Vast greenhouses that use sea water for crop cultivation could be combined with solar power plants to provide food, fresh water and clean energy in deserts, under an ambitious proposal from a team of architects and engineers.
The Sahara Forest Project, which is already running demonstration plants in Tenerife, Oman and the United Arab Emirates, envisages huge greenhouses with concentrated solar power (CSP), a technology that uses mirrors to focus the sun's rays, creating steam to drive turbines to generate electricity.
The installations would turn deserts into lush patches of vegetation, according to its designers, and do away with the need to dig wells for fresh water, an activity that has depleted aquifers across the world.
Charlie Paton, a member of the team, and the inventor of the Seawater Greenhouse, said the scheme was a proven way to transform arid environments. "Plants need light for growth but they don't like heat beyond a certain point," he said.
Above certain temperatures the amount of water lost through leaves' stomata rises so much plants stop their photosynthesis and do not grow. The solar farm planned by the project runs seawater evaporators, pumping damp, cool air through the greenhouses. This reduces the warmth inside by about 15C, compared with the temperature outside.
At the other end of the greenhouse from the evaporators, water vapour is condensed. Some of this fresh water is used to water the crops, some for cleaning the solar mirrors.
"So we've got conditions in the greenhouse of high humidity and lower temperature," said Paton. "The crops sitting in this slightly steamy, humid condition can grow fantastically well."
The designers said that virtually any vegetables could be grown in the greenhouses. The demonstration plants already produce lettuces, peppers, cucumbers and tomatoes. The nutrients to grow the plants could come from local seaweed or be extracted from the seawater.
Michael Pawlyn, of Exploration Architecture, based in London, worked on the Eden Project for seven years and is now part of the Sahara Forest team. He said that the Seawater Greenhouse and CSP provided substantial synergies for each other. "Both technologies work extremely well in hot, dry, desert locations. CSP produces a lot of waste heat and we'd be able to use that to evaporate more seawater from the greenhouse. And CSP needs a supply of clean, de-mineralised water in order for the [electricity generating] turbines to function and to keep the mirrors at peak output. It just so happens the Seawater Greenhouse produces large quantities of this."
Paton said the greenhouse produced more than five times the fresh water needed to water the plants inside, so some of the water could be released to the outside, creating a microclimate for hardier plants such as jatropha, a crop that can be turned into biofuel.
The cost of the Sahara Forest Project could be relatively low as both CSP and Seawater Greenhouses are proven technologies. The designers estimate that building 20 hectares (nearly 50 acres) of greenhouses combined with a 10MW CSP scheme would cost about €80m (£65m).
Paton said groups in countries across the Middle East, including in UAE, Oman, Bahrain, Qatar and Kuwait, have expressed interest in possibly funding demonstration projects.
He said use of Seawater Greenhouses could reverse the environmental damage done by the glasshouses already built in places such as the desert region of Almeria, southern Spain, where, constructed over the past 20 years to grow salad crops, they now covered more than 40,000 hectares.
Paton said: "They take water out of the ground something like five times faster than it comes in, so the water table drops and becomes more saline. The whole of Spain is being sucked dry. If one were to convert them all to the Seawater Greenhouse concept it would turn an unsustainable solution into a more sustainable one."
Pawlyn said: "In places like Oman they've effectively sterilised large areas of land by using groundwater that's become increasingly saline. The beauty of the Sahara Forest scheme is that you can reverse that process and turn barren land into biologically productive land."
Neil Crumpton, an energy specialist at Friends of the Earth, said the potential of these desert technologies was huge. "Concentrated solar power mirror arrays covering just 1% of the Earth's deserts could supply a fifth of all current global energy consumption. And 1 million tonnes of sea water could be evaporated every day from just 20,000ha of greenhouses."
Governments should invest in the technologies and "not be distracted by lobbyists promoting dangerous nuclear power or nuclear-powered desalination schemes", Crumpton added.
The International Energy Agency estimates that the world needs to invest more than $45 trillion (£22.5 trillion) in new energy systems over the next 30 years.
Source - The guardian
Showing posts with label food. Show all posts
Showing posts with label food. Show all posts
Sunday, 28 September 2008
Sunday, 20 April 2008
The cost of green tinkering is in famine and starvation
Farewell the age of reason, welcome the idiocracy. Only George Orwell could have invented - and named - the government's Renewable Transport Fuel Obligation (RTFO) that came into operation yesterday. It is the latest in a long line of measures intended to ease the conscience of the rich while keeping the poor miserable, in this case spectacularly so.
