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October 2007

Opinion

 

Peak Oil and South African Synfuels - a positive lesson for the world

By Dr Garth Cambray

This article explores how energy sanctions shaped a nations future energy security providing useful examples to the rest of the world.

Peak oil refers to the point at which global crude oil production peaks, after which its production will decline. South Africa was exposed to gradually increasing oil sanctions culminating in those of the 1970's & 80's and in many ways was subjected to peak oil like conditions prematurely. The result is that more than 30% of South African liquid fuels can be produced from coal and natural gas, with plans for a further 10% to be synthesized from these sources. In many ways the energy alternatives developed in South Africa provide an investor with an understanding of how peak oil will change the way we power the global economy.

To understand how synthetic oil and gas can replace that derived from crude oil it is important to have a brief look at the SA synthetic fuel industry (synfuel). Two feed stocks are currently used to produce synthetic fuels. Coal to liquid technology is used by SASOL, and (natural) gas to liquid technology is used by SASOL and PetroSA to produce liquid fuels.

In coal to liquid (CTL) synthesis coal is gasified to syngas, which consists of a mixture of carbon monoxide and hydrogen. Fischer Tropsch synthesis converts these starting materials into different liquid fuels such as petrol or diesel. In the gas to liquid (GTL) system natural gas is substituted for coal. One of the interesting aspects of this system is that low grade coal can be used as a feedstock, and in the process, many of the pollutants in the coal can be removed without being pumped out of a chimney stack. Burning low grade coal releases amongst others sulphur, cadmium, lead and certain radioactive substances. In the CTL process, many of these can be removed as solids rather than being released into the atmosphere. Sulphur has to be removed prior to synthesis steps as it corrupts the catalysts, hence the fuel is by default low in sulphur.

Synthetic fuels have serious environmental impacts if manufactured in an unregulated fashion. Careful environmental planning can however negate many of these. As an example, synfuels released nearly twice as much carbon into the atmosphere as conventional fuels. In a market such as South Africa however, the distance of crude oil deposits from South Africa means that considerable quantities of fuel are burnt to transport crude oil to the country, hence the carbon balance is slightly less severe when this is taken into consideration. However, any carbon released is a problem, and in this light carbon sequestration is becoming more attractive. As an example a coal gasification plant in Beulah, North Dakota (USA), pipes its flue gas emissions, which are rich in carbon dioxide, to an oilfield 700km away in Weyburn, Saskatchewan. The waste gas is pumped deep into the ground where it helps to displace additional oil. The gas will eventually react chemically with substances in the earth and be removed from potential circulation into the atmosphere.

Depending on the energy requirements of the market, various percentages of final products can be produced using the synthetic fuel route. In South Africa, demand for diesel has grown faster than that for petrol, hence more diesel is synthesized to meet this demand. This is primarily because diesel is more efficient as a fuel.

Economies such as the USA can learn from the SA experience. As fuel prices rise, fuel economy becomes more important. The most fuel efficient engines are diesel engines. Using low grade crude oil based diesel in a diesel engine produces many pollutants. High quality synthetic diesel however burns extremely cleanly. Diesel engines can be made more powerful by the use of a turbo charger - an engine component which also requires high quality fuel. Hence, if synthetic diesel is used as a fuel the 5% improvement in efficiency of the diesel engine translates technically into 5% more fuel to be used for the same amount of carbon released. As a simple example, US liquid fuel demand grew 3.5% last year. Increased conversion to diesel could theoretically therefore completely counter the real growth in fuel volume needed.

Synthetic gas to liquid fuel technology has another important role to play in converting natural gas to liquid fuel in places where the natural gas is too far away from markets to be viably sold as gas. Typically gas from these so called 'stranded gas' fields is flared resulting in total loss of the resource while oil below is extracted. One only has to fly over North Africa to see the monstrous flares of gas in remote places flickering eerily down below to realize the size of this resource. The conversion of such resources to liquid fuel can further increase fuel stability, and reduce unnecessary wastage of energy.


Related articles:

 Coal in South Africa

  Low sulphur diesel and the SASOL story

  Oryx Gas to Liquid Plant in Qatar

  Transporting Mozambican Natural gas to South Africa

 

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