Benefits of Green Roofs
Green roofs are booming in popularity because they bring multiple benefits to buildings and to communities.
These benefits include:
Reducing roof replacement costs. In Minnesota, a typical gravel-ballasted flat roof is expected to perform for 15-20 years before replacement is necessary. Roof membranes deteriorate when exposed to the hot and cold temperature extremes we experience in Minnesota, and also when exposed to UV radiation from sunlight. The components of a green rooftop protect a roof membrane from these aging factors. The membrane under a green rooftop can be expected to perform for 35 – 50 years before replacement is necessary. This means that a building can avoid 1 – 2 roof replacements over a 50-year lifespan. This reduces life cycle costs as well as significantly reducing the volume of roofing materials deposited in our landfills.
Reducing energy costs. Green roofs can reduce heating and cooling demands. During a Minnesota winter, the insulation layer and growing medium of a green roof can add r-value to a building’s roof. In the summer, the impact is more significant. Living plant material evaporating moisture from leaf surfaces will cool the rooftop surface, reducing cooling demand up to 25 percent.
Reducing stormwater management costs. An extensive green roof with four inches of growing medium can be expected to hold a one-inch rainfall event before any water runs off the roof surface. Nearly all the rainfall events we receive in Minnesota are less than one inch. This four-inch green roof can be expected to capture two-thirds of the rain that falls on its surface. With a deeper layer of growing medium or with rainwater or greywater harvesting systems, a green roof can be used to manage a significantly larger volume of water. As a part of a building’s stormwater management infrastructure, a green roof can reduce the cost of other stormwater management systems, and in some cities can reduce monthly stormwater management fees. The City of Minneapolis uses a stormwater utility fee structure that provides incentives for using green roofs to manage stormwater on-site.
Improving urban air quality.. Green space is good for air quality. Green rooftops provide opportunities to increase the amount of green space in densely developed urban areas where green space can be hard to find. A 1998 study by Green Roofs for Healthy Cities developed a model showing that, if six percent of the rooftop surfaces in the City of Toronto were replaced with green rooftops, the additional green space would remove 30 tons of airborne particulate pollution each year.
Mitigating Climate Change and the Urban Heat Island Effect. Urban areas like Minneapolis-Saint Paul are generally 2 – 5 degrees (f) warmer than surrounding rural areas. This is known as the Urban Heat Island effect. On top of that, the USEPA projects a 2 – 7 degree (f) increase in aggregate temperature for our region over the course of the 21st Century. It is projected that a three-degree aggregate temperature increase in Minneapolis would triple annual heat-related deaths from 60 to nearly 200. By cooling rooftop surfaces and improving air quality, a critical mass of green rooftops can mitigate all of these impacts.
Providing urban green space. Green roofs can provide opportunities for significant green space amenities in urban areas. East Village Apartments in the Elliot Park neighborhood of Minnepaolis features an at-grade green rooftop installed over underground parking. The green space includes picnic tables and provides an amenity to this affordable housing development. The green rooftop at Brit’s Pub on Nicollet Mall in Minneapolis can be used for lawn bowling and private parties. And pedestrians using the Loring Greenway in Minneapolis may not even realize that they are walking on green roof surfaces above occupied spaces. Hospital administrators know that patients who can see green space outside their windows can recover more quickly. Nursing home and elder care facilities can use green roofs as part of horticultural therapy programs.
Tuesday, August 9, 2011
13 tips to go green
13 tips to go green
Today, we are helping our customers reduce their carbon-footprint and utility costs at the same time. Our slogan “Go Green & Save Money” says it all.
Our goal is to provide cost-effective energy solutions that make as much sense financially as they do environmentally. Energy Savers is proud to be at the forefront of America’s movement towards sustainability.
1) Turn down the thermostat. Lowering it by just one degree can reduce heating energy costs by about four percent.
2) Use ceiling fans in the summer AND winter. By reversing the direction of the blades, warm air is pushed down, helping to keep rooms warm in winter.
3) Conserve energy by purchasing major appliances with an Energy Star rating. Compared to a 1990 model, an Energy Star-qualified refrigerator would save enough electricity to light a home for more than four and a half months.
4) Repair leaky fixtures: one drop per second from a leaky faucet can waste as mush as 10 gallons of water each week.
5) Install low-flow showerheads, faucets, and toilets. Low-flow faucets reduce water consumption and the cost of heating water by as much as 50 percent; using a low-flow toilet can save Americans 2.1 trillion gallons of water and $11.3 million nationwide every day.
6) Choose carpeting, rugs, window treatments and other textiles made from natural fibers, such as cotton or wool, which are untreated and free of toxins, such as pesticides or chemical cleaners.
7) Ask for flooring products made from rapidly renewable resources, such as bamboo. Bamboo is one of the fasted growing plants in the world, requiring no replanting and little fertilization or pesticides.
8) Select solid woods harvested from sustainably-managed forests, when possible, for furniture or cabinetry, rather than pressed woods or composites that may contain formaldehyde or other chemicals that may be toxic and hazardous to your health.