The consequences of the RTFO have been much trumpeted on these pages. It says enough that one car tank of bio petrol needs as much grain as it takes to feed an African for a year, or that a reported one-third of American grain production is now subsidised for conversion into biofuel. Jeremy Paxman pleaded the cause of this latest green wheeze on Monday's Newsnight, while the United Nations food expert, Jean Ziegler, screamed for it to stop: "Children are dying ... It is a crime."
The transport secretary, Ruth Kelly, said this week: "The government has consistently stressed that biofuels are only worth supporting if they deliver genuine environmental benefits." Yet she must know that, at present, the opposite is the case. Kelly pleaded that rescinding her policy might impede investment and "weaken our influence over the direction of EU policy". She did not mention biofuels' threat to rainforests, food self-sufficiency and global warming generally, through needing costly fertiliser and road transport. Nor did she mention the role in her decision of such lobbies as the British Association for Biofuels and Oils, and the National Farmers' Union.
The RTFO is the latest in a series of policies, proselytised by the green movement and then commandeered by commercial lobbies, which fit a pattern of irrationality worthy of Moral Re-Armament. Until recently, most greenery has seemed no more than a feelgood parlour game. Now it is getting serious.
I have tried to follow the global warming debate, and will admit that it has changed my mind on occasions. I was once a sceptic on nuclear power and genetically modified foods. Security made the former expensive, and ignorance made the latter suspect, vulnerable to such greed-motivated cul-de-sacs as the "terminator gene" (increasing output but for just one harvest). I could also see the virtue of harnessing wind and waves, and seeking new ways of using the sun's rays, either directly or through plant photosynthesis.
Source - green tinkering famine and starvation
The consequences of the RTFO have been much trumpeted on these pages. It says enough that one car tank of bio petrol needs as much grain as it takes to feed an African for a year, or that a reported one-third of American grain production is now subsidised for conversion into biofuel. Jeremy Paxman pleaded the cause of this latest green wheeze on Monday's Newsnight, while the United Nations food expert, Jean Ziegler, screamed for it to stop: "Children are dying ... It is a crime."
The transport secretary, Ruth Kelly, said this week: "The government has consistently stressed that biofuels are only worth supporting if they deliver genuine environmental benefits." Yet she must know that, at present, the opposite is the case. Kelly pleaded that rescinding her policy might impede investment and "weaken our influence over the direction of EU policy". She did not mention biofuels' threat to rainforests, food self-sufficiency and global warming generally, through needing costly fertiliser and road transport. Nor did she mention the role in her decision of such lobbies as the British Association for Biofuels and Oils, and the National Farmers' Union.
The RTFO is the latest in a series of policies, proselytised by the green movement and then commandeered by commercial lobbies, which fit a pattern of irrationality worthy of Moral Re-Armament. Until recently, most greenery has seemed no more than a feelgood parlour game. Now it is getting serious.
I have tried to follow the global warming debate, and will admit that it has changed my mind on occasions. I was once a sceptic on nuclear power and genetically modified foods. Security made the former expensive, and ignorance made the latter suspect, vulnerable to such greed-motivated cul-de-sacs as the "terminator gene" (increasing output but for just one harvest). I could also see the virtue of harnessing wind and waves, and seeking new ways of using the sun's rays, either directly or through plant photosynthesis.
Source - green tinkering famine and starvation
Monday, 11 February 2008
51 Things We Can Do to Save the Environment
1. Turn Food Into Fuel
By Alice Park
Are corn husks better than corn for producing energy? Ethanol is the alternative fuel that could finally wean the U.S. from its expensive oil habit and in turn prevent the millions of tons of carbon emissions that go with it. The Department of Energy has doubled its 2005 commitment to funding research into biofuels—any non-petroleum fuel source, including corn, soybean, switchgrass, municipal waste and (ick) used cooking oil. Already, half of the nearly 11 billion bushels of corn produced each year is turned into ethanol, and most new cars are capable of running on E10 (10% ethanol and 90% gas).
Yet the eco-friendly fuel is beginning to look less chummy of late. Some of the 114 ethanol plants in the U.S. use natural gas and, yes, even coal to run the processors. And ethanol has to be trucked. Existing gas pipelines can't carry it because it corrodes iron. Then there are the economics. Producers depend on federal subsidies, and increasing demand for corn as fuel means the kernels keep getting pricier.
