Future energy demand and supply
Future energy demand and supply

Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course

Future energy demand and supply

4.2 Developing current energy systems

4.2.1 Cleaner fossil fuels

A variety of techniques have been developed for manufacturing liquid or gaseous hydrocarbon fuels from coal or crude oil (in some cases to redress a deficit of a particular fuel in a single country). An historic example is 'town gas', mainly hydrogen and carbon monoxide with minor amounts of methane, which is produced by destructive distillation of coal in the absence of air (pyrolysis) and with steam injection. The process was associated with the production of coke, coal tar and other industrially useful materials. In the UK, town gas was a major domestic and industrial fuel from 1804 to the 1970s, when it was rapidly replaced by natural gas from the North Sea. It was also produced from oil in the UK between 1960 and 1975.

Plentiful supplies of oil and gas have curbed research into developing these technologies; after all, why bother with complex conversions when the stuff simply comes out of the ground virtually ready to use? However, the large reserves of coal may offer a source of oil by liquefaction, as well as more sophisticated gasification. Production of oil from coal was first developed on a commercial scale in Germany during the 1930s and 40s, and has operated in South Africa since the mid-1950s (Figure 17), prompted initially by the country's lack of oil, abundant coal deposits, and increasingly isolated political stance. Although three plants remain operational, the real costs of production are not competitive with crude oil, unless oil prices continue to rise. Although the South African plants employ a two-stage process (gasification followed by catalytic synthesis), research currently favours the development of a different, relatively low-temperature, catalytic process where the coal is first dissolved in a suitable solvent before treatment with hydrogen.

Figure 17 The Sasol plant in South Africa that converts coal into oil products.

Other non-conventional sources of liquid petroleum are estimated to represent a vast, untapped resource (they include tar sands, oil shales and heavy oil. However, these are not clean fuels, and in the main they require extensive (and expensive) processing to produce petroleum comparable to crude oil. The difficulty in their exploitation, and their potential environmental effects, have retarded their development thus far, and may continue to do so unless the world remains addicted to petroleum as an energy source beyond the lifetime of conventional reserves. Methane hydrates, currently residing in seafloor sediments and some terrestrial settings, represent huge potential resources. They also present a major potential hazard to climate, should warming of deep water destabilise them. Yet their formation involves another gas hydrate that incorporates carbon dioxide, and methane-hydrate exploitation could be combined with sea-floor CO2 sequestration.

S278_19

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371