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Solar Photovoltaic
Today's photovoltaics have come a long way since the solar-energy heyday of the late 1970s and early '80s. Creating electricity from sunlight, photovoltaic panels can be big and strong enough not only to provide a household's power but also to return excess electricity to the power grid for others to use. Fine Homebuilding contributing editor Scott Gibson takes a look at the current state of photovoltaic energy, including system costs and efficiency.
The electric meter spins backwards on sunny days, and spins very slowly at night. The roof has plants on it -- by design. This award-winning house (2005 National Association of Home Builders Green Custom House Award) is green, and built to stay that way. Photovoltaic panels on the roof produce as much electricity as the house consumes on a yearly basis. Solar thermal panels heat all of the water and also provide heating. In addition to the energy-efficient, green, and healthy-home details, the house features amazing craftsmanship inside and out.
Now in its seventh year and with more than 20 homes on the tour, the Build It Green! Homes Tour + Info Fair held in Portland, Ore., draws an eager crowd. FineHomebuilding.com attended this year's event, gathered practical information on green-building and design strategies as well as techniques, and captured footage of two notable, feature-packed green homes in northeast Portland. Among the homes' features you'll find extensive use of environmentally friendly products, advanced water-conservation systems, and highly efficient HVAC systems.
There is no such thing as the perfect green home. Every house is unique. Each is built in a specific climate where there are varying amounts of sunshine; winds blow from a different direction by season and each site affords different views. Local building products are available or not, there will be small children in the home, or not. And so forth. There is no single green building solution that meets all possible conditions.
The best way to start is to take on some aspect of green building and get really good at it. Dont try to do everything at once. Take on energy conservation and increased R-values in walls and roofs. Get a blower door test done on one of your homes. Try changing the paints and finishes you have always used. Test materials in your garage or on your own home. See what works best for you and your trade contractors. Identify the resistance points in your company or with your trades. Education is the top priority any time you are making changes in your business. Let them know why you are making the changes.
At the same time, there are certain inevitabilities that will affect all of us. Climate change will bring about increasingly weird weather. Floods and droughts will be more frequent, occur in strange places, and last longer. Hurricanes will become more intense as the oceans warm. More frequent and unusual tornados will strike unexpected places. The weather is unpredictable even when it is normal. Build to withstand the harshest weather conditions you can imagine for your region.
We will reach peak oil during the life span of homes built today. What than means is that all forms of energy will become increasingly expensive and with little forewarning by the powers that be. Natural gas is in greater demand just as it is starting to decline from existing wells in the U.S. How much will heating and cooling our homes cost in 5 years, 10, or 20? All we know is a lot more that it does today.
Fresh water will be one of the things that is most radically affected by climate change. When it rains and where will shift all over the globe. Snow pack in mountain areas that provide the water for agriculture in the summer may be hardest hit. Less snow pack means less irrigation water, which affects food prices. Since globalization is so entrenched, particularly when it comes to food, when climates are impacted in Chile food prices go up in the U.S. Grains are particularly vulnerable to fluctuating water availability. Chinas grain is irrigated with fossil water that is predicted to go away in as little as two years. Their demand for wheat will affect U.S. wheat prices. The price of corn is already rising as it is diverted away from food to produce ethanol.
We are not growing old trees anymore. The ones that are still standing are the ones that anchor the forest ecologies of the world. At the current rate of deforestation and clear-cutting, our forests are destined for agriculture, even if that means replanting with mono-cultures of Douglas fir or eucalyptus. Our voracious appetite for wood, paper, and other forest products makes for a dire future for the planets forests (the lungs of the planetour primary defense against climate change) and all the wildlife that lives within their protective canopies. If we dont reverse this trend soon many of the plants and animals we take so for granted will only be seen in zoos and arboretums.
Time for change is now
This story can go on and on. We are at a critical juncture in the history of humans on earth. With 40% of the worlds resources going into buildings, 66% of the electricity generated used for heating, cooling, and lighting buildings, the demand for new coal-burning power plants grows ever stronger. China is planning to build one coal-burning power plant a week for the next 20 years. There are 154 new coal-fired plants on the drawing boards in the U.S. in 42 states. There are currently about 600 coal plants in the U.S. that according to the Union of Concerned Scientists burn 1.4 million tons of coal each every year.
Its time to start planning, designing, and building homes that reduce the need for new coal-fired plants and help us prepared for the inevitability of more expensive power. Homes that produce as much energy as they consume and allow their owners to collect and store rainwater are things that we can do now.
