Lexicon: Single & Dual Axis Solar Trackers

photo: Concentrix Solar

Nevermind Single or Dual Axis varieties, what are solar trackers?

In the broadest sense solar trackers move the solar panel so that it is position as close to optimum as possible in relation to the angle of the sun, across seasons and time of day. Compared to just laying a panel flat, correct positioning can boost the panels output by up to 15%, but by using a motorized tracker gains due to efficiency of between 27-40% can be achieved.

Currently, there exist two types: Single Axis and Dual Axis. Single axis trackers move on one axis over the course of the day, following the sun; doing so can boost output by about one-third. Dual axis trackers on the other hand move both east and west but also vertically; this can increase output by 35-40% as compared to a flat panel.

Single-axis tracking is one of the most straightforward ways to improve the potential performance and economics of a commercial solar installation. By using relatively simple equipment, considerably more performance can be expected. Tracking system manufacturer RayTracker, for example, says its systems have been proven to improve energy yield over fixed angle modules by up to 23% and over flat modules by 38%.

Manufacturers of the simpler, single-axis devices have claimed that the additional net energy yield delivered by a dual-axis system over a single-axis system is frequently lost as a result of additional installation, permitting and on-going maintenance costs. And, such systems are at greater risk of failure, having more moving parts than a single-axis tracker. Furthermore, single-axis trackers tend to have a lower profile, sometimes half the height of dual-axis trackers, and are therefore more likely to receive planning permits.

The Copenhagen Call

At the World Business Summit on Climate Change, the latest of the climate change meetings going on in Copenhagen in the run-up to the COP15 UN Climate Change Conference, global business leaders have issued what has been dubbed as the Copenhagen Call – a six-point statement of what they believe is required to create an effective new global climate change treaty. The points are stated and elaborated below

1. Agreement on science-based greenhouse gas stabilization path with 2020 and 2050 emission reduction targets

We support the scientific evidence of the IPCC’s 4th. We are concerned that some recent scientific evidence suggests the problem may be worse than many of the IPCC estimates.

An effective global climate treaty must establish an ambitious goal and set emission targets that protect us and future generations from the risks of climate destabilization. Limiting the global average temperature increase to a maximum of 2°C compared to pre-industrial levels would entail abatement of around 17Gt versus business-as-usual by 2020.

This will require an immediate and substantial change in the current global greenhouse gases emission trend: it must peak and begin to reduce within the next decade. Longer-term targets must be informed by the evolving science, but the IPCC’s 4th Assessment Report indicates that global emissions must fall by at least half of 1990 levels by 2050.

We believe that working to reduce emissions now is less costly than delaying our efforts. There is nothing to be gained through delay. The deepest reductions should initially be made by developed economies though global emissions reduction will require all nations to play a part.

Emissions reduction at this scale will profoundly affect business, and business is already taking action to drive down greenhouse gas emissions. We are ready to make those changes and support ambitious political decisions to address the climate challenge wherever we operate. If policies are well designed and implemented, the benefits of early action will outweigh the short-term adjustment costs. This early action can only be achieved by setting an ambitious 2020 target.

2. Effective measurement, reporting and verification of emissions

Achieving and tracking greenhouse gas emissions reduction is vital to measuring convergence towards the objectives of an effective climate treaty. As businesses we can set an example by contributing to a unified, coherent and reliable measurement, reporting and verification discipline leading to mandatory reporting. Accounting for the emissions we are responsible for will provide the basis for emissions reduction beyond what may be required by regulation and allow our performance to be properly judged and rewarded by investors and the public.

3. Incentives for a dramatic increase in financing low emission technologies

To promote effective, efficient, equitable and ambitious action to address climate change the world will need to mobilize the scale of investment necessary to achieve the emissions reduction required. Properly established, an international carbon market framed around ambitious reduction targets can enable both cost-effective abatement and create the carbon price stability to drive the deployment of technologies that will deliver large-scale emissions reductions.

The first steps to establishing a global market will be to enable linkage between national and regional carbon markets. An international agreement will help secure investor confidence in the carbon market, and national actions will help generate new financial flows for climate investment.

