Oil company announces installation of solar panels at 5,000 gas stations, first step to convert them into EV charging stations?

Posted on November 15th, 2016 in solar by Spencer R.

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(www.electrek.co)

Total, the major French multinational oil and gas company, announced today a $300 million investment to install about 200 MW of solar capacity at 5,000 gas stations around the world. The investment is being presented as a way for Total’s operations to reduce its carbon footprint, but what if its the first step to convert the gas stations into electric vehicle charging stations?

As the global car fleet transition from being powered by gasoline and diesel to being powered by electricity, the refueling infrastructure is also bound to change. Gas stations have already mostly all become convenience stores, but they still depend on the traffic from drivers refueling their tanks.

Obviously, we will need less charging stations than gas stations when electric vehicles will be more common since the majority of the charging happens at home, but a significant number of stations will still be required for long distance travel and for EV owners without home access to charging, like apartment dwellers.

If you are to offer charging, you might as well produce the electricity from solar energy on location where it is economically viable, which is far from being everywhere yet, but it is quickly expanding in different markets.

Total didn’t specify where its new solar installations will be deployed other than at “5,000 of its service stations worldwide” including “800 in France” and they will be deployed over the next five years.

The panels will be supplied by Sunpower, which is owned by Total.

Philippe Sauquet, President of Gas, Renewables & Power at Total, commented on the announcement:

 “The project is fully aligned with Total’s ambition of becoming the responsible energy major and its commitment to developing solar power. It will reduce our carbon emissions by 100,000 tons per year and cut our electricity bill by $40 million per year. The panels will be supplied by our affiliate SunPower, which offers the world’s most efficient solar technology. This project demonstrates Total’s confidence in SunPower, especially its ability to bring our customers competitive, clean energy.

But it wasn’t a first globally. Last year, we reported that Tesla sold 12 Superchargers to the Manaseer Group to be installed at three of their gas stations in Jordan. Those are privately held Superchargers and not officially part of Tesla’s network.

With charging stations and solar arrays being installed (separately for now) at gas stations around the world, I think we are seeing a glimpse of an important part of our future transport infrastructure starting to emerge. Soon enough, we should see stations with large solar arrays storing the electricity in battery packs and charging electric vehicles.

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Scientist develops filaments that harvest and store solar energy

Posted on November 15th, 2016 in solar by Spencer R.

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(www.pvbuzz.com)

Marty McFly’s self-lacing Nikes in Back to the Future Part II inspired a UCF scientist to develop filaments that harvest and store the sun’s energy.

The breakthrough would essentially turn jackets and other clothing into wearable, solar-powered batteries that never need to be plugged in. It could one day revolutionize wearable technology, helping everyone from soldiers who now carry heavy loads of batteries to a texting-addicted teen who could charge his smartphone by simply slipping it in a pocket.

“That movie was the motivation,” Associate Professor Jayan Thomas, a nanotechnology scientist at the University of Central Florida’s NanoScience Technology Center, said of the film released in 1989. “If you can develop self-charging clothes or textiles, you can realize those cinematic fantasies — that’s the cool thing.”

The research was published Nov. 11 in the academic journal Nature Communications.

Thomas already has been lauded for earlier ground-breaking research. Last year, he received an R&D 100 Award — given to the top inventions of the year worldwide — for his development of a cable that can not only transmit energy like a normal cable but also store energy like a battery. He’s also working on semi-transparent solar cells that can be applied to windows, allowing some light to pass through while also harvesting solar power.

His new work builds on that research.

“The idea came to me: We make energy-storage devices and we make solar cells in the labs. Why not combine these two devices together?” Thomas said.

Thomas, who holds joint appointments in the College of Optics & Photonics and the Department of Materials Science & Engineering, set out to do just that.

Taking it further, he envisioned technology that could enable wearable tech. His research team developed filaments in the form of copper ribbons that are thin, flexible and lightweight. The ribbons have a solar cell on one side and energy-storing layers on the other.

