This is the second part of a discussion of the energy problem. The first part is an introduction with ideas for ending our reliance on fossil fuels. It is accessible "here"
Heat engines are inherently inefficient. The efficiencies of even large multi-cycle steam turbines driving generators in electric power plants seldom reach 50%. The waste is in the form of heat. It is possible to organize matters so that most of this waste heat is put to good use, in industrial processes, for space and water heating, or even for cooling. Such dual use, referred to as cogeneration [1], can increase overall efficiency to over 80%. It is more easily implemented when generation is localized.
Over 20% of US electric power in homes and a much larger percentage of commercial energy is used for lighting. There is room for considerable reductions via more widespread use of compact fluorescent lamps, which are about four times as efficient as incandescent bulbs, and have much longer lives. But they are more costly. It appears that light emitting diodes (LEDs), now developing at a rapid pace, will soon be even more efficient and longer lived [2]. They do not contain mercury, an environmentally hazardous element used in fluorescent lamps. LEDs are already widely used in flashlights. The ultimate in low cost lighting, at least during the day, is using sunlight, via traditional or tubular skylights.
Energy efficiency improvements are doubtless possible for virtually all the numerous devices used in our homes, as well as in most industrial processes. Even where this implies increased cost for the units, the costs generally are paid off early in the lifetimes of the units by the reduced expenditures on energy. So increasing efficiency is a valuable means for improving our environment. But the biggest drain on energy resources is thoughtless waste.
This lack of local temperature control is unfortunately very common, affecting heating as well as cooling. I have seen offices with the windows wide open on bitter cold winter days, because of a lack of zone heating controls. A somewhat different phenomenon with similar effects is the need for sweaters in restaurants or stores on hot days. This probably stems from a belief that people appreciate being cold in the summer. (I don't.)
We have here prime examples of energy waste: expending energy in a way that makes people uncomfortable. More controversial are significant expenditures for marginal increases in comfort or convenience. Should a home thermostat in the winter be set so that the most cold-sensitive person in the house can walk around dressed in summer clothes?
The energy cost of excessive space heating or cooling is substantial. Maintaining a given differential between inside and outside temperature requires an energy expenditure rate proportional to that differential. So, if the outside temperature is 90 degrees, cooling a room down to 66 degrees is twice as costly as cooling it to 78 degrees. The waste is even greater, and not easily estimated, when windows are opened in the winter to allow heat to flow out of an over-heated room.
The potential for reducing energy use for space heating and cooling is enormous. The kinds of waste mentioned above, could be eliminated by zone heating controls and common sense. Major savings would accrue from proper building design with attention paid to solar orientation, use of trees for shade and wind shielding, adequate use of insulation, leak elimination, and heat exchangers. Heat pumps operating with underground sinks are often a valuable option.
Packaging could well be the poster child for wasteful American practices. A ball point pen, a pocket comb, a pair of tweezers, each comes embedded in an over-sized plastic case. Tools (or teeth) are often needed to extract the product. Items purchased in stores are further packaged in bags or boxes. Internet purchases often arrive in over-size cartons packed with plastic foam pellets. Energy is dissipated in the manufacture, transport, and disposal of all this stuff.
In general, we are increasingly a throw-away society. When the ink cartridge in a ball point pen is empty, the whole pen is generally discarded. The elaborate ink tanks for ink jet printers are similarly junked when empty. All manner of shoddy consumer goods are made with life expectancies of a few years. Re-use and recycling are generally considered as fringe activities advocated by wacky tree-huggers.
The use of switches to turn off lights, air conditioners, electronic devices, etc., when they are not needed is considered in the same category. For most modern devices there is no switch to really turn them off, and sometimes no way to determine if a device is on or off. (I have a DVD player with an indicator light that goes on when the device is nominally off.) The result is that a substantial portion of electric energy consumption, in the neighborhood of 5% is "standby power", i.e., energy consumption while the device is nominally "off". This is in addition to often redundant clocks incorporated in many appliances (we have three in our kitchen). Standby power is usually very small for any particular unit, perhaps only a watt, but the energy wasted is significant because it is continuous (analogous to over a metric ton of water loss that can result in a year from a steady one drop per second leak).
