In the high desert of southern Spain, not far from Granada, the Mediterranean sun bounces off large arrays of precisely curved mirrors that cover an area as large as 70 soccer fields.  These parabolic troughs follow the arc of the sun as it moves across the sky, concentrating the sun’s rays onto pipes filled with a synthetic oil that can be heated to 750 degrees Fahrenheit.  That super-heated oil is used to boil water to power steam turbines, or to pump excess heat into vats of salts, turning them a molten, lava-like consistency.  The salts are just fertilizers — a mix of sodium and potassium nitrate — but they represent a significant advance in the decades-old technology of solar thermal power production, which has traditionally used mirrors to heat water or oil to generate electricity-producing steam.  Now, engineers can use the molten salts to store the heat from solar radiation many hours after the sun goes down and then release it at will to drive turbines.  That means solar thermal power can be used to generate electricity nearly round-the-clock…..Some of the recent claims for solar thermal power have been stunning.  Researchers at the German Aerospace Center have estimated that 16,000 square kilometers of solar thermal power plants in North Africa — paired with a new infrastructure of high-voltage, direct-current transmission lines — could provide enough electricity for all of Europe.  And scientists have estimated that constructing solar thermal power plants on less than 1% of the world’s deserts — an area roughly the size of Austria — could meet the entire world’s energy needs…..The case for solar thermal power hinges on economics.  The sun bathes the Earth with an average of 6 kilowatt-hours of power per square meter over the course of a day, and a concentrated solar power plant like Andasol is the cheapest way to harvest a portion of that.  Photovoltaics — semiconductor panels that convert sunlight to electricity — deliver power at roughly 40 cents per kilowatt-hour, while conventional solar thermal power plants can do so for around 13 cents per kilowatt hour, according to the U.S. National Renewable Energy Laboratory.  This is only marginally more expensive than the average U.S. price for coal-generated electricity in 2008 of 11 cents per kilowatt hour.  The cutting-edge technology of using molten salts to store solar-generated heat is considerably more expensive, but experts expect that price to fall steadily as the technology improves and is mass-produced.  Roughly 612,000 megawatt-hours of electricity from the sun were produced in 2007, according to the Energy Information Administration (EIA), and solar thermal collectors sufficient to cover more than 15 million square feet were shipped and ready for installation that year — more than double the amount in 1998.  In the United States, some 3,100 megawatts of solar thermal power are planned by 2012, and capacity worldwide is expected to reach 6,400 megawatts within 3 years — roughly 14 times the current amount.  Still, electricity from the sun contributes just 1% of the renewable energy generated in the U.S., and all renewables taken together only provide 7% of U.S. energy needs. 

…..The Andasol power plant uses more than 28,000 metric tons of sodium and potassium nitrates to store some of the sun’s heat for use at night or on a rainy day.  The molten salts are stored in enormous hot and cold vats, able to be employed on command to soak up extra heat or drive the generation of electricity.  “The turbine is running more hours every day because we have storage and we have the possibility to plan our electricity production,” said Sven Moormann, a spokesman for Solar Millennium, the German company building Andasol…..But molten salts don’t have to be just used for storage, as they are at Andasol and will be at Solana.  They can also be used directly as a fluid in solar thermal power plants that operate at a much higher temperature, replacing the synthetic oil or water used in power towers.  In this variation of the solar thermal technology, large fields of mirrors concentrate the sun’s heat on a central tower that glows with intense light.  Such plants operate at more than 1,000 degrees Fahrenheit — closer to the temperatures employed at a coal-fired power plant — and therefore can use the salts directly as a heating medium.  At night, when temperatures begin to drop, the cooling salts that have already transferred their heat to drive a turbine simply drain to the bottom of the tower, where they are stored in tanks, ready to be heated again the next sunny day…..In addition, there is another way to use this technology for capturing the sun’s heat — cleaning up existing fossil fuel-fired power plants or other operations that burn a lot of CO2-emitting fossil fuels.  By employing the mirrors of a solar thermal array to pre-heat steam, the amount of natural gas, oil, or coal that must be burned can be reduced…..Ausra argues that it can generate the same steam without any CO2 emissions by employing its solar thermal technology…..“People need to look at this as a hedge against fossil fuel prices,” says Murphy.  “You could start deploying a new type of power plant.  We used to burn coal and natural gas — now we can use the sun to make steam.”

Reference :

(click for full image)

Grand Designs, the UK television programme that documents individuals’ ambitious residential building projects, regularly features houses based on wooden frames. It has even showcased homes made out of old car tyres, mud and recycled jam jars.  Although these examples demonstrate that alternative materials can be used to make impressive buildings, steel, glass and concrete still dominate most constructions.  Few people in the industry think these fundamental materials will disappear from building design in the foreseeable future.  It is not, however, a foregone conclusion, according to Paul King, chief executive of the UK Green Building Council. He complains that in modern architecture, “there is an ascendancy of form over function” and questions whether glass and steel in particular should be the primary building materials.  “Architects have become carried away with sexy structures,” he says.  “And since the 1970s, there is an expectation that iconic buildings have to be made from glass and steel.”  He also draws attention to the significant carbon footprint produced by the manufacturing process of the materials.  “In 20 years, it is possible that such designs could become socially unacceptable.” 

