Fossil fuel Reserves


Of the three significant fossil fuel reserves of oil, gas and coal, oil provides the mobility characterising our current way of life. As finite resources, all three will be subject to the inexorable Hubbert peak cycle of a build-up in production followed by a slow decline. The most serious effect on our economies is the rising price of crude oil - and those of the related oil products, particularly liquid fuels, giving problems to motor and aircraft manufacturing, the harbingers of the problems we face. For example, there will be insufficient jet fuel to allow the predicted increase in air traffic assumed by Boeing and AirBus.


Effect of GTL and CTL on fossil fuel reserves


The energy industry has taken cognisance of the need to replace oil as the principle provider of liquid fuels by developing gas-to-liquid (GTL) and coal-to-liquid (CTL) processes. Although both these processes work, the actual thermal efficiency is low. The actual practical results are difficult to elicit as they are kept as commercial secrets. BP ran a GTL pilot plant in Alaska, but declined to reveal the performance. Sasol in South Africa has run CTL processes for many years, but press releases fail to relate the liquids output to the coal input.


As far as can be ascertained, GTL is around 50% thermally efficient and CTL around 40%. This means that the deployment of processes to convert natural gas and coal to petrol and diesel will empty the reserves faster than the use of the gas and coal to provide energy as heat.


A possible scenario is illustrated in a plot of oil, gas and coal based on barrels of oil equivalent in Figure 1 .


Types of coal and reserves


It is a common misconception that there are hundreds of years of coal still to recover, whereas the situation is complex. The assumption is that if we can capture and sequestrate the carbon dioxide produced by its combustion, coal can continue to provide most of our electricity while ameliorating its effect on climate change. Coal is also an essential ingredient in steelmaking and could provide an alternative to petrochemicals.


Figure 2 is from the World Coal Institute’s website (1)



The heating values of the various types of coal vary widely depending on their carbon and water contents. The best is anthracite (<1% of reserves) at 27-30 megajoules/kilogram, next is bituminous (52% of reserves) at 27 MJ/kg, sub-bituminous (30% of reserves) at 20 – 28 MJ/kg and the lowest ranking lignite (17% of reserves) at 15-19 MJ/kg. The average heating value of the reserves works out at around 24MJ/kg. So the amount of coal used to produce a certain volume of liquid fuel depends on its origin.


BP provides an assessment of coal reserves in its annual statistical review of energy. In the 2009 version the reserves at the end of 2008 (at the then level of production) were forecast to last for 122 years. (2) However if coal is increasingly used to substitute for crude oil in the production of liquid fuels at the low conversion efficiencies anticipated, the arrival of a peak in coal production before mid-century can be envisaged. If hypothetically all the remaining coal was used for production of liquid fuels at 40% conversion efficiency and there was a market for the products, it would be gone in 50 years. Assuming that a good proportion of the remaining coal is used for the production of liquid fuels, a coal production peak around mid-century is a realistic prospect. See EWG’s Report (3)


Inefficiency of generation with CCS


MIT published an exhaustive report “The Future of Coal” which examined the various technologies for carbon capture and sequestration (CCS). (4) There is an economic penalty in adopting clean coal technologies as more coal is needed to provide the additional energy for the ancillary processes for the separation and sequestration of the carbon dioxide.


Reference to Table 3.1 on page 19 of its Chapter 3 – Coal-Based Electricity Generation shows that for the same generation and additional 27% to 37% of coal is consumed, dependent on the technology used and assuming a higher heating value for the coal of 25.35 MJ/kg. Moreover the extra capital for a new CCS plant is considered to be from 60% to 74% more than a conventional station. However there is an exclusion below the table “Does not include costs associated with transportation and injection/storage”.


Adding the cost of the transport pipework and injection equipment it must be concluded that a coal-fired generation plant incorporating CCS would cost twice as much and use 50% more coal than a conventional plant. It would also mean that the remaining coal reserves dedicated to generation would be depleted by a third.


Retrofitting is shown in the MIT report to be impractical, but even it were, the additional capital required and the reduction in revenue by a third would bankrupt existing coal-fired station owners.


It is assumed that in most cases CO2 injection will be into existing or depleting oil and gas wells to enhance the recovery of oil and gas. As around two-thirds of the injected CO2 returns to the surface with the oil and gas it would then have to be separated and re-injected. Permanent CO2 injection can lead to a build-up in reservoir pressure and eventually lead to leakage. (5)


It seems highly unlikely that CCS will ever be applied to a full scale coal-fired station.