9) Eliminate waste by choosing products that are biodegradable or recyclable. Consider the “lifecycle” of furnishings and accessories before purchasing: Are they made of materials that can be reused or recycled when the item eventually wears out or is no longer needed?
10) Recycle packing and shipping materials from any newly purchased items, and safely dispose of paint cans and other containers with contents that could potentially contaminate the ground or water supply.
11) Install exterior window shades on Southern and Western exposure windows.
12. Install insulation in attic and crawl space and install attic fans.
13) Speak with a friendly Energy Consultant from Energy Savers and start going green today!
Today, we are helping our customers reduce their carbon-footprint and utility costs at the same time. Our slogan “Go Green & Save Money” says it all.
Our goal is to provide cost-effective energy solutions that make as much sense financially as they do environmentally. Energy Savers is proud to be at the forefront of America’s movement towards sustainability.
1) Turn down the thermostat. Lowering it by just one degree can reduce heating energy costs by about four percent.
2) Use ceiling fans in the summer AND winter. By reversing the direction of the blades, warm air is pushed down, helping to keep rooms warm in winter.
3) Conserve energy by purchasing major appliances with an Energy Star rating. Compared to a 1990 model, an Energy Star-qualified refrigerator would save enough electricity to light a home for more than four and a half months.
4) Repair leaky fixtures: one drop per second from a leaky faucet can waste as mush as 10 gallons of water each week.
5) Install low-flow showerheads, faucets, and toilets. Low-flow faucets reduce water consumption and the cost of heating water by as much as 50 percent; using a low-flow toilet can save Americans 2.1 trillion gallons of water and $11.3 million nationwide every day.
6) Choose carpeting, rugs, window treatments and other textiles made from natural fibers, such as cotton or wool, which are untreated and free of toxins, such as pesticides or chemical cleaners.
7) Ask for flooring products made from rapidly renewable resources, such as bamboo. Bamboo is one of the fasted growing plants in the world, requiring no replanting and little fertilization or pesticides.
8) Select solid woods harvested from sustainably-managed forests, when possible, for furniture or cabinetry, rather than pressed woods or composites that may contain formaldehyde or other chemicals that may be toxic and hazardous to your health.
9) Eliminate waste by choosing products that are biodegradable or recyclable. Consider the “lifecycle” of furnishings and accessories before purchasing: Are they made of materials that can be reused or recycled when the item eventually wears out or is no longer needed?
10) Recycle packing and shipping materials from any newly purchased items, and safely dispose of paint cans and other containers with contents that could potentially contaminate the ground or water supply.
11) Install exterior window shades on Southern and Western exposure windows.
12. Install insulation in attic and crawl space and install attic fans.
13) Speak with a friendly Energy Consultant from Energy Savers and start going green today!
Sunday, August 7, 2011
Use alternative energy
Use alternative energy
Oil prices are skyrocketing and it affects more than just your price at the pump. Utility companies are increasing their prices and the cost of batteries is always high, but there's no way to live in the modern world and enjoy modern amenities without relying on a utility company or batteries to power the electronics which are so integral to our lives. Right?
Wrong! There are many forms of alternate energy sources that could not only save you thousands of dollars annually, but will help decrease pollution and its negative effects on our environment.
Most utility plants are coal-burning and even the ?clean coal? produces some smog. The clean energy-producing nuclear power plants are few and far between and even they present the problem of possible nuclear meltdown and of how to dispose of toxic waste.
Alternative energy sources eradicate these pollution problems. Why, then, do traditional utility plants still exist? There are groups dedicated to the widespread promotion of alternative energy sources, but it is difficult for a culture so dependant on oil to change, especially when alternative energy sources require special arrangements and can sometimes have problems meeting the energy needs of thousands of homes and businesses all at once.
You can make a difference in your own home or business, though, by changing your individual energy source to an alternative energy option. Solar power, for example, is an alternative energy source frequently used in lieu of batteries to run accessories like flashlights or the electrical needs of an RV, but it also can produce enough power to power entire homes and businesses.
The solar cells on the panels convert sunlight photons into electrical energy and that energy is sent to an inverter, which converts the alternative energy into useable electricity. Excess energy not used immediately is stored for later use at night or on cloudy days. By installing solar power panels on the roof of or on the ground near your home or business, you can enjoy pollution-free, no-cost energy after an initial installation fee, which could cost you between $10,000-100,000, depending on the size and energy needs of your building.
Hydropower, another pollution-free, no-cost alternative energy source, is more often used to power large buildings or entire towns, but if you have the appropriate environment, you may want to look into it or you could even build the environment! Hydropower is an alternative energy source that uses the force of water moving downward most often in waterfalls to turn turbines that generate electrical energy.
Wind power is another popular source of alternative energy. If you live in an area with adequate wind, you can build a tall structure that's similar to a giant fan on your property. This fan is an electrical generator powered by the wind, and similarly to other alternative energy sources, excess energy is stored for use when the wind is not strong.
