Wednesday, October 17, 2007

Underground Coal Gasification.

Coal gasification is the conversion of coal into gases that can be used directly as fuel or as feedstocks for the creation of liquid fuels (e.g. hydrocarbons) or for commercial processes such as the production of fertilizers and other chemicals, including pharmaceuticals. As oil stocks begin to run short and an inexorable demand is placed on natural gas to substitute for it, either to be burned per se or indeed turned into synthetic oil, we face an energy supply crisis which will hit civilization across the board, with soaring prices of all goods including food, and even food shortages, since modern agriculture is now entirely underpinned by oil and gas: e.g. oil to run farm machinery and gas to produce hydrogen which is combined with nitrogen to make ammonia, the mainstay raw material for synthetic fertilizers.

If this crisis will begin to bite within a decade following the arrival of Peak Oil, and then grip humankind more determinedly in subsequent decades, what is there that might be implemented to take the place of oil and gas? The only other carbon-based material in substantial abundance is coal, and so we need to dig more of it. There are estimated to be upward of six trillion tonnes of coal available for extraction on earth, and probably much more in locations that are hard to access. For example, some three trillion tonnes of coal have been identified under the sea off the coast of Norway, but this is not amenable to conventional mining and extraction. The UK has around 220 million tonnes of coal (to be compared with the 60 million tonnes or so we use each year, two thirds of which is imported) in known mines and it is thought that a total of 1.5 billion tonnes could be got by extending the existing mining infrastructure - i.e. just keep digging the seams that are already underway. Indeed, some mines that were closed in the 1980's in Yorkshire and in South Wales are now being re-opened, and so there are efforts ongoing in this respect.

It was however, estimated that there are some 190 billion tonnes of coal altogether underlying the UK, particularly if regions under the southern part of the North Sea are included in the tally, as I commented in a previous posting ("Coal May be Crowned King after all!", Monday December 4th, 2006). However, while this would amount apparently to nearly 700 years worth of supply, not all of that is readily accessible, and to dig it out by conventional means, covering an underground area of probably around one third that of the UK mainland, is not a realistic option unless some extremely efficient new technology were devised and implemented by the industry.

As an alternative strategy, the conversion of coal to gas in situ is being considered. The putative process is called Underground Coal Gasification (UCG). In UCG, two boreholes are drilled into a coal-seam underground, one to introduce oxygen and water (to provide steam), and the second to bring the gaseous products of the partial combustion/steam reforming of the coal to the surface. The gas will consist principally of hydrogen and carbon monoxide along with smaller amounts of methane and other flammable hydrocarbons that are formed by in situ pyrolysis of the coal itself in consequence of the high temperatures incurred.

There are many potential advantages to the UCG approach, namely that actual coal extraction is unnecessary, along with the usual detritus of coal mining, e.g. slag-heaps of rock and coal waste (such as engulfed a school at Aberfan, in South Wales, forty years ago, killing 129 children). Furthermore, the process would make available a clean fuel/chemical feedstock gas, and on our own shores. As noted, there is the considerable appeal too that it might be thus possible to utilise huge stocks of coal that would otherwise remain inaccessible. The essential premise of UCG has been shown to work in trials e.g. in Russia, but it is mandatory to evaluate the controllability of the process over sustained periods of operation (we are talking about hundreds of years), and any negative environmental impact on underground aquifers (i.e. groundwater pollution) and on any adjacent strata, such as subsidence. The latter is of particular concern since coal often intersperses rock layers and provides a supporting medium for them and so, if the coal is dug out, either literally, or by conversion from solid to gas, will not the overlying rock simply collapse into the "hole" that has been created?

The gasification of coal seams in situ was first done by the Russians in the 1930's and processes have been in operation since WWII. One, ongoing in Uzbekistan, is still in operation now, and experimental UCG technology is being undertaken in Australia, as advised by experts on the subject from Uzbekistan. In the 1950's, Britain established its own UCG trial in shallow mines in Derbyshire with success, but the National Coal Board later abandoned the project on economic grounds. In the US, technology from the oil and gas industries was adapted in the 1970's to make UCG a more readily controllable process, while in Europe UCG has been applied to work both shallow and deep seams; the latter in Spain during 1992 - 1999, and funded by the British DTI, the EU and Spanish and Belgian organisations.

Hence the overall vista for UCG appears optimistic, and a six-year project has been inaugurated in the UK at a cost of $15 - 20 million, with the following aims:

(1) To improve the accuracy of in-seam drilling.
(2) To examine the implications of burning UCG gas in electricity-generating turbines.
(3) To evaluate the real land-reserve capacity for UCG.
(4) To identify a semi-commercial site to undertake the process.
(5) To work-out the likely costs.
(6) To carry-out a feasibility study of offshore coal-exploitation by UCG methods.

