Other Source of Energy

Inhabitat has a post on a particularly unlikely plan for space based solar power - Japanese Corporation Plans to Turn the Moon Into a Massive Solar Power Plant.

Man hasn’t been back to the moon since 1972, but that hasn’t stopped a team of Japanese engineers from developing a plan to turn our celestial neighbor into a massive solar power plant. The disaster at the Fukushima nuclear power station has made Japan think more seriously about alternative energy, and as a result Shimizu Corporation‘s crazy plan has been gaining traction. The plan calls for a massive 12 mile-wide, 6,800 mile long “Luna Ring” of solar panels to be constructed on the moon’s surface. The solar belt would then harness solar power directly from the sun and then beam it straight to Earth via microwaves and lasers.

Shimizu Corporation’s plan would see 13,000 terawatts of continuous energy sent to receiving stations around the Earth, where it will be then distributed to the planet’s population. With NASA’s plans to return the moon currently on hold, Shimizu is planning on building the massive lunar construction project with robots. In fact, humans will barely be involved and will only be present in an overseeing capacity.

Todd Woody at Forbes has a post on a new, dispatchable solar thermal power plant planned for Nevada - Obama administration grants $737 million for a 24/7 solar power plant

The Obama administration on Thursday offered Santa Monica solar startup SolarReserve a $737 million loan guarantee to build a 110-megawatt solar thermal power plant in Nevada that can generate electricity 24 hours a day.

That’s the holy grail for intermittent sources of carbon-free energy such as solar and wind and the SolarReserve loan guarantee is a sign that the United States Department of Energy is willing to gamble on a technology untested on a commercial scale.
SolarReserve literally was founded by rocket scientists from United Technologies’ Rocketdyne division in 2007 and licenses its molten salt technology.

Like rival BrightSource Energy, SolarReserve will deploy massive arrays of mirrors called heliostats around a very tall tower – in this case, one that tops 640 feet – with a boiler attached. BrightSource’s heliostats focus the sun on a water-filled boiler to create steam that drives an electricity-generating turbine.

SolarReserve fills its boiler with millions of gallons of molten salt. Some 17,500 heliostats heat the salt to 1,050 degrees Fahrenheit. The liquefied salt then generates steam to drive the turbine before returning to the receiver. The salt retains heat that can be released at night or when the sun is not shining to continously to produce power.

“This solar technology is a genuine alternative to baseload coal, nuclear or natural gas burning electricity generation facilities," Kevin Smith, SolarReserve’s chief executive, said in a statement.
The Nevada project, called the Crescent Dunes Solar Energy Project, will be built on federal land in Tonopah, Nev., about 220 miles northwest of Las Vegas. SolarReserve said the molten salt can extend Crescent Dunes’ daily operation by 10 to 12 hours and the project can power 75,000 homes at peak output. Whether the utility that has contracted to buy the Crescent Dunes’ electricity, NV Energy, will want the plant to actually run around the clock depends on how it balances demands placed on the grid.

SolarReserve, which also has a license to build a 150-megawatt solar farm in the Southern California desert, is counting on the ability to provide carbon-free power when the sun isn’t shining as a competitive advantage. Rivals are also offering solar storage – Abengoa’s federally funded Solana solar trough power plant in Arizona, for instance, will feature up to seven hours’ storage.

Low Tech Magazine has a look at the use of solar thermal energy in industrial applications - The bright future of solar powered factories.

A large share of energy consumed worldwide is by heat. Cooking, space heating and water heating dominate domestic energy consumption. In the UK, these activities account for 85 percent of domestic energy use, in Europe for 89 percent and in the USA for 61 percent (excluding cooking).

Heat also dominates industrial energy consumption. In the UK, 76 percent of industrial energy consumption is heat. In Europe, this is 67 percent. I could not find figures for the US and for the world as a whole, but these percentages must be similar (and probably even higher on a worldwide scale because many energy-intensive industries have been outsourced to developing countries). Few things can be manufactured without heat. ...

The missing element in our sustainable energy strategy is a renewable source of thermal energy. Geothermal energy produces heat, but its potential is limited to regions that have volcanoes. Biomass is another option, but it faces many problems. If we were to try to provide an important share of heat demand by burning biomass, we would quickly come up against the limits of what the planet can produce. There is only one source of heat energy left, and it is a powerful and inexhaustible one: solar energy.

We tend to see solar energy as yet another way to generate electricity, using photovoltaic panels or solar thermal power plants. But solar energy can also be applied directly, without the intermediate step of generating electricity. Basically, harvesting direct solar energy can happen in two ways: by means of water-based flat plate collectors or evacuated tube collectors, which collect solar radiation from all directions and can reach temperatures of 120 °C (248 °F), and by means of solar concentrator collectors, which track the sun, concentrate its radiation, and can generate much higher temperatures. These can be parabolic trough systems, linear concentrating Fresnel collectors, parabolic dish systems or solar power towers. Almost all of these technologies were developed at the turn of the 20th century.

