Archives January 2008

From the Industrial Revolution we learned that economic growth is inextricably linked to energy and as a result, our future is dependent upon equitable access to energy. When the Stourbridge Lion made entry as the first American steam locomotive in 1829 it was used to transport Anthracite coal mined in nearby Carbondale, PA to a canal in Honesdale that in turn linked to the Hudson River and onto New York City. Coal fueled the growth of New York and America’s Industrial Revolution because coal was cheap and more efficient than wood.

Advances in science and technology gave way to improvements in manufacturing, mining, and transportation. Energy became the catalyst to industrial growth. Steam power such as Thomas Newcomen’s steam powered pump in 1712 developed for coal mining and James Watt’s steam engine in 1765 were initially used to bring energy to market.

In terms of heating efficiency, coal at the time offered almost double the energy, pound for pound, in comparison to wood. Energy Units and Conversions KEEP Oil offers higher energy efficiencies over coal and wood, but as with most hydrocarbon fuels, carbon and other emissions are costly to our economy and environment.

With rapid growth in automobile production in the U.S., oil became the predominant form of fuel. According to the Energy Information Administration, in 2004 the U.S. spent over $468 billion on oil.

Figure 1 U.S. Energy Consumption by Fuel

We all need to become more conversant in understanding energy costs and efficiency and as a corollary, better understand the benefits of renewable energy such as solar, wind, and hydrogen fuel cells. A common metric we should understand is the kilowatt-hour (KWH) – the amount of electricity consumed per hour. The KWH is how we are billed by our local electric utility and can be used to compare costs and efficiency of hydrocarbon fuels and alternative energies.

One-kilowatt hour equals 3,413 British Thermal Units (BTUs). One ton of Bituminous Coal produces, on the average, 21.1 million BTUs, which equals 6,182 KWH of electric at a cost of about $48 per short ton (2,000 pounds). That means coal cost approximately $0.01 per KWH. To put that into perspective, a barrel of oil at $90/barrel distilled into $3.00 gallon gasoline is equivalent to 125,000 BTUs or 36.6 KWH of energy. Gasoline at $3.00/gallon equates to $0.08 per KWH. So gasoline at $3.00 per gallon is eight times more expensive than coal.

Is oil and gasoline significantly more efficient than coal? Let’s compare on a pound for pound basis. A pound of coal equates to about 10,500 BTUs or approximately 3.1 KWH per pound. A gallon of gasoline producing 125,000 BTUs weighs about 6 pounds equating to 6.1 KWH per pound (125,000 /3,413 /6). While gasoline is almost twice as efficient as coal, coal’s lower cost per KWH is why it is still used today to generate electric.

The Bottom Line: the economics of energy determines its use – coal still accounts for approximately half of our electric generation because it has a lower cost than other fuels. However, there are two factors to consider 1) the cost of carbon is not calculated into the full price of coal or other hydrocarbon fuels and 2) the cost of conventional fuel is calculated on a marginal basis while alternative fuel costs are calculated on a fixed cost basis. Meaning the cost of roads, trucks, and mining equipment is not factored into the price of each piece of coal, only the marginal cost of producing each ton of coal. For solar, hydrogen fuel cells, and wind energy systems, the cost to construct the system is factored into the total cost while the marginal cost of producing electric is virtually free. We need a framework to better measure the economics of alternative energy. The impact of carbon on our climate and global warming are clearly not measured in the costs of hydrocarbon fuels nor is the cost of protecting our access to oil such the cost the Iraq War.

Despite the carbon issues surrounding coal, (coal has higher carbon-to-hydrogen ratio in comparison to oil or gas) coal is more abundant and therefore is cheaper than oil. As electric utilities in 24 states embrace alternative energies through such programs as Renewable Portfolio Standards (RPS), perhaps the benefits of alternative energies will begin to combat the negative economics of hydrocarbon fuels.

Ethanol may emit less CO2 and help reduce the demand for foreign oil in the short term, but ethanol and in particular, corn-based ethanol raises food prices, is less efficient than gasoline, diesel, and biodiesel, and is not a substitute for oil.

According to research compiled by National Geographic Magazine , the energy balance of corn ethanol, (the amount hydrocarbon fuel required to produce a unit of ethanol) is 1-to-1.3 whereas for sugar cane ethanol the ratio is 1-to-8. This suggests corn-based ethanol requires significantly more energy to produce than sugar cane ethanol. Corn ethanol is only marginally positive.

