BioCycle June 2011, Vol. 52, No. 6, p. 61
I AM enamored with technical efficiency and the ability to continually produce more with less. Efficiency is measured as output per unit of input. An easy example in agriculture is yield, or bushels per acre. The order of inputs and outputs in the ratio is not important. Efficiency is also expressed as input per unit of output.
These simple measures work great as long as there is only one kind of input and one kind of output. This occurs when looking at a single process rather than an entire facility with multiple inputs and outputs. Convenient, single process measures are more difficult to track in larger systems and they typically only measure product or wastes.
The economy and the environment are not simple relationships but there are increasingly more examples of how one positively affects the other in terms of inputs and outputs. The technical ability to recycle materials or recirculate unused heat is an example of pulling undervalued outputs back into use. From a system standpoint, it matters less where the individual processes begin and end. Technical efficiency is still a matter of getting more out of the system from fewer inputs going in. When undermanaged – or treated as single processes – the leftover materials become emissions and wastes.
In the last few years, corporations and consumers have begun to realize that efficiency is good for both company profits and the environment. This is not a new concept, but it is easy to miss when we value profits narrowly on one or two products. Large corporations like Walmart, Anheuser-Busch InBev, BP, UPS, FedEx, and so on, are reportedly saving millions of dollars by using less water, fuel and recycling wastes. UPS reports that in the last 10 years its fleets have driven 77.3 million miles more using 3.2 million gallons less. Walmart reports it is two-thirds of the way toward its goal of doubling fleet efficiency, delivering more cases of product with less fuel. Display case lighting has been replaced with LED lights in 1,000 stores. These achievements are pretty exciting and carry both environmental and economic benefits.
TALLYING CONSUMPTION REDUCTIONS
The U.S. Department of Transportation can identify efficiency increases in the U.S. fleet of passenger cars. In 1980, passenger cars are estimated to have gotten 16.0 miles per gallon (mpg). The latest U.S. passenger car fleet (2008) is estimated at 22.6 mpg. When limiting the estimate only to new passenger cars, the mpg has risen from 24.3 mpg in 1980 to 33.7 mpg in 2010. These kinds of gains are occurring in every sector. With this notable progress energy reductions should be showing up in our national energy use statistics.
The US Department of Energy, Energy Information Administration (EIA) has not yet released its detailed analysis of renewable energy consumption in 2010, but has been releasing the 2010 energy consumption data in its Monthly Energy Review for some time. In 2010 the amount of renewable energy consumption jumped from 7.59 quadrillion btu (quad) to 8.05 quad. Hydropower and wood make up 56 percent, about 4.5 quad, of renewable energy. The other 44 percent has come from increases in biofuels, wind, waste, geothermal and solar.
Total 2010 U.S. energy consumption however, jumped up from the lowest level since 1997, 94.48 quad, to 98.00 quad. The recession-related, big drop in 2009 caused people and businesses to reduce their travel because revenues were down and costs were up. With all the energy savings, I believed and hoped that some of the shifts away from our conspicuous energy consumption would have longer-term effects. But the jump from 94.48 quad to 98.00 quad is 3.52 quad or 44 percent of the 8.05 quad of renewable energy production in 2010 (everything but the wood and hydro).
ENERGY INPUT PER UNIT OF HUMAN
Another measure of efficiency is to compare U.S. energy consumption on a per capita basis. This is accomplished by dividing the annual energy consumption by the established population for each year back to 1973. The results are interesting. The U.S. per-capita energy consumption has been declining for the last 15 years. During the decade of the 1990s the average annual U.S. per-capita energy consumption was 345 million btu (MMbtu). During the decade of the 2000s the average annual consumption was 335 MMbtu. For the last five years, which includes the consumptive years of 2007-2008 in addition to the recession years of 2009-2010, the average annual per-capita consumption was 324 MMbtu. Over 20 years that is an 8 percent reduction.
Quite honestly, 324 MMbtu is still a lot of energy per person. To get some sense of what that means this number was divided by the energy equivalent of a gallon of gasoline, 124,000 btu. The 324 MMbtu is equivalent to 2,613 gallons of gasoline for every man, woman and child in the United States. This annual energy use includes the traditional centralized-distribution model of transporting food, fuels, power and waste hundreds of miles. The adoption of local, distributed generation models could provide further energy reductions.
When the renewable energy consumption of 8.05 quad is divided by the U.S. population, it is fairly constant at about 23 MMbtu per person. So the U.S. population is growing at about the same rate as renewable energy use. My efforts to illustrate that U.S. energy consumption is declining are admittedly weak, but it could just take a few more years for the technical innovations being implemented now to show up in the data.
As a nation, our energy consumption has plateaued at 100 quad with steady increases in renewable energy. On a per capita basis, however, our energy consumption is declining with the rate of renewable energy staying about the same. Progress is steady, but slow. There is still enormous potential to adopt distributed, more efficient combined heat and power (CHP) systems, but the U.S. is making small but measurable gains in less conspicuous consumption.
Mark Jenner, PhD, and Biomass Rules, LLC, has joined the California Biomass Collaborative. Burning Bio News and other biomass information is available at www.biomassrules.com.
June 16, 2011 | General
Biomass Energy Outlook: Less Conspicuous Consumption
BioCycle June 2011, Vol. 52, No. 6, p. 61