TetraSun Produces Solar Power With Pennies Thanks to NREL

The majority of silicon solar photovoltaics use silver to conduct electricity but thanks in part to help from the National Renewable Energy Laboratory, TetraSun is using copper as a conductor instead of silver.

The approach, along with the results and the cost-savings have helped TetraSun and NREL win a 2013 R&D top 100 award fromR&D Magazine and stoked enough interest in TetraSun that First Solar bought the company in April, allowing one of the world’s leading thin-film PV manufacturers to get into the silicon PV market.

The company is making the waves primarily because it’s looking at doing silicon PV in a way that significantly reduces the cost of PV solar power by using simplified manufacturing techniques and cheaper materials—namely copper instead of silver—to harvest electrons produced by the cell. While copper is a good conductor of electricity, it has been hard to apply it in a way that produces the wanted results in a silicon PV cell because the copper doesn’t want to stay in that form. And the copper ribbons on the cells are about 50 microns wide—about one-twenty-fifth the width of a human hair, according to NREL.

“As the margins go down with silicon, the cost of every component becomes significant, especially when you’re talking about square miles of this material,” said NREL Principal Scientist Mowafak Al-Jassim. “We’re trying to make enough of these solar panels to generate gigawatts of power. That’s a lot of silver. We needed to replace silver with an equally good conductor, but one that was much cheaper.”

“It’s a potentially disruptive technology, and that’s why we decided to work with TetraSun,” said NREL’s Martha Symko-Davies. She headed the Energy Department’s SunShot Initiative PV Incubator program, which awarded TetraSun a grant in 2010. The technology already is capable of producing silicon PV cells that are about 21 percent efficient—rivaling the performance of many current silicon PV cells that are about 22 percent efficient, according to NREL.

The team was able to produce the 21 percent efficient cells just 18 months after starting up, which Harin Ullal with NREL said is unusual. “That compares to 17 percent to 19 percent efficiency for screen-printed silicon cells,” he said. Ullal managed the research for NREL. “By 2020, this technology could potentially reach the Energy Department’s SunShot target of one dollar per watt for PV systems and about 6 cents per kilowatt hour for electricity generation,” Ullal said.

Courtesy: http://www.nesea.org/

Amazing Glass that Tints on Demand is now Solar Powered

One of the most exciting products from this year’s Greenbuild expo is SageGlass’ solar-powered windows. Sage’s electrocromic windows can be darkened and lightened to filter the sun’s heat and light according to a room’s needs and the inhabitant’s desires. See a full explanation of the technology here.

That takes a small amount of energy, which until now, could only by plugging into a building’s existing power supply. The new product is powered with a slim strip of photovoltaic panels. It’s not only sustainable that the glass can power itself, but it’s also opens up the product’s design possibilities because it’s cordless.

SageGlass has currently been installed in 250 projects, including both residential and commercial buildings. This glass is often used to fix a design problem. Philadelphia’s Kimmel Center is an example of a space where a window dressing isn’t feasible, but the space was overheated. Bryan Green of Sage says he hope that architects and designers can start using the glass more creatively.

Another new feature for SageGlass is the introduction of different control zones within the same pane of glass. These different zones can be independently controlled. So, imagine you have a Eastward-facing pane of SageGlass next to your breakfast table. You want lots of light in the room, but you don’t want glare on you iPad. You can darken the lower zones to cut down on glare, while keeping the zones more clear to light the room, creating a kind of ombre effect. The zones can be either manually controlled, or automated with timers.

Like the original product, the solar-powered glass remains somewhat clear even at its darkest tint. “If it weren’t for people’s desire for natural sunlight and a connection to the outdoors, people wouldn’t put windows in buildings,” said John Van Dine, founder of Sage. In some ways, windows are a the weak point in our structures, at times letting too much heat and light. Shutters and curtains solve the problem of too much light, but they still absorb heat. You might still want a curtain for privacy’s sake, but both these methods block the view to the outdoors. “You defeat the purpose of windows in the first place.”

Courtesy: http://www.treehugger.com/

Solar Power Could Be A Total Game-Changer

Christine Armario/AP

It’s very easy to hype solar, which we’ve been doing for much of the year.

Capacity is irrefutably going up, and prices are collapsing.

However, the absolute capacity figures remain relatively low compared with conventional generation. And in most cases, even large-scale solar is still not cost competitive with traditional sources of electricity.

There’s basically one thing holding solar back: storage.

Here’s the problem: To run a commercially viable power plant, you need a continuous source of fuel. For run-of-the-mill power plants, this is basically not a problem — you just keep ordering up more coal, or natural gas, or uranium isotopes.

But in a cruel paradox of nature, you actually can’t control the supply of solar — or wind, for that matter — despite their infinite abundance. Sometimes it’s cloudy, or the wind is not blowing, or it’s nighttime.

And electric grids cannot function unless they are able to balance supply and demand. An imbalance results in voltage fluctuations, or worse.

Germany is already running into problems with this, as its solar capacity has skyrocketed. Soon, solar will be capable of meeting most of the country’s electricity demand between 12 p.m. and 2 p.m. As Citi’s Jason Channell writes, “any further installations beyond this point could push structural solar power supply above demand and cause permanent mid-day grid instability.”

Here’s what he’s talking about (“double penetration” refers to Germany having doubled its solar capacity): Without batteries, that bulge is literally disruptive because it eats into conventional baseload generation, the backbone of current supply needs.

