Rabu, 23 Desember 2009

Energy Saving: Much Cheaper Than Building Power Plants!


by Thomas R. Blakeslee, Clearlight Foundation

On an electrical grid, supply must always exactly equal demand or the voltage goes unstable. Our utility laws very effectively encourage building of power plants to meet an ever-growing demand. This seemed like wise policy in the days of almost free energy but today it encourages gross investment inefficiencies. Power utilities maximize profits by spending as much as possible on expansion of supply even though energy saving could much more efficiently accomplish the same result.

It costs about $2.50/watt to build a new coal power plant. But replacing light bulbs can decrease demand for only $.025/watt! (A 13-watt compact florescent bulb replacing a 60 watt incandescent bulb reduces demand by 47 watts for only $1.19. $1.19/47= $.025/watt) A properly motivated power utility can accomplish the equivalent of building an expansion power plant at much lower cost by just giving compact florescent lamps to their customers.

That's exactly what Southern California Edison did in 2007 by sending out sample CFLs to their customers with discount coupons that resulted in over a million lamp replacements. That's 47 megawatts demand reduction when they're all turned on! Another program paid $100 towards an efficient, Energy Star refrigerator and offered free pickup of the old refrigerator. Eight hundred thousand refrigerators were replaced on this program.

In most states this would be a suicidal move for a utility because selling less electricity means making less money. However, California made it good business by rewriting the utility laws to decouple earnings from sales. Utilities are rewarded per customer, based on meeting goals rather than the amount of power sold. . They established a loading order that makes energy saving a top priority. Everybody wins because less fuel is burned so there is less pollution and less global warming.

In the 1970s refrigerators used an average of 1800 kwh per year. In 1975 the US tightened efficiency standards for refrigerators. The manufacturers complained loudly that costs would skyrocket. They were wrong. Today, refrigerators cost half as much and consume one fourth as much power.

This pattern is repeated again and again as people naturally defend the status quo when it is challenged. The EPA Energy Star program periodically raises the bar on energy standards. Reduced standby power consumption on TVs and computers is a recent campaign against waste. Back when power was almost free, these wasteful ways seemed to make sense.

We must continually reexamine traditional assumptions as history often takes us down a wrong path. The urinals found in men's public bathrooms are a perfect example. For a century urinals have had a flush handle on them. Then somebody invented the automatic flusher triggered by electronically sensing body heat. It seemed like a great invention till somebody realized that this complexity was totally unnecessary.

The waterless urinal needs no flusher, no power and no water because it has an ingenious plastic trap filled with a heavy blue liquid that keeps sewer smells in without flushing. Each flush urinal wastes 20,000-40,000 gallons of water a year. If all of the urinals in the US were waterless we would save 160 billion gallons of water per year! Sometimes it pays to stand back and rethink the assumptions of the past.

Early in this century we had a nice life based on very little energy consumption. Almost-free energy has led us to change our lifestyle in many ways that should probably be re-examined now. Modern lighting, heating and air conditioning went from uneven coverage to uniformity because cheap energy made that possible. It may be a good time to question whether uniform light and temperature is really better.

Modern lighting spotlights the beautiful or useful and leaves the rest in shadow. A family gathered in front of the fireplace accepts it as natural that the rest of the room is cooler. A fan, an open window or a front porch provides an enjoyable oasis from warm weather. Perhaps we could save a lot of energy by learning to accept uneven temperatures in parts of rooms that we only pass through briefly. A ceiling fan can cool sitting areas with much less energy than it takes to air condition every corner of the house.

Those old stone buildings never get very hot or cold because the massive stone walls cool them during the heat of the day and warm them at night with stored heat from the day. Modern lightweight construction has lost this thermal inertia and requires much more heating and cooling.

PCM wallboards (Phase Change Material) embed wax beads that melt at 78 degrees in the plaster. Just like melting ice, they they cool the wall when it tries to get hotter than 78. At night , when the wall gets cooler, the wax refreezes, giving back heat in the process. A 15 mm PCM wallboard is as effective for heat retention as a 90 mm of concrete or 150 mm of brick! Tiny acrylic microspheres filled with wax are embedded in wallboard allowing normal nailing and cutting without worry. The microspheres can also be mixed into concrete or plaster.

Ceiling fans make it possible to greatly reduce air conditioning use. On warm days you can just open the windows and you'll enjoy the coolness under the fan and enjoy the day. If it gets too hot, try setting the thermostat to eighty degrees and letting the fans cool just your sitting areas.

During cold weather you can keep the heat at sixty or so and enjoy sitting by a fire or pellet stove. Ceiling mounted radiant heating panels can make you feel very cozy even though the room is only sixty. NAHB research found they could save 52% compared to electric baseboard heaters. When you are walking around, sixty feels just fine. Sitting is what makes you cold and you usually do that in only a few places in the house.

Try to give your body a chance to adapt to heat or cold. Your comfort zone is partly a matter of conditioning. Push yourself a bit and you will find that you don't really need such a uniform temperature.

If you live in a very hot or very cold climate a ground source heat pump can save a lot of energy. Deep in the ground the temperature is mild and stable. Buried heat exchange tubing can be used to pump heat to or from the house to the ground. Efficiency can be as high as 500% compared to traditional heating. These systems are expensive to install but can greatly reduce high heating and air conditioning bills.

The seemingly-expensive upfront costs are cheap compared to the cost of building the additional power generating capacity to power a conventional air conditioner. Currently you can take a tax write-off if you install a heat pump system. In an ideal world a rational choice would be made between spending money on building more generating capacity or reducing demand by installing heat pumps. Currently, utility laws in most states make it inevitable that we will overspend on generating capacity and underspend on efficiency.

Insulation is one of the home upgrades with the fastest payoff. An attic fan can pay for itself in one year in some cases. Roof insulation is very cost effective too. Window replacements can pay for themselves in a few years, particularly if windows are leaky. New infrared cameras can spot heat leaks in a moment. They show as red, areas where repair work is needed (see images, below). Professional consultants can do an energy audit on your house that typically result in a 20-40% savings if indicated repair work is done.

Hot water is very inefficiently done in the US. In Europe most people have tankless water heaters that come on only when they use hot water. These are more efficient and they save water because you don't have to waste it waiting for the hot water to arrive from a distant tank. In China most new construction uses solar hot water from vacuum tubes on the roof. In Japan, Honda makes a combined heat and power (CHP) system that uses natural gas to generate electricity and uses the waste heat from the generator to make hot water. The overall efficiency is 85% and the electricity generated can run the meter backwards.

Volkswagen is introducing a similar unit in Germany and Australia has a new unit based on a solid oxide fuel cell. Several European power utilities are planning to these units to customers at discount as a more economical and efficient way to expand power generation.

Now that the almost-free energy is used up we must break our old wasteful habits and begin to respect efficiency. We are wasting so much now that it will be easy and fun to discover new and more efficient ways to live.

If we can improve our efficiency it will cost us less, not more. We just have to take the money we would have spent to build more and more power plants and spend it instead on efficiency improvements. The problem is in our legal structure that subsidizes the wrong things. If we can change our utility laws, the technical solutions are easy.

Tidak ada komentar:

Posting Komentar