For the foreseeable future, however, the benefits of glass and steel will continue to outweigh their carbon cost.  Glass provides natural light and is seen as the key to beautiful design, while steel has excellent tensile strength and is the best material for a strong frame on which to base the building.  Phil Brown, regulatory marketing manager at Pilkington, the glass maker, says: “Producing glass might be energy-intensive, but the maximum payback time for that energy cost in most buildings is four to five years.  Some buildings generate savings within a year,” he says.  Modern high-performance single-pane solar control glass allows 70% of the light to pass through, he adds, while keeping out two-thirds of the sun’s heat and retaining as much of the internal warmth as a solid brick wall from 10 years ago.  “And this is before we even start thinking about double-glazing,” he adds.  “There is an expectation that most new buildings will have triple-glazed windows that have superior [heat retention] to an old cavity wall, too.”  The European Concrete Platform, a trade body, says that concrete is “extremely versatile in terms of its structural and material properties” and that most buildings use it for “its strength, fire protection, sound insulation and, increasingly, for its thermal mass”.  Marshalls, which makes concrete paving blocks, says it now uses waste products such as blast-furnace slag and pulverised fuel ash, from iron manufacture and coal fired power stations respectively, to reduce the embodied carbon dioxide in its concrete blocks by up to 39%.  Combined with the benefits of its high thermal mass in terms of passive heating and cooling, concrete is likely to remain an important material in the future, particularly for the proofing of buildings against climate change.

Reference :

US Is Big Daddy Of CO2 World

Sunday, November 9, 2008

Awesome graphic detailing the US’s mammoth CO2 footprint –

(click for larger image)

Very useful “big picture” view to go with this one here and here.

(click for larger image)

Slick looking graphic which is also very informative.

(click thumbnail for larger image)

FOR 40 years or so, the price of solar panels fell steadily, as volumes grew and technology improved.  But in 2004 Germany enormously increased subsidies for solar power, prompting a surge in demand.  The supply of pure silicon, the main component of most solar cells, did not keep pace.  Its price rose from $25 a kilogram in 2003 to as much as $250 this year, abruptly halting the downward march in the price of panels.  If making energy from sunlight is ever to become as cheap as burning fossil fuels, the price of silicon will have to fall.  Happily, it seems likely to do so soon.  Silicon producers, whose biggest customers were always chipmakers, have been slow to cater to the solar industry.  They were scarred by the memory of the technology bust of 2001, which had weighed them down with excess capacity, and so delayed expansion—despite the boom in solar.  Moreover, it takes three years or so to get a new plant going, so new silicon supplies are only just beginning to materialise.  New Energy Finance, a research firm, expects the output of silicon for the solar industry almost to double next year.  It has asked big buyers and sellers what prices they have agreed on this year for silicon to be delivered in the future.  The responses suggest that participants in the industry expect prices to fall by more than 40% next year, and over 70% by 2015 (see chart).

Other analysts are more cautious.  HSBC, an investment bank, expects shortages to last throughout 2009.  Cyrus Mewawalla of Westhall Capital, a broker, notes that predictions of silicon prices were notoriously unreliable even when chipmakers were the sole customers; the rise of the solar industry adds another variable.  One source of uncertainty is demand.  This may be softer than expected because of cuts in subsidies for solar power in Germany and Spain, and because of the looming expiry of a big tax-break in America.  The chief source of uncertainty, though, is on the supply side—in particular, the troubled outlook for a host of planned new plants in Asia.  Most observers expect that some of these will never materialise, others will take longer than scheduled to build and many will be less efficient than their backers claim.  Earlier this year Trina Solar, a Chinese firm, abandoned plans for a big new silicon plant.  Although more setbacks of this kind would slow the price’s fall in the short run, says Jenny Chase of New Energy Finance, the construction of a few less efficient, higher-cost plants will eventually create a tier of marginal producers, and so temper future price swings.  Yet even if the silicon price falls, other bottlenecks may well appear.  The first step in making solar cells is to shape silicon into ingots and then slice it into wafers.  Ingot- and wafer-makers hope a surge in the silicon supply will expose a lack of capacity in their fields.  Others wonder whether there will be enough of the specialist chemicals that coat cells.  HSBC predicts that the solar industry will grow by 45% a year until 2012.  Such searing expansion is bound to cause more growing pains.

Reference :

T. Boone Pickens.  You know you are in the company of someone really important when their middle name is spelt out and the first isn’t.  Dude is worth $3b, all made the good ole’ fashioned Texas way – black gold.  Oil tycoon par excellence, he appeared on the Imus In The Morning show on July 23rd.  What makes this interview so interesting is that at 80, after having “raped and plundered” (energy-wise) for most of his life, he now sees the light on green energy.  In fact, he is leading the US Legislative charge on this front with some genuinely good ideas.  Only in America !!

(click image for audio which runs 10m 23s)