Energy matters

Acronyms

• GW Global warming.
  
  
• GW Gigawatt. One (US) billion watts.

Basic data

• BTU One BTU is about one kilowatt-second.
  
  
• Coal use per gigawatt At 35% overall efficiency, a 1GW coal fired plant uses one ton of coal every six seconds. A typical coal train contains 17,000 tons of coal, which will fire a 1GW coal fired plant for about 28 hours.
  
  
• Households in the US About 135M in 2006.
  
  
• Oil One barrel of oil is 42 gallons.
  
  
• Oil One barrel of oil is taken to be 5.6M BTU.
  
  
• Oil to CO2 One barrel of oil produces about 0.38 US ton of CO2.
  
  
• Oil use per gigawatt At 35% overall efficiency, a 1GW oil fired plant uses one barrel of oil every two seconds.
  
  
• Transmission losses Thought to be 3% to 6% in the US in year 2007. The losses are more likely in older parts of the system.
  
  
• Weight of the atmosphere The earth's atmosphere weighs approximately 5.65 quadrillion tons. 5.65*10^15 tons.

Conversions

• Coal One ton of coal is 3 barrels of oil equivalent. Coal is an enormously variable substance. It ranges from anthracite, which is essentially pure carbon, to coal which is is to 20% rock, water, and a large spectrum of metals and other substance. So 3 barrels of oil equivalent is a very rough number.
  
  
• Natural gas One cubic foot of high grade natural gas at standard temperature and pressure is 1,000 BTU. So 5,600 cubic feet of high grade natural gas is equivalent to one barrel of oil. There is also sour gas, which comes from dumps and other sources, that contains 300 BTU per cubic foot at standard temperature and pressure. One mostly talks about high grade natural gas.

US and world energy reserves

• Coal Year 2006 estimates for US coal reserves are 500B tons, or about 1.5T barrels of oil equivalent.
  
  
• Ethanol from corn Basically a farm program, use of corn to produce ethanol competes with food use, and will likely cause food inflation while contributing very little fuel. In year 2006 the US uses about 130B gallons of gasoline per year. Using almost all of the US corn production, with about 2 gallons of ethanol per bushel, would displace perhaps 10% of gasoline use, and leave the US with expensive food, and perhaps the need to import corn. Estimates are that 7 gallons of oil equivalent energy are needed to produce 10 gallons of ethanol. But ethanol has only 85% of the the energy content of gasoline, so the real number is closer to 7 gallons in for 8.5 gallons out. The program makes no basic sense, except in the political arena.
  
  
• Ethanol from cellulose Has vast potential if it can be made to work. Essentially any plant material could be used to make ethanol, and a kind of recycled CO2 could be used to make an equilibrium between fuel used and CO2 taken up by plants. Plant production of methane, as explained in the February, 2007, issue of Scientific American, is another matter. It's anyone's guess as to whether methane is a bigger GW problem than CO2. As of February, 2007, ethanol from cellulose is not a viable process.
  
  
• Natural gas Proven reserves in Russia are 276B barrels of oil equivalent in year 2006. This is 30% of the world's known reserves. Iran apparently has another 15%. The US and Canada combined have about 3%. In year 2006 the US uses NG equivalent to about 10M barrels of oil per day.
  
  
• Nuclear No reliable estimates of how much uranium is available in the world exists. In year 2006 Australia has about 40% of known reserves. The issue is complicated by the fact that less than 1% of natural uranium is actually useful as fuel, yet breeder reactors could make much more of that available. Like ethanol use, nuclear power in the US is now more political than technical in nature. Like wind, no CO2 is produced.
  
  
• Oil Year 2006 estimates are global proven reserves of 1T barrels of oil, about the same amount that has already been used over the last 125 years or so. At year 2006 global rates of use - about 82M barrels per day - this is approximately a 33 year supply. In year 2007 the US uses 22M barrels of oil per day.
  
  
• Oil shale There are mountains of oil shale in Colorado. Estimates run to 1T barrels of oil and more. A lot of input energy and water are needed to process oil shale. But prototype plants in the early 1980s did produce 100K barrels of oil per day.
  
  
• Tar sands Year 2006 estimates for oil from Canadian range from 250B barrels of easily availble oil to 2,500B barrels of oil from more diffuse sources. The concept of net energy is important with tar sands - a great deal of energy and water is required to process tar sands.
  
  
• Wind Year 2006 estimates are for US wind resources of 1.5TW, or about 3X the current US baseload generating capacity. It is not clear whether that figure includes potenial off shore sites.