There are quite a few alternative energy sources that are still undergoing testing, but you can do your part to help the environment today! Yes, converting to alternative energy sources can be expensive at first, but they are all virtually free to run after installation. Plus, without utility bills, you will more than make back your money over time. If you're not ready to spend the money, look for alternative energy for accessories like flashlights!
Ready to install an alternate energy source in your home, business, or RV? Want to buy alternate energy-powered accessories? Eager to help spread the word about the benefits of alternate energy? Visit the Alternate Energy Resource Network at alternate-energy.net.
Oil prices are skyrocketing and it affects more than just your price at the pump. Utility companies are increasing their prices and the cost of batteries is always high, but there's no way to live in the modern world and enjoy modern amenities without relying on a utility company or batteries to power the electronics which are so integral to our lives. Right?
Wrong! There are many forms of alternate energy sources that could not only save you thousands of dollars annually, but will help decrease pollution and its negative effects on our environment.
Most utility plants are coal-burning and even the ?clean coal? produces some smog. The clean energy-producing nuclear power plants are few and far between and even they present the problem of possible nuclear meltdown and of how to dispose of toxic waste.
Alternative energy sources eradicate these pollution problems. Why, then, do traditional utility plants still exist? There are groups dedicated to the widespread promotion of alternative energy sources, but it is difficult for a culture so dependant on oil to change, especially when alternative energy sources require special arrangements and can sometimes have problems meeting the energy needs of thousands of homes and businesses all at once.
You can make a difference in your own home or business, though, by changing your individual energy source to an alternative energy option. Solar power, for example, is an alternative energy source frequently used in lieu of batteries to run accessories like flashlights or the electrical needs of an RV, but it also can produce enough power to power entire homes and businesses.
The solar cells on the panels convert sunlight photons into electrical energy and that energy is sent to an inverter, which converts the alternative energy into useable electricity. Excess energy not used immediately is stored for later use at night or on cloudy days. By installing solar power panels on the roof of or on the ground near your home or business, you can enjoy pollution-free, no-cost energy after an initial installation fee, which could cost you between $10,000-100,000, depending on the size and energy needs of your building.
Hydropower, another pollution-free, no-cost alternative energy source, is more often used to power large buildings or entire towns, but if you have the appropriate environment, you may want to look into it or you could even build the environment! Hydropower is an alternative energy source that uses the force of water moving downward most often in waterfalls to turn turbines that generate electrical energy.
Wind power is another popular source of alternative energy. If you live in an area with adequate wind, you can build a tall structure that's similar to a giant fan on your property. This fan is an electrical generator powered by the wind, and similarly to other alternative energy sources, excess energy is stored for use when the wind is not strong.
There are quite a few alternative energy sources that are still undergoing testing, but you can do your part to help the environment today! Yes, converting to alternative energy sources can be expensive at first, but they are all virtually free to run after installation. Plus, without utility bills, you will more than make back your money over time. If you're not ready to spend the money, look for alternative energy for accessories like flashlights!
Ready to install an alternate energy source in your home, business, or RV? Want to buy alternate energy-powered accessories? Eager to help spread the word about the benefits of alternate energy? Visit the Alternate Energy Resource Network at alternate-energy.net.
Monday, August 1, 2011
Green Power - Alternative Energy Sources
Green Power - Alternative Energy Sources
We use energy for industry, business, residential consumption, and transportation. Oil, coal, natural gas, and nuclear are non-renewable energy sources that account for 93% of the energy used worldwide. Only 7% is derived from renewable sources—what we call “green energy” or, more often, alternative energy. Alternative energy sources include hydroelectric, wind, solar, biomass, biofuel, and geothermal.
Hydroelectric Energy
Hydropower, the largest form of alternative energy, is derived by harnessing energy from moving water. From the earliest use of a waterwheel to grind grain, forge metals, or make paper to today’s massive hydroelectric plants that provide electricity to entire cities, mankind has learned to harness the power of moving water.
Hydroelectric Power from Large Dams
Dams were first used for hydropower around 1890. There were more than 45,000 large dams in more than 140 countries by the end of the 20th century. But only a fraction of these dams are used for hydropower. Most are used for irrigation, flood control, and water supply. The percentage of dams constructed for hydropower has been decreasing over the last 20 years. In the year 2000, the distribution of large hydropower dams was as follows: Africa 6%; North America 11%, South America 26%; Asia 7%; Australasia (Australia, New Zealand, New Guinea and neighboring islands) 19%, and Europe 31%.
Hydropower provides 96% of the renewable energy utilized in the United States, though it provides only 10-11% of its electricity.
Hydropower can be generated from the movement of any body of water. Rivers,
movement of any body of water. Rivers, waterfalls, streams, ocean tides, and ocean waves are all potential energy sources.
When we think of hydropower, we usually imagine a massive dam. Behind the dam, water is backed up to form a reservoir or an artificial lake. Gravity pulls water into the intake area from the reservoir where it flows through a penstock (a chute, sluice, tunnel, or pipe) downhill to pass through a turbine propeller, which spins the turbine shaft. The hydraulic turbine converts mechanical energy into electricity. [For an interesting in-depth explanation and great graphics, check out the U.S. Geological Services website.]