There are two ways to address this problem. One way is to address the electricity grid itself. That is indeed happening — whenever you hear about “smart grids,” it refers to folks trying to find better ways of eliminating gaps in electricity supply and demand.

The other avenue is batteries. With storage, “any excess generation above the natural run rate of conventional baseload is captured and spread across the day,” Channel says.

So why don’t we have large-scale batteries yet? Mainly, solar hasn’t been widespread enough to justify what remain very expensive technologies. That’s obviously on the verge of changing, but the most promising type of large-scale renewable storage system, lithium-ion battery packs, still costs $1000 per kilowatt hour, according to Channell. The average fridge uses about 5 kilowatt hours a day.

However, thanks to investment from the electric vehicle industry, lithium ion costs continuously come down. We also just told you about a pilot project in Maryland that uses lithium ion batteries to modulate the solar generation from panels installed on a nondescript office building’s rooftop.

Lots of businesses are working on this problem, and other potential solutions include liquid metal batteries, which use relatively cheap components and manufacturing processes; and compressed air storage, where kinetic energy gets turned into pressurized air that’s pushed underground.

We’re still in the earliest stages of widespread storage deployment, and we’re likely to see some kind of convergence between smart grid and battery solutions as more renewable capacity emerges.

That latter bit is not in doubt.

Courtesy: http://www.businessinsider.com/

Two for One in Solar Power

Left: This shows laser set-up in the lab in Cambridge. Right: This is the Celestia sun. Credit: Brina Walker

Solar cells offer the opportunity to harvest abundant, renewable energy. Although the highest energy light occurs in the ultraviolet and visible spectrum, most solar energy is in the infrared. There is a trade-off in harvesting this light, so that solar cells are efficient in the infrared but waste much of the energy available from the more energetic photons in the visible part of the spectrum.

When a photon is absorbed it creates a single electronic excitation that is then separated into an electron and a positively charged hole, irrespective of the light energy. One way to improve efficiency is to split energy available from visible photons into two, which leads to a doubling of the current in the solar cell.

Researchers in Cambridge and Mons have investigated the process in which the initial electronic excitation can split into a pair of half-energy excitations. This can happen in certain organic molecules when the quantum mechanical effect of electron spin sets the initial spin ‘singlet’ state to be double the energy of the alternative spin ‘triplet’ arrangement.

The study, published today in the journal Nature Chemistry, shows that this process of singlet fission to pairs of triplets depends very sensitively on the interactions between molecules. By studying this process when the molecules are in solution it is possible to control when this process is switched on.

When the material is very dilute, the distance between molecules is large and singlet fission does not occur. When the solution is concentrated, collisions between molecules become more frequent. The researchers find that the fission process happens as soon as just two of these molecules are in contact, and remarkably, that singlet fission is then completely efficient—so that every photon produces two triplets.

This fundamental study provides new insights into the process of singlet fission and demonstrates that the use of singlet fission is a very promising route to improved solar cells. Chemists will be able to use the results to make new materials, say the team from Cambridge’s Cavendish Laboratory, who are currently working on ways to use these solutions in devices.

“We began by going back to fundamentals; looking at the solar energy challenge from a blue skies perspective,” said Dr Brian Walker, a research fellow in the Cavendish Lab’s Optoelectronics group, who led the study.

“Singlet fission offers a route to boosting solar cell efficiency using low-cost materials. We are only beginning to understand how this process works, and as we learn more we expect improvements in the technology to follow.”

The team used a combination of laser experiments – which measure timings with extreme accuracy – with chemical methods used to study reaction mechanisms. This dual approach allowed the researchers to slow down fission and observe a key intermediate step never before seen.

“Very few other groups in the world have laser apparatus as versatile as ours in Cambridge,” added Andrew Musser, a researcher who collaborated in the study. “This enabled us to get a step closer to working out exactly how singlet fission occurs.”

Courtesy: http://phys.org/news/

GM Gets Steamy with Detroit Renewable Energy

DETROIT (WWJ) – General Motors and Detroit Renewable Energy announced a renewable energy project to turn solid municipal waste from Metro Detroit into process steam that will be used to heat and cool portions of GM’s Detroit-Hamtramck assembly plant.

When the project is operational, 58 percent of the plant’s energy needs will come from renewable energy, making Detroit-Hamtramck the top GM plant in the world by percentage of renewable energy used.

“We have 107 landfill-free facilities across the globe that recycle or reuse their waste, with some of it turned into energy,” said Rob Threlkeld, GM’s global manager of renewable energy. “It made sense to explore this option with DRE at Detroit-Hamtramck, given their quality work in helping us manage our energy use at some of our other GM plants.”

Detroit Renewable is able to process more than 1 million tons of municipal solid waste into electric power and steam while also recycling nearly 40,000 tons of metal annually.

The steam will travel 8,300 feet through a pipe originating at Detroit Renewable Power and ending at the Detroit-Hamtramck plant.

“We have a long history of working with GM in providing energy to its assembly plants,” said Detroit Renewable Energy chairman and CEO Steven White. “To incorporate a sustainable and renewable energy source into the Detroit-Hamtramck Assembly Plant adds real value to the value chain.”

The steam pipe will provide 15.8 megawatts of renewable energy to the plant, which equates to 12 percent of GM’s overall goal of putting 125 megawatts of renewable energy into its energy portfolio by 2020.

Construction of the new steam line and associated energy infrastructure will begin later this month and become operational next spring.

Courtesy: http://detroit.cbslocal.com/