With dwindling fossil fuel supplies, coal has been viewed as the energy source of last resort. This outlook is changing as estimated global coal supplies seem to have been severely inflated. Is coal’s future in doubt?
Many experts are saying yes. Professor David Rutledge of CalTech believes that world coal reserves are grossly overstated and could be substantially exhausted this century. This is in stark contrast to earlier forecasts.
Coal Reserves Inflated
In the last 20 years, official coal reserves have fallen by 170 billion tons. To put this number in perspective, global coal consumption in 2007 was 6 billion tons. Reserves figures are dropping far more quickly than actual extraction.
The European Commission’s Institute for Energy in 2000 estimated global supplies of coal to last 277 years. In 2007, that number was lowered to 155 years.
This forecast may sound like plenty of time to adjust to meeting our energy needs in from other sources, but how accurate are these numbers really? The National Academy of Sciences Report on Coal, from June 2007 isn’t very encouraging.
“Present estimates of coal reserves are based upon methods that have not been reviewed or revised since their inception in 1974, and much of the input data were compiled in the early 1970′s. Recent programs to assess reserves in limited areas using updated methods indicate that only a small fraction of previously estimated reserves are actually minable reserves.”
To make matters worse, some countries, such as Vietnam and China have not changed their official reserves figures for decades. This seems suspicious because billions of tons of coal have been mined during this period.
Much Coal is Expensive to Mine
The US has a staggering 27% of global coal reserves, which is widely estimated to be a 250 year supply. These estimates are based on a USGS study from the 70s that assumes that 25% of known coal reserves can be recovered at today’s prices with current technology. Today the USGS believes only 5% is recoverable at today’s prices with current technology.
New Coal Discoveries Unlikely
While oil lurks below the surface and can be hard to detect, coal fields can be identified by outcrops. This means that the locations of coal reserves are known and new coal discoveries are unlikely.
“Clean” Coal Requires More Coal
30% more energy is required to pump carbon underground for carbon capture and sequestration (CCS). The captured carbon dioxide has to be compressed to 100 times the atmospheric pressure, transferred to an underground storage reservoir and then pumped in the ground. All of this requires large amounts of energy, thus the coal plant must burn an additional 30% more coal to generate the same amount of usable electricity.
Policy Does Not Address Dwindling Reserves
It is important to have more accurate reserve information to respond to diminishing reserves in a successful manner. A 2007 report issued by Energy Watch anticipates global coal reserves to peak as soon as 2025. Policy-makers have been using forecasts issued by the International Energy Agency, which relies on official reserves figures. It is certainly hard to create effective policy when reserve estimates vary so widely.
Affects of Peak Coal
When taking climate change and air quality into account, smaller coal reserves are probably good news, considering that coal is the dirtiest of the fossil fuels. Supply constraints may cause the market to adjust without the need for climate change policy alone to decrease coal consumption. For countries that tend to not want to interfere with commerce and prefer a free market, lower quantities of coal reserves will force the utilization of other energy sources.
On the downside, a staggering 40% of electricity globally is generated from coal and two thirds of the steel industry uses it for fuel. The economic ramifications of peak coal could be significant if other energy sources are not implemented.
Many people fear that declining supplies of oil could cause an increase in the use of coal as a last resort. Perhaps coal is not a good last resort.
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