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Some Basic Concepts. www.uh.edu/energyinstitute. UNIVERSITY of HOUSTON. BAUER COLLEGE of BUSINESS ADMINISTRATION. Econ 3385 – Economics of Energy S. G ürcan Gülen, Ph.D. ENERGY INSTITUTE. Measuring Energy. We measure: Crude oil in barrels (bbl) or tons (t)
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Some Basic Concepts www.uh.edu/energyinstitute UNIVERSITY of HOUSTON BAUER COLLEGE of BUSINESS ADMINISTRATION Econ 3385 – Economics of Energy S. Gürcan Gülen, Ph.D. ENERGY INSTITUTE
Measuring Energy • We measure: • Crude oil in barrels (bbl) or tons (t) • Natural gas in cubic feet (cf) or cubic meters (cm) • Coal in tons • Electricity generation capacity in watts and generation & consumption in watthours • And, energy in barrels (or tons) of oil equivalent, or British thermal units (Btus), or joules (J), or calories (cal)
Measuring Energy • Some conversion factors • 1 ton of oil = 7.33 barrels of oil • 1 barrel = 42 gallons • 1 gallon = 3.8 litres • 1 cubic meter of gas = 35.3 cubic feet of gas = 0.00629 barrels of oil equivalent = 0.0009 tons of oil equivalent • 1 terawatt = 1,000 gigawatts (= 1,000 megawatts (= 1,000 kilowatts))
Measuring Energy • Common unit that measures the “heat content” is Btu: • The quantity of energy needed to raise the temperature of one pound of water by one degree Fahrenheit. • 1 Btu = 1,055 Joules = 0.252 kilocalories • 1 Joule = 0.00024 kilocalories • Therm = 1,000,000 Btus • Quad = 1015 Btus
Measuring Energy • Some examples • 1 barrel of oil 5.8 million Btus • 1 cubic foot of gas 1,030 Btus • 1 short ton of coal 14.6 – 26.8 million Btus • 1 kWh of fossil-fuel generation 10,300 Btus • 1 kWh of consumption 3,412 Btus • Sources for further information • www.eia.doe.gov (Annual Energy Review) • www.bp.com/worldenergy/calculator/main.htm
Measuring Energy • 1 cubic meter of gas = 35.3 cubic feet of gas = 0.00629 barrels of oil equivalent = 0.0009 tons of oil equivalent • 1 cubic meter of gas = 35.3 x 1,030 Btus = 36,359 Btus • 36,359/5,800,000 = 0.00627 (boe) • 0.00627/7.33 = 0.0009 (toe)
Energy Efficiency THERMAL Oil 4 Coal 13 Gas 4 Combustion Heat and/or mechanical energy Generator system Nuclear 6 Electricity Hydro 8 Other Output: 11 mboe/d or 6,825 TWh/yr Photovoltaic Fuel Cell Input: 35 mboe/d
Energy Efficiency • Output equivalency: • 11 mboe x 5.8 mBtus x 365 = 23,287 x 1012 • 1 TWh = 109 kWh = 3,412 x 109 Btus • 23,287 x 1012 / 3,412 x 109 = 6,825 TWh • Efficiency • Input: 35 mboe x 5.8 mBtus = 203 x 1012 • Output: 11 mboe x 5.8 mBtus = 63.8 x 1012 • Efficiency: 63.8 x 1012 / 203 x 1012 = 31.4%
Energy Efficiency • Heat rate: 3,412 Btus / efficiency rate • 3,412 / .314 = 10,866 • If you know cost of fuel and heat rate, you can calculate fuel cost per kWh • If coal is $30/t (or, $30 per 20 mBtus), a plant with the above heat rate will generate 1 kWh at 0.016 $/kWh or 1.6 ¢/kWh: • (Heat rate/Btu content of 1t of coal) x Price of coal = (10,866/20,000,000) x 30 = 0.016
Energy Efficiency • 10,866 is very high and represent old technology; new combined-cycle gas plants have a heat rate of about 6,000. • 3,412/6,000 = .57 or 57% efficiency • Last year, natural gas was $2.5 per 1,000 cf: (6,000/1,030,000) x 2.5 = 0.015 $/kWh • This winter, natural gas was $10 per 1,000 cf: 0.06 $/kWh • Note, however, that fuel cost is only part of generating electricity! (www.eia.doe.gov/oiaf/kyoto/tbl16.html)