By Kevin Bullis
Soitec, a French manufacturing company, says it has used techniques designed for making microprocessors to produce solar cells with a record-setting efficiency of 46 percent, converting more than twice as much sunlight into electricity as conventional cells.
Although the cells are more complicated to produce, using established manufacturing techniques promises to keep production costs down.
Ordinary solar cells use one semiconductor to convert sunlight into electricity. The cells made by Soitec have four semiconductors, each designed to target a different part of the solar spectrum. Soitec produced its first four-semiconductor cell about a year ago. Since then, it’s been improving efficiencies rapidly, and it looks on track to be the first company to hit the long-awaited milestone of 50 percent efficiency.
Over the last several years, the costs of solar power have come down by over 80 percent, mostly because companies have found cheaper ways to manufacture conventional silicon solar cells. But solar power is still more expensive than fossil fuels in most places.
Soitec is one of several companies attempting to lower costs by making solar cells more efficient, so fewer are needed to generate the same amount of power. That cuts installation costs, which can account for more than half the cost of solar power (see “Solar Panels That Configure Themselves”). The challenge is achieving high efficiencies without significantly increasing the cost of making the cells.
Combining multiple semiconductors in a solar cell is an old idea that’s hard to execute in practice. It is possible to grow the semiconductor materials separately and then bond them together, but that requires multiple crystalline templates, which is expensive, and it can result in imperfect bonds.
To make its four-semiconductor solar cells, Soitec starts by growing two atomically compatible semiconductor materials on one template and two different compatible semiconductors on another. One of the templates is then removed so it can be reused (the structure of the final solar cell makes it difficult to remove the other one). Finally, the two pairs of semiconductors are stacked together. Soitec has already used the process of reusing the template and bonding the semiconductors for years to make components for microprocessors and other electronics.
The company plans to begin high-volume manufacturing of its four-semiconductor cells in 2016. Some questions remain about how cheap its process will be, though. The company isn’t providing specific estimates for the cost per kilowatt of solar power using its technology, saying the numbers depend on location.
Other companies are vying to be the first to reach 50 percent efficiency. This year the startup Semprius demonstrated four-semiconductor cells that were 44.1 percent efficient, and the company says it’s on track to break the world record next year.
Hyper-scale data center operators like Google, Amazon Web Services, and Apple have been very public about their renewable energy usage and commitments. It’s good for the environment and it makes people look upon them favorably. However, these operators contribute only a small fraction (think around 5 percent) of overall data center energy usage. The multitenant market is driving data center growth, but what is their role in terms of renewable energy?
Data centers (big and small) consume around 3 percent of energy in the U.S. They consumed an estimated 91 billion kilowatt-hours of electricity in 2013, with annual consumption projected to increase by roughly 47 billion kilowatt-hours by 2020, according to the National Resources Defense Council (NRDC). For the common person on the street, this can be alarming.
Greenpeace and the NRDC have both targeted data center energy usage. Greenpeace has primarily targeted the large hyper-scale clouds and the type of energy they use (though multi-tenant providers were assessed somewhat harshly in the most recent report card). The NRDC recently argued that colocation providers are particularly inefficient on the inside.
Do colocation providers have the same responsibility when it comes to renewable data center energy, and should they be held to the same standards as an Apple or Google? Yes and no. The Googles and Facebooks of the world have the sway to effect real change on the grid, recently lobbying Duke Energy to commit $500 million to renewables. Continue Reading »
A Michigan bill aims to classify fuel made by burning tires and hazardous industrial waste as renewable energy, but environmentalists say that’s setting a dangerous precedent.
Under the state’s Clean, Renewable and Efficient Energy Act of 2008, Michigan utility companies are required to derive 10 percent of their energy from sources like wind and solar power by 2015; the new House Bill 5205 would make it easier for them to hit the target by expanding the definition of renewable energy to include types of solid waste.
Introduced by Rep. Aric Nesbitt (R-Lawton), the new bill passed 63-46 last week with support from several Democrats and has been sent to the state Senate. Nesbitt said the legislation would be an economic and environmental boon for the state, because converting previously non-recyclable materials into energy through advanced processes with stringent regulations would reduce landfill waste.
“I think this provides Michigan a stepping stone to being a leader in both clean energy and landfill diversion,” he told The Huffington Post.
But environmental groups have soundly rejected the idea that incinerating hazardous waste should count as a renewable fuel source, saying it would be a step in the wrong direction for the state’s energy policy.
“We should be discussing bills that increase our use of clean, renewable energy — not turn the clock backwards,” Lisa Wozniak, executive director of the Michigan League of Conservation Voters, said in a phone conference Monday held with representatives from Clean Water Action and the Michigan Chapter of the Sierra Club.
Nesbitt questioned why groups opposed to his bill would rather have materials like plastics sitting in landfills than used in an efficient manner, and suggested that objections were based on political motives rather than policy.
Andrew Hoffman, a professor of sustainable enterprise at the University of Michigan, told HuffPost that the technology exists to burn hazardous waste safely — and that it’s important to look at how the state can reduce landfill waste. But he said HB 5205 would “water down” the 2008 law’s purpose of stimulating investment in renewable energy.
“We have to do something with the piles, the mountains of waste tires we have in this country,” he said. “I just think calling that ‘renewable energy’ is rather cynical.”
Hoffman added that the bill could divert investments in “real” renewable energy sources if companies find it’s cheaper or easier to meet Michigan’s renewable energy standards by burning waste.
In recent years, more than 30 states have put varying renewable energy mandates in place as part of a commitment to reduce reliance on coal and move to cleaner energy sources. And University of Michigan professor Barry Rabe, who specializes in environmental policy, said it appears the state is on track reach its 10 percent requirement by the end of next year.
