Wednesday 08-03-16

Interesting concept we should watch this one.

The Inevitable Solar-Powered March Of The Hydrogen Fuel Cell

Researchers at Rice University are on to a relatively simple, low-cost way to pry hydrogen loose from water, using the sun as an energy source. The new system involves channeling high-energy “hot” electrons into a useful purpose before they get a chance to cool down. If the research progresses, that’s great news for the hydrogen fuel cell electric vehicle market, which has been growing in some niche sectors but stumbling over the cost barrier when it comes to passenger cars and buses.

Renewable Hydrogen From Water
For those of you new to the topic, the high energy density of hydrogen makes it ideal for fuel cell electric vehicles, but manufacturing hydrogen is an energy-intensive process that currently depends on fossil natural gas as a source.
The emergence of solar water-splitters could solve both of those problems together, by using renewable energy to split water into hydrogen and oxygen. Wind, hydropower, and tidal energy are also possible “clean” power sources for manufacturing hydrogen from water. Potable water resources aren’t necessarily compromised, as emerging technology works on less-than-clean water, including municipal wastewater.

The Rice University Solar Water-Splitter

The new Rice University hydrogen system resolves some of the problems besetting conventional water-splitting attempts.
The research team developed a three-layer material, which starts with a thin sheet of aluminum coated with a nanoscale, transparent layer of nickel oxide. The topmost layer is a smattering of ultra-tiny gold disks ranging from 10 to 30 nanometers in diameter.
The material can collect sunlight both directly and as a reflection from the aluminum layer. In either case, the gold nanoparticles convert light into high energy “hot” electrons (more on that later). Low-energy electron “holes” are attracted to the aluminum layer and the nickel oxide layer lets them pass through, while making the hot electrons stay behind on the gold discs.
So far, the researcher team has determined that the photocurrent generated by the new material is potentially sufficient for water-splitting, and is “on par” with more complex, costly systems.
The next step is to take direct measurements of the hydrogen and oxygen gases produced by the reaction.

Hot Electrons & Water-Splitting

Because they are very energetic, “hot” electrons can be very useful in driving chemical reactions. The problem is that they decay rapidly. To get a handle on just how rapidly, the Rice research team suggests that you consider this:

…most of the energy losses in today’s best photovoltaic solar panels are the result of hot electrons that cool within a few trillionths of a second and release their energy as wasted heat.

If you can grab hot electrons and put them to use before they cool down, the payoff is a huge improvement in solar conversion efficiency.
For a solution, the Rice team looked to the university’s previous work in plasmons. Plasmons refer to electrons that travel across metal surfaces like waves. As with hot electrons, plasmons have an extremely short lifespan, but the magic happens when you put the two together.
Hot electrons and their corresponding holes are caused by a plasmonic “jolt” of energy. The challenge is to keep the two states separated, so the hot electron can’t revert to its low energy state.
The conventional way to do this is by pushing the hot electrons over an energy barrier. It’s an inefficient approach but it is widely used because it is based on familiar technology. The Rice team came at the problem from the opposite angle:

We took an unconventional approach: Rather than driving off the hot electrons, we designed a system to carry away the electron holes. In effect, our setup acts like a sieve or a membrane. The holes can pass through, but the hot electrons cannot, so they are left available on the surface of the plasmonic nanoparticles.