Though more comfortable with advanced nanotechnology, Thomas and his team then bought a small, tabletop loom. After another UCF scientists taught them to use it, they wove the ribbons into a square of yarn.

The proof-of-concept shows that the filaments could be laced throughout jackets or other outwear to harvest and store energy to power phones, personal health sensors and other tech gadgets. It’s an advancement that overcomes the main shortcoming of solar cells: The energy they produce must flow into the power grid or be stored in a battery that limits their portability.

“A major application could be with our military,” Thomas said. “When you think about our soldiers in Iraq or Afghanistan, they’re walking in the sun. Some of them are carrying more than 30 pounds of batteries on their bodies. It is hard for the military to deliver batteries to these soldiers in this hostile environment. A garment like this can harvest and store energy at the same time if sunlight is available.”

There are a host of other potential uses, including electric cars that could generate and store energy whenever they’re in the sun.

“That’s the future. What we’ve done is demonstrate that it can be made,” Thomas said. “It’s going to be very useful for the general public and the military and many other applications.”

 

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Creating Solar Energy From Trash

Posted on November 14th, 2016 in solar by Spencer R.

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 (www.euronews.com)

Electricity and hot water are a given in many parts of the world, but in the marginalised town of Garin, north of the Argentinian capital Buenos Aires, there used to be neither.

Things have changed thanks to ingenious but very simple solar panels made from recycled plastic bottles.

It’s the result of an initiative by Argentinian NGO Sumando Energias, which directly involves local communities.

“This is a poor neighbourhood and sometimes we have no light or water,” says resident Luis Alberto Quinona. “These recycled solar panels help us a lot, we have children and it’s useful having light and hot water even though we have no electricity.”

So how does it work? The homemade system is made of used soda cans, plastic bottles and milk cartons. As the sun heats the tubes of the solar collector, hot water flows into the storage tank. Volunteers paint the pipes black to adsorb heat from the sun. In this way, the solar collector keeps water hot all night long without the need for electricity or gas.

Volunteer Julien Laurençon quit his job in banking in Singapore to work on the project.

“Sustainable development and sustainable energy are important trends that we need to follow and foster,” he says. “There is too much waste today. And I’m not just talking about Third World and developing countries. I believe that developed countries, too, have to follow this trend. Developed nations are the biggest polluters,” he says.

One third of Argentinians live in poverty, according to official figures, which reveal that nearly 17% have no water.

For Pablo Castaño, co-founder of the NGO, the project is innovative because it brings renewable energy to the doorstep of impoverished communities in a South American nation with many natural resources.

“Argentina has a huge potential for solar and wind energy. To give you an idea, if we had the same capacity as Germany – which is at the same latitude as Santa Cruz – in Buenos Aires or in the north, where we have a lot of sun, we could produce enough energy to supply not only Argentina but also neighbouring countries,” he says.

The NGO has assembled 36 solar panels since 2014 and proposes a two-day workshop to those who want to learn how to make the solar-powered heaters.

Getting the families involved in the construction process is key to the NGO’s plans to empower locals and teach them about recycling.

Angel Guelari is among those who will receive a solar-powered bathroom thanks to the initiative. “These are things that we normally throw away and which contaminate the environment. Instead, we can recycle them and get hot water in the house, for example. It’s good to recycle. I never used to. I would throw away everything I used, like bottles. The rubbish would stay in plastic bags because the garbage man would not come and pick it up,” he says.

The plan is to build solar panels for 3.000 families a year.

In 2005, Buenos Aires became the first Latin American city to vote for a Zero Waste policy, but environmental group Greenpeace argues investment in recycling infrastructure remains woefully inadequate.

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Las Vegas Streetlight Harness the Power of Solar Energy and Your Footsteps

Posted on November 9th, 2016 in solar by Spencer R.

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(www.digitaltrends.com)

Sin City may actually be transforming into the City of Sensibility. Well, in part, at least. A new clean-energy project in downtown Las Vegas looks to harness the energy of pedestrian foot traffic to power a series of streetlights.

