Fossil Fuel Resources Chapter 5 1. Fossil Fuels provide about 2/3 rd of the planet s electricity and about 85% of Earth s total energy production. 2. Not all fossil fuels are the same. a. Availability b. Energy capacity c. Climate impact 3. Let s look at the state of fossil fuels a. Worldwide consumption b. Estimated remaining resource base c. Cost per unit of energy 4. Let s also look at the CO 2 emissions of various fossil fuels. 5. Finally let s predict the future. Fossil fuels sourced from prehistoric caches of carbonaceous materials compressed into energy-dense solids, liquids or gasses that can fuel human energy needs. Our dependence on fossil fuels is relatively recent, geologically speaking. Coal surpassed wood as the primary energy source domestically and industrially in the 19 th century about (0.04% of human existence ago). Only the poorest nations still rely on wood or dung (bio-fuels) for primary energy sources. Our dependence on fossil fuels makes it imperative that they be fully understood and properly utilized as we bridge to sustainable methods of energy production. Primary Fossil Fuels Coal stationary energy production (can t use in ICE) Oil flexible (stationary or mobile), but requires refining. Natural Gas (or just gas) pretty useful stuff. Emerging Fossil Fuels
Shale Oil Tar Sands Energy Density Coal GJ/Tonne or million BTU/Ton 15-30 GJ/Tonne, $20-$50/Tonne Varies a good bit, new coal is wetter and has lower energy density than old coal. Oil GJ/barrel or million BTU/Barrel 5.2 GJ/barrel, $50-$100/barrel Varies moderately depending on impurities, like sulfur and nitrogen. Natural Gas kj/m3 or BTU/ft3 36.4 MJ/m3, $0.29-$0.44/m3 Constant value at atmospheric pressure Upstream losses (do not include exploration costs) Coal extraction costs including transportation are estimated to be 2-4%. Petroleum upstream losses are on the order of 17%. Gas losses are estimated at 12%. Worldwide Energy Production as of 2005 Natural Gas 23% Crude Oil 36% Coal 27% Other 14% (primarily nuclear and hydropower, with small solar, wind and biomass components). CONSUMPTION The pattern of use varies a bit with wealth, with underdeveloped countries deriving a larger portion of their energy from coal DUH! RESERVES Reserve - A proven quantity of fossil fuel known to exist in a given location within agreed tolerances on the accuracy of estimating fuel quantities.
Resource An estimated quantity of fuel yet to be fully explored and evaluated. One estimate is that the worldwide coal resource is 5 times the known reserve. 1. Coal energy reserves are 4 times that of oil or gas. 2. Coal energy resource is likely that much higher as well. 3. Coal fired energy production will likely extend much further into the future than gas or oil based energy production. 4. China and the US have small oil reserves (and thus resources) and will continue to rely on imports until our habits change. 5. Reserved to consumption data cannot accurately predict when we will run out (because of the unknown nature of resources), but can likely predict what will run out first NOT COAL! 5-2 CO 2 EMISSIONS and a DECARBONIZATION STRATEGY Fossil fuels are combusted with oxygen to produce energy. The amount of energy released is proportional to the number of molecular bonds broken in combustion. Fossil fuels with more hydrogen (high H to C ratio) have more bonds to break per unit of CO 2 released (burn cleaner) COAL - A carbon molecule plus an oxygen molecule yields a molecule of CO 2 plus 30 MJ/kg of energy. GAS A methane molecule plus two oxygen molecules yields a CO 2 molecule plus two water molecules plus 50 MJ/kg of energy. Oil A gasoline molecule (C 8 H 18 ) plus 12.5 oxygen molecules yield eight CO 2 molecules plus nine water molecules and 50 MJ/kg of energy. Molecular weights of interest: Carbon 12, Oxygen 16, Hydrogen 1; methane 16, CO2 44, gasoline 114 Considering the weights and energy production, example 5-2 shows that coal gives 8.18 MJ/kg CO 2, gasoline gives 16.1 MJ/kg CO 2 and natural gas wins at 18.2 MJ/kg CO 2 IF YOU ARE INTERESTED ONLY IN CO 2 production per unit of energy. DECARBONIZATION replacing coal as an energy source with gas or oil. Good for Canada, not so for US or China. Will get bad for everyone when gas and oil deplete.
5-3 CONSUMPTION Gaussian or Hubbert curve can be fit to US and worldwide oil consumption. The peak of the smooth curve for the US was 1976, but this was 6 years after the actual peak year when we extracted 3.22 billion barrels. Similar analysis estimates a worldwide peak year between 2013 and 2034 depending on what is chosen as an Estimated Ultimate Recovery (EUR). A smaller recovery (2.5 trillion barrels) results in an earlier peak. The 2034 peak presumes a 4 trillion barrel recovery. All of this begs the question of how society will accommodate a decline in oil, which all agree will begin no later than 2050, while demand for energy is anticipated to continue to increase. Which brings us to 5-3-2 NON-CONVENTIONAL FOSSIL RESOURCES AS OIL/GAS SUBSTITUTES Tar Sands about 3.6 trillion barrels in Canada and Venezuela. Conversion in Alberta, CN produced about 1 million barrels a day in 2005. Oil Shales about 2.6 trillion barrels in US, Brazil, Asia, Europe and Middle East Cost more to convert to oil/gas. Gasification of coal has been going on in North Dakota since 1985 and produces natural gas clean enough to introduce into the pipeline grid. Still costs too much. POTENTIAL EFFECT ON CLIMATE CHANGE Non-conventional fossil fuels will likely have twice the upstream costs, and correspondingly more CO 2 load. OTHER ENVIRONMENTAL IMPACT Earth crust disruption (scars). Poor industry track record for remediation. Underground extraction via boreholes can be modest, but oil shales and tar sands
tend to require surface mining. This could be a problem going forward as more dependence on coal and non-conventionals will push fossil fuel harvesting inexorably to the surface crust. Coal and non-conventionals now account for about 100/350 EJs of fossil fuel generated energy. Some predict that will become 400/500EJs by 2050 four times the surface impact. What is likely is that the mining will have better mediation techniques and some extraction sites, like those in the Rocky Mountains will be put off limits. 5-3-3 FOSSIL FUELS; PAST AND FUTURE High energy density + Concentrated deposits + Highly developed harvesting methods = cheap energy BUT; we now have a tight association with use of fossil fuels and atmospheric degradation. Scenario 1: Use fossil fuels only long enough to develop clean alternatives. This approach will likely take at least a century to effect. If after making this change over, we used fossil fuels only as feedstock for petrochemical industries, the remaining reserves could last a millennium. Scenario 2: Develop CO 2 sequestering methods that will allow us to continue using fossil fuels as our primary source of energy, thereby pushing forward the need to transition to alternate energy sources. Regardless of the scenario, as shown in figure 5-4, the age of fossil fuels will pass in a relatively short time of around 500 700 years.