A major issue with corn ethanol is its impact on corn prices and subsequently, food prices in general. It is the price of oil that is impacting the price of corn because nearly all ethanol produced in the U.S. is derived from corn. Therefore, corn prices are inextricably linked to oil prices as well as to the supply and demand of corn as food and feedstock. Corn Prices while volatile and impacted from weather and other variables appear to follow the rising price of oil as illustrated in Figure 1. In turn, corn prices are also influencing other commodity prices where corn is used for feed for livestock.

The rising motor vehicle usage in China and India is escalating the already tenuous situation in the oil markets. With ethanol tied to oil prices we are beginning to see corn prices exacerbate the inflationary pressures at the retail level. Over the last year consumers are paying more for food with large increases in the prices of eggs, cereal poultry, pork, and beef which are tied to corn.

Figure 1 Corn Prices

Senate legislation for Renewable Fuels Standard calls for ethanol production to increase to 36 billion gallons by 2022 with 21 billion derived from as cellulosic material such as plant fiber and switchgrass . Corn is expected to comprise 42% of the ethanol production in 2002 from virtually all today. The fact is that ethanol production at its current level of 6 billion gallons equates to only 4% of our gasoline usage and is already impacting food prices. Gasoline consumption in 2005 amounted to 3.3 billion barrels or 140 billion gallons. Current estimates put gasoline consumption at 144 billion gallons a year in 2007. Even if vehicles could run entirely on ethanol, there is not enough corn harvest to substitute our demand for oil. We need a cohesive and coordinated effort using multiple technologies to develop alternative energies to reduce our dependence on foreign oil.

Performance

According to Renewable Fuels Association ETHANOL FACTS:
ENGINE PERFORMANCE, ethanol offers higher engine performance with octane rating of 113 in comparison to 87 for gasoline and has a long history in the racing circuit. In 2007, the Indy Racing League, sponsors of the Indianapolis 500 started using ethanol in racecars. However, the higher engine performance may come at a cost of lower fuel efficiency.

Table 1 Specific Energy, Energy Density & CO2

Efficiency

Gasoline offers 56% higher energy efficiency (specific energy) over ethanol as measured by kilo-joules per gram (kj/g). (As a reference: 1 kilowatt-hour = 3,600 kilojoules = 3,412 British Thermal Units) Biodiesel with 35 kj/g is 33% more energy efficient than ethanol at 24.7 kj/g.

In terms of energy density, ethanol would require larger storage capacity to meet the same energy output of gasoline diesel, and biodiesel. Ethanol requires a storage tank 48% larger than gasoline and 41% larger than diesel for the same energy output.
Please see Hydrogen Properties and Energy Units

For a quick review of Specific Energy and Energy Density – (Molecular Weight Calculator) the specific energy of a fuel relates the inherent energy of the fuel relative to its weight and is measured in kilo-joules per gram.

CO2 Emission

The molecular weight of CO2 is approximately 44 with two oxygen molecules with an approximately weight of 32 and one carbon atom with a weight of 12. During the combustion process, oxygen is taken from the atmosphere producing more CO2 then the actual weight of the fuel. In the combustion process a gallon of gasoline weighing a little over six pounds produces 22 pounds of CO2.

CO2 emission is a function of the carbon concentration in the fuel and the combustion process. During combustion ethanol produces approximately 13 pounds of CO2 per gallon. Gasoline and diesel produce approximately 22 and 20 pounds per gallon, respectively. CO2 emissions per gallon appear quite favorable for ethanol. However, the results are less dramatic when CO2 emissions are compared per unit of energy produced.

Figure 2 CO2 per KWH

When measured in pounds of CO2 per kilowatt-hours (KWH) of energy, the results show ethanol producing 6% less CO2 than diesel or biodiesel and 5% less than gasoline. In the case of ethanol, the lower specific energy of the fuel negates the benefit of its lower CO2 emissions. Meaning more ethanol is consumed to travel the same distance as gasoline or diesel thereby limiting the benefit of its lower CO2 emissions.

The bottom line is ethanol does not ameliorate our dependence on foreign oil and while it demonstrates higher performance for racecars, it is still less efficient than gasoline diesel, and biodiesel, and diverts food production away from providing for people and livestock. The reality is there are special interest groups that obfuscate the facts about ethanol for their own benefit. The real solution to our imminent energy crisis is alternative energies including cellulosic ethanol, solar, hydrogen fuel cells, and wind.