 

Las Vegas has partnered with the startup EnGoPlanet on the project. EnGoPlanet aims to address the problem of poor access to electricity worldwide. It recently began crowdfunding a campaign to install lights in portions of Africa. As part of the Las Vegas trial, the company installed four cutting-edge streetlights in the downtown Boulder Plaza. These lights work entirely off the grid, utilizing only kinetic as well as solar energy.

 

Whenever a person steps onto one of the eight pads built into the sidewalk, three micro generators below the surface convert this energy into electricity. The level of pressure and consequently the amount of kinetic energy produced varies, however, EnGoPlanet estimates each footstep can create between four and eight watts of energy. The solar panels are mounted on top of the light.

The streetlights also double as individual charging stations. Several universal USB ports and wireless charging pads are built into the poles. Each unit also provides Wi-Fi for added functionality. People love a good Wi-Fi hot spot and this feature will surely only attract more pedestrians and therefore more traffic. Brilliant.

EnGoPlanet provided the streetlights to Las Vegas for free. The startup hopes to expand the upon the project in Las Vegas as well as other cities in the near future.

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Solar Energy Chemistry: Is This The Future?

Posted on November 9th, 2016 in solar by Spencer R.

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(www.itechpost.com)

People are looking for the next sustainable energy source. That energy source should not only be practical, but inexpensive as well. Many of today's alternative sustainable energy sources aren't exactly cheap. Scientists are now looking at solar energy chemistry, and wonder is this the future?

The study has been made by a group of European chemists that is led by Professor Joost Reek. He comes from the University of Amsterdam's research priority area of Sustainable Chemistry. The concept being proposed is solar energy chemistry that can possibly be used in the future for fuel, chemicals and material.

 

Professor Reek is known for his involvement in solar-driven chemistry. For the study, he said that there is a need for breakthroughs in order to move solar-driven chemistry to reality. He envisions a movement that would involve a wide European solar-driven community that could do research as well as be more active in the industry.

Professor Reek cites examples of such recent work involving solar-driven chemistry, according to the University of Amsterdam's site. One such example that he notes is the use of novel molecules for solar-driven hydrogen generation. This has been done by the French company PorphyChem. Another one that he notes is for the development of a photoelectrochemical cell that can convert carbon dioxide to methanol.

Two Dutch research institutes have joined the University of Amsterdam and the Vrije Universiteit Amsterdam in getting energy from the Sun through the use of photovoltaics, photocatalysis and photosynthesis, as Science Daily reports. These two institutes are ECN and FOM-AMOLF. This is the sort of European community for solar-driven chemistry that Professor Reek envisions.

Solar-driven energy is a long-term initiative for a much more sustainable energy future. The paper made by Professor Reek and his colleagues state that solar-driven chemical energy from the Sun is needed for the future. This will create a competitive European effort in the industry as well as in research. Solar energy chemistry then can answer the question: is this the future? Earlier also cheaper solar cells were reportedly being developed.

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Arcadia Power launches a solar energy service for renters across the U.S.

Posted on November 6th, 2016 in solar by Spencer R.

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(www.techcrunch.com)

The renewable energy services company Arcadia Power has just launched a new product that allows renters across the U.S. to buy renewable energy.

It’s a significant step forward for the renewable energy project developer and operator, which had previously integrated with utilities as an offset provider and load management company. And it’s potentially a game changer for the renewable energy movement.

I’m going to unpack that a bit because it gets a mite confusing. Before this announcement, Arcadia was offering services that would offset customers’ energy use with an equal investment in a renewable energy project (typically a wind farm).

Now, because of the company’s partnerships with utilities and status as a project developer, it has amassed a small group of projects through which it’s offering renewable energy investment to folks across the country who would want to install solar, but can’t.

Arcadia’s logic is simple. There are a number of renters or non-homeowners who would like to be able to invest in sustainable energy, but don’t have the means.

“That’s one of the most important parts of what we’re doing,” said Kiran Bhatraju, the chief executive of Arcadia Power. “The vast majority of Americans can’t do rooftop solar. There’s only about 8% of Americans that can.”

