Heating and Cooling with Renewables

Renewable heating and cooling are too often the neglected twins when it comes to climate change and energy policies. They account for 40-50 percent of global energy demand. A large share comes from fossil fuels and is provided inefficiently by electricity or direct combustion.35

As early as the Bronze Age, wood was used to turn sand into glass, extract metals from stone, and fuel furnaces to make bronze and pottery. There is evidence that high-temperature geothermal water was used to heat buildings in ancient Pompeii, while Greeks and Romans captured the sun's warmth to do the same job. Today renewable energy and improved efficiency options exist to meet a wide range of heating and cooling needs, from residential and district heating and cooling systems to industrial-scale refrigeration and high-temperature heat. (See Table 4-1.)36 Among new renewables, solar heating ranks second only to wind power for meeting world energy demands. China leads the world in the production and use of solar thermal systems, with an estimated 1 in 10 households tapping the sun to heat water; Cyprus, Israel, and Austria top the list for per person use. Solar water heating is mainstream in Israel thanks to a 1980s law requiring its use in new homes. Hybrid solar hot water/photovoltaic systems are now available to capture a large amount of the heat absorbed by PVs, thereby cooling them and increasing their efficiency while simultaneously heating domestic water. One of the first systems sits atop the roof of a central building in Beijing's Olympic Village.37 The majority of solar thermal systems in use are for domestic water and space heating, yet solar heating systems—including systems similar to solar heaters for residential buildings and concentrating solar collectors—offer enormous potential for meeting industrial heat demand, particularly at low and medium temperatures (up to 250 degrees Celsius). By late 2007 about 90 solar thermal plants provided process heat for a broad range of industries, from chemical production to desalination and the food and textile industries. Existing plants worldwide represent a tiny fraction of the industrial heat potential available in Europe alone.38

Across Europe, the United States, and elsewhere, people are turning to efficient pellet stoves and in some cases using liquid biofuels in boilers to meet heating needs. Between 1980 and 2005, taxes on energy and CO2 in Sweden drove a major shift from

An Enduring Energy Future

Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

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