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DESIGN OF ZERO ENERGY COMMUNITIES

An exciting new concept in sustainable urban and regional planning is the building of zero-energy communities. This is not a theoretical concept as one community has already done it. This community is the Island of Samso in Denwark. In size, it is approximately equal to the size of Nantucket. What Samso did was to implement an integrated system of alternative energy systems at the community level, with the entire community sharing in all the costs and benefits. District heating plants use straw waste to provide steam heat to buildings throughout the island. Biofuel fuel is used to replace the use of oil in automobiles. Wind turbines and solar photovoltaic sells are used to generate electricity. Improved methods of building construction and insulation have reduced the cost of heating and cooling buildings, while geothermal heat pumps which draw on the constant temperature of the underground air have proved to significantly reduce the cost of heating and air-conditionig buildings. Samso has been so successful that it now is a zero-energy community that exports energy to surrounding areas. Following are examples of renewable atlternative energy sources that can be used to help a community make itself into a zero-energy community.

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Biofuels

Biofuels are plant materials or waste that can be converted to solid fuels or liquid fuels such as ethanol. Even food cooking waste oil can be collected and, after being filter, can be directly used as a fuel in specially converted biodiesel vehicles.

Geothermal Power

Geothermal energy production is a renewable energy source that extracts the heat from the earth's interior. The cost of geothermal energy production is greatly dependent upon how close to the earth's surface are located geothermal vents. In locations such as Iceland and Hawaii where there exists active volcanic activity, geothermal energy is an attractive source of renewable energy. Pictured above is a geothermal power plant built in Iceland.

Solar Power Plants

Solar power, or energy from the sun, is by the earth's most abundant renewable energy source. Unfortunately, while having great potential, last year solar energy production accounted for only 0.02 percent of the world's energy consumption. With concern about global warming, however, governments are providing financial incentives for solar energy production, which helps to create demand and bring down the cost of solar energy technologies. Also, new approaches for solar energy production are being developed, such as that illustrated above where solar rays are concentrated in a single collecting mirror that allows for the building of large solar energy power plants. Examples of such solar energy power plants include the 46 MW Moura solar power plant in Portugal, the 40 MW Waldpolenz solar power plant in Germany, and the 11 MW PS10 solar power plant (illustrated above) in Seville, Spain.

Wind Energy Farms

Wind energy is another form of renewable energy. Modern wind turbines have become very efficient at transferring the energy of the wind to electricity. To demonstrate the potential of wind energy, electrical generation from wind turbines grew by 28.8 percent world-wide last year. Two innovative new uses of wind energy are: (1) specially designed new wind turbines that can be mounted on the roofs of urban buildings; and (2) the idea of creating a smart grid where wind energy can be exported from areas of high winds to urban areas needing the energy. Another innovative proposal is to build a grid of wind turbines in the upper midwest of the U.S. to provide cheap energy to extract natural gas from lands containing oil shale.

DESIGN OF SUSTAINABLE "GREEN" BUILDINGS

The heating, cooling and lighting of our buildings accounts for 48 percent of all U.S. energy consumption. As such, building energy usage is the greatest contributor to green house gases and global warming. This will only increase as the world becomes more urbanized and the built environment represents a greater and greater portion of our environment. Stormwater runoff from buildings is also one of the greatest non-point sources of water pollution, while the manufacturer of synthetic materials used in the construction of buildings leads to hazardous waste and an increasing number of "sick" buildings. One example of a community that has made a commitment as part of its sustainable urban and regional planning to attempt to convert all buildings in the community to sustainable "green" buildings is the town of Greensburg, Kansas. After being devastated by a tornado, the town enlisted the support of various corporate sponsors and enlisted the help of the non-profit studio 804 of the University of Kansas to help rebuild the community with "green" buildings. Following is a discussion of methods of constructing "green" buildings so as to promote a more sustainable environment.

Green Roofs

Green roofs are one of the most visible ways to build more sustainable, "green" buildings. A study conducted for Toronto, Canada estimated that the installation of green roofs on buildings could: reduce the heat island effect of urban areas by 1 to 2 degrees C, reduce smog alerts in cities by 5 to 10 percent, absorb CO2 emissions from automobiles and thus reduce green house gases, reduce the energy needs of buildings for heating and air conditioning, filter storm run-off and thus reduce water pollution, and expand recreational and open space in urban areas by creating roof-top gardens.

Solar Photovoltaic Panels

Solar photovoltaic panels are used to convert the sun's energy into electricity. A converter is used to convert the electricity from DC to AC electricity. Any excess electricity can be stored in batteries or exported to the electrical grid and sold to the local electrical utility.

Solar Hot Water Systems

Solar hot water systems are systems that absorb the heat of the sun to heat water for the use within a building.

Passive Solar

Passive solar is any means to use the heat from the sun to provide for the heating or energy needs of a building without any means of mechanical assistance. The easiest method of passive solar involves the proper siting of a building to take advantage of the sun when it is at a low horizon or angle, but to provide shading when the sun is at its highest during the hottest part of the day. Another means of passive solar design is to build the floor of a building with some type of thermal mass such as concrete that absorbs the heat - and releases the heat at night when it is cooler.

Wind Turbines on Buildings

Previously, wind turbines as an energy source were typically not located on building or within urban areas. With the concern about green energy and global warming, however, new technologies have recently been developed to allow wind turbines to be built on top of buildings -- and be able to deal with the shifting wind directions typical of urban areas. As such, wind turbines are increasingly a part of sustainable green buildings.

Recycled Cellulose Insulation

Traditional fiberglass insulation is harmful to the environment both in its manufacturer and in its use. A more eco-friendly type of insulation is recycled cellulose insulation. The cellulose can come from such diverse sources as recycled newspapers or recycled blue jeans.

Geothermal Heating and Cooling

Geothermal heating and cooling involves the use of ground source heat pumps to take advantage of the fairly constant ground temperature to reduce the cost of normal heat pumps to provide for heating and cooling. Wells are dug to a depth of typically 200 feet to obtain a source of air that is approximately 55 degrees year around. This reduces the need for cooling the outside air for air conditioning in the summer and for heating the outside air in the winter, and thus provides for a more efficient form of heating and air conditioning of buildings.

Natural Ventilation - to Vent Hot Air

Another method of sustainable green building design is to incorporate means of natural ventilation into a building to vent hot air in the summer time, and thus reduce the need for energy used for air conditioning.