The new climate treaty must “push” the development of new technologies through the use of public funds to leverage private finance in early stage demonstration and deployment. This will require policy measures that create clear, predictable, long-term incentives to stimulate private investment and enable the global diffusion of capital and technology.

4. Deployment of existing low emission technologies and the development of new ones

The private sector is already the source of over two-thirds of the world’s investments in clean technology innovation, and is the most effective source of know-how and technology dissemination and transfer. Many low-technologies already exist and can significantly reduce global emissions. Significant emissions reduction can be achieved through energy efficiency, much of it with positive financial returns. Standards and regulations are the best way to achieve this. A new treaty must support deployment of low-carbon solutions by encouraging incentives for public and private purchasers to choose the lowest emissions infrastructure and technologies and for investors to account for climate risk in their decisions.

Government and business must work together to ensure that all nations have equitable access to new clean energy technologies and other innovations by, among others, working with developing countries to improve the infrastructure required for effective deployment.

An effective global climate treaty must provide the means to fund research, development and the deployment of new clean energy technologies. Pricing can help “pull” these technologies through the innovation chain, generate revenue and enhance the flow of investment to developing countries. Governments should strive to end the current perverse subsidies that favour high-emissions transport and energy infrastructure and promote deforestation.

A shift to a low-carbon economy, supported by private sector participation and government, has the potential to drive the next generation of technological innovation, address the environmental and economic challenges that climate change presents, and contribute to global development.

5. Funds to make communities more resilient and able to adapt to the effects of climate change

We recognize that adaptation is as important as mitigation in an effective global climate treaty. Adaptation planning will require a holistic and long-term planning perspective, which will require different levels of activity at the international, national and local levels. Businesses will be responsible for building much of the infrastructure needed to protect us from climate impacts. An effective global climate treaty will mobilize funding that supports public private partnerships to enhance development, adaptive capacity, climate resilience and management of risk.

6. Innovative means to protect forests and balance the carbon cycle

Because a significant proportion of the CO2 reduction required by 2020 comes from the sequestration of carbon in forests and agriculture lands, an effective climate treaty must facilitate such sequestration. If emissions reductions targets are to be met, there is an immediate need to protect forests and enhance carbon sequestration. The private sector can play an important role in reducing deforestation, particularly in developing countries, through mechanisms structured to value conservation.

We believe these elements should form the core of the international climate change treaty agreed at Copenhagen. As business leaders we stand ready to innovate and operate within the framework established through that treaty and national policies.

Reducing the emissions that until now have been so linked to our economic growth and betterment will be an enormous, unprecedented global challenge but will also provide significant opportunities for sustainable growth, development and innovation. Acting together, we owe it to future generations to meet this challenge. Now is the time to create the foundations for long term, low carbon prosperity. We are willing to work with government to do so.

For more information, the Call itself, transcripts of the special address by Cate Blanchett and opening address by Ban Ki-Moon, do visit the Copenhagen Climate Council’s website.

Breakthrough Design Uses Electrical Towers to Harvest Wind Power

The winners of this year’s Next Generation design competition have unearthed an idea that’s brilliant in its simplicity: retrofitting wind turbines onto already existing electrical towers. The project, aptly called Wind-It, would have wind turbines built on pylons and towers along high voltage lines across the US, sparing the need to build entirely new structures on private or government land while generating as much as a megawatt of power per tower.

The concept is the brainchild of French designers/architects Nicola Delon and Julien Choppin, and Raphaël Ménard, an engineer.

Wind-it answers one of the greatest challenges to the development of wind power: where to site wind turbines. Choppin, Delon and Menard’s design uses existing infrastructure – the towers and pylons that dot the more than 157,000 miles of high voltage power lines in the U.S. – to locate their turbines, which can be stacked within already sited structures. Moreover, Wind-it solves the problem of linking energy generation and electricity transmission in the same way – by co-locating them.

- Metropolis

Wind-it XL calls for new and taller pylons. The design is most promising for developing regions and can generate as much as one megawatt of power for each pylon.

Wind-it L loads eggbeater turbines onto the core of existing towers in medium- and high-voltage grids.

