Green Tech

Despite all the talk about needed breakthroughs in batteries, Pacific Gas & Electric is pursuing a less high-tech approach to store wind power: underground compressed air.

The utility on Wednesday said that it is seeking $25 million in smart-grid stimulus funds to build an underground compressed-air storage facility that would be able to deliver as much electricity as a medium-size power plant for about 10 hours.

PG&E said the project is part of its smart-grid initiative and would take about five years to develop and build but, in a company blog post, didn't offer any other details on the proposal.

With compressed-air energy storage (CAES), air is compressed and then pumped in natural underground reservoirs. The air is released later and converted into electricity.

There are currently two compressed-air energy storage facilities in operation--one in Alabama and one in Germany--but the technique has been getting more attention because it is a relatively cheap approach to storage.

Utilities are starting to use flywheels to smooth out fluctuations on the grid or truck-size batteries to provide backup power for a couple of hours for a single substation.

CAES is well-suited to an intermittent source of energy like wind because a large amount of energy can be stored for many hours. PG&E's proposal calls for storing 300 megawatts worth of power for 10 hours, while most utility storage batteries being tested are 1 or 2 megawatts for shorter periods.

PG&E said that it plans to use wind turbines to compress the air during off-peak times and then draw from the reservoir during peak times. Shifting the energy from off-peak to peak times, such as the middle of the day, makes it more valuable as utilities pay more for energy at peak times. A wind farm in Iowa has been working on CAES storage for a few years to take advantage of peak pricing for wind.

PG&E quoted a Princeton University study on CAES that concluded that "CAES appears to have many of the characteristics necessary to transform wind into a mainstay of global electricity generation."

Industry executives say that the most cost-effective utility storage is pumped hydro, where water is pumped uphill and released at peak times to make electricity.

This technique, which has been around for decades, is tough to beat on cost. But like compressed-air storage, it requires that utilities find the suitable geography.

Updated at 12:45 p.m. PT to clarify the capacity and energy storage of the facility.

The Wall Street Journal recently opined that "the inconvenient truth is that the earth's temperatures have flat-lined since 2001, despite growing concentrations of CO2," causing a greater number of scientists to question the science behind global warming. Whatever your opinion in the matter, it's certainly true that the world would be better off if we wasted less energy, which is what makes open-source Ecobot so useful.

While programs like Amee help businesses measure their carbon footprints, Ecobot offers a personal "carbon trainer" for Mac users.

Designed by Taxi, a Canadian corporation, Ecobot is derived from Taxi's participation in the "Green for Green" competition. The program "calculates your carbon footprint by measuring the fuel, power, and paper you use," and, importantly, does a lot of this data aggregation automatically. ("Automatically" is good - heck, if we weren't so lazy, we probably wouldn't need all these vehicles to power us from Point A to Point B.)

Not only does Ecobot keep track of how many pages you print from your laptop, but it also tracks the wireless networks to which you connect and works with you to figure out how you got from one to the other, and calculates the carbon emissions required to make the journey.

Pretty slick.

Even if you're not a tree-hugging, carbon-footprint-obsessed member of the Greenimati, Ecobot is an easy-to-use, unobtrusive way to monitor how much carbon your lifestyle requires. Of course, it only works if you're a Mac user.

Even so, despite Dell's insistence that Apple's Macs aren't as green as Apple claims, Ecobot lets you be as green as you want to be...and brag about it to anyone patient enough to listen to you.

Follow me on Twitter @mjasay. But please consider the environment before printing out my 3,000-plus tweets.

Fledgling company Chromasun plans to put the sun's heat to work cooling commercial buildings.

Founder Peter Le Lievre established the company to apply concentrating solar power techniques used in utility-scale power plants on a small scale, he said on Wednesday.

The potential of applying this technology in dry, sunny areas, such as the southwest U.S. or southern Europe, to cut peak electricity usage is vast, says Le Lievre. If used widely, solar-powered cooling could cut peak electricity usage by about 15 percent, he said.

Le Lievre is scheduled to discuss the solar cooling device, now still in development, at Greentech Media's Green Building Summit on Thursday where he will disclose some initial performance data.

Cooling accounts for a huge portion of the peak-time electrical load, representing about half of the peak electrical load in California. Le Lievre projects the Chromasun device can cut that consumption by a third and make dramatic reductions in individual buildings. A LEED-certified green building could cut its peak electrical load by about 90 percent, he said.

The technology behind Chromasun's solar concentrator box originated at the Australian National University and is being commercialized by Ausra, the concentrating solar power company co-founded by Le Lievre.