That's why researchers are prospecting for more alternatives, preferably ones that don't rely on food crops or a 51 cents-per-gallon tax break. Municipal waste, wood pulp and leftover grain and corn husks are all quite attractive; they can produce something called cellulosic ethanol, which contains more energy than corn. But they don't give up their bounty easily, so for now they're more expensive than corn-based ethanol to produce. Undeterred, researchers at several cellulosic-ethanol plants are developing innovative enzyme concoctions and heating methods to make the process more economic. Nothing like haste to make something out of waste.
2. Get Blueprints For a Green House
By Laura Locke
Reducing your impact on the earth is not just a question of what you drive but also of what you live in. Residential energy use accounts for 16% of greenhouse-gas emissions. If you begin thinking green at the blueprint stage, however, low-tech, pragmatic techniques will maximize your new home's efficiency. Installing those systems from the ground up is cheaper than retrofitting. "Doing simple things could drastically reduce your energy costs, by 40%," says Oru Bose, a sustainable-design architect in Santa Fe, N.M. For example, control heat, air and moisture leakage by sealing windows and doors. Insulate the garage, attic and basement with natural, nontoxic materials like reclaimed blue jeans. Protect windows from sunrays with large overhangs and double-pane glass. Emphasize natural cross ventilation. "You don't need to have 24th century solutions to solve 18th century problems," Bose says. Next, consider renewable energy sources like solar electric systems, compact wind turbines and geothermal heat pumps to help power your home. When you're ready to get creative, GreenHomeGuide.com will help you find bamboo flooring, cork tiles, and countertops made from recycled wastepaper.
3. Change Your Lightbulbs
By Maryanne Murray Buechner
The hottest thing in household energy savings is the compact fluorescent lightbulb (CFL), a funny-looking swirl that fits into standard sockets. CFLs cost three to five times as much as conventional incandescent bulbs yet use one-quarter the electricity and last several years longer. They are available virtually everywhere lightbulbs are sold. Most labels don't say "CFL" (GE calls its bulbs Energy Savers), and in some cases the telltale twist is enclosed in frosted glass. The wattage gives them away: many 7-watt CFLs are comparable to a regular 40-watt bulb, 26 watts is the typical CFL equivalent of 100 watts and so on. Or just look for the Energy Star label.
CFLs have come a long way since they were first introduced in the mid-'90s (they don't flicker as much when you turn them on, for one thing), but because each bulb still contains 5 mg of mercury, you're not supposed to toss them out with the regular trash, where they could end up in a landfill. So the bulbs are one more thing for you to sort in the recycling bin.
Light-emitting diodes, or LEDs (see item 4), don't have this problem, but they can require a bit of DIY rewiring. LEDs work great as accents and task lights, and you can also buy LED desk and floor lamps. But if you're just looking to put a green bulb in your favorite table lamp, CFL is the way to go.
4. Light Up Your City
By Maryanne Murray Buechner
Cities can save energy—and money—by illuminating public spaces with LEDs, or light-emitting diodes. Last December Raleigh, N.C., turned one floor of a municipal parking garage into a testing ground for LEDs (see the before-and-after photos at cree.com/LEDcity). The new white, brighter fixtures use 40% less electricity than the high-pressure sodium bulbs they replaced. Although they cost two to three times as much, they can go five or more years without upkeep. Traditional bulbs must be replaced every 18 months. Other types of LEDs are already at work in traffic lights, outdoor displays (like those in New York City's Times Square) and stadiums; airports even use LEDs on their taxiways. If your city is still burning tax money on old lights, ask the mayor why.
5. Pay the Carbon Tax
By Bryan Walsh
Everyone agrees that it's necessary to reduce carbon emissions around the world. There is less agreement over exactly how nations should go about achieving a more carbon-free planet. Hence, the environmental equivalent of Elvis vs. the Beatles: cap-and-trade carbon emissions, or impose a carbon tax on all users? With cap-and-trade programs, governments limit the level of carbon that can be emitted by an industry. Companies that hold their emissions below the cap can sell their remaining allowance on a carbon market, while companies that exceed their limit must purchase credits on that market. Carbon taxes are more straightforward: a set tax rate is placed on the consumption of carbon in any form—fossil-fuel electricity, gasoline—with the idea that raising the price will encourage industries and individuals to consume less. At the moment, cap-and-trade has the upper hand, since it serves as the backbone of the current Kyoto Protocol, and helped the U.S. reduce acid rain in the 1990s—but don't write off the tax just yet.