Wind-it retrofits low- and medium- voltage pylons for a nominal one ten kilowatts of power.

Here are the artist impressions

Here’s how the retrofit would look on a standard transmission line.

“The genius of the proposal is that it solved probably the biggest issue of wind production, which is where to locate these very large structures. By incorporating them into transmission towers, which are already located and of the same scale as wind towers, the idea of how it looks on the landscape is very cleverly integrated.”

- Alexandros Washburn, NY Chief Urban Designer and Next Generation Judge

Australia: The Politics of Environment – A Brief Round-Up

Kudos to Warren McLaren, Sydney for writing this great article for treehugger.com

They say “a week is a long time in politics.” And this was my first thought when Matthew asked me, a month ago, to consider a round-up of business and politics events from Australia.

It may be a large sunburnt land blessed with many natural assets, but the so called Lucky Country might be using up some of its nine lives, if recent events are anything to go by. Some of the worst weather since records began suggest the climate is a changing. And not just atmospherically, politically as well. Not only are international icons like the Great Barrier Reef at risk via climate change, so are one of the oldestindigenous peoples on the planet. So what should a country, which can claim the dubious distinction of being the world’s highest emitters of carbon dioxide per capita, do to improve it’s environmental footprint? We peek at a smattering of the issues below.

Renewable Energy Feed-In Tariffs

Photo: Peak Energy

Australia has a bit of reputation for being world class innovators, but lousy entrepreneurs. We can problem solve with great flair, but we’re not particular brilliant at bringing products to market, oftentimes selling the new technology to someone else to commercialise. This has been our experience with solar. As a staffer at one of our leading photovoltaic research universities recently told me, “We make engineers, we don’t make solar panels.”

So Australia has the technology. In many cases we invented it. We certainly have the sun. But we have just lacked the political and commercial will to forge this country into the solar dynamo it should be. One of Australia’s leading suppliers of renewable energy, Energy Matters, put its bluntly. Germany, “ … while having half the sunshine of Australia, have 200 times the solar production capacity of our country …” And they put this down to Germany having a generous feed-in tariff program.

A feed-in tariff is where the owner of a a grid connected renewable energy system, like solar, is paid a premium (usually greater than the retail price of electricity) for the energy they feed into the grid (that their electricity utility can on-sell to other users.) There are two basic types of tariffs, net and gross. Net is only paid for any energy supplied to the grid that is greater than what was used. For example, if the system generated 12 units of power, but also drew down on the grid for 10 units, then the tariff would only be paid for the 2 units that were in surplus. With a Gross Feed-In Tariff (FIT) the premium is paid for the full 12 units.

Australia has no national feed-in tariff, with some of the states only just implementing their own disparate versions in the past couple of years. At the time of writing, the Australian Capital Territory (ACT) had the most generous solar program. In this our tiniest self governing region, they offer, to those of their 340,000 residents who have grid-connected photovoltaic systems, just over 50 cents AUD (38c USD) per kilowatt hour, for up to 10kw of solar capacity. This is roughly four times the retail price of electricity, depending on the plan an ACT customer is on. The program went live for residential solar systems in March 2009.

However, according to the recently announced Western Australian budget, the ACT has been trumped by a more generous feed-in tariff of 60 cents AUD (45c USD) per kilowatt hour. This high premium will only be open to those customers who also sign up for 100% GreenPower for the energy they purchase. With these rates it has been calculated by the WA Sustainable Energy Association that a solar system could be paid off in nine years. (Most solar panels are designed to function for 20-25 years.) The most populous Australian state of New South Wales (NSW) is currently deliberating on what form of feed-in tariff it will legislate. A result is expected by June 2009. The rest of country has a mish mash of tariff, but there remains a push for a national gross feed-in tariff of 80c /kWh.

Solar Power Adoption

Photo: PV-Tech

The feed-in tariff argument has recently reached prominence, due the success that Germany and Spain have had in rolling out photovoltaic systems. But it has not been the only influencing factoring in the slow adoption of solar technologies in Australia. Being a long way from anywhere has meant panels have been expensive to import. And with a relatively small population, (only 57% that of California!) sparsely spread around the country, they have tricky to produce locally, given high wages and small economies of scale. BP Solar, the only on-shore producer of PV panels announced in December 2008 they would close their Sydney plant to concentrate on production out of Asia.