Although hydro-electrical power is green energy that is clean, renewable, and sustainable, it has negative environmental and societal impacts.
Damming a river creates a reservoir which floods a large area, burying whatever was there before, whether it was a town or a wilderness area. Rotting vegetation releases methane gas. Habitats are destroyed. Natural fish migration is disrupted. Water released through the dam carries less silt and it scours and erodes the banks and the riverbed downstream.
The World Commission on Dams report (Nov. 2000) estimates 40-80 million people have been displaced through forced
resettlement due to dam construction, with whole societies losing their cultural heritage, their homes, and their livelihoods. Many did not receive any form of compensation or resettlement assistance.
Downstream communities are at great risk if a dam fails. The Association of State Dam Safety Officials has concluded that the U.S. safety expenditures for dams are insufficient. They rate 9,326 of the 80,000 large and small dams in the U.S. as high hazard and 1,600 of these dams lie within one mile upstream of a city. Less than 40% of high hazard dams have an emergency action plan for nearby residents to follow.
Smaller Dams and Run-of-the-River Systems
Smaller dams and run-of-the-river systems exert less environmental and societal impact. A smaller dam may be built with storage and pumping capacity, reusing water it pumps back into its reservoirs. Run-of-the-river systems either place turbines within the river or divert water through pipes which run through a turbine and flow back into the river downstream.
If we are to increase our use of inland hydropower as an alternative power source with low impact on the environment, we must do a better job of assessing and mitigating its
short-term and long-term consequences.
Energy from the Ocean Tides
Tidal energy plants build a low dam or barrage across an inlet. Water passes through gates or sluices into the inlet. When the tide goes out, it turns turbines to produce energy. There is no pollution, the fuel is free, the plants are easy to maintain, and they should last for a hundred years. Unfortunately, there are few locations in which to build them. Construction costs are expensive. Fortunately the environmental impact appears to be minimal. The French tidal plant, La Rance, has been producing electricity since 1968.
Energy from Ocean Waves
There are several ways to capture energy from ocean waves. Wave motion can push air through a pipe; the air spins a turbine. Or water can be focused into a narrow channel to increase its power and is used to spin turbines or can be channeled into a catch basin. Currently this potential energy source is being explored for use in Japan, but there are no large commercial energy wave plants at this time. One demonstration tower built in Norway proves the potential of this technology with one drawback, noise pollution. The whine of the turbines can be heard for miles.
Ocean Thermal Energy Conversion
In tropical areas where the difference between the surface temperature of the water and the deep water temperature is 38 degrees or more, this difference in temperature can be used to create energy. Hawaii has experimented with ocean thermal energy conversion since the 1970s, but it is estimated to be 15-20 years before this technology, which is limited to tropical climates, will be available.
Wind Energy
Windmills have been used to harness energy for thousands of years, first for transportation (sailing ships), later for grinding grain and pumping water. Today, single wind towers are providing green energy to isolated homes or farms, while large-scale wind farms are being built both on land and off shore to provide energy for national electrical grids and pre-planned communities.
The U.S. Department of Energy’s website states, “Today, U.S. wind energy installations produce enough electricity on a typical day to power the equivalent of more than 9.7 million homes. The five-year average annual growth rate for the wind industry is now 39%, up from 32% between 2003 and 2008. America's wind power fleet will avoid an estimated 62 million tons of carbon dioxide annually, equivalent to taking 10.5 million cars off the road, and will conserve approximately 20 billion gallons of water annually, which would otherwise be consumed for steam or cooling in conventional power plants.”
Wind energy is gaining in popularity across the world. Britain is investing in offshore wind farms with a goal of generating enough green power to light every home in Britain by wind energy. European countries, Canada, the U.S., Brazil, China, India, and Mexico are all pursuing wind as a viable source of energy.
This renewed interest has resulted in vast improvements in wind tower design and efficiency. It has also sparked creative and innovative ideas such as wind kites; deep water (floating rather than fixed), off-shore wind farms; and overhead turbines placed on freeways that are powered by wind created by passing cars.
While wind power is sustainable and pollution free, the power generated is intermittent. Noise has been cited as a factor. A cute video comparing the noise of a single tower to everyday urban and rural noise suggests traffic noise is much more disruptive. Many argue the huge towers are an eyesore, whether onshore or offshore. Bird and bat mortality is also a consideration, but this issue is being researched and addressed by the industry.
Solar Energy
By far the most utilized alternative power source throughout mankind’s history, solar power seems to have been the least exploited in recent years. Solar energy, both active and passive, is a well known source of power. But for years we have heard large scale use is cost prohibitive, takes up too much space, is too affected by the weather, and produces too little output. Due to the rising costs of fossil fuel, new research, new technology, and new application will hopefully give rise to an increase in the use of solar power.