But such laws are facing pushback. Rabe told HuffPost that Michigan’s attempt to change the state’s renewable energy definition is in line with a nationwide trend of legal challenges, rather than deeper commitments, to measures that increase renewable energy use.
According to the Lansing State Journal, there are no current plans to hold a vote on Nesbitt’s bill before the legislative session ends this month, so HB 5205 could die. But the state approach to renewable energy will still be up for debate as the original mandate expires at the end of next year.
Rabe said it’s a similar situation to those in other states, many which also have mandates ending soon. While advocates push for increases to the mandates — one failed Michigan ballot proposal would have required 25 percent renewable energy by 2025 — nationwide Republican gains in state legislatures could stop or roll back states’ progress on renewable energy, Rabe suggested.
Hoffman added that Nesbitt’s legislation may signal that in Michigan, setbacks to renewable energy and other environmental issues are possible.
“With a strongly Republican House, Senate and Republican governor, there’s a good question of whether [the bill] is just the tip of the iceberg, ” he said.
Australian researchers have developed a new method of using commercial solar panels that converts more electricity from sunlight than ever before.
The new photovoltaic (PV) system created by University of New South Wales (UNSW) researchers converts 40 percent of solar light into electrical energy, which is a 15 percent increase over regular panels.
Laboratory tests have shown the solar cell method can convert up to 46 percent of the sun’s energy into electricity. The new Australian technique works with regular commercial PV panels under normal conditions, and could potentially make solar plants more competitive with other energy sources, such as fossil fuels.
“This is the highest efficiency ever reported for sunlight conversion into electricity,” UNSW Professor Martin Green said in a statement. “We used commercial solar cells, but in a new way, so these efficiency improvements are readily accessible to the solar industry.”
Traditional solar energy production uses one solar cell, which limits the conversion of sunlight to electricity to around 33 percent. The new UNSW technology distributes the sunlight into four different cells, thus boosting the conversion levels, Green told AFP.
The breakthrough involved two steps: three solar panels were set to capture energy from sunlight of different wave lengths, and then excess light from the cells is reflected by a mirror and filters, and is directed to a fourth PV panel. Thus, previously spare sunlight is used in the process and contributes to the increased efficiency.
The UNSW solar researchers have made a number of advancements in solar energy in the past forty years, including the first photovoltaic system to achieve a conversion rate of over 20 percent in 1989. The latest breakthrough doubles that.
The technology was can be used with photovoltaic power towers developed by Australia’s RayGen Resources. Power towers use sun-tracking mirrors to focus sunlight on a tall collector building.
Martin Green hopes the technology could be adapted to be used on domestic solar panels on people’s roofs in the future. They currently have just a 15 to 18 percent of efficiency.
The UNSW solar energy research has been funded by the Australian Renewable Energy Agency (ARENA).
The agency’s CEO Ivor Frischknecht says the new panel technology demonstrates the advantage of Australia investing in renewable energy.
“We hope to see this home grown innovation take the next steps from prototyping to pilot scale demonstrations,” says Frischknecht. “Ultimately, more efficient commercial solar plants will make renewable energy cheaper, increasing its competitiveness.”
By Katie Fletcher
In late October, $12.5 million in Pennsylvania Energy Department Authority grants were awarded to 28 local governments, schools and businesses for alternative and clean energy projects, including projects deploying various technologies such as biogas, solar energy, hydropower, biomass and more. The West Branch Area School District in Clearfield County Pennsylvania is one of the 28 grant recipients.
The West Branch School Board officially accepted a $500,000 PEDA grant at a special meeting in late November to go towards the estimated $2.17 million biomass boiler system installation and implementation. Although specific technology and suppliers have not been selected yet for the project, preliminary steps have been taken. “We have a handful of clean, screened, green woodchip suppliers and boiler manufacturers that we have contacted,” said Jason McMillen, business manager at West Branch Area School District. “The selection of these vendors will be completed through a bid process and consultation with McClure Company.”
The McClure Co. is a mechanical contracting, engineering and service organization, and will serve as the school’s energy services company (ESCO). The company will oversee the installation of the boiler, as well as the new building construction that will house the boiler.
Members of the McClure Company gave a presentation to the school board about the project at the November meeting. Account manager Jennifer Ponce de Leon suggested housing the biomass boiler in an approximately 1,500 square-foot building behind the room where the school’s current oil boiler resides. This boiler will still be used as a backup system. “Seventy-five percent of the school’s heating needs will be satisfied by the biomass boiler,” McMillen said. “The school will still need to use an estimated 20,000 gallons of heating oil for the shoulder months and some domestic hot water.”
The biomass boiler will be fueled by woodchips, which may be delivered to the school on a moving floor truck. Some of the board members at the meeting expressed concern with the need for moving floor trucks to deliver the chips. According to McMillen, the concerns with the walking floor trucks are two-fold. “One, by limiting the delivery method to walking floor trucks the number of woodchip suppliers may also be limited. Two, several board members were concerned that the trucks’ mechanics could malfunction,” he said. “Although this could happen with any type of mechanical device, walking floor trucks are the most common delivery method for woodchips.”
Alternatives to the trucks are dump trailers and tri-axle among others. Each trailer load to the facility would hold around 25 tons of woodchips. The boiler is conservatively estimated to consume 1,087 tons per year; McMillen suggests it will most likely be less than that.
Annual savings for the district are expected to start around $133,000 in the first year and increase to nearly $265,000 after 20 years. This reduction in heating costs is one of the benefits of installing a biomass boiler at the school; the project will have guaranteed savings through performance contracting ESCO process. Utilizing a locally-sourced carbon neutral energy is another benefit, but ensuring that delivery options are not limited by building design may be a challenge, McMillen said.
If all goes as planned project construction will begin next spring with the boiler running by the 2015-2016 heating season.