In the face of such pricing pressures, various Australian federal and state governments have, over the years, rolled out different rebates for solar panel purchases. Initially these were to assist people in remote areas, but more recently with utilities embracing grid-connect systems, rebates for photovoltaics became more pervasive. In general the federal government will pay $8,000 towards the cost of 1 kW residential solar installations. In the 2008 budget the government announced the $8,000 rebate would ‘means tested’ and only available to those households with a combined income of less than $100,000. This sent a tremor of fear through the Australian solar industry. However, they need not have worried as, inexplicably, installation applications increased in such demand that rebate processing times about doubled.

It may have been that the political debate over the changes alerted more people to the fact that rebates were available, or maybe the announcement raised concerns that the rebate was being reviewed and interested parties needed to get in quick while it was still on offer. If the latter, then their instincts were spot on, for change was coming. For as of 30 June 2009 the $8,000 is gone, replaced by a new Solar Credits scheme.

Under this new process, there is no direct cash rebate, but tradable renewable energy credits (RECs) will allocated on a sliding scale of points, depending of the carbon reduction efficiency of the installed system. RECs are already in place for the likes of solar hot water rebates, but with the new Solar Credits program their value will beartificially increased five fold.

This process has drawn flak from many quarters. Some believe it means polluters, like coal-fired power stations, buying the exchangable credits on the market, will be purchasing much cheaper credits to allow them to continue their carbon dioxide emissions,negating the efforts of the homeowner to reduce CO2 output . In pure economic terms, the RECs will not, in many instances, reward the residential householder as much as the current lump sum $8,000 rebate.

Couple these rebate changes, with the aforementioned move to gross feed-in tariffs and with the newly emerging business model of communities, co-ops and businesses bulk buying panels and inverters to bring the price down even further, and you have a mad rush of residential solar installations.

Renewable Energy Targets

Photo: Wind in the Bush

All of which goes to help the government inch closer (sounds better than ‘centimetre closer’) to their stated aim of 20% renewable energy by 2020. Back in April of this year the federal and state governments under the umbrella of the Council of Australian Governments’ (COAG) agreed to expand the existing Mandatory Renewable Energy Target (MRET) to this goal. In reality this means that nationally Australia will strive for a legislated target of 45,000 gigawatt-hours by 2020. More than four times larger than the present MRET.

This won’t just come from solar, but also the likes of wind, biomass and geothermal (aka “hot rocks”). But on the solar side of things, the government of Kevin Rudd, just this weekend past detailed one the ways the federal government will be contributing to this target.

It plans under its Clean Energy Initiative to build four solar plants, which in aggregate will amount to “largest solar energy project in the world.” As the Australian newspaper understands the Solar Flagships proposal, there will be almost $1.4 billion AUD invested in two solar thermal, and two solar photovoltaic stations with a combined output of 1000MW coming on stream by 2015.

Other government initiatives like Solar Schools and Solar Cities will also contribute towards the national MRET. As will wind power, although rolling out wind farms tends to more problematic when the NIMBY (not in my back yard) element comes into play.

Geothermal energy holds great promise as water is flushed into deep holes in the earth’s crust, to be heated by hot rocks and returning to the surface as steam, to drive turbines. Although feasible to the point it is said it could provide for all of Australia’s energy needs, it is currently experiencing some technical teething issues. But not everyone will need to make a contribution, like the big polluters, known as ”emissions-intensive, trade-exposed industry”, who’ll be largely exempt.
In the federal Budget just announced last week the government said they would invest $465 million to establish Renewables Australia to support this sort of leading edge research and make it commercial.

Emission Trading Scheme (ETS)

Photo: AAP / Dean Lewins from the ABC

However Australian governments aren’t having the good news stories all flow their way.

The federal Rudd Government have come under concentrated attack from green groups, and particularly the national Greens poltical party, for their 2009 budget announcement, that they’ll be funding so called ‘clean coal’ to the turn of $2.4 billion AUD, most of which will be directed a Carbon Capture and Storage Flagships program. That’s $0.4 billion more than the Solar Flagships program.