Whether active or passive, or photovoltaic, solar lends itself to onsite green energy applications. Active solar energy can be used to heat hot water, an obvious need, but heated water can also be used to heat a home or pool and solar energy can be used to heat air. Solar panels can also be used to create electricity, while passive solar design utilizes the sun’s rays for both heat and light.
Solar energy plants (also called thermal plants) collect the suns energy and convert it to electricity through various means. Solar cells are the most widely known, but solar energy can also be used to make steam
which is used like wind or water to turn turbines.
Solar energy is clean, renewable, free and worldwide, but of course can be collected only during daylight hours. Pollution and cloud cover adversely affect solar power collection, but newer technology is addressing these factors.
Like wind technology, investment in solar research and design is booming. It will be exciting to see what the next few years hold in store for utilization of this age old resource.
Biomass and Biofuel
Biomass is used as a fuel or is converted to biofuel. Biomass is organic matter, vegetable or animal, including crops, wood, refuse from industry such as paper mills, or matter from landfills. It can be burned to create electricity; gases from decomposition can be collected and used, or crops can be grown to make fuel, such as corn grown to make ethanol.
Proponents argue that burning biomass, which releases CO2 into the atmosphere, is green power because it is part of the carbon cycle. They claim, on the other hand, that burning fossil fuels disrupts the carbon cycle. If the Earth is viewed as a closed system, this logic seems suspect and a weak argument for cutting down forests for biofuel.
It is interesting, however, to remember that Henry Ford built a car out of biomass that was stronger than steel. And the fuel he chose was made from the oil of seeds. Today we are manufacturing new bio-degradable plastics from biomass and raising crops for ethanol. But it is essential we consider the entire impact of turning to biofuels to replace fossil fuels, including the stewardship of croplands and food sources.
Geothermal Energy
Geothermal energy can refer to the use of the Earth to provide heating and/or cooling on a small scale through the design of a home or through the utilization of a heat pump. Or it can refer to the use of the Earth’s heat to run power plants.
Geothermal Design and Heat Pumps
If you dig below the frost line, the temperature of the ground remains constant—about 50 degrees. This median temperature can be used as an aid to cool a building in the summer and heat it in the winter. Combined passive solar and geothermal designs circulate air around and under a building, venting heat in the summer, trapping it in the winter.
Heat pumps pipe water or coolant
underground to heat or cool it to 50 degrees, cutting down on the amount of electricity needed to reach the desired temperature.
Geothermal Plants
The depth of the Earth’s crust varies on average from 5-25 miles deep. But there are places on the Earth where magma oozes or explodes to the surface, mud flats boil and bubble, and steam shoots into the sky. And there are places where the Earth’s crust is thin and drilling below the surface can easily tap into heat sources below.
Geothermal power plants use water, steam, and/or heat from below the Earth’s crust to make electricity or to provide a direct source of heat. Underground bodies of water heated by hot rocks or magma can be pumped through buildings, under streets, and under sidewalks. In Iceland, this method is used to heat most of the homes and commercial buildings in the nation.
Geothermal electric power plants use steam to turn turbines and make electricity in one of three ways: a direct source of steam is tapped, hot water sources are tapped and turned into steam, or above ground water sources are diverted into deep wells where water is heated by hot rocks or magma and turned into steam. One process utilizes chemicals in addition to hot water to make steam.
Proponents of geothermal energy tell us it is safe, sustainable, and non-polluting. These sweeping statements are not entirely true. Destruction from drilling, landslides, earthquakes, and pollution from released gases and toxic elements impact the environment.
A geothermal plant in California, believing their source of steam to be an inexhaustive supply, vented the steam rather than capturing it and returning it to the source. The underground water source, which had produced geysers for thousands of years, was depleted.
Open system plants vent steam along with gases such as hydrogen sulfide, carbon dioxide, ammonia, and methane and toxic elements such as mercury and arsenic, though some systems capture gases and other pollutants and either return them to the source or utilize them. But accidents can happen as well. A blow-out in a Hawaiian geothermal plant caused toxic gases to spew into the sky for thirty hours.
Enhanced Geothermal Systems (EGS) drill down to dry, hot, non-porous rock and pump in water under high pressure into the well to create steam which rises through a second bore hole. The water, once cooled, is again injected into the well in a closed loop system.
One plant in Switzerland was forced to close within days of starting operation due to seismic activity generated by this process. But EGS technology is in its infancy. New research is underway using carbon dioxide instead of water for EGS systems.
We use energy for industry, business, residential consumption, and transportation. Oil, coal, natural gas, and nuclear are non-renewable energy sources that account for 93% of the energy used worldwide. Only 7% is derived from renewable sources—what we call “green energy” or, more often, alternative energy. Alternative energy sources include hydroelectric, wind, solar, biomass, biofuel, and geothermal.
Hydroelectric Energy
Hydropower, the largest form of alternative energy, is derived by harnessing energy from moving water. From the earliest use of a waterwheel to grind grain, forge metals, or make paper to today’s massive hydroelectric plants that provide electricity to entire cities, mankind has learned to harness the power of moving water.