Transportation accounts for a substantial portion of US energy consumption (roughly 30%), particularly in the form of petroleum. Obvious examples of wasteful US usage is the low fuel mileage rates for cars in the US. Europeans, inspired by very high gasoline taxes, do much better, but there is plenty of room for improvement there too. The technology exists today, demonstrated by existing models of hybrid cars, to build autos that get at least 60 miles per gallon. Why shouldn't cars marketed in the US starting three or four years from now be required to meet that sort of standard?
More important is the need to reduce substantially our dependence on automobiles. Rather than investing further in the hugely expensive infrastructure supporting auto use, and trying to revive failing US auto companies, we need to put money into building mass transit and modern rail systems. On the very local level the use of bicycles and Shank's mare should be encouraged. (This would confer substantial health benefits as a desirable side effect.) A more powerful approach would be to re-think municipal ordinances and city planning so as to encourage living arrangements that would relieve more people of the need for long trips to work or to shop.
Anybody who has spent time on (or trying to get on) the George Washington Bridge on a weekday morning will have a gut-level understanding of the vast quantity of goods moved into a big city, mostly on big trucks. Waiting at a rail crossing for a hundred car freight train to roll by gives one a further appreciation of how much merchandise is moved over very long distances. Ships and airplanes haul additional large quantities of stuff, often thousands of miles.
We could try to reduce the amount of energy consumed in such haulage by increasing the efficiency of the vehicles used, and surely there are real gains to be made here. But a lot more energy could be saved by reducing the amount of material transported over great distances. Is it really necessary to haul soy beans from China and broccoli from California to New York City? Can someone explain to me why blueberries from Minnesota are now in Rockland County, NY supermarkets?
The fact that all manner of manufactured goods are imported from China to the US, while an order of magnitude less moves the other way is a clear indication that we are not seeing the results of rational free trade. The principal explanation is more along the lines of deliberately undervalued Chinese currency, and various restrictions China places on imports [3]. In addition, US companies scour the world to find producers (very often in China) that can slash costs by using grossly underpaid workers and trashing the environment.
Consider, for example, the problem of increasing substantially the gasoline mileage numbers for autos. There are people who need no persuasion to buy cars that will save them a lot of money at the gas pump. Some don't care so much about the cost of fuel, but are happy to buy cars that will be less harmful to the environment. At the other extreme are those who have no problem paying the costs associated with gas guzzling cars and who strongly oppose any measures that would interfere with their "right" to operate them.
There is, I believe, a large middle group whose position is more complex. Cost alone does not motivate them, but they do recognize the harm associated with excess fuel consumption. Nevertheless, they don't feel that, as individuals, giving up their own guzzlers would make any noticeable difference to the planet. They are not interested in making futile gestures. They don't want to be regarded as eccentrics, perhaps as suckers. But they would be happy to do their share as part of a community effort that would have a real impact. Such people are likely to support legislation that would create such a community effort [5].
We need to think about reasonable kinds of laws and regulations that would effectively address the kinds of wasteful practices mentioned above. For example, there might be regulations on temperature ranges in facilities open to the public. Wasteful electric energy use in homes could be discouraged by steeply graded taxes that would kick in at high usage rates. Some sort of "trash tax" might be devised to call attention to packaging waste. Zoning laws and perhaps real estate taxes might be designed to encourage higher density housing in close proximity to shopping and commercial areas. Public funds might be transferred from road building to mass transit. Agricultural subsidies could be revised to encourage food production closer to populous areas. These are off-the-cuff ideas intended to suggest what might be done. Some might not be feasible, and there are doubtless many other measures that would be acceptable and effective.
This article is a follow-up to an introduction to the energy problem and a discussion of energy sources, accessible "here".
Comments can be sent to me at unger(at)cs(dot)columbia(dot)edu