It’s A Hydrogen World, Somewhere

When Tesla Motors cofounder Elon Musk famously quipped that fuel cell vehicles (FCEVs) are BS, at least one FCEV maker took him at his word, pointing out that you could potentially run a FCEV on hydrogen sourced from cow manure.
We’re not quite there yet — fossil natural gas is still the primary source of hydrogen for fuel cells for monetary reasons — but in the meantime, FCEVs are making inroads in a number of important niche markets, particularly logistics.
Things are also moving along on the research end. Last spring CleanTechnica was invited on a technology of Germany, which included a discussion of fuel cells with Professor Dr. Gunther Kolb, head of the Department of Decentralized and Mobile Energy Technology at Fraunhofer ICT-IMM. While showcasing one recent marketing fail, Dr. Kolb affirmed that fuel cell technology is “absolutely competitive” with battery technology for stationary storage.
Just a few weeks ago, CleanTechnica also visited Switzerland and got an up-close look at the country’s solar hydrogen and power-t0-gas research at École polytechnique fédérale de Lausanne, and the deployment of hydrogen in homes and vehicles at Empa, the Swiss federal Materials & Technology institute — where researchers made it clear that Switzerland is all over hydrogen as a long-term energy storage solution for winter, with is the “dry” season for the country’s massive hydropower systems.
As for the tension between battery and fuel cell EVs, during our tour, Empa showcased a battery-powered electric street sweeper that incorporates a fuel cell as a range extender, so stay tuned.

http://cleantechnica.com/2015/09/07/inevitable-solar-powered-march-hydrogen-fuel-cell/


Solar projects can't save the forest for the trees?

WADING RIVER, N.Y. (AP) — A green energy project has some environmentalists seeing red.

Solar energy ordinarily wins praise from groups that want to cut greenhouse gases, but a proposed solar project at a defunct Long Island nuclear power plant has stirred outrage because it requires demolishing 350 acres of woodlands."Choosing solar over forests anywhere in the world is just plain stupid," said Dick Amper, of the Long Island Pine Barrens Society. "Solar is very important to fight global warming and beyond, but I'm afraid we're making false choices when you destroy portions of nature and the environment to accomplish that end."
Similar projects are happening elsewhere.
A court fight is brewing over a plan by New Jersey's Six Flags Great Adventure amusement park to cut down nearly 15,000 trees to make way for a solar farm. In Connecticut, state officials recently approved a plan to raze 134 acres of trees in the town of Sprague, near Norwich, for a solar energy project.
Alex Hobson, a spokeswoman for a Solar Energy industry group in Washington, D.C., declined to comment on the Long Island proposal, but said the industry "is committed to responsible use of the land on which we operate and we go to great lengths to protect biodiversity and ecologically fragile lands."
Under the proposal, a company called LI Solar Generation, LLC, a joint venture between NextEra Energy Resources and National Grid, would construct the facility on the grounds of the defunct Shoreham nuclear power plant.
The plant was completed in 1984 for $6 billion but never opened because of community opposition over potential safety concerns. The solar project backers are hoping to plug into existing electric energy infrastructure on the Shoreham property, with plans for up to 72 megawatts of solar energy, providing power for more than 13,000 homes.
A part of the plan mentions replanting trees elsewhere to offset the cutting of the forest but a spokesman for the company did not have details.
Walter Thomas, who teaches a course on solar energy at the University of Massachusetts-Lowell, questioned why it was necessary to eliminate any trees at all.
"I would think Long Island would have giant rooftops and parking lots in shopping malls that could be used for large solar projects if that's what's needed," Thomas said. "There's so much acreage available for that stuff."
Sid Bail, president of the Wading River Civic Association, who lives about a half mile from the Shoreham site along the Long Island Sound, isn't buying it. "I favor renewable energy, but in this case it's a very bad trade-off," he said.
The proposal submitted last month still requires extensive regulatory review.
"We are prepared to work closely with all public officials and the local community to come up with the best solution to have renewable solar energy at Shoreham, and preserve as much of the property as possible," Ross Groffman, executive director of NextEra Energy Resources and LI Solar Generation said in a statement.
Neal Lewis, executive director of the Sustainability Institute at Molloy College, an environmental advocacy group on Long Island that supports the Shoreham project, said it is always preferable to build solar projects in open spaces that don't require the elimination of large numbers of trees. But he notes that "of all the potential options, there is nothing less impactful on the environment than putting in a solar farm."
"That's the real world we live in and they have a right to develop it."

http://www.richmond.com/business/ap/article_6b803c75-71ff-5002-99c5-f4db50e126c1.html
http://wtop.com/national/2016/07/solar-project-cant-save-the-forest-for-the-trees/