Solar thermal power versus solar thermal heat

Solar power tower The problem is that we mostly use this technology for the wrong purpose. In todays solar thermal plants, solar energy is converted into steam (via a steam boiler), which is then converted into electricity (via a steam turbine that drives an electric generator).

This process is just as inefficient as converting electricity into heat: two-thirds of energy gets lost when converted from steam to electricity. This is one of the main reasons why the use of solar thermal energy to produce electricity is only cost-effective in deserts. ...

If we were to use solar thermal plants to generate heat instead of converting this heat into electricity, the technology could deliver energy 3 times cheaper than it does today and become cost-effective also in less sunny regions. The crucial difference between solar thermal electricity and other renewables producing electricity is that solar thermal actually starts with heat energy. Thus, contrary to other renewables, the cost of heat energy using the technology is far lower than the cost of electricity, and so it can compete with burning fossil fuels at the thermal level. ...

Without a doubt, solar heat for domestic purposes should continue to be encouraged and a lot of potential remains. But it does not stop there. According to a 2008 report (pdf), which analyses the situation in Europe, the potential for solar heat in industrial processes is even larger than in the domestic market. About 30 percent of industrial heat demand in Europe is below 100 °C (212 °F), which could be delivered by commercially available flat plate collectors (< 80 °C) and evacuated tube collectors (< 120 °C) currently used for domestic purposes.

Another 27 percent of industrial heat demand requires medium temperatures (100 to 400 °C or 212 to 752 °F), which could be reached by improved versions of these collectors (up to 160 °C, see this document) and by commercially available solar concentrator technologies now mostly used for electricity production: parabolic troughs, parabolic dishes and linear concentrating Fresnel collectors.

Technology Review has an article on solar power research at UNSW - A Material That Could Make Solar Power “Dirt Cheap”.

A new type of solar cell, made from a material that is dramatically cheaper to obtain and use than silicon, could generate as much power as today’s commodity solar cells.

Researchers developing the technology say that it could lead to solar panels that cost just 10 to 20 cents per watt. Solar panels now typically cost about 75 cents a watt, and the U.S. Department of Energy says 50 cents per watt will allow solar power to compete with fossil fuel.

In the past, solar researchers have been divided into two camps in their pursuit of cheaper solar power. Some have sought solar cells that can be made very cheaply but that have the downside of being relatively inefficient. Lately, more researchers have focused on developing very high efficiency cells, even if they require more expensive manufacturing techniques.

The new material may make it possible to get the best of both worlds—solar cells that are highly efficient but also cheap to make.

One of the world’s top solar researchers, Martin Green of the University of New South Wales, Australia, says the rapid progress has been surprising. Solar cells that use the material “can be made with very simple and potentially very cheap technology, and the efficiency is rising very dramatically,” he says.

Perovskites have been known for over a century, but no one thought to try them in solar cells until relatively recently. The particular material the researchers are using is very good at absorbing light. While conventional silicon solar panels use materials that are about 180 micrometers thick, the new solar cells use less than one micrometer of material to capture the same amount of sunlight. The pigment is a semiconductor that is also good at transporting the electric charge created when light hits it.

“The material is dirt cheap,” says Michael Grätzel, who is famous within the solar industry for inventing a type of solar cell that bears his name. His group has produced the most efficient perovskite solar cells so far—they convert 15 percent of the energy in sunlight into electricity, far more than other cheap-to-make solar cells. Based on its performance so far, and on its known light-conversion properties, researchers say its efficiency could easily rise as high as 20 to 25 percent, which is as good as the record efficiencies (typically achieved in labs) of the most common types of solar cells today. The efficiencies of mass-produced solar cells may be lower. But it makes sense to compare the lab efficiencies of the perovskite cells with the lab records for other materials. Grätzel says that perovskite in solar cells will likely prove to be a “forgiving” material that retains high efficiencies in mass production, since the manufacturing processes are simple.

The LA Times reports that the US government is trying to fast track large scale solar power development in the Mojave desert - Obama administration announces desert solar energy zones.

The Obama administration on Thursday unveiled its road map for solar energy development, directing large-scale industrial projects to 285,000 acres of desert land in the western U.S. while opening 20 million acres of the Mojave for new development.

The Bureau of Land Managements long-awaited "solar energy zones" are intended to make some of the deserts most sensitive landscapes less desirable for solar prospecting by identifying "sweet spots" that have already passed environmental requirements and therefore promise expedited permitting, U.S. Interior Secretary Ken Salazar said. "These 445 square miles of zones are … where development will be driven," Salazar said on a conference call with reporters.

The 17 solar energy zones in six western states — including two extensive areas in California — were identified by their absence of major environmental or cultural conflicts. But nothing prevents a developer from requesting permission to build on federal land outside the preferred areas.

The policy, which is expected to be finalized sometime next year, would not apply to the 13 solar projects already under construction across the West, nor the 79 pending applications that would occupy 685,000 acres of public land. There are 20 utility-scale solar applications awaiting approval in California.