Hydroelectric Power from Large Dams
Dams were first used for hydropower around 1890. There were more than 45,000 large dams in more than 140 countries by the end of the 20th century. But only a fraction of these dams are used for hydropower. Most are used for irrigation, flood control, and water supply. The percentage of dams constructed for hydropower has been decreasing over the last 20 years. In the year 2000, the distribution of large hydropower dams was as follows: Africa 6%; North America 11%, South America 26%; Asia 7%; Australasia (Australia, New Zealand, New Guinea and neighboring islands) 19%, and Europe 31%.
Hydropower provides 96% of the renewable energy utilized in the United States, though it provides only 10-11% of its electricity.
Hydropower can be generated from the movement of any body of water. Rivers,
movement of any body of water. Rivers, waterfalls, streams, ocean tides, and ocean waves are all potential energy sources.
When we think of hydropower, we usually imagine a massive dam. Behind the dam, water is backed up to form a reservoir or an artificial lake. Gravity pulls water into the intake area from the reservoir where it flows through a penstock (a chute, sluice, tunnel, or pipe) downhill to pass through a turbine propeller, which spins the turbine shaft. The hydraulic turbine converts mechanical energy into electricity. [For an interesting in-depth explanation and great graphics, check out the U.S. Geological Services website.]
Although hydro-electrical power is green energy that is clean, renewable, and sustainable, it has negative environmental and societal impacts.
Damming a river creates a reservoir which floods a large area, burying whatever was there before, whether it was a town or a wilderness area. Rotting vegetation releases methane gas. Habitats are destroyed. Natural fish migration is disrupted. Water released through the dam carries less silt and it scours and erodes the banks and the riverbed downstream.
The World Commission on Dams report (Nov. 2000) estimates 40-80 million people have been displaced through forced
resettlement due to dam construction, with whole societies losing their cultural heritage, their homes, and their livelihoods. Many did not receive any form of compensation or resettlement assistance.
Downstream communities are at great risk if a dam fails. The Association of State Dam Safety Officials has concluded that the U.S. safety expenditures for dams are insufficient. They rate 9,326 of the 80,000 large and small dams in the U.S. as high hazard and 1,600 of these dams lie within one mile upstream of a city. Less than 40% of high hazard dams have an emergency action plan for nearby residents to follow.
Smaller Dams and Run-of-the-River Systems
Smaller dams and run-of-the-river systems exert less environmental and societal impact. A smaller dam may be built with storage and pumping capacity, reusing water it pumps back into its reservoirs. Run-of-the-river systems either place turbines within the river or divert water through pipes which run through a turbine and flow back into the river downstream.
If we are to increase our use of inland hydropower as an alternative power source with low impact on the environment, we must do a better job of assessing and mitigating its
short-term and long-term consequences.
Energy from the Ocean Tides
Tidal energy plants build a low dam or barrage across an inlet. Water passes through gates or sluices into the inlet. When the tide goes out, it turns turbines to produce energy. There is no pollution, the fuel is free, the plants are easy to maintain, and they should last for a hundred years. Unfortunately, there are few locations in which to build them. Construction costs are expensive. Fortunately the environmental impact appears to be minimal. The French tidal plant, La Rance, has been producing electricity since 1968.
Energy from Ocean Waves
There are several ways to capture energy from ocean waves. Wave motion can push air through a pipe; the air spins a turbine. Or water can be focused into a narrow channel to increase its power and is used to spin turbines or can be channeled into a catch basin. Currently this potential energy source is being explored for use in Japan, but there are no large commercial energy wave plants at this time. One demonstration tower built in Norway proves the potential of this technology with one drawback, noise pollution. The whine of the turbines can be heard for miles.
Ocean Thermal Energy Conversion
In tropical areas where the difference between the surface temperature of the water and the deep water temperature is 38 degrees or more, this difference in temperature can be used to create energy. Hawaii has experimented with ocean thermal energy conversion since the 1970s, but it is estimated to be 15-20 years before this technology, which is limited to tropical climates, will be available.
Wind Energy
Windmills have been used to harness energy for thousands of years, first for transportation (sailing ships), later for grinding grain and pumping water. Today, single wind towers are providing green energy to isolated homes or farms, while large-scale wind farms are being built both on land and off shore to provide energy for national electrical grids and pre-planned communities.
The U.S. Department of Energy’s website states, “Today, U.S. wind energy installations produce enough electricity on a typical day to power the equivalent of more than 9.7 million homes. The five-year average annual growth rate for the wind industry is now 39%, up from 32% between 2003 and 2008. America's wind power fleet will avoid an estimated 62 million tons of carbon dioxide annually, equivalent to taking 10.5 million cars off the road, and will conserve approximately 20 billion gallons of water annually, which would otherwise be consumed for steam or cooling in conventional power plants.”