And the Victorian government has been chastised for its feed-in tariff, which will be a net system, not gross and be eligible for only up to 3.2 kW energy systems (the ACT’s is 10 kW) and will be a credit on their electricity bill, not a payment.

On the much bigger picture is the federal government’s emission trading scheme, or as they prefer to call it, the Carbon Pollution Reduction Scheme. Many believe that the Labor party was successful at the 2007 election, in part because they promised to sign the Kyoto Protocol and actually do something about climate change, unlike the previous government.

Professor Ross Garnaut, was employed to inform the Australian government on the economic impact of global warming to the country. Part of his recommendations included the establishment of an Emissions Trading Scheme (ETS). (The US has been talking around a similar idea, but using the terminology ‘cap and trade.’ In short, enterprises who want increase their emissions beyond an allowance (or cap), set by the government need to buy (trade) credits from businesses who emit less greenhouse gases.

Anyhow. acting on the Garnaut report, the government developed their version of an ETS. But up until recently they have had no joy getting anyone to like it. Malcolm Turnbull, the leader of the federal opposition party, the Liberal/National Coalition was right when he said, “It’s literally completely friendless.” Environmentalists and The Greens felt it was wishy washy, because it only strove to reduce emissions by 5% and gave a heap of ‘get out of jail’ free cards to the big emitters. The influential mining industry (Australia is the world’s largest exporter or coal) obviously are not keen on any legislation that impedes business opportunities. It was so universally disliked that it did not pass through the parliament. It didn’t look like anything was going to be place by the election promised date of 2010.

Then at the start of May 2009 the government reneged, coming out with a revised plan. They were now moving it back to 2011 and implementing a raft of compromises, like a new low price for carbon — $10 a tonne — and yet more free permits for large polluting industries. Yet these changes enabled them to drop their bombshell (the Prime Minister, Kevin Rudd, had repeatedly stated that “It would be reckless and irresponsible for our economy and for our environment,” to delay the introduction of an emissions trading scheme), supported on the day, by the Business Council of Australia, the Australian Industry Group, the Australian Chamber of Commerce and Industry, and mainstream enviro groups like the Australian Conservation Foundation, the Climate Institute and the World Wildlife Fund.

One of the concessions was that Australia would move to a 25% Greenhouse Gas reduction by by 2020. Which on the surface sounded great. But devil is always in the detail. This cut would only occur if a comprehensive global agreement on emissions reduction can be signed in Copenhagen in December 2009. Of course, the Greens are incensed at what they see as ‘smoke and mirrors.’ But the government wants some sort of scheme passed by parliament, so it can attend the United Nations Climate Change Conference in Copenhagen with at least something in its pocket, as a bargaining chip.

And There’s More?

Photo: Warren McLaren / INOV8

With all this talk of emissions trading and solar programs one could be forgiven in thinking there weren’t other environment issues stalking the corridors of Australian political office. Let’s briefly touch on just a few.

As previously noted here the state governments couldn’t agree on national campaign to rid shops and waterways of the dreaded plastic shopping bag, so South Australia went it alone. (As they many years ago, being the only state to have Container Deposit Legislation, placing a redeemable deposit on all beverage containers.)

The food bowl of Australia is the catchment of two major river, the so-called Murray-Darling basin; it is, as Reuters points out, “as large as France and Germany combined, accounts for 41 percent of Australia’s agriculture and provides A$21 billion ($13.54 billion) worth of farm exports to Asia and the Middle East. Around 70 percent of irrigated agriculture comes from the basin. And whether due to the worst drought in over a century, or the early onset of climate change the region is under some pretty severe stress.

“The drought has already wiped more than A$20 billion from the $1 trillion economy since 2002. It is the worst in 117 years of record-keeping, with 80 percent of eucalyptus trees already dead or stressed in the Murray-Darling region.”

