is a more efficient source of fermentable carbohydrates than corn as well as much easier to grow and process. Brazil has the largest sugarcane crop in the world, which, besides ethanol, also yields sugar, electricity, and industrial heating. Sugar cane growing requires little labor, and government tax and pricing policies have made ethanol production a very lucrative business for big farms. As a consequence, over the last 25 years sugarcane has become one of the main crops grown in the country.

Sugarcane is harvested manually or mechanically and shipped to the distillery (usina) in huge specially built trucks. There are several hundred distilleries throughout the country; they are typically owned and run by big farms or farm consortia and located near the producing fields. At the mill the cane is roller-pressed to extract the juice (garapa), leaving behind a fibrous residue (bagasse). The juice is fermented by yeasts which break down the sucrose into CO2 and ethanol. The resulting "wine" is distilled, yielding hydrated ethanol (5% water by volume) and "fusel oil". The acidic residue of the distillation (vinhoto) is neutralized with lime and sold as fertilizer. The hydrated ethanol may be sold as is (for ethanol cars) or be dehydrated and used as a gasoline additive (for gasohol cars). In either case, the bulk product was sold until 1996 at regulated prices to the state oil company (Petrobras). Today it is no longer regulated.

One ton (1,000 kg) of harvested sugarcane, as shipped to the processing plant, contains about 145 kg of dry fiber (bagasse) and 138 kg of sucrose. Of that, 112 kg can be extracted as sugar, leaving 23 kg in low-valued molasses. If the cane is processed for alcohol, all the sucrose is used, yielding 72 liters of ethanol. Burning the bagasse produces heat for distillation and drying, and (through low-pressure boilers and turbines) about 288 MJ of electricity, of which 180 MJ is used by the plant itself and 108 MJ sold to utilities.

The average cost of production, including farming, transportation and distribution, is US$0.63 per US gallon (US$0.17/L); gasoline prices in the world market is about US$ 1.05 per US gallon (US$0.28/L). The alcohol industry, entirely private, was invested heavily in crop improvement and agricultural techniques. As a result, average yearly ethanol yield increased steadily from 300 to 550 m3/kmy between 1978 and 2000, or about 3.5% per year.

Sucrose accounts for little more than 30% of the chemical energy stored in the mature plant; 35% is in the leaves and stem tips, which are left in the fields during harvest, and 35% are in the fibrous material (bagasse) left over from pressing.

Part of the bagasse is currently burned at the mill to provide heat for distillation and electricity to run the machinery. This allows ethanol plants to be energy self-sufficient and even sell surplus electricity to utilities; current production is 600 MW for self-use and 100 MW for sale. This secondary activity is expected to boom now that utilities have been convinced to pay fair price (about US$10/GJ) for 10 year contracts. The energy is especially valuable to utilities because it is produced mainly in the dry season when hydroelectric dams are running low. Estimates of potential power generation from bagasse range from 1,000 to 9,000 MW, depending on technology. Higher estimates assume gasification of biomass, replacement of current low-pressure steam boilers and turbines by high-pressure ones, and use of harvest trash currently left behind in the fields. For comparison, Brazil's Angra I nuclear plant generates 600 MW (and it is often off line).

Presently, it is economically viable to extract about 288 MJ of electricity from the residues of one ton of sugarcane, of which about 180 MJ are used in the plant itself. Thus a medium-size distillery processing 1 million tons of sugarcane per year could sell about 5 MW of surplus electricity. At current prices, it would earn US$ 18 million from sugar and ethanol sales, and about US$ 1 million from surplus electricity sales. With advanced boiler and turbine technology, the electricity yield could be increased to 648 MJ per ton of sugarcane, but current electricity prices do not justify the necessary investment. (According to one report, the World bank would only finance investments in bagasse power generation if the price were at least US$19/GJ.)

Bagasse burning is environmentally friendly compared to other fuels like oil and coal. Its ash content is only 2.5% (against 30-50% of coal), and it contains no sulfur. Since it burns at relatively low temperatures, it produces little nitrous oxides. Moreover, bagasse is being sold for use as a fuel (replacing heavy fuel oil) in various industries, including citrus juice concentrate, vegetable oil, ceramics, and tyre recycling. The state of Sao Paulo alone used 2 million tons, saving about US$ 35 million in fuel oil imports.

Most cars in Brazil run either on alcohol or on gasohol; only recently dual-fuel ("Flex Fuel") engines have become available. Most gas stations sell both fuels. The market share of the two car types has varied a lot over the last decades, in response to fuel price changes. Ethanol-only cars were sold in Brazil in significant numbers between 1980 and 1995; between 1983 and 1988, they accounted for over 90% of the sales. They have been available again since 2001, but still account for only a few percent of the total sales.

Ethanol-fuelled small planes for farm use have been developed by giant Embraer and by a small Brazilian firm (Aero~lcool), and are currently undergoing certification.

Domestic demand for alcohol grew between 1982 and 1998 from 11,000 to 33,000 cubic metres per day, and has remained roughly constant since then. In 1989 more than 90% of the production was used by ethanol-only cars; today that has reduced to about 40%, the remaining 60% being used with gasoline in gasohol-only cars. Both the total consumption of ethanol and the ethanol/gasohol ratio are expected to increase again with deployment of dual-fuel cars.

Presently the use of ethanol as fuel by Brazilian cars - as pure ethanol and in gasohol - replaces gasoline at the rate of about 27,000 cubic metres per day, or about 40% of the fuel that would be needed to run the fleet on gasoline alone. However, the effect on the country's oil consumption was much smaller than that. Although Brazil is a major oil producer and now exports gasoline (19,000 m3/day), it still must import oil because of internal demand for other oil byproducts, chiefly diesel fuel (which cannot be easily replaced by ethanol).

The improvement in air quality in big cities in the 1980s, following the widespread use of ethanol as car fuel, was evident to everyone; as was the degradation that followed the partial return to gasoline in the 1990s.

So the scare about running out of oil is nothing like the problem people pretend. If American cars were kept going by tankers of ethanol from Australia and Brazil rather than tankers of oil from the Middle East, what's the problem? You would have a lot more price stability that way too. And since the tropics are the best place to grow cane, it would give much of the third world a cash-crop alternative to subsistence farming -- which would undoubtedly be of benefit to all concerned (though Greenies would find fault of course. There is no such thing as a happy Greenie)


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