6. Ditch the Mansion
By Bryan Walsh
Oversize houses aren't just architecturally offensive; they also generally require more energy to heat and cool than smaller ones, even with efficient appliances. And in the U.S., big houses are becoming the norm, even though a relatively inefficient small house consumes less energy than a greener large house and uses fewer building materials, which expand the carbon footprint. A typical new single-family home in the U.S. is nearly 2,500 square feet today, up from about 1,000 square feet in 1950, even as the average household has shrunk from 3.4 to 2.6 people.
If you really want to live small, visit Jay Shafer. The former art professor dwells alone in a home fit for a hobbit, 100 sq. ft. in northern California that he designed and built himself in 1999. Shafer now runs Tumbleweed Tiny House and sells custom designs for miniature dwellings that range from 70 sq. ft. to 350 sq. ft. He made his move because he felt guilty about the size of his residential carbon footprint, and now prefers life tiny and tidy. "If I throw my jeans down on the floor, I can't get across the room."
7. Hang Up a Clothes Line
By Bryan Walsh
You could make your own clothes with needle and thread using 100% organic cotton sheared from sheep you raised on a Whole Foods diet, but the environmental quality of your wardrobe is ultimately determined by the way you wash it. A recent study by Cambridge University's Institute of Manufacturing found that 60% of the energy associated with a piece of clothing is spent in washing and drying it. Over its lifetime, a T shirt can send up to 9 lbs. of carbon dioxide into the air.
The solution is not to avoid doing laundry, tempting as that may be. Rather, wash your clothes in warm water instead of hot, and save up to launder a few big loads instead of many smaller ones. Use the most efficient machine you can find—newer ones can use as little as one-fourth the energy of older machines. When they're clean, dry your clothes the natural way, by hanging them on a line rather than loading them in a dryer. Altogether you can reduce the CO2 created by your laundry up to 90%. Plus, no more magically disappearing socks.
Source -time
By Alice Park
Are corn husks better than corn for producing energy? Ethanol is the alternative fuel that could finally wean the U.S. from its expensive oil habit and in turn prevent the millions of tons of carbon emissions that go with it. The Department of Energy has doubled its 2005 commitment to funding research into biofuels—any non-petroleum fuel source, including corn, soybean, switchgrass, municipal waste and (ick) used cooking oil. Already, half of the nearly 11 billion bushels of corn produced each year is turned into ethanol, and most new cars are capable of running on E10 (10% ethanol and 90% gas).
Yet the eco-friendly fuel is beginning to look less chummy of late. Some of the 114 ethanol plants in the U.S. use natural gas and, yes, even coal to run the processors. And ethanol has to be trucked. Existing gas pipelines can't carry it because it corrodes iron. Then there are the economics. Producers depend on federal subsidies, and increasing demand for corn as fuel means the kernels keep getting pricier.
That's why researchers are prospecting for more alternatives, preferably ones that don't rely on food crops or a 51 cents-per-gallon tax break. Municipal waste, wood pulp and leftover grain and corn husks are all quite attractive; they can produce something called cellulosic ethanol, which contains more energy than corn. But they don't give up their bounty easily, so for now they're more expensive than corn-based ethanol to produce. Undeterred, researchers at several cellulosic-ethanol plants are developing innovative enzyme concoctions and heating methods to make the process more economic. Nothing like haste to make something out of waste.
2. Get Blueprints For a Green House
By Laura Locke
Reducing your impact on the earth is not just a question of what you drive but also of what you live in. Residential energy use accounts for 16% of greenhouse-gas emissions. If you begin thinking green at the blueprint stage, however, low-tech, pragmatic techniques will maximize your new home's efficiency. Installing those systems from the ground up is cheaper than retrofitting. "Doing simple things could drastically reduce your energy costs, by 40%," says Oru Bose, a sustainable-design architect in Santa Fe, N.M. For example, control heat, air and moisture leakage by sealing windows and doors. Insulate the garage, attic and basement with natural, nontoxic materials like reclaimed blue jeans. Protect windows from sunrays with large overhangs and double-pane glass. Emphasize natural cross ventilation. "You don't need to have 24th century solutions to solve 18th century problems," Bose says. Next, consider renewable energy sources like solar electric systems, compact wind turbines and geothermal heat pumps to help power your home. When you're ready to get creative, GreenHomeGuide.com will help you find bamboo flooring, cork tiles, and countertops made from recycled wastepaper.
