Thread: Fossil Fuel Alternatives

Sustainable hydrogen for fuel cells with new artificial leaf

Researchers from Lawrence Berkeley National Laboratory are developing a new bionic leaf that can convert energy from sunlight into an energy-dense fuel, imitating the photosynthetic process of plants. We’ve covered the artificial leaf concept before but aside from using a cool new name (bionic leaf sounds much cooler than artificial leaf, right?) the Berkeley project represents a new twist on the technology that could lead to far greater efficiencies.

The Artificial Leaf Concept

Whether you call it an artificial leaf or a bionic leaf, the basic concept is relatively simple. Instead of using a photovoltaic cell to generate electricity directly from sunlight, you deploy a chemical reaction that stores solar energy in the form of hydrogen, which you can then use in a hydrogen fuel cell to generate electricity.

That sunlight-to-hydrogen chain means you can store solar energy indefinitely, potentially in huge quantities, so think of it as a kind of battery and you’re on the right track. The fuel cell connection means that the intermittent nature of solar energy is not an issue, and neither is its resistance to mobility.

As for how you get there, you drop a photoelectrochemical cell in a bucket of water and let it go to work stripping out the hydrogen.

That’s a much more sustainable way to produce hydrogen than the current standard, which involves a good deal of fossil energy. With Toyota, GM and other auto manufacturers poised to deliver hydrogen fuel cell vehicles to the mass market, the race is on to develop solar powered hydrogen production at scale.

The Berkeley Lab Bionic Leaf
The trick behind the photoelectrochemical cell is to find the right combination of materials that give you a cost-effective reaction, otherwise your bionic leaf is going to sit in the lab and amuse visitors forever.

We’ve been following one solution, an actual leaf-sized artificial leaf that is being developed with a focus on low cost materials to serve households in underserved communities. The absolute efficiency of the cell is not as important as the overall cost, since in this market electricity consumption is almost negligible (in the latest development, the artificial leaf has been tweaked to function effectively in impure water).

The Berkeley team is also taking cost into consideration while moving along a tack that is focused on revving up the performance of the photocathode at the molecular level (the cathode is the part of the cell that generates an electrical current).

The team has been focusing on a hybrid photocathode of gallium phosphide (a semiconductor that absorbs visible light), and cobaloxime, a hydrogen-producing catalyst.

Both materials are relatively abundant and inexpensive compared to conventional precious metal catalysts like platinum.

So far, so good. The team just published its latest analysis of the photocathode in the journal Physical Chemistry Chemical Physics under the title “Energetics and efficiency analysis of a cobaloxime-modified semiconductor under simulated air mass 1.5 illumination,” which demonstrated that almost 90 percent of the electrons generated by the hybrid material were stored in the target hydrogen molecules.

The team has also found that the ability of the gallium phosphide to absorb solar energy is far outstripping the ability of the cobaloxime to catalyse a reaction. The result is that only 1.5 percent of the photons that hit the surface get converted into a photocurrent.

So, the search is on for a faster and more efficient catalyst.

little more here: Promising news for solar fuels from Berkeley Lab researchers at JCAP | e! Science News

Blue Is The New Green: How Oceans Could Power The Future

In February, a natural gas power plant along the Central California coast closed after operating for more than 50 years, thus ending an era that saw the surrounding community of Morro Bay grow up around it. In an unlikely partnership, the shuttering may also help usher in a new era of energy generation — this one reliant on power from the waves that undulate through the bay before crashing up against the nearby shoreline.

The antiquated Morro Bay plant is part of a pattern of seaside plants closing due to a combination of stricter environmental regulations coupled with California’s requirement that 33 percent of electricity in the state come from renewable sources by 2020. Two companies have filed preliminary permits with the Federal Energy Regulatory Commission (FERC) to test wave energy projects off the coast of Morro Bay, a town of about 10,000 people north of Los Angeles. Both projects would use the defunct plant as a much-needed transmission hub to push energy to the grid and from there to consumers throughout the region.

“If we aren’t able to use Morro Bay, there are other shore-based power plants shutting down along the coastline,” said Paul Grist, president and chairman of Archon Energy, one of the companies applying for a FERC permit. “They can’t meet the Renewable Portfolio Standard and they suck in and spew out millions of gallons of water.”