Those people are barred from such direct investments in a solar project because they live in multi-tenant houses, and can’t just throw up a solar panel anywhere they want.

Using Arcadia, these environmentally minded consumers can invest in projects across the United States and reap the benefits of that energy generation as if it were coming from their own home.

“We built technology over the last few years that allows us to push bill credits onto their utility bills,” said Bhatraju. “We can remotely connect you to a distributed generation asset. As that solar produces electricity we take the billed credits locally and that’s distributed onto the bill.”

 

Arcadia’s current projects aren’t huge, but they do prove that commercial customers and governments are buying into their thesis — if you offer renewable energy generation to renters — they will come.

The company posits that while there’s a will for renewable generation, consumers still don’t have a way that’s convenient enough for them to make the switch to solar power. Arcadia’s offering changes that.

So far, the Arcadia Power has projects in Washington, DC, Massachusetts and California. “We source the project and we work with the customers to get the buy-in into the program.”

For Bhatraju, the new offering is just the next step along the path that the company charted back in May when it raised $3.5 million from BoxGroup and Wonder Ventures.

When the financing was announced in August, Arcadia had 10,000 customers on its premium offer, matching customer usage with renewable energy at 1.5 cents per kilowatt-hour. The company also launched a free 50 percent wind option to people who wanted to split their bill between traditional utility power generation (typically coal and natural gas) and wind power.

The next product in the company’s pipeline is on-bill financing for energy-efficient products like smart thermostats and LED lighting, which Arcadia says can save customers between 10 percent and 30 percent of their annual energy costs.

Today, the company is rolling out its service with about 250 kilowatts worth of projects (enough energy to power roughly 41 homes, according to estimates by the Solar Energy Industries Association). According to Bhatraju, there’s another 2.5 megawatts of power in the pipeline.

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Flashy Recyclable Photovoltaic System Breaks Record for Solar Energy

Posted on November 6th, 2016 in solar by Spencer R.

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(www.spectrum.ieee.org)

If you want your home to stand out, a flashy new photovoltaic module might be just what you’re looking for. The leaf-shaped prototype uses color and shape to redirect light to two silicon solar cells.

 

Researchers announced last month at the annual Photovoltaic Science and Engineering conference in Singapore that their 0.11-square-meter photovoltaic modules had achieved a record high for efficiency in converting the sun’s rays to electricity: 5.8 percent.

 

“[This technology could] become more attractive to architects and people involved in the building sector,” says Angèle Reinders, an industrial design engineer at University of Twente in the Netherlands.

 

With traditional silicon solar cells on roofs, costs can add up quickly. With that in mind, many researchers, with an eye toward commercial viability, have tried using materials that can concentrate light into one or two solar cells.

 

Typically, engineers place solar cells on the edges of panels and guide the light using novel materials such as quantum dots and organic dyes. For example, in research published in 2008, one group achieved 7.1 percent efficiency with four expensive gallium arsenide solar cells on the edges of a tiny luminescent solar concentrator with colored dyes. Earlier this year, a Journal of Renewable and Sustainable Energy article described research using silicon solar cells on the back of PMMA (acrylic glass) panels; those modules achieved only 3.8 percent efficiency.

 

Reinders favors the use of plastic because chemical processes exist to remove the PMMA and recover the electronics, so the photovoltaic modules are recyclable. In glass sheet photovoltaics, the solar cells and wires in between them end up as waste. But in order to improve the performance of medium-size solar concentrators using plastic, Reinders and her colleagues came up with new designs aided by computer simulations of different shape combinations, colors, numbers of silicon solar cells, and solar cell positioning.

 

Here’s how the designs work. When sunlight strikes a flat PMMA film mixed with a particular colored dye, the light reflects inside the film. Depending on the dye’s color, it adjusts the wavelength of the light so that it’s closer to the infrared range. This is advantageous because the two silicon solar cells at the bottom of the panel absorb more light in the infrared range. 

 

The researchers tried to strike a balance between the photovoltaic module’s size and accessibility of light.

