Thursday, February 26, 2009

MIT Undergrads Create Shock Absorber That Generates Energy

February 23, 2009
Photo Credit: Donna Coveney
by David Chandler, MIT
Massachusetts, United States []

A team of MIT undergraduate students has invented a shock absorber that harnesses energy from small bumps in the road, generating electricity while it smooths the ride more effectively than conventional shocks. The students hope to initially find customers among companies that operate large fleets of heavy vehicles. They have already drawn interest from the U.S. military and several truck manufacturers.

"Simply put -- we want this technology on every heavy-truck, military vehicle and consumer hybrid on the road."

-- Shakeel Avadhany, MIT Senior

Senior Shakeel Avadhany (pictured in lead image, top left) and his teammates say they can produce up to a 10 percent improvement in overall vehicle fuel efficiency by using the regenerative shock absorbers. The company that produces Humvees for the army, and is currently working on development of the next-generation version of the all-purpose vehicle, is interested enough to have loaned them a vehicle for testing purposes.

The project came about because "we wanted to figure out where energy is being wasted in a vehicle," senior Zack Anderson (below, with prototype shock absorber)explains. Some hybrid cars already do a good job of recovering the energy from braking, so the team looked elsewhere, and quickly homed in on the suspension.

They began by renting a variety of different car models, outfitting the suspension with sensors to determine the energy potential, and driving around with a laptop computer recording the sensor data. Their tests showed "a significant amount of energy" was being wasted in conventional suspension systems, Anderson says, "especially for heavy vehicles."

Once they realized the possibilities, the students set about building a prototype system to harness the wasted power. Their prototype shock absorbers use a hydraulic system that forces fluid through a turbine attached to a generator. The system is controlled by an active electronic system that optimizes the damping, providing a smoother ride than conventional shocks while generating electricity to recharge the batteries or operate electrical equipment.

In their testing so far, the students found that in a 6-shock heavy truck, each shock absorber could generate up to an average of 1 kW on a standard road — enough power to completely displace the large alternator load in heavy trucks and military vehicles, and in some cases even run accessory devices such as hybrid trailer refrigeration units.

They filed for a patent last year and formed a company, called Levant Power Corp., to develop and commercialize the product (pictured below, right). They are currently doing a series of tests with their converted Humvee to optimize the system's efficiency. They hope their technology will help give an edge to the military vehicle company in securing the expected $40 billion contract for the new army vehicle called the Joint Light Tactical Vehicle, or JLTV.

"They see it as something that's going to be a differentiator" in the quest for that lucrative contract, says Avadhany. He adds, "it is a completely new paradigm of damping."

"This is a disruptive technology," Anderson says. "It's a game-changer."

"Simply put — we want this technology on every heavy-truck, military vehicle and consumer hybrid on the road," Avadhany says.

The team has received help from MIT's Venture Mentoring Service, and has been advised by Yet-Ming Chiang, the Kyocera Professor of Ceramics in the Department of Materials Science and Engineering and founder of A123 Systems, a supplier of high-power lithium-ion batteries.

Not only would improved fuel efficiency be a big plus for the army by requiring less stockpiling and transportation of fuel into the war zone, but the better ride produced by the actively controlled shock absorbers makes for safer handling, the students say. "If it's a smoother ride, you can go over the terrain faster," says Anderson.

The new shocks also have a fail-safe feature: If the electronics fail for any reason, the system simply acts like a regular shock absorber.

David Chandler is a writer in the MIT News Office.

Monday, February 23, 2009

Major Electric Car Agreement Signed by 19 Israeli Companies


by Malkah Fleisher

( Thrilling Israeli opponents to foreign energy dependence as well as environmentalists across the country, 19 Israeli companies have signed cooperation agreements to test the suitability of electric cars for their company fleets in the first stage of the electric car program of Israeli venture-company Better Place.

Aiming to reduce global oil dependency and provide consumers with cleaner, sustainable personal transportation, Better Place employs swappable batteries, battery charging spots and battery exchange stations, and is aiming to operate its first electric car charging network in Israel and Denmark by 2011.

Israeli companies taking part in the test project represent Israeli high tech, agriculture, pharmaceuticals, finance, food, manufacturing and telecommunications industries. Participants include Israel Corporation, Teva Pharmaceutical Industries, Pelephone Communications, Partner Communications, Matrix IT, Direct Insurance- Financial Investments, Rafael Advanced Defense Systems, Netafim, Keter Plastics, Orbotech, Jafora Tabori, Manpower Israel, SQlink, Nike Israel, and Glasshouse Technologies.

The first stage of development will include designing and installing recharging points for company parking lots and employee homes.

Better Place CEO Shai Agassi called the program "the tip of the iceberg of global demand," saying he believes there is a potential global market of 50 million cars.

Sunday, February 22, 2009

Unique Quantum Effect Found in Silicon Nanocrystals

July 27, 2007

Quantum dot materials may improve efficiency of silicon solar cells.
Golden, Colorado []

Researchers at the U.S. Department of Energy's National Renewable Energy Laboratory (NREL), collaborating with Innovalight, Inc., have shown that a new and important effect called Multiple Exciton Generation (MEG) occurs efficiently in silicon nanocrystals. MEG results in the formation of more than one electron per absorbed photon.

