Should Europe Cover the Sahara With Solar Panels for Power?

Could one solution to climate change be to harvest the power of sunlight where it shines brightest on the planet? Should we solar panel the Sahara desert?

Four experts discuss the radical proposal with the BBC World Service Inquiry programme.

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A bit Pollyanna: Morgan Stanley Predicts Tesla Will be Disruptive for the Power Industry

There's a reason that power companies are attacking rooftop solar across the nation: They see those silicon panels as nothing short of an existential threat. As the cost of solar continues to fall, and more people opt for the distributed power offered by solar, there will be less demand for big power plants and the utilities that operate them. And one major investment giant has now released three separate reports arguing that Tesla Motors is going to help kill power companies off altogether.

Earlier this year, Morgan Stanley stirred up controversy when it released a report that suggested that the increasing viability of consumer solar, paired with better battery technology—that allows people to generate, and store, their own electricity—could send the decades-old utility industry into a death spiral. Then, the firm released another one, further emphasizing the points made in the first. Now, it's tripling down on the idea with yet another report that spells out how Tesla and home solar will "disrupt" utilities.

“There may be a 'tipping point' that causes customers to seek an off-grid approach," the March report argued. "The more customers move to solar, the [more the] remaining utility customers' bills will rise, creating even further 'headroom' for Tesla’s off-grid approach.”

Yes, Tesla Motors, everyone's favorite electric car company. And that's where the controversy comes in. Morgan Stanley breathlessly pegged Tesla as “the most important auto company in the world" in part because its electric car business was pushing it to develop better energy storage technology, and then mass manufacture said batteries. That's exactly what Tesla CEO Elon Musk and company will be doing at its forthcoming Gigafactory, which it is building in the Southwest with Panasonic.

With the new manufacturing facility, Morgan Stanley reasons, Tesla stands to double its business (adding another $2 billion in revenue) by selling the lithium ion batteries it typically ships under the hood of a Model S to homeowners with solar panels, too. If consumers can store energy the panels generate during the day for use at night, it would ostensibly render the need for utilities to pipe in faraway power—and their electric bills—obsolete.

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Japanese Design, Plan (?) Solar Power Satellites

Imagine looking out over Tokyo Bay from high above and seeing a man-made island in the harbor, 3 kilometers long. A massive net is stretched over the island and studded with 5 billion tiny rectifying antennas, which convert microwave energy into DC electricity. Also on the island is a substation that sends that electricity coursing through a submarine cable to Tokyo, to help keep the factories of the Keihin industrial zone humming and the neon lights of Shibuya shining bright.

But you can’t even see the most interesting part. Several giant solar collectors in geosynchronous orbit are beaming microwaves down to the island from 36 000 km above Earth.

It’s been the subject of many previous studies and the stuff of sci-fi for decades, but space-based solar power could at last become a reality—and within 25 years, according to a proposal from researchers at the Japan Aerospace Exploration Agency (JAXA). The agency, which leads the world in research on space-based solar power systems, now has a technology road map that suggests a series of ground and orbital demonstrations leading to the development in the 2030s of a 1-gigawatt commercial system—about the same output as a typical nuclear power plant.

It’s an ambitious plan, to be sure. But a combination of technical and social factors is giving it currency, especially in Japan. On the technical front, recent advances in wireless power transmission allow moving antennas to coordinate in order to send a precise beam across vast distances. At the same time, heightened public concerns about the climatic effects of greenhouse gases produced by the burning of fossil fuels are prompting a look at alternatives. Renewable energy technologies to harvest the sun and the wind are constantly improving, but large-scale solar and wind farms occupy huge swaths of land, and they provide only intermittent power. Space-based solar collectors in geosynchronous orbit, on the other hand, could generate power nearly 24 hours a day. Japan has a particular interest in finding a practical clean energy source: The accident at the Fukushima Daiichi nuclear power plant prompted an exhaustive and systematic search for alternatives, yet Japan lacks both fossil fuel resources and empty land suitable for renewable power installations.

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An Astounding Graph on Solar Power Costs

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ATK Demonstrates 40 kilowatt, Light Weight Solar Arrays

ATK (NYSE: ATK) demonstrated full deployment of a large MegaFlex™ solar array under a NASA contract to further the development of a high-power system to be used for future robotic and manned exploration missions.

ATK’s 9.6 meter (32 ft) diameter Solar Electric Propulsion (SEP) MegaFlex solar array design is capable of generating approximately 40kW of power with two wings when fully populated with solar cells, and it has been considered for near-term mission concepts such as NASA’s Asteroid Redirect Mission. The full deployment demonstration of MegaFlex was successfully conducted at ATK’s Goleta, Calf. facility on Dec. 9. The system completed validation testing through December before being shipped to NASA’s Glenn Research Center Plum Brook Station for thermal vacuum deployment testing this month.

