Category Carbon Economics

There are several studies evaluating ethanol as fuel for transportation that offer both positive and negative impacts from ethanol. On the positive side there is less CO2 emitted from ethanol than conventional hydrocarbon fuels, domestic producers gain economic value from employment and purchasing power, and there is less dependence on foreign oil. Other studies have concluded less efficiencies from ethanol such as negative energy values because of the fertilizers and energy used to produce ethanol is larger than the amount of energy produced, CO2 is released during the fermentation and combustion process, and it still must be blended with hydrocarbon fuels leaving us dependent on foreign oil.

Ethanol is alcohol-based fuel made from crops. Fermenting and distilling starch crops, typically corn, into simple sugars produce ethanol. Chemically ethanol is similar to hydrocarbon fuels in that they both contain carbon and hydrogen atoms.

To understand the economics, let’s compare ethanol to hydrocarbon fuels by efficiency and costs. The first step is to convert the BTU (British Thermal Unit) value of ethanol into Kilowatt-Hours (KWH) in order to have a common measure of energy. Remember the KWH is a useful measure of energy because we can equate KWH to engine horsepower performance and compare hydrocarbon fuels to alternative energies like solar and wind and compare these energy costs on a common level.

Our fuel energy conversion links Energy Units and Conversions KEEP, and Fuel BTUs provide some useful measures to evaluate ethanol in comparison to hydrocarbon fuels like diesel and gasoline.

One KWH equals 3,413 BTUs so we divide the BTU value for each fuel by 3,413 to arrive at its corresponding KWH energy value.

Energy Comparison
1 gallon of ethanol = 84,400 BTUs = 24.7 KWH
1 gallon of diesel = 138,690 BTUs = 40.6 KWH
1 gallon of gasoline = 125,000 BTUs = 36.6 KWH
1 gallon of oil = 138,095 BTUs = 40.5 KWH

Figure 1 Kilowatt-Hours per Gallon

As seen from figure 1, ethanol is not the most efficient fuel because of its low BTU value in comparison to hydrocarbon fuels. However, ethanol is a form of renewable energy because the crops can be grown to generate more fuel.

Energy Economics

To compare the energy cost of ethanol to hydrocarbon fuels we convert each fuel into a cost per KWH. Our prices are quarterly average U.S. energy prices by fuel type: Ethanol Prices, , and Oil Prices

Figure 2 Cost per Kilowatt-Hours

On a cost per KWH basis, ethanol is similar to hydrocarbon fuels. So depending on current fuel cost, which varies by location, ethanol could be higher or lower than diesel or gasoline.

On the production of ethanol a bushel of corn produces about 2.76 gallons of ethanol according a study by AgUnited . According to U.S. Department of Agriculture it takes 57,476 BTUs of energy to produce one bushel of corn Energy Balance of Corn Ethanol therefore, for BTU of energy used to produce ethanol there are 4 BTUs of energy gained from the ethanol for transportation.Carbon EconomicsEthanol is produced from fermentation of starch to sugars and is represented by the equation C6H12O6 = 2 CH3CH2OH + 2 CO2 according to University of Wisconsin Chemistry Professor Bassam Z. Shakhashiri The two CO2 molecules given off from the fermentation process of ethanol does add to CO2 emissions, but the growing process and biomass also extract CO2 from the atmosphere.

Emission of CO2 from hydrocarbon fuels depends on the carbon content and hydrogen-carbon ratio. When a hydrocarbon fuel burns, the carbon and hydrogen atoms separate. Hydrogen (H) combines with oxygen (O) to form water (H2O), and carbon (C) combines with oxygen to form carbon dioxide (CO2). How can a gallon of gas produce 20 pounds of CO2 To measure the amount of CO2 produced from a hydrocarbon fuel, the weight of the carbon in the fuel is multiplied by (44 divided 12) or 3.67. For ethanol we compared its basic structure to gasoline, diesel, and crude oil.

In the combustion process, ethanol produces CO2 at a rate that is below that of gasoline. The equation for ethanol combustion is C2H5OH + 3 O2 –> 3 H2O + 2 CO2. Ethanol Combustion In our simple example, the carbon weight in ethanol (two carbon with a combined atomic weight of 24 to a total weight of 46 for the molecule of C2H5OH) is multiplied by 3.67 to determine the amount of CO2 produced from ethanol. We then compared the output of CO2 to the amount of energy produced to arrive at pounds of CO2 per KWH. Bottom line is that ethanol emits 11% less CO2 than gasoline and is a renewable fuel.

Figure 3 Pounds of CO2 by Fuel Type

There are several studies on ethanol with the majority indicating benefits. Some of these include: High-level ethanol blends reduce nitrogen oxide emissions by up to 20% and ethanol can reduce net carbon dioxide emissions by up to 100% on a full life-cycle basis. Ethanol Benefits and Clean Cities While ethanol produces less CO2 than gasoline, it still emits CO2 and keeps us dependant upon hydrocarbon fuels.

