With a view to meet the future demand of energy, it is important to understand the available reserves of non-renewable energy resources including fossil fuels and the limitations posed on them due to environmental considerations.
There is considerable debate and disagreement on the estimates of recoverable oil reserves. However, there seems to be a good agreement on the amount of proven oil reserves in the world. According to British Petroleum, total identified or proven world oil reserves are about 1200 billion barrels. This estimate is close to the reserves of 1266 billion barrels from other sources listed by IEA. The differences among them lie in their accounting for the Canadian tar sands. Considering the present production rate of over 80 million barrels per day, these reserves will last for about 41 years if there is no increase in production. Of course, there may be additional reserves that may be discovered in the future. A recent analysis estimates the ultimately recoverable world oil reserves (including resources not yet discovered) at between 2.2×10^12 barrels and 3.9×10^12 with a mean estimate at 3×10^12 barrels.
Ever since geologist Hubbert correctly predicted in 1956 that US oil production would reach a peak in 1973 and then decline, scientists and engineers have known that worldwide oil production would follow a similar trend. Today, the only question is when the world peak will occur. Barlett has developed a predictive model based on a Gaussian curve similar in shape to the data used by Hubbert. The predictive peak in world oil production depends on the assumed total amount of recoverable reserves.
If the estimates of oil reserves are correct, we may have already peaked in world oil production. If however estimates of the ultimate reserves (discovered and undiscovered) are used, we may expect the oil production to increase a little longer before it peaks. However, changing the total available reserves from 3×10^12 to 4×10^12 barrels increases the predicted time of peak production merely 11 years. There is no question that after the world peak is reached and oil production begins to drop, either alternative fuels will have to be supplied to make up the difference between demand and supply, or the cost of fuel will increase and create an unprecedented social and economic crisis.
The present trend of yearly increases in oil consumption, especially in China and India, shortens the window of opportunity for a managed transition to alternative fuels even further. Hence, irrespective of the actual amount of oil remaining in the ground, peak production will occur soon. Therefore, the need for starting to supplement oil as the primary fuel is urgent because an orderly transition to develop substitutes will take time and careful planning.
According to BP the total proven world natural gas reserves at the end of 2004 were 179.5 trillion m3. Considering the production rate of gas in 2004, with no increase in production thereafter, these reserves would last 67 years. However, production of natural gas has been rising at an average rate of 2.5% over the past 4 years. If production continues to rise because of additional use of gas for transportation and increased power production, the reserves would last for fewer years. Of course, there could be additional new discoveries. However, even with additional discoveries, it is reasonable to expect that all the available natural gas resources may last about 50 years with a peak in production occurring much earlier.
Coal is the largest non-renewable resource available to us and the most problematic from an environmental standpoint. From indications, coal use will continue to grow for power production around the world because of expected increases in China and India. From an environmental point of view, this would be unsustainable unless advanced Clean Coal Technology (CCT) with carbon sequestration is deployed.
Clean Coal Technology is based on an integrated gasification combined-cycle (IGCC) that converts coal to a gas that is used in a turbine to provide electricity with CO2 and pollutant removal before the fuel is burned (Hawkins, Lashof and Williams). According to an Australian study (Sadler), no carbon capture and storage system is yet operating on a commercial scale, but may become an attractive technology to achieve atmospheric CO2 stabilization.
According to BP, the proven recoverable world coal resources were estimated to be 909 billion tons at the end of 2004 with a reserve to production ratio of 164 years. The BP data also shows that coal use increased at an average rate of 6% from 2002 to 2005, the largest increase of all non-renewable resources. Because China and India are continuing to build new coal power plants, it is reasonable to assume that coal use will continue to increase for at least some years in the future. Therefore the reserve to production ratio will decrease from the present value of 164 years. This ratio will decrease even more rapidly when clean coal technologies are utilized instead of direct combustion.
The current 3rd generation Nuclear Power Plants is not sustainable and not proliferation resistant. Currently research is carried out for the 4th generation nuclear power plants which could be sustainable and proliferation resistant. This 4th generation Nuclear Power Plants will not be on the market before 2030. Therefore nuclear energy is currently not a sustainable renewable energy source. A presentation on nuclear energy can be found on nuclear energy presentation
Even though there are widely differing views and estimates of the ultimately recoverable non-renewable resources, it is fair to say it lasts for around 50 years with a peak in production occurring much earlier. However, a big concern is the climatic threat of additional carbon that will be released in the atmosphere. According to the estimates from the IEA, if the present shares of non-renewables are maintained up to 2030 without any carbon sequestration, a cumulative amount of approximately 1000 Gigatons of carbon will be released into the atmosphere. This is especially troublesome in view of the fact that the present total cumulative emissions of about 300 Gigatons of carbon have already raised serious concerns about global climate change.
On Global Fossil Energy Problem a presentation can be found on the problems of the non-renewable energy resources.
On Energy Until 2100 a presentation can be found which illustrates this analysis.
On Environmental Impacts you find a presentation on the Environmental Impacts of non-renewable energy conversion and use