“NASA’s over-arching objective is to further the development of low mass solar arrays that can be stowed very compactly for high-power SEP systems to be used for future robotic and manned exploration missions,” said David Shanahan, vice president and general manager of ATK Aerospace Group’s Space Components division. “By building on our family of solar arrays, our team was able to develop this breakthrough with affordable innovation and in rapid fashion to support NASA’s far-reaching planning efforts.”

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Artificial Photosynthesis Created at Berkeley Lab

SEM images of Si (top) and TiO2 (bottom) nanowire electrodes show light being absorbed and generating a photocurrent that can carry out the water-splitting reaction.

In the wake of the sobering news that atmospheric carbon dioxide is now at its highest level in at least three million years, an important advance in the race to develop carbon-neutral renewable energy sources has been achieved. Scientists with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have reported the first fully integrated nanosystem for artificial photosynthesis. While "artificial leaf" is the popular term for such a system, the key to this success was an "artificial forest."

"Similar to the chloroplasts in green plants that carry out photosynthesis, our artificial photosynthetic system is composed of two semiconductor light absorbers, an interfacial layer for charge transport, and spatially separated co-catalysts," says Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division, who led this research. "To facilitate solar water- splitting in our system, we synthesized tree-like nanowire heterostructures, consisting of silicon trunks and titanium oxide branches. Visually, arrays of these nanostructures very much resemble an artificial forest."

Yang, who also holds appointments with the University of California Berkeley's Chemistry Department and Department of Materials Science and Engineering, is the corresponding author of a paper describing this research in the journal NANO Letters. The paper is titled "A Fully Integrated Nanosystem of Semiconductor Nanowires for Direct Solar Water Splitting." Co-authors are Chong Liu, Jinyao Tang, Hao Ming Chen and Bin Liu.

Solar technologies are the ideal solutions for carbon-neutral renewable energy – there's enough energy in one hour's worth of global sunlight to meet all human needs for a year. Artificial photosynthesis, in which solar energy is directly converted into chemical fuels, is regarded as one of the most promising of solar technologies. A major challenge for artificial photosynthesis is to produce hydrogen cheaply enough to compete with fossil fuels. Meeting this challenge requires an integrated system that can efficiently absorb sunlight and produce charge-carriers to drive separate water reduction and oxidation half-reactions.

"In natural photosynthesis the energy of absorbed sunlight produces energized charge-carriers that execute chemical reactions in separate regions of the chloroplast," Yang says. "We've integrated our nanowire nanoscale heterostructure into a functional system that mimics the integration in chloroplasts and provides a conceptual blueprint for better solar-to-fuel conversion efficiencies in the future."

When sunlight is absorbed by pigment molecules in a chloroplast, an energized electron is generated that moves from molecule to molecule through a transport chain until ultimately it drives the conversion of carbon dioxide into carbohydrate sugars. This electron transport chain is called a "Z-scheme" because the pattern of movement resembles the letter Z on its side. Yang and his colleagues also use a Z-scheme in their system only they deploy two Earth abundant and stable semiconductors – silicon and titanium oxide - loaded with co-catalysts and with an ohmic contact inserted between them. Silicon was used for the hydrogen-generating photocathode and titanium oxide for the oxygen-generating photoanode. The tree-like architecture was used to maximize the system's performance. Like trees in a real forest, the dense arrays of artificial nanowire trees suppress sunlight reflection and provide more surface area for fuel producing reactions.

"Upon illumination photo-excited electron−hole pairs are generated in silicon and titanium oxide, which absorb different regions of the solar spectrum," Yang says. "The photo-generated electrons in the silicon nanowires migrate to the surface and reduce protons to generate hydrogen while the photo-generated holes in the titanium oxide nanowires oxidize water to evolve oxygen molecules. The majority charge carriers from both semiconductors recombine at the ohmic contact, completing the relay of the Z-scheme, similar to that of natural photosynthesis."

PG&E to Buy 200 MW from Space Based Solar Power Sat Company

Solar power beamed down from space will generate electricity for California homes as soon as 2016, under a new plan by a utility company to ramp up renewable energy technology far beyond solar panels on roofs.

PG&E would buy 200 megawatts of space solar power from Solaren Corp. over 15 years under a power purchase agreement, enough to power tens of thousands of homes. The utility company has begun seeking approval for the deal from California state regulators.

