Supplying power without using the fossil fuels that contribute to climate change is not easy. Wind farms, for example, produce far less electricity than fuel-burning power plants, and the wind does not blow all the time. But if we all used less energy, technologies such as wind and solar power would be able to cope with a bigger proportion of the demand. We can help to achieve this by improving energy efficiency, or making sure things use less power to do the same job. This applies both to the people who design equipment, and to the people who use it.
Some home equipment such as fridges must be left on all the time, and others such as washing machines may run for many hours a day. They can waste a lot of energy if they work inefficiently. New kitchen appliances in most 1 "
parts of the world are now labeled with their efficiency rating, so people can avoid buying energy-wasting designs. These labels for a washing machine in New Zealand show its energy consumption and efficiency, as well as its water conservation rating.
A lot of the electrical devices that we buy have been designed without considering the energy that they use. Anything that has a separate power supply plugged into a power socket uses power all the time —even if it is not in use—unless the power supply is switched off at the wall. Many gadgets are designed never to be switched off, like DVD recorders and digital TV receivers with built-in clocks and tuners. If they are unplugged they may need reprogramming, so they have to be left on "standby"all the time. Plasma-screen TVs like this one use almost five times as much energy as smaller traditional TVs, and 30-65 percent more energy than equally big LCD models.
Used in our houses since being invented by Thomas Edison in 1879, normal incandescent bulbs are highly inefficient. About five percent of the electricity used to power a standard 100-watt light bulb is actually converted into light—the other 95 percent is wasted as heat. Compact fluorescent "energy-saving"bulbs like this one produce about four times as much light per watt of electricity. Bulbs that use clusters of light-emitting diodes (LEDs) are even more efficient.
In winter many houses lose heat through their walls, windows, doors, roofs, and even through their floors—heat that is replaced by their heating systems using more energy. This infrared image shows heat escaping from a house as white and red, while the cooler areas are blue. Better design and building standards can help prevent this. New houses that meet the strict building standards in Sweden, for example, use roughly four times less energy than many older houses in the UK.
STORES AND OFFICES Vast amounts of energy are wasted in stores and offices. Big food stores have rows of open fridges that spill cold air. Office lights and computers are often left running all night. By contrast, the Swiss Re Tower in London is designed to save energy. This building's shape minimizes the cooling effects of the wind and maximizes natural light, reducing the use of heating and lighting.
There are ways of building homes that use virtually no energy at all for heating or air-conditioning. They are naturally warmer in winter and cooler in summer, thanks to very efficient wall and roof insulation, and triple-glazed windows that make the most of natural light energy. This European housing scheme is also designed to use only energy from renewable sources, generated by solar panels and a local combined heat and power plant fueled by waste products.
Whole communities have been converted or designed with energy-saving as a priority. They include Freiburg in Germany, which has some 6,500 energy-efficient homes incorporating solar technology. The new city of Dongtan on Chongmin Island off Shanghai, China, is being built from the ground up as the world's first"eco-city,"with renewable power from its own wind farm. This artist's impression by Arup, the project managers, shows the proposed South Village area.
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