CO2 and climate change  

The relationship between climate change and CO2 emissions is subject to much debate. There has been a significant rise in emission concentrations in the last 100 years which can reasonably be attributed to the combustion of fossil fuels. The weather does seem to be disturbed, but whether there is an underlying warming trend is disputed.


The decisive occurrence is the so-called medieval warming (900 – 1300 AD) during which temperatures were higher than at present and when there was little industrial activity. The rapid rise in temperature in the latter years of the Mann “hockey-stick plot” matches the rise in carbon dioxide emissions, but the veracity of its “proxy” temperature estimates is challenged and the IPCC is accused of masking the medieval warming rise from the plot. In the last 10 years or so sceptics have claimed that temperatures have dropped, so an assessment as to whether this is but a temporary “blip” in a continually rising trend has to await events over the next decade or so.


The argument has to be settled, because if climate change, real or imagined, is independent of anthropogenic emissions, then the case for CCS fails..


Emission reduction by depletion of fossil fuel reserves


If climate change is caused by carbon dioxide emissions, or partially so, then the progressive depletion of fossil fuel reserves will alleviate it somewhat. The reduction in emissions will perhaps not match the levels required in the Kyoto and Copenhagen protocols, but certainly by the end of the century there will be just a modicum of coal remaining. To worry about a temperature rise in 2100 from fossil fuel combustion is somewhat far-fetched if by then there is little fuel to burn!


In contrast, the various reports assume no reduction in fuel availability and indeed imagine energy use will expand, hence the introduction of carbon emission trading.

There is clearly no need for carbon trading as the depletion of fossil fuels will progressively raise the cost of current economic activity and reduce it. Depletion may lead to global economic collapse or force an alternative energy-lean lifestyle on those societies able to adapt.


Future contribution of renewables

There is little doubt that renewables will be unable to match the current or envisaged need for energy. In any case electricity demand will decline as the motor and aviation industries decline due to escalating fuel costs. Renewables will be mostly associated with micro-generation as localisation movements get under way as a response to restrictions in movement.


Large centralised power plants, such as nuclear and CCS coal (and large off-shore wind farms) require additional power transmission lines. Much depends on the creation of pumped storage schemes to compensate for the variability of wind and solar. There are also molten salt heat storage systems. If the variability can be reduced locally it will reduce the capacity of the associated transmission lines.


Some transmission lines may be made unnecessary depending on the degree of self-generation from residential solar power and domestic micro combined heat and power (CHP) boilers and of course the severe reduction in demand as movement of people and goods decreases in volume.


As oil, gas, coal and also uranium as well as the materials needed for construction are all subject to depletion, the survival of developed societies depends on their ability to adjust to a low-energy lifestyle.


Biomass, solar, wind, marine energy


The problem with energy crops that they are in competition with food crops for land use and for oil-based fertilisers, insecticides, herbicides and fungicides, all of which will be in short supply. Fuel crops can be grown in hydroponics greenhouses heated and lit by CHP and with enhanced CO2 atmospheres to increase yield, thus avoiding conflict with organic farms over land use.


Solar water heaters are effective and increasingly being installed, while solar photo-voltaic systems will benefit from the new feed-in tariffs. It is unlikely that major schemes like those in Spain and Nevada and as proposed in North Africa will be installed in Northern Europe. There may be huge solar generator projects in North Africa deploying orientated mirrors..


Utilisation of small wind generators will decline, but a variety of medium size types producing 10 KW – 25 KW are likely to be installed at farms and on windswept countryside, also benefiting from the feed-in tariffs. Off-shore wind is currently the favoured large-scale renewable, especially as planning permission for inland wind is increasingly opposed.


In Stanford Lough near Belfast is a prototype large sea-current project utilising the regular tides. (6) As tidal currents are associated with the phases of the moon and occur with a certain regularity there may be many off-shore generating developments. Wave power is subject to the wind and sea “fetch”. The equipment has to be very strong as it is subject to enormous forces and erosion. So systems using underwater sea currents may eventually predominate.


In what should we invest?


The recent credit crunch has highlighted the need to spend wisely and as the imposition of CCS to coal-fired generation will accelerate the emptying of coal resources, particularly of the best quality coals, it should be dropped from utility and government programmes.


Basically we need to invest in an energy descent. Society has to adjust to an energy-lean life-style for its survival. Globalisation has to be replaced with localisation, in which communities come together to survive the mid-century economic catastrophe resulting from the lowering concentration of minerals and the resulting inefficiency of capital.


© John Busby 11 March 2010


(1)  World Coal Institute

(2)  BP annual Statistical Reviews

(3)  EWG Coal Report

(4)  MIT’s “The Future of Coal”

(5)  “Injecting realities”

(6)  Strangford Lough