A concentrating solar system creates heat by focusing light onto a pipe carrying a liquid, which can be water or oil. Chromasun is using a Fresnel lens to concentrate the light and make heat. Over the course of a day, the lenses will follow the sun to maximize the heat.

Normally, chillers create cool air either by using a building's boiler to make steam or, more commonly, by using electricity to power a compressor. Chromasun's solar concentrator can replace a boiler's heat with solar energy and feed it to existing air conditioning systems, Le Lievre explained. The system can also pull in cool air at night and introduce it into the building.

"The payback under rebates available from California and the federal government is four to five years. But when you buy a conventional air conditioning system, it never pays back--you always need to power it," he said.

Le Lievre argued that a solar thermal system will be more efficient than buying solar electric panels. He said he expects the solar air conditioner can replace existing equipment, although builder owners need to have a back-up system.

The company expects to test its systems at an office building in Dubai and a data center in California early next year, and have a commercial product available in the second half of next year. The plan is to sell the solar air conditioner through exiting HVAC distributors.

Chromasun is in the process of seeking a series B round of investment, Le Lievre said.

Updated on June 12 6:30 a.m. PT with clarification on chillers.

A new type of air-fueled battery being studied could provide up to 10 times the energy storage of designs currently available, and someday be used to power electric cars, mobile phones, and laptops, say researchers.

"Our results so far are very encouraging and have far exceeded our expectations," said professor Peter Bruce, of the University of St Andrews' chemistry department, in a news release Monday.

The new idea the researchers are examining is to replace the lithium cobalt oxide electrode in today's rechargeable lithium batteries with a porous carbon electrode. This allows lithium ions and electrons in the cell to react instead with oxygen in the ambient air, according to a press release from the U.K.'s Engineering and Physical Sciences Research Council, which finances the research conducted at the University of St. Andrews in Scotland. The project has received about 1.6 million British pounds ($2.4 million) from the EPSRC.

According to the researchers, the new design could potentially improve the performance of portable electronic devices and provide a big boost to the renewable-energy industry. The researchers see a scenario in which the batteries will enable a constant electrical output from sources such as wind or solar. Also the STAIR (St. Andrews Air) cell could help power electric cars.

The STAIR cell is expected to be cheaper than rechargeable batteries of today, the researchers said. The new component is made of porous carbon, which is much less expensive than the lithium cobalt oxide it would be replacing.

"The key is to use oxygen in the air as a reagent, rather than carry the necessary chemicals around inside the battery," Bruce said.

The four-year research project began two years ago and is scheduled to end in June 2011. Bruce expects it will be at least five years before the STAIR cell is commercially available.

Hybrid engines aren't the only way to improve fuel efficiency. Scuderi Group unveiled a cutaway of its Scuderi Split-Cycle Engine prototype at the Society of Automotive Engineers (SAE) 2009 World Congress in Detroit. The new design is the first major change in engine dynamics since its creation 130 years ago, says Bill Wren, representative for the family-run start-up.

Most conventional internal combustion engines operate using the Otto Cycle. The Otto Cycle uses four strokes of a piston--intake, compression, power, and exhaust--that fire in quick succession using two revolutions of the crank shaft to complete the cycle. This process is only 30 percent efficient, which means you get only 30 percent the energy contained in a gallon of gasoline.

In the Scuderi Split-Cycle Engine, the four strokes are divided over two paired cylinders--one intake/compression cylinder and one power/exhaust cylinder. On a conventional engine, the combustion occurs as the piston is going up. But in the Split-Cycle engine, the piston pair fires after top-dead center, and combustion occurs as the pistons comes down, producing more efficient, cleaner combustion with one cylinder pair and compressed air in the other.

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Biofuels are on the way up, while carbon emissions are on the way down, a global airline industry spokesman said Tuesday at the annual Aviation and Environment Summit in Geneva.

After a successful run of pilot programs from Continental, Virgin, Air New Zealand, and JAL, sustainable biofuels are on track to be approved by the International Air Transport Association (IATA) for wide commercial use in planes by 2010 or 2011, Giovanni Bisignani, director general of the IATA, said in a speech given at the summit.

The IATA includes more than 230 airlines that make up about 93 percent of the world's airline traffic.

"Biofuels may even hold the promise of improved fuel efficiency on top of the potential to reduce emissions by up to 80 percent over the lifecycle of the fuel," said Bisignani.

He also had a positive spin to share on the fact that airlines have had to reduce flights due to a decrease in cargo and passenger demand throughout this economic downturn. The IATA expects to see a 7.8 percent drop in aviation carbon emissions for 2009.

Six percent will be due to a decrease in the number of cargo and passenger flights, while 1.8 is related to technology, operations, and infrastructure improvements, according to IATA figures.