It’s not just ecosystems at imminent risk of devastation. If the current dry conditions continue, as they are forecast to, then the South Australian capital of Adelaide may run out of water within two years. Other states have offered to sent drinking water for the city of over 1 million people, but they too draw upon the Murray river, which only has 18% of its capacity at the moment. The federal government has given the The Murray-Darling Basin Authority (MDBA) $50 million to buy back some of the seven billion litres of water from water licence holders along the catchment, who are willing to sell.

The devastating bushfires in the state of Victoria, which claimed around 170 lives and 2,000 homes, are another aspect of Australia’s dry climate. There are claims that not enough fuel reduction burns were undertaken preceding the fires, though the bush and forest is the reason many of the people live in those locations in the first place. Others believe that with the ongoing drought, there are not enough safe days in the year to undertake the scale of reduction burns needed. A Royal Commission is presently underway to determine the factors that contributed to the most deadly natural disaster in Australian history.

Before the Commission convened and on behalf of more than 13,000 firefighters and support staff, the National Secretary of United Firefighters Union of Australia sent an open letter to the Australian Prime Minister and Victorian Premie. It said, in part:

“Something is going on. As we battle blazes here in Victoria, firefighters are busy rescuing people from floods in Queensland. Without a massive turnaround in policies, aside from the tragic loss of life and property, we will be asking firefighters to put themselves at an unacceptable risk. Firefighters know that it is better to prevent an emergency than to have to rescue people from it, and we urge state and federal governments to follow scientific advice and keep firefighters and the community safe by halving the country’s greenhouse gas emissions by 2020.”

And how about this one: The ABC reports that “Tasmania’s Department of Environment, Parks, Heritage and the Arts will be shut down to help cover a looming budget black hole.”

But there is some good news. A massive amount of environmental rebates available from state and national government to help householders, landlords, schools and community groups. These cover ceiling insulation; rainwater tanks (with added incentives if these are connected up to washing machines and flushing toilets); solar hot water systems; energy and water efficient washing machines; compost bins; drip water gardening systems; grey water systems, green loans, and more.

And we have to stop there. For next week there’ll be a whole new set of challenges and opportunities confronting our elected representatives.

US Department of Energy: $786 Million for Biofuels Research & Commercialization

photo: Steve Jurvetson via flickr

The latest allocation of funds from the stimulus bill by the Department of Energy has been announced. This time it’s for biofuels and in the amount of $786.5 million. Here’s where it’s all going:

$480 Million for Integrated Pilot- and Demonstration-Scale Facilities

Projects selected under this Funding Opportunity Announcement will work to validate integrated biorefinery technologies that produce advanced biofuels, bioproducts, and heat and power in an integrated system, thus enabling private financing of commercial-scale replications.

DOE anticipates making 10 to 20 awards for refineries at various scales and designs, all to be operational in the next three years.  The DOE funding ceiling is $25 million for pilot-scale projects and $50 million for demonstration scale projects.

These integrated biorefineries will reduce dependence on petroleum-based transportation fuels and chemicals. They will also facilitate the development of an “advanced biofuels” industry to meet the federal Renewable Fuel Standards.

$176.5 Million for Commercial-Scale Biorefinery Projects

$176.5 million will be used to increase the federal funding ceiling on two or more demonstration- or commercial-scale biorefinery projects that were selected and awarded within the last two years.

The goal of these efforts is to reduce the risk of the development and deployment of these first-of-a-kind operations. These funds are expected to expedite the construction phase of these projects and ultimately accelerate the timeline for start up and commissioning.

$110 Million for Fundamental Research
This allocation will be further divided as follows,

Expand the resources available for sustainability research through the Office of Science Bioenergy Research Centers and establish a user-facility/small-scale integrated pilot plant ($25 million).

Create an advanced research consortium to develop technologies and facilitate subsequent demonstration of infrastructure-compatible biofuels through a competitive solicitation ($35 million).

Create an algal biofuels consortium to accelerate demonstration of algal biofuels through a competitive solicitation ($50 million).

$20 Million for Ethanol Research

The Biomass Program is planning to use $20 million of the Recovery Act funding in a competitive solicitation to achieve the following:

• Optimize flex-fuel vehicles operating on high octane E85 fuel (85 percent ethanol, 15 percent gasoline blend).
• Evaluate the impact of higher ethanol blends in conventional vehicles
• Upgrade existing refueling infrastructure to be compatible with fuels up to E85.