For further information on fuel combustion Combustion Equations and for Energy to Produce Ethanol Ethanol Production

The second category 5 hurricane to hit Caribbean in two weeks leaves uncertainty in the energy market as oil prices head higher. While it is hard to draw the direct correlation between global warming and hurricanes strength, the fact is the oil production in the Gulf of Mexico accounts for 32% of our total oil production. In addition, the Gulf of Mexico is one the most productive oil and gas region as the U.S. faces declining petroleum product production despite significant increase in the number of oilrigs. The increasing likelihood of a weather related energy supply disruptions particularly from the Gulf area could dramatically increases to energy prices similar to Hurricane Katrina’s impact in 2005.

Higher oil prices have driven demand for energy exploration and investment into oil and gas drilling rigs. Since 1999, the number of drilling rigs has increased 112%. In the U.S., rig count is up 181% with 1,749 rigs in operation in 2007 from 622 in 1999 according to Baker Hughes. Worldwide Rig Count
According to RigZone there are 278 offshore drilling rigs in the Gulf of Mexico RigZone

Figure 1 Worldwide Rig Count

Figure 1 provides the rig count for the U.S. and the world. The U.S. accounts for over half the world oil drilling rigs yet our production is less than 10% of total global production. The Gulf of Mexico with 278 drilling rigs produces 32% of our oil with only 16% of the rigs. Hurricane Impacts on the U.S. Oil and Natural Gas Markets The rigs in the Gulf of Mexico are more productive and therefore any weather related disruption in the Gulf leaves us more vulnerable to energy shocks.

Figure 2 US Rig Count and Oil Production

While the U.S. rig count is up 118% from 1999, petroleum production is actually down 7%. On a global basis, oil and petroleum product production increased 13% since 1999 and this includes a 60% increase in the number of drilling rigs excluding the U.S. The bottom line is the U.S. and the rest of the world is experience diminishing returns on investments in oil production.

With diminishing returns on investment into oil, would it not be better to invest into alternative energy such as solar or wind. The truth is the cost of solar and wind are still dramatically higher than hydrocarbon fuels. The cost of solar on a kilowatt-hour (KWH) basis is approximately $0.38 per KWH in comparison to oil at $0.05 per KWH.

Figure 3 Cost per Kilowatt-Hours

Initiatives such as the trading of carbon credits leave little economic incentive to invest into alternative energy. A survey last year by TreeHugger found carbon credits trading for $5.50 to $13 per metric ton of carbon dioxide. Survey of Carbon offsets A metric ton of carbon dioxide equates to about 110 gallons of gasoline and at these prices, the carbon emission amounts to about $0.05-to-$0.12 to a gallon of gasoline. The carbon penalty does not even come close to bringing solar or wind energy on the same playing filed with hydrocarbon fuels. The Carbonfund organization offers a means to offset your carbon emissions with tax-deductible contributions

The cost of carbon emissions is not reflected in the market for energy. In addition, the market is unable to establish a fair price for carbon because there is no market force used to establish the value of carbon credits. We need a mechanism to bring solar energy at par with hydrocarbon fuels to limit our vulnerability to energy shocks and supply disruptions.

To measure the efficiency of conventional hydrocarbon fuels, we need a common measure of energy. The Kilowatt-Hours (KWH), the billing quantity of electric usage, serves as a useful measure of energy because we can equate KWH to engine horsepower performance, heat energy of a fuel, and compare energy costs on a common level. KWH can be used to determine which fuel is most efficient by measuring the heat output of each fuel.

A BTU is the amount of heat necessary to raise one pound of water by one degree Fahrenheit and each fuel has its own BTU measure. For example, one ton of coal produces about 21.1 million BTUs, which would equate to 6,182 KWH. One KWH equals 3,413 BTUs.

A framework to measure energy costs is to convert each fuel type into KWH of energy. Some helpful links to common fuel conversions Energy Units and Conversions KEEP, BTU by Tree, and Fuel BTUs

We want to establish common energy measure to evaluate home heating fuel efficiency for each fuel type. Our first step is to measure the BTU value for each fuel type. The next step is to divide the BTU value for each fuel by 3,413 to arrive at its corresponding KWH energy value.

Kilowatt-Hour per Unit of Fuel
The energy value of a unit of fuel depends on its mass, carbon and hydrogen content, and the ratio of carbon to hydrogen. In general, hydrogen generates approximately 62,000 BTU per pound and carbon generates around 14,500 BTUs per pound. The combustion process is complex and while higher hydrogen content improves energy BTU levels, not all hydrogen goes to heat. Some hydrogen combines with oxygen to form water. Coal Combustion and Carbon Dioxide Emissions

Energy Comparison
1 pound of wood = 6,401 BTUs = 1.9 KWH
1 pound of coal = 13,000 BTUs = 3.8 KWH
1,000 cubic foot of natural gas = 1,000,021 BTUs = 299 KWH
1 gallon of oil = 138,095 BTUs = 40.5 KWH
1 gallon of propane = 91,500 BTUs 26.8 KWH

Figure 1a Kilowatt-Hours per Pound

As seen from figure 1, natural gas provides the highest efficiency level followed by oil. Wood offers the lowest efficiency per pound at 1.9 KWH/lb and is followed by coal with twice the efficiency at 3.8 KWH/lb. Oil offers almost a 70% efficiency improvement over coal and propane is just slightly more efficient than coal.