Solaren would use solar panels on satellites in orbit to capture the sun's power, and then convert it into radio frequency energy that could beam down to a receiving station. The energy would then undergo a conversion to electricity and feed into PG&E's power grid.

Having solar panels in orbit could provide a clean, reliable source of solar power that avoids the interruptions of cloudy days and bad weather on Earth. That tempting prospect has led NASA and the U.S. Defense Department to investigate possibilities for space solar power, despite the hefty cost of launching solar panels into orbit.

A former NASA scientist went so far as to demonstrate the radio wave transmission technology that would carry energy from space to Earth. He and his team transmitted solar power over a distance of 92 miles between two Hawaiian islands, during a four-month experiment in 2008.

No one has built a system with equivalent size and scale to what Solaren envisions. But the transmission technology is "very mature" and based on what communications satellites use today, said Gary Spirnak, Solaren CEO.

Now THAT'S a salesman.

No prototype. No hardware at all.

And as far as I can tell...no website even. Sheesh. Solaren.com goes to an Armenian company.

Damn. he's far better than I am.

BrightSource Energy Wins 1.3 GigaWatt Solar Contracts

Solar power's explosive growth in California may have been stunted by the credit crisis and the recession, but the boom isn't over yet.

In what could be the world's largest solar deal to date, BrightSource Energy of Oakland announced Wednesday that it will sell Southern California Edison 1,300 megawatts of electricity from seven large solar plants planned for the California desert.

That's enough juice to light 845,000 homes, and it easily eclipses other recent deals signed by utilities here and abroad that are trying to expand their use of renewable power.

"It's a significant statement by Southern California Edison in their commitment to renewable energy and BrightSource's technology," said John Woolard, BrightSource's chief executive officer. "America and California have long called for clean renewable energy, and we look forward to working with Southern California Edison to meet this need."

That's enough for around 7% of the households, iirc. A nice bit of sunshine on this cloudy economic day. I'm still a little fascinated by Nanosolar though.

"Green" Renewnable Energy Not So Green Compared to Nuclear

Renewable does not mean green. That is the claim of Jesse Ausubel of the Rockefeller University in New York. Writing in Inderscience's International Journal of Nuclear Governance, Economy and Ecology, Ausubel explains that building enough wind farms, damming enough rivers, and growing enough biomass to meet global energy demands will wreck the environment.

Ausubel has analyzed the amount of energy that each so-called renewable source can produce in terms of Watts of power output per square meter of land disturbed. He also compares the destruction of nature by renewables with the demand for space of nuclear power. "Nuclear energy is green," he claims, "Considered in Watts per square meter, nuclear has astronomical advantages over its competitors."

On this basis, he argues that technologies succeed when economies of scale form part of their evolution. No economies of scale benefit renewables. More renewable kilowatts require more land in a constant or even worsening ratio, because land good for wind, hydropower, biomass, or solar power may get used first.

He does some ratios that people ought to consider and runs through the whole gauntlet of 'renewable' energy sources. One of the worst - *gasp*shock* - is biomass compared to nuclear power. All of them fall far short of what a nuclear power plant can do. This includes solar which he goes on to outline as needing 150 square kilometers of solar panels to replace a single nuclear reactor. The United States at this point has a total of 103 active power generating power plants. This means we need a total of 15,600 square kilometers of solar generating capacity: this is approximately an area of 125 miles by 125 miles for those of stuck on our own, anachronistic measurement system. Nuclear power only represents 20% of the electricity generating industry. To replace all the coal, natural gas, etc, plants you would need another four times the above (or more simply put, approximately 280 miles by 280 miles of solar panels to power the United States as is with nor growth). 280 miles is HUGE. It more than the distance between Las Cruces, New Mexico - almost on the border of Mexico - to Albuquerque, New Mexico! That's a vast piece of habitat wiped out.

It is truly too bad that the Greens are so adamantly, ridiculously opposed to nuclear power. It may in fact do the most damage to the environment because of it. It makes you wonder if there hadn't been the wild outcry during the 1970s what our power mix would be now and if the impact of green house gases might have been less.

Don't get me wrong. I support solar power. I think it would excellent as the secondary source of power for peak usage. After all, those times that solar happens to be the most effective are during the times that the highest demand is present (summer/daylight). That seems like a match made in heaven to me.

I am also not at all friendly to biomass, but that's another post for another time.

California to build 'world's largest' solar farm

A San Francisco company said Friday it plans to build the world's largest solar power farm near Fresno, California.

The 80-megawatt farm is to occupy as much as 640 acres and upon completion in 2011 will be 17 times the size of the largest U.S. solar farm, said Cleantech America LLC, a privately held 2-year-old company.

640 acres. That's a square mile. For 80 MW. Hm.