It sounds great, so let's get started! What are our realistic alternatives? Nuclear, renewables on a gargantuan scale, or increasingly vulnerable imports of natural gas from unstable regions of the world. If it works, UCG answers some questions about security of supply, and with carbon-capture technology it could also cut our CO2 emissions. It still doesn't mean we can readily match our current requirements of imported fuel (although UCG gas could be converted into some synthetic fuel using Fisher-Tropsch technology) and so transportation remains almost certain to be curbed on a substantial scale, hence forging local communities/economies, if people need to stay put and it is less feasible to transport food/goods over significant distances.


Related Reading.
http://www.coal.gov.uk/resources/cleanercoaltechnologies/ucgoverview.cfm


2 comments:

sustain_ability said...

According to Colin Campbell, Peak Oil occurred in 2005. Please see below.
Sustain
http://transitions.stumbleupon.com
http://peaknik.blogspot.com

Wednesday, June 20, 2007

World: Clock Ticking On Global Oil Supply

By Roman Kupchinsky

Russia -- Nodding donkey oil pumps at Yermakovskoye oilfield operated by Tyumenneftegaz, a TNK-BP subsidiary, Nizhnevartovsk District, 05Feb2007
Russian oil wells will be pumping air in 23 years, according to BP (file photo)
(TASS)
June 19, 2007 (RFE/RL) -- The debate over how much readily accessible oil remains on Earth has been revived with the release of a new report that suggests there is enough to last about 40 years.

But critics say British Petroleum's 2007 "Statistical Review Of World Energy," released this month, is far too optimistic.

In 2003, a team of scientists from Sweden's University of Uppsala presented evidence that purported to prove that the world's oil reserves are up to 80 percent less than predicted. They claim that production levels will peak by 2013.

Colin Campbell, a former chief geologist and vice president of BP, disagrees with the company's latest oil-reserve estimates. He recently explained in the "Independent" that he believes the production of regular oil, the kind which is easy and cheap to extract, peaked in 2005. By his estimates oil will become a rare commodity by 2011.

And Campbell confesses that he mistrusts figures provided by oil companies. He told the "Independent" in a recent article that, "When I was the boss of an oil company I would never tell the truth. It's not part of the game."

Saudi And Russian Reserves

Estimates of proven oil reserves in the Middle East have befuddled analysts for years because the Kingdom of Saudi Arabia has kept estimates of its reserves a state secret.

BP estimates of countries' oil reserves:

Iran: 86.7 years
Kazakhstan: 76.5
Saudi Arabia: 66.7
Azerbaijan: 29.3
Russia: 22.3 years
India: 19.3
United States: 12
China: 12
Turkmenistan: 9.2
United Kingdom: 6.5


Nevertheless, the BP report states that by the end of 2006, Saudi Arabia had reserves of 264.3 billion barrels, or almost 30 percent of the world's reserves.

Matthew Simmons, author of "Twilight In The Desert -- The Coming Saudi Oil Shock And The World Economy," published in 2005, believes that the Saudis are overstating the size of their reserves. Simmons writes: "Saudi Arabian production is at or very near its peak sustainable volume (if it did not peak almost 25 years ago) and is likely to go into decline in the very foreseeable future."

Simmons based his analysis on technical documents about the kingdom's seven giant oil fields that have been the workhorses of Saudi oil production for decades.

Fatih Birol, the chief economist of the International Energy Agency admitted in 2004 that Saudi production was "about flat."

Russian oil reserves are also a state secret. BP reported that by the end of 2006 Russia's proven oil reserves were 79.5 billion, or 6.6 percent of the world's total.

Estimates of Russian oil reserves keep increasing almost yearly. In 2004 BP's survey listed them to be 69.1 billion barrels, up from 45 billion in 2001. Some oil auditing firms believe that the reserves are much greater -- between 150 billion barrels and 200 billion barrels.

Dry Holes

Part of the problem of predicting how long oil will be readily available is the tremendous pressure placed on oil companies by shareholders to meet demand.

In January 2004 Royal Dutch Shell, the third-largest oil company in the world, shocked energy markets around the globe by announcing that its proven oil reserves were overstated by 23 percent.

At the time Shell was falling behind its competition in new oil-field discoveries and in acquiring other oil companies and their reserves. That year, two-thirds of Shell's most promising wells had been determined to be dry holes, and in an apparent attempt to maintain its market position the company overstated its proven reserves.

Accurate information is key at a time when many states are seeking to cut their growing consumption of oil in order to stave off global warming and reduce their dependence on foreign producers.

And the stakes are high, as once oil consumption overtakes production, an unprepared world faces a volatile situation.

Radio Free Europe / Radio Liberty © 2007 RFE/RL, Inc. All Rights Reserved.

energybalance said...

The Swedish 2013 estimate would fit with the Norwegian Statoil's prediction that the peak is due anywhere between 2010 and 2015.

80% less than thought would mean there is only about 200 billion barrels worth left in the ground for extraction, i.e.about 6 - 7 years left!

I had read Colin campbell's 2005 figure, and I wonder if it is just that technology has disguised this by keeping production up? If so then we can expect an oil plummet in production, way in excess of Hubbert theory which appears benign by comparison!

Thanks for all your comments and information on this blog! It is very informative (if frightening!), and I appreciate it!

Chris.