Fuel Energy Efficiency
Wood = 1.9 KWH per pound
Coal = 3.8 KWH per pound
Natural Gas = 6.9 KWH per pound (liquid and gas measures are calculated at 6.3 pounds per gallon)
Oil = 6.4 KWH per pound
Propane = 4.3 KWH per pound

This is not the full story. While the energy efficiency of the fuel is important, a lot depends on the fuel efficiency of the stove or furnace that is used to heat your home. The heating efficiency of your stove or furnace has a substantial impact on the overall efficiency of the fuel’s heat value. The adjusted KWH in figure 1 indicates the fuel efficiency adjusted for the efficiency of the heating system. There is also some variance in the fuel efficiency given impurities, temperature, and water presence.

Adjusted Fuel Energy Efficiency
Wood @ 1.9 KWH per pound and stove efficiency of 70% equals 1.3 KWH/lb
Coal @ 3.8 KWH /lb and stove efficiency of 70% = 2.7 KWH/lb
Natural Gas @ 6.9 KWH /lb and furnace efficiency of 95% = 6.5 KWH/lb
Oil @ 6.4 KWH /lb and furnace efficiency of 85% = 5.5 KWH/lb
Propane @ 4.3 KWH /lb and furnace efficiency of 95% = 4.0 KWH/lb

Figure 1b Kilowatt-Hours per Kilogram

Figure 1b proves the same fuel types measured by liters and kilograms. While the absolute numbers are different, the relative fuel efficiency among the fuels is the same.

Energy Economics

The final phase of our fuel efficiency exercise is to compare an economic measure of fuel cost. The market price of fuel will vary by location, usage amount, and market conditions. Our prices were quarterly average U.S. energy prices by fuel type:
Natural Gas Prices, , Oil Prices, and Propane Prices
Coal and wood prices were based on local residential delivery.

Figure 2 Cost per Kilowatt-Hours

Coal and wood are among the lowest priced fuels. However, coal and wood require extensive hands-on control and cleaning which are not factored into costs. Natural gas is offered in many urban areas and is currently priced below oil or propane. Natural gas offers higher energy efficiency and is priced lower than oil or propane, but is not available in all urban markets and very limited rural availability.

The trade off between oil and propane, which can be found in most markets, is operating efficiency and maintenance. Modern oil furnaces are demonstrating higher operating efficiencies, but cost significantly more than propane. Oil does offer higher efficiency than propane, but maintenance costs are higher for oil furnaces and that cost is not reflected in these fuel costs measures.

Electric heat in some markets where utility rates are below oil or gas may offer favorable economics, but electric rates might be going higher as utilities switch to lower carbon emission fuels. The challenge is to migrate electric utilities from lower-priced coal with high CO2 emissions to natural gas with lower carbon emissions. The cost to lower CO2 emissions from coal burning utilities could force natural gas prices to rise. The bottom line is that energy prices will continue to rise with natural gas tide to oil production. Even with higher fuel prices, there is still a tremendous disparity between conventional and alternative energies with the cost of solar near $0.38 per KWH and residential electric rates of $0.11 per KWH.

Carbon Economics

Emission of CO2 from hydrocarbon fuels depends on the carbon content and hydrogen-carbon ratio. When a hydrocarbon fuel burns, the carbon and hydrogen atoms separate. Hydrogen (H) combines with oxygen (O) to form water (H2O), and carbon (C) combines with oxygen to form carbon dioxide (CO2).
How can a gallon of gas produce 20 pounds of CO2

From this example, a carbon atom has an atomic weight of 12, combines with two oxygen atoms each with a weight of 16, to produce a single molecule of CO2 an atomic weight of 44. To measure the amount of CO2 produced from a hydrocarbon fuel, the weight of the carbon in the fuel is multiplied by (44 divided 12) or 3.67.

Wood has half the carbon content than coal, but coal is twice as efficient as wood and therefore both have nearly the same high level carbon footprint. Oil benefits from having higher energy efficiency than propane giving oil 30% lower CO2 emissions pound for pound.

Figure 3 Pounds of CO2 by Fuel Type

Natural gas, because of its low carbon content and high fuel efficiency, achieves lower CO2 emissions than oil, propane, or coal. Natural gas produces 46% less CO2 than coal and 10% less than oil. With coal relatively abundant and cheap in comparison to oil or natural gas, energy prices may increase as electric utilities switch to lower CO2 emission natural gas or invest into emission reduction processes that add to capital costs and operating expense.