3. Change Your Lightbulbs
By Maryanne Murray Buechner
The hottest thing in household energy savings is the compact fluorescent lightbulb (CFL), a funny-looking swirl that fits into standard sockets. CFLs cost three to five times as much as conventional incandescent bulbs yet use one-quarter the electricity and last several years longer. They are available virtually everywhere lightbulbs are sold. Most labels don't say "CFL" (GE calls its bulbs Energy Savers), and in some cases the telltale twist is enclosed in frosted glass. The wattage gives them away: many 7-watt CFLs are comparable to a regular 40-watt bulb, 26 watts is the typical CFL equivalent of 100 watts and so on. Or just look for the Energy Star label.
CFLs have come a long way since they were first introduced in the mid-'90s (they don't flicker as much when you turn them on, for one thing), but because each bulb still contains 5 mg of mercury, you're not supposed to toss them out with the regular trash, where they could end up in a landfill. So the bulbs are one more thing for you to sort in the recycling bin.
Light-emitting diodes, or LEDs (see item 4), don't have this problem, but they can require a bit of DIY rewiring. LEDs work great as accents and task lights, and you can also buy LED desk and floor lamps. But if you're just looking to put a green bulb in your favorite table lamp, CFL is the way to go.
4. Light Up Your City
By Maryanne Murray Buechner
Cities can save energy—and money—by illuminating public spaces with LEDs, or light-emitting diodes. Last December Raleigh, N.C., turned one floor of a municipal parking garage into a testing ground for LEDs (see the before-and-after photos at cree.com/LEDcity). The new white, brighter fixtures use 40% less electricity than the high-pressure sodium bulbs they replaced. Although they cost two to three times as much, they can go five or more years without upkeep. Traditional bulbs must be replaced every 18 months. Other types of LEDs are already at work in traffic lights, outdoor displays (like those in New York City's Times Square) and stadiums; airports even use LEDs on their taxiways. If your city is still burning tax money on old lights, ask the mayor why.
5. Pay the Carbon Tax
By Bryan Walsh
Everyone agrees that it's necessary to reduce carbon emissions around the world. There is less agreement over exactly how nations should go about achieving a more carbon-free planet. Hence, the environmental equivalent of Elvis vs. the Beatles: cap-and-trade carbon emissions, or impose a carbon tax on all users? With cap-and-trade programs, governments limit the level of carbon that can be emitted by an industry. Companies that hold their emissions below the cap can sell their remaining allowance on a carbon market, while companies that exceed their limit must purchase credits on that market. Carbon taxes are more straightforward: a set tax rate is placed on the consumption of carbon in any form—fossil-fuel electricity, gasoline—with the idea that raising the price will encourage industries and individuals to consume less. At the moment, cap-and-trade has the upper hand, since it serves as the backbone of the current Kyoto Protocol, and helped the U.S. reduce acid rain in the 1990s—but don't write off the tax just yet.
6. Ditch the Mansion
By Bryan Walsh
Oversize houses aren't just architecturally offensive; they also generally require more energy to heat and cool than smaller ones, even with efficient appliances. And in the U.S., big houses are becoming the norm, even though a relatively inefficient small house consumes less energy than a greener large house and uses fewer building materials, which expand the carbon footprint. A typical new single-family home in the U.S. is nearly 2,500 square feet today, up from about 1,000 square feet in 1950, even as the average household has shrunk from 3.4 to 2.6 people.
If you really want to live small, visit Jay Shafer. The former art professor dwells alone in a home fit for a hobbit, 100 sq. ft. in northern California that he designed and built himself in 1999. Shafer now runs Tumbleweed Tiny House and sells custom designs for miniature dwellings that range from 70 sq. ft. to 350 sq. ft. He made his move because he felt guilty about the size of his residential carbon footprint, and now prefers life tiny and tidy. "If I throw my jeans down on the floor, I can't get across the room."
7. Hang Up a Clothes Line
By Bryan Walsh
You could make your own clothes with needle and thread using 100% organic cotton sheared from sheep you raised on a Whole Foods diet, but the environmental quality of your wardrobe is ultimately determined by the way you wash it. A recent study by Cambridge University's Institute of Manufacturing found that 60% of the energy associated with a piece of clothing is spent in washing and drying it. Over its lifetime, a T shirt can send up to 9 lbs. of carbon dioxide into the air.
The solution is not to avoid doing laundry, tempting as that may be. Rather, wash your clothes in warm water instead of hot, and save up to launder a few big loads instead of many smaller ones. Use the most efficient machine you can find—newer ones can use as little as one-fourth the energy of older machines. When they're clean, dry your clothes the natural way, by hanging them on a line rather than loading them in a dryer. Altogether you can reduce the CO2 created by your laundry up to 90%. Plus, no more magically disappearing socks.
Source -time
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