Bisignani said governments of the world should focus on "replacing the growing patchwork of green taxes, charges, and emissions trading proposals" aimed at airlines with a more comprehensive system that takes into account that aviation carbon emissions contribute about two percent of the world's annual manmade carbon emissions.

The funds sponsoring environmental projects, as well as the degree to which airlines are held responsible for carbon emissions, should both proportionately reflect the two percent figure, according to Bisignani.

"We have a responsibility to secure the future of the 32 million jobs and $3.5 trillion in economic activity dependent on aviation. We need global leadership that unites industry and governments with the common purpose of reducing emissions," he said.

Among the plethora of alternative fuels being put forth to replace oil, the most odd might seem simple: air. But MDI International, based in Luxembourg, showed off a car at the 2009 Geneva auto show that runs on just that. What motivates the little AirPod concept is the energy from compressed air stored in a tank at 5,000 pounds per square inch (PSI).

The AirPod vehicle is small, holding just three passengers, with a single seat facing front for the driver and a bench facing backward for two more people. MDI claims a range of more than 112 miles in an urban setting, and less than two minutes to refill the 46-gallon air tank. But even though the AirPod can reach speeds of just less than 45 mph, the air-powered engine produces only 8 horsepower, suggesting slow acceleration.

Because of the low horsepower, the AirPod is designed to be exceptionally light, coming in at 485 pounds. Because the air tank and engine don't take up much room, most of the AirPod is devoted to passenger space. The car is a three-wheeler, and the driver uses a joystick to turn, rather than a conventional steering wheel.

Although air power means the AirPod drives emission-free, some energy is required to compress air into its tank. MDI puts the cost of a tank refill at just 1 euro.

MDI has announced deals with Air France and KLM to run a test fleet of the AirPod cars at Charles De Gaulle airport in Paris and Schipol airport in Amsterdam.

See more coverage of the 2009 Geneva auto show.

Air New Zealand, along with Boeing, Rolls-Royce, and Honeywell, retooled one of the four Rolls-Royce RB211 engines on a Boeing 747-400 to run on an unusually fruity blend of half Jet A1 fuel and half jatropha oil, according to Air New Zealand.

Jatropha is a succulent plant commonly grown in the semi-arid areas of India that produces seeds containing an oil that can be harvested and processed into a biofuel.

Jatropha has been used in making biodiesel for cars and trucks, but this is one of the first known attempts to use it as a biofuel in a commercial-size airplane.

Air New Zealand is not, however, the first commercial airline to try flying on a mixture containing biofuels. Several airlines, including Virgin Atlantic, have been testing out the sustainable idea of bio jet fuel mixed with jet fuel.

The jatropha bio jet fuel was supplied by Terasol Energy, which certified that the fuel supply met sustainability criteria.

The fuel stock in no way affected the environment or displaced other crops, David Morgan, chief pilot at Air New Zealand, explained in a video press release (below).

The two-hour test flight took off and landed from an Auckland, New Zealand, airport on Tuesday.

The test run was part of a program to research better sustainable air travel.

International Air Transport Association (IATA) lists jatropha as a promising next-generation bio-jet fuel for the airline industry because the hardy plant can be grown in poor quality soil needing little water.

Tiny bits of toner wafting from laser printers can't be blamed for polluting indoor air, according to research released this week.

In 2007, a study from Queensland University of Technology in Australia suggested that breathing toner particles from printers could hurt the lungs as much cigarette smoke.

But researchers from that school and the Fraunhofer Wilhelm Klauditz Institute in Germany have found no evidence to support that claim, after examining the makeup of chemicals released from laser printers.

They determined that such airborne materials include paraffins and silicon oils that evaporate when a printer's fixing unit, which attaches dry toner ink to paper, reaches temperatures as high as 428 degrees Fahrenheit.

"One essential property of these ultra-fine particles is their volatility, which indicates that we are not looking at toner dust," said Tunga Salthammer, a professor who worked on the study, in a statement.

The study did not describe how breathing in the ultra-fine chemicals could affect human health. However, volatile organic compounds are a major source of pollution indoors, where they are found in the air at levels up to 10 times higher than outdoors, according to the Environmental Protection Agency.

The nonprofit GreenGuard Environmental Institute offers a directory of electronics that emit relatively few of such chemicals, but that does not include printers. Last year's Australian study identified printer models with the highest emissions.

Add-on filters would do little to prevent printer emissions, according to researchers participating in the latest study, who noted that volatile organic substances are also released into the air from other household activities, such as toasting bread and cooking.

Printer makers belonging to the German Association for Information Technology partly funded the research.

German lawmakers plan to talk about the potential for laser printers to cause health problems at a meeting in January , according to Heise Online.