More: Department of Energy – Recovery and Reinvestment

Texas Wind Farm Uses NASA Radar to Prevent Bird Deaths

Photo Credit: Chrishna via flickr

What do you do if you build a wind farm smack dab in the middle of a major bird migration route? A radar system that’s designed to shut down the entire thing when it detects a mass of birds on the way has been installed at the 202 MW Peñascal Wind Farm in Texas.

System Detects Birds Approaching Four Miles Away
The system uses radar originally developed for NASA and the US Air Force to detect birds as far as four miles away, The Guardian reports. When it picks up the approaching birds, it analyzes the existing weather conditions and determines in real time whether those birds are in danger of flying into the blades. The system then automatically restarts the turbines when the birds have passed.

During Inclement Weather Birds May Fly Lower
The reason that the system takes into account the weather is that in ordinary conditions the migratory birds—at peaks times which can number 4,000 an hour—pass well over the wind farm, flying thousands of feet up. But when the weather turns nasty, the birds, which typically fly at night, can become disoriented. The risk which the radar system attempts to minimize is that when they’re disoriented the birds will lose altitude and crash into the turbines.

Buildings & Cats More Threat to Birds Than Turbines
It’s estimated that about 7,000 birds are killed annually in the US by wind turbines (and that in some areas bats are more in danger than birds), but all told that’s a far lower number than are killed by birds simply flying into buildings or are killed by your neighbor’s cat.

via: The Guardian

Wind Power
Offshore Wind Power in Great Lakes Touted as Untapped Resource
Common Eco-Myth: Wind Turbines Kill Birds
Cool Interactive US Wind, Solar & Biomass Power Potential map Released by NRDC

World’s Largest Solar Tower Now Powers 10,000 Homes

Photo via Abengoa

The world’s largest solar power tower just began operating outside Seville, Spain—and it marks a historic moment in the saga of renewable energy. The solar tower PS20, seen above right next to its smaller sister PS10, produced even more power than expected over the course of its trial testing. It’s been confirmed that the groundbreaking solar tower generates 20 megawatts of electricity: and it’s now powering 10,000 homes with renewable energy.

The tower, built and operated by Abengoa Solar, is one of the more innovative examples of solar technology. Though we’ve seen similar solar towers before, we’ve never seen it executed on such a scale.

How the World’s Largest Solar Tower Works
Here’s how it works, according to Abengoa:

PS20 consists of a solar field made up of 1,255 mirrored heliostats designed by Abengoa Solar. Each heliostat, with a surface area of 1,291 square feet, reflects the solar radiation it receives onto the receiver, located on the top of a 531 feet-high tower , producing steam which is converted into electricity generation by a turbine.

As for the energy benefits? Well, of course there are many: by Abengoa’s calculations, the plant will prevent over 12,000 tons of CO2 from entering the atmosphere. And combined with PS10, which generates 10 megawatts of power, both stations combined are a renewable energy force to be reckoned with.

This is yet another sign that the renewable energy revolution is ramping up—Spain has long been a leader in alternative power, and this is yet another clean energy victory. But what’s even more encouraging is that Abengoa Solar now has a presence in 70 countries around the world—will we be seeing massive solar power towers springing up all over?

Sun-Powered Self-Healing Plastic – The End of Scratched Gadgets?

Image via Ars Technica, Credit: Marek Urban/Science

Two clever scientists from the University of Southern Mississippi have developed a plastic that can utilize UV rays to heal scratches. Think of the way skin mends itself when cut, except imagine that being the surface of your cell phone or iPod.

The science behind it is summed up very well by Ars Technica:

At the core of their design is polyurethane, which is an elastic polymer that already has decent scratch resistance. To enhance its ability to withstand mechanical damage, Ghosh and Urban added two more components, OXE and CHI. OXE has an unstable chemical structure (a four-membered ring containing three carbons and one oxygen) that makes it prone to being split open. CHI is UV sensitive.The idea is that, if the polyurethane gets damaged by a scratch, the unstable ring structure of OXE will open to create two reactive ends. Then, UV light can trigger CHI to form new links with the reactive ends of OXE and thereby fix the break in the polymer.