In a solar cell device it is necessary to extract the electrons produced in the quantum dots and pass them through an external circuit to generate electrical power. Such experiments are currently underway at NREL, Innovalight and other laboratories to demonstrate that MEG can indeed lead to enhanced solar cell efficiencies.

Until this discovery, MEG had been reported over the past two years to occur only in nanocrystals (also called quantum dots) of semiconductor materials that are not presently used in commercial solar cells, and which contained environmentally harmful materials (such as lead).

The new result opens the door to the potential application of MEG for greatly enhancing the conversion efficiency of solar cells based on silicon because more of the sun's energy is converted to electricity. This is a key step toward making solar energy more cost-competitive with conventional power sources.

In a paper published on July 24 in the initial online version of the American Chemical Society's Nano Letters Journal, an NREL team reported that silicon nanocrystals, or quantum dots, obtained from Innovalight can produce more than one electron from single photons of sunlight that have wavelengths less than 420 nanometers (nm). When today's photovoltaic solar cells absorb a photon of sunlight, about 50% of the incident energy is lost as heat. MEG provides a way to convert some of this energy lost as heat into additional electricity.

To date, all experiments showing the production of more than one electron per absorbed photon have been based on various types of optical spectroscopy. In a solar cell device it is necessary to extract the electrons produced in the quantum dots and pass them through an external circuit to generate electrical power. Such experiments are currently underway at NREL, Innovalight and other laboratories to demonstrate that MEG can indeed lead to enhanced solar cell efficiencies.

Wednesday, February 18, 2009

Israel and California cut world's largest solar energy deal

The BrightSource Luz Power Tower reflects sunlight from the heliostats onto a boiler atop a tower.
This produces steam which is piped to a turbine to generate electricity. Photo credit: Eilon Paz
By Karin Kloosterman
February 12, 2009

An Israeli company and a Californian one are making solar power history: Southern California Edison (SCE) and BrightSource Energy from Israel have signed the world's largest solar energy deal.

Now awaiting approval from the California Public Utilities Commission, when the contracts are fulfilled -- this could happen by as early as 2013 -- the Israeli-CA sun project will power almost 1 million California homes.

Israel Kroizer, the chief operating officer, and president of BrightSource in Israel tells ISRAEL21c that when completed, it will be the world's largest solar energy project. Some 1,300 megawatts of energy will be created, with the first plant to be built in Ivanpah, California, expected to generate 286,000 megawatt-hours per year. The project will also create more jobs in the region.

"It's the biggest solar energy project ever signed," Kroizer emphasizes, and when complete it will be the largest solar energy plant in the world, he adds.

Towering sun stations

Last year, BrightSource created a media sensation when it launched its pilot plant in Israel's Negev Desert. Employing thousands of tiny mirrors called heliostats, BrightSource unveiled the Luz Power Tower -- the LPT 550 -- to reflect sunlight from the heliostats onto a boiler atop a tower. Producing steam from the concentrated heat, the steam is piped to a turbine to generate electricity.

Built with water-conserving principles in mind, the BrightSource system uses air-cooling to convert the steam back into water. The environmentally friendly closed cycle solution is, according to the company, designed to offer the highest operating efficiencies and lowest costs in the industry.

"We opened a pilot in Israel last year -- a demo plant to run some tests -- and we were really satisfied with the results. Now we are focusing in the States, and will respond to the [solar energy] tender being published in Israel. Israel is a target market for us, but it's not the same size as the US," Kroizer tells ISRAEL21c.

As part of the deal with its American partner SCE, BrightSource will maintain its engineering and logistics facilities in Israel. Equipment will be purchased from around the world, while the company's corporate offices for project and business development and financing will continue working out of Oakland, California. BrightSource, which was officially founded in 2004, and started operating in 2006, employs 30 people in the US, and 90 in Israel.

Next Up: Arizona and New Mexico

In a few months, Kroizer says, BrightSource will start constructing the solar project in the US, and next on its list for solar energy power plants are US sunny states -- all over southwest California, Arizona and New Mexico.

In the United States, BrightSource's partner SCE, is the country's leading buyer of renewables. In 2007, it purchased about 80 percent of all the solar energy used in the US. As the largest electric utilities company in California, it serves a population of about 13 million people, living within a 50,000-square-mile area in central, coastal and Southern California.

"These contracts represent a significant addition to our renewable portfolio, which is already the nation?s largest." said Stuart Hemphill, the VP of Renewable and Alternative Power at SCE. "This innovative solar technology helps to further our position as the nation's largest purchaser of solar energy, as well."

The World Economic Forum voted BrightSource as a 2009 Technology Pioneer. It was the only solar company to win this year's award, and is recognized for helping industrial customers reduce their dependence on fossil fuels.

While BrightSource's contribution is significant -- the new plants will prevent two million tons of carbon dioxide greenhouse gases emissions from entering the atmosphere annually (about 335,000 cars-worth of emissions) -- it's not a golden bullet solution.

Says Kroizer: "I think it's important to have a variety of energy solutions. Solar energy won't solve the world's problems; we need a variety of solutions and solar can be one of them. Solar can supply a very nice percentage of energy in sunny countries," he concludes.