Wind energy is gaining in popularity across the world. Britain is investing in offshore wind farms with a goal of generating enough green power to light every home in Britain by wind energy. European countries, Canada, the U.S., Brazil, China, India, and Mexico are all pursuing wind as a viable source of energy.
This renewed interest has resulted in vast improvements in wind tower design and efficiency. It has also sparked creative and innovative ideas such as wind kites; deep water (floating rather than fixed), off-shore wind farms; and overhead turbines placed on freeways that are powered by wind created by passing cars.
While wind power is sustainable and pollution free, the power generated is intermittent. Noise has been cited as a factor. A cute video comparing the noise of a single tower to everyday urban and rural noise suggests traffic noise is much more disruptive. Many argue the huge towers are an eyesore, whether onshore or offshore. Bird and bat mortality is also a consideration, but this issue is being researched and addressed by the industry.
Solar Energy
By far the most utilized alternative power source throughout mankind’s history, solar power seems to have been the least exploited in recent years. Solar energy, both active and passive, is a well known source of power. But for years we have heard large scale use is cost prohibitive, takes up too much space, is too affected by the weather, and produces too little output. Due to the rising costs of fossil fuel, new research, new technology, and new application will hopefully give rise to an increase in the use of solar power.
Whether active or passive, or photovoltaic, solar lends itself to onsite green energy applications. Active solar energy can be used to heat hot water, an obvious need, but heated water can also be used to heat a home or pool and solar energy can be used to heat air. Solar panels can also be used to create electricity, while passive solar design utilizes the sun’s rays for both heat and light.
Solar energy plants (also called thermal plants) collect the suns energy and convert it to electricity through various means. Solar cells are the most widely known, but solar energy can also be used to make steam
which is used like wind or water to turn turbines.
Solar energy is clean, renewable, free and worldwide, but of course can be collected only during daylight hours. Pollution and cloud cover adversely affect solar power collection, but newer technology is addressing these factors.
Like wind technology, investment in solar research and design is booming. It will be exciting to see what the next few years hold in store for utilization of this age old resource.
Biomass and Biofuel
Biomass is used as a fuel or is converted to biofuel. Biomass is organic matter, vegetable or animal, including crops, wood, refuse from industry such as paper mills, or matter from landfills. It can be burned to create electricity; gases from decomposition can be collected and used, or crops can be grown to make fuel, such as corn grown to make ethanol.
Proponents argue that burning biomass, which releases CO2 into the atmosphere, is green power because it is part of the carbon cycle. They claim, on the other hand, that burning fossil fuels disrupts the carbon cycle. If the Earth is viewed as a closed system, this logic seems suspect and a weak argument for cutting down forests for biofuel.
It is interesting, however, to remember that Henry Ford built a car out of biomass that was stronger than steel. And the fuel he chose was made from the oil of seeds. Today we are manufacturing new bio-degradable plastics from biomass and raising crops for ethanol. But it is essential we consider the entire impact of turning to biofuels to replace fossil fuels, including the stewardship of croplands and food sources.
Geothermal Energy
Geothermal energy can refer to the use of the Earth to provide heating and/or cooling on a small scale through the design of a home or through the utilization of a heat pump. Or it can refer to the use of the Earth’s heat to run power plants.
Geothermal Design and Heat Pumps
If you dig below the frost line, the temperature of the ground remains constant—about 50 degrees. This median temperature can be used as an aid to cool a building in the summer and heat it in the winter. Combined passive solar and geothermal designs circulate air around and under a building, venting heat in the summer, trapping it in the winter.
Heat pumps pipe water or coolant
underground to heat or cool it to 50 degrees, cutting down on the amount of electricity needed to reach the desired temperature.
Geothermal Plants
The depth of the Earth’s crust varies on average from 5-25 miles deep. But there are places on the Earth where magma oozes or explodes to the surface, mud flats boil and bubble, and steam shoots into the sky. And there are places where the Earth’s crust is thin and drilling below the surface can easily tap into heat sources below.
Geothermal power plants use water, steam, and/or heat from below the Earth’s crust to make electricity or to provide a direct source of heat. Underground bodies of water heated by hot rocks or magma can be pumped through buildings, under streets, and under sidewalks. In Iceland, this method is used to heat most of the homes and commercial buildings in the nation.
Geothermal electric power plants use steam to turn turbines and make electricity in one of three ways: a direct source of steam is tapped, hot water sources are tapped and turned into steam, or above ground water sources are diverted into deep wells where water is heated by hot rocks or magma and turned into steam. One process utilizes chemicals in addition to hot water to make steam.
Proponents of geothermal energy tell us it is safe, sustainable, and non-polluting. These sweeping statements are not entirely true. Destruction from drilling, landslides, earthquakes, and pollution from released gases and toxic elements impact the environment.
A geothermal plant in California, believing their source of steam to be an inexhaustive supply, vented the steam rather than capturing it and returning it to the source. The underground water source, which had produced geysers for thousands of years, was depleted.