Dynegy, the owner of the power plant, is the other company that applied for a FERC permit. A Houston-based utility company with around 13,000 megawatts (MW) of nationwide power generation capacity, their February 6 application with FERC came several months after Archon’s. If their project tests successfully and goes on to get the two dozen or so licenses and permits that would be needed, it would eventually generate 650 MW of power and cost more than $1 billion to build.

“Dynegy filed their permit many months after we did,” Grist said. “Our goal was to use that transmission corridor to the coast and Dynegy basically followed. Their application is further towards land than ours. I’ve talked with them and we’re going to try to work together and help each other out as much as we can.”

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“There’s a lot of technology happening in wave energy conversion,” Grist said. “Wave energy will be coming of age in the immediate future.”

Wave and tidal power are both hydrokinetic sources of energy. Wave power harnesses the energy of surface waves through a number of different mechanisms, many still in early stages of development. Currently the primary method involves floating buoys the size of lighthouses that are moored to the ocean floor. In another example, a group of researchers at UC-Berkeley have developed what they call a “seafloor carpet” that absorbs the impact of ocean waves much as muddy seabeds do.

Tidal power uses the flow of ocean currents, tides or inland waterways to capture the potential energy between high and low tides as they occur every 12 hours. “The rotation of the earth creates wind on the ocean surface that forms waves, while the gravitational pull of the moon creates coastal tides and currents,” the National Renewable Energy Laboratory (NREL) explains.

As the search for new forms of clean, sustainable energy persists, the global potential of wave and tidal power represents an untested but immensely promising frontier. Oceans cover 70 percent of the Earth’s surface — and they do so densely. Ocean current resources are about 800 times denser than wind currents, according to NREL, meaning a 12-mph marine current generates the equivalent amount of force as a 110-mph wind gust. With more than half of all Americans living near the coastline, wave and tidal power is also appealing for its proximity to electricity demand centers, whereas the many of the best wind and solar sites are hundreds of miles from population hubs.

A 2012 report prepared by RE Vision Consulting for the Department of Energy found that the theoretical ocean wave energy resource potential in the U.S. is more than 50 percent of the annual domestic demand of the entire country. The World Energy Council has estimated that approximately 2 terawatts — 2 million megawatts or double current world electricity production — could be produced from the oceans via wave power.

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While oceans may cover more than two-thirds of the planet, wave and tidal power require concentrated energy locations with strong currents or consistently large waves. This limits the opportunities to a tiny percentage of the ocean, according to Fraenkel. So on top of technological advances and economic favorability, siting, natural resources availability, and transmission access must all align for a successful wave or tidal power project. Even so, Fraenkel views the challenges as not only worth overcoming, but necessary to overcome.

“The oceans contain a huge amount of energy so logic dictates that we need to learn to extract energy where possible bearing in mind that future use of fossil fuel is going to be inhibited both by the effects of pollution induced climate change and by resource depletion,” he said. “So my message is that although extracting energy from the oceans is more difficult and perhaps less successful so far than some people might have wished, it has been shown to be possible and will no doubt become increasingly important in future.”

much more in the link above

Nice to read the Department of Defense planning ahead and at no cost to US tax payers,…

Department Of Defense Undertakes Largest Solar Project To Date

The U.S. Army announced plans on Monday to begin construction on the Department of Defense’s largest solar array on a military installation. Groundbreaking for the 20-megawatt project will take place on April 25, with commercial operations slated to begin late this year. It will provide about a quarter of the annual electricity use for Fort Huachuca in southeast Arizona.

“The project establishes a new path for an innovative partnering opportunity among the U.S. Army, other federal agencies, private industry and the utility provider,” said Richard Kidd, deputy assistant secretary of the Army for energy and sustainability. “I applaud the significant efforts and teamwork to bring this project to fruition — and set the example for other large scale renewable energy opportunities.”

The project is being installed under a purchase power agreement in which the solar installer, in this case Tucson Electric Power, pays for installation, operation, and maintenance and then pays down costs and generates revenue through sales of electricity. The project is an example of public-private industry collaboration in which no taxpayer dollars will be spent. The installation, design, engineering and construction of the project will be overseen by E.ON, a multinational investor-owned energy supplier.

The U.S. Army is committed to sustainable energy practices for a number of reasons, not least of which is the acknowledgement of climate change as a threat to geopolitical order and a national security threat multiplier.