When tested out with a 120 W fluorescent UV lamp (just slightly stronger than natural sunlight), scratches created by the scientists were healed to the point of being negligible within just a half an hour. It is reminiscent of the self-healing paint we heard about a few years ago.

This kind of development could hold great potential for us as consumers of plastic, helping to create plastic products that last far longer and that stay polished looking so we aren’t so quick to buy something new just because our current product looks unattractive.

Before it goes to market, a few things need to be sorted out, such as the shelf life and if the area of a healed scratch can be scratched and healed a second time. We also want to know things like the safety and recyclability of the polymer. But should this get worked out, it could mean longer lives for products, and hopefully a smaller waste stream.

Via Ars Technica via Science

Thermal Photovoltaics Breakthrough Boasts Theoretical Efficiency of 85%

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Theoretical Efficiency of 85%!
Thermal photovoltaics has been around since the 1960s, but it never produced enough power to compete with solar thermal using steam turbines, or more traditional photovoltaic solar panels. However, recent breakthroughs at MTPV Corp. (which stands for Micron-Gap Thermal Photovoltaics, the name of the technology they’re using) supposedly deliver “an order of magnitude” more power than regular thermal photovoltaics.

What’s the difference between conventional solar panel and photovoltaics from thermal photovoltaic systems?

A conventional solar panel absorbs light from the entire spectrum, but it only converts certain colors efficiently. Much of the energy in the other wavelengths of light goes to waste. As a result, the maximum theoretical efficiency of a conventional solar cell is 30 percent, or 41 percent if the sunlight is first concentrated using a mirror or lens. In a thermal photovoltaic system, light is concentrated onto a material to heat it up. The material is selected so that when it gets hot, it emits light at wavelengths that a solar cell can convert efficiently.As a result, the theoretical maximum efficiency of a thermal photovoltaic system is 85 percent.

-Technology Review

Using “micron-gaps” between the heated part and the photovoltaic part (instead of the traditional bigger gaps), they claim to have increased the flow of photons to the solar panel by 10 times compared to traditional TPV technology, which not only makes the whole thing less expensive (coupled with the fact that 1/10 as much solar-cell material as traditional TPV is used), but also lowers its working temperature significantly.

The 85% efficiency theoretical figure mentioned above is of course very hard to reach, but MTPV’s computer models show that 50% efficiency should be possible. So far the company has reached 10 to 15%, which is similar to many other solar panels on the market (not bad). With a bit more progress (it probably hasn’t been getting much R&D effort compared to silicon and thin film solar cells), this technology could become a big player in the solar power world.

Via Technology Review, MTPV

New Battery Technology Improves MacBook Pro Battery Life by 60%

Source: “New Battery Technology Improves MacBook Pro Battery Life by 60%“, treehugger.com, Jaymi Heimbuch, 6th Jan 2009

Photo via Gizmodo

New battery technology in the 17″ MacBook Pro was shown off at MacWorld today, which lays claim to a battery life improvement of 60%. The new battery can last up to 8 hours on a charge, and can be charged 1,000 times, equivalent to about 5 years. It’s also recyclable at the end of it’s life. But there are even more green features to this new technology.

Apple made a block of batteries, rather than the usual cylindrical cells that end up wasting space. The newly utilized space allows the notebook to have a 40% bigger battery, without making the notebook bigger. The problem, of course, is that you have to take the notebook apart if you want to replace the battery. 

But the upside is that it will last three times longer than the industry standard. The trick for making it last longer is using a chip within the battery that communicates with each cell to make adjustments to the current for each cell. This means a maximized battery life.

With it lasting so much longer, and being recyclable at the end of it’s life, that alone is enough to get Dell to hush up a bit. But additionally, Apple has a take-back program for the batteries, making recycling even easier, and it is EPEAT Gold, arsenic, BFR, mercury, PVC free, and touts 34% smaller packaging.

Via Gizmodo Live Blogging at MacWorld

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