Open system plants vent steam along with gases such as hydrogen sulfide, carbon dioxide, ammonia, and methane and toxic elements such as mercury and arsenic, though some systems capture gases and other pollutants and either return them to the source or utilize them. But accidents can happen as well. A blow-out in a Hawaiian geothermal plant caused toxic gases to spew into the sky for thirty hours.
Enhanced Geothermal Systems (EGS) drill down to dry, hot, non-porous rock and pump in water under high pressure into the well to create steam which rises through a second bore hole. The water, once cooled, is again injected into the well in a closed loop system.
One plant in Switzerland was forced to close within days of starting operation due to seismic activity generated by this process. But EGS technology is in its infancy. New research is underway using carbon dioxide instead of water for EGS systems.
Friday, May 6, 2011
How to choose the right Energy Efficient Light Bulb for each fixture in your home--and save more energy and money than you ever thought possible
How to choose the right Energy Efficient Light Bulb for each fixture in your home--and save more energy and money than you ever thought possible
When the incandescent bulbs are gone*, which of these energy saving light bulbs will you choose?
•CFLs?
•LEDs?
•ESLs?
•Energy Saving Halogen Bulbs??
From: Holly Martin, B.S. Environmental Engineering
RE: The Truth about Energy Efficient Light Bulbs
Dear Concerned Homeowner or Renter,
The truth is...you want to save energy and you need to save money on your electricity bills--but like most people, you're confused.
Here's the problem you and every other concerned homeowner or renter face right now...
You've probably already bought a few of those "curly" CFL bulbs and tried them out at home. But you couldn't tell how much energy or money they really saved.
Besides, a lot of them didn't last as long as the package guaranteed--and the light they put out wasn't bright enough and had a strange color.
You're not sure if you can install them in your dining room chandelier, because it has a dimmer switch.
And you've heard that CFLs contain poisonous mercury and cause migraine headaches.
Like millions of other people, you wonder--is it better to wait for LEDs to drop from $100 apiece, to a price that regular people can afford?
With all these concerns swirling around in your mind, how could anyone make the right choices?
But it's worse than you think! Here's why...
This problem isn't just going to go away while you bury your head in the sand. The U.S., Canadian, Australian and European governments have already ruled that traditional light bulb technology must go.
Their reasoning is that these old standbys use too much energy for the amount of light they produce. Using more energy leads to more air pollution, and of course, more CO2, which some believe will cause catastrophic global climate change.
*Unless its repealed by Republicans in Congress (and signed into law by President Obama), the U.S. ban on standard incandescent bulbs begins January 1, 2012. The ban begins with 100 watt bulbs or higher, but it will extend to all incandescent bulbs by 2014.
That means you may have only a few months left to act. And by putting off your decision now, you're losing money, wasting energy, and possibly making yourself and your loved ones sick.
How to reduce your electricity bill
How to reduce your electricity bill
“It is Cheaper to Save Energy than Make Energy”
If you have been bogged by the enormous electricity bills you have been getting, it is time to take some concrete steps. You can reduce your electricity bills by following very simple steps and use green energy technology.
This post will list some simple, easy-to-do things to reduce your electricity bill.
Limited use: Start with the room you are sitting in. If you were to take a call in another room or join your family at the dining table, would you just step out of your room without any concern for the electrical appliances in the room? If you would, stop right there, and look around. Switch off all the appliances even if you would be back in five minutes. Yes, even that will help. Every drop of water constitutes to the ocean.
Another thing to take care of here is what you perceive as an electronic appliance. Would you switch off the television set, turn off the fan, but not the light bulb? Yes, you need light, but not now when you are leaving the room. Taking care of these small things will go a long way in reducing the dreaded huge electricity bills.
Smart investments: Make some smart power investments by replacing your incandescent bulbs with compact fluorescent light (CFL) bulbs. These bulbs are a great power-saving investment.
Buy the Power Save gadget. The gadget helps monitor the power supply to your house and uses the minimum that is needed.
Home appliance usage: Most of us complain that the electricity bill touches the sky because of the number of electrical appliances they have at home. However, the electricity bill is not directly proportional to the number of gadgets you use but the way you use them. Let’s see how you can avoid the typical power-wasters.
• Use the washing machine only when there is a full load of clothes.
• Keep the geyser on for the minimal amount of time.
• Keep the air-conditioner at the minimum low or high temperature, just enough to keep you off the heat or the cold outside.
• Switch off the computer monitor even when you take a one-minute break. It takes just a second to switch on the monitor again!
Yeah, you have to stick to this way of life for saving power at home and for the world.
Remember, reducing your electricity bill is equivalent to saving power, thus helping the world save power for its future generations.
Green Power
Green Power
For those of us who cannot or don't want to install a renewable energy system on our homes, purchasing green power from an electricity marketer is a way to make sure that your power still comes from clean, renewable sources. This option is new to Ohioans, and still unavailable to most of us. Ohio restructured its electric utility industry beginning January 1st, 2001 to provide for retail competition among electric utilities. Unfortunately, the number of electricity marketers entering Ohio has been small, and none thus far have offered a green product for Ohio consumers.
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