 

The team built a prototype—which has continued to convert photons to electrons with 5.8 percent efficiency for the past 1.5 years—by cutting each of the two solar cells into three pieces and attaching them to the bottom of films featuring a red dye. In simulations, the geometry of a rhombic shape appeared to harvest more light rays than a rectangular shape.

 

Sue Carter, a physicist at the University of California Santa Cruz who was not involved in the study but has designed solar concentrators for greenhouses, points out several potential issues with the design.

 

First, she says the company she consults for, Soliculture, ships solar concentrator systems for greenhouses that can achieve up to 7 percent efficiency with reflective backgrounds. The work, says Carter, is unpublished because she is focusing on commercialization. Referring to the Dutch research, she said it’s misleading to list efficiency in the whole system, because efficiency can always be improved by adding additional silicon photovoltaic cells.

 

“People can make their own conclusions by going to the website,” Carter says.

 

She added that although photovoltaic cells function better on acrylic, it can become more expensive than glass and be more difficult to certify. Also, it is challenging to prove 20-plus-year lifetimes on the organic plastic luminescent materials; it took her team “a lot of work” to find a combination of techniques that made it possible, she writes in an email.

 

Carter says the size of a photovoltaic system wouldn’t have a noticeable effect on its overall efficiency, but Reinders says the main difference between her lab’s work and Carter’s work is that, because the new prototype uses smaller modules, it’s easier for photons to become concentrated because they aren’t as widely distributed across the surface. Also, there are differences in dye concentrations and in where the cells are positioned on the back of the PMMA film.

 

Reinders agrees that plastics are not as durable as glass—she says pieces of glass from Roman times are still found at archaeological sites—but she’s confident that they will stand the test of time. She says it’s not reasonable to expect that a plastic sheet would last 25 years. But it’s possible to make plastic headlights that can resist degradation for a period of 15 years, so a five to 10 year lifetime would certainly be reasonable as research progresses.

 

Reinders says she’s found that the plastics are about half the cost of glass—mainly because they are thinner. But the cost will ultimately depend on how the materials are processed, which requires further investigation. Usually plastics manufacturing is a lot faster than the glass production process.

 

As far as certification goes, Reinders points out that requirements in the United States could be different than those in the Netherlands. And as such, it might be difficult to meet all certification requirements with plastic. She doesn’t see any problems with electrical performance, but it is easier to scratch plastic than it is to scratch glass. This, however, could possibly be remedied by using some sort of coating.

 

Sayantani Ghosh, a physicist at the University of California, Merced, who was also not involved in the research, writes in an email that “once certain issues are addressed, this could potentially prove a novel way of capturing solar power in houses, with significantly lower costs” than covering a roof with silicon photovoltaic cells.

 

According to Ghosh, the questions that still have to be answered include whether the materials would be stable under weather conditions such as snow and rain, and how their thinness could affect their robustness. There’s also the issue of putting the cells underneath the solar concentrator tile instead of on its edge, which allows a “significant portion” of the reemitted light to escape because there isn’t a solar cell to capture it. Also at issue is whether other light harvesting materials could have a broader light absorption spectrum. Finally, she isn’t sure whether a proposed idea of mixing dyes would work in practice because the emission range of one would overlap with the absorption of another.

 

Reinders writes in an email that she has not tested the prototype in harsh weather conditions yet, but it “may be more suitable for climates with a diffuse irradiance than the glass sheet-based photovoltaic modules.” She writes that diffuse irradiance usually “goes hand in hand” with climates with lots of clouds and rain.

 

Reinders also admitted more work needs to be done on ensuring that it can handle the heat on rooftops. “We still can do a lot of research in this field,” she says. 

 

Read more...

Flexible solar panels recycle indoor light

Posted on November 6th, 2016 in solar by Spencer R.

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(www.treehugger.com)

Integrating solar panels into windows and walls seems to be the obvious next step for the technology, but what about all of the light indoors? What if there could be a way to harness, or recycle, that light energy along with the light from the sun?

Researchers at Virginia Tech have proven that it's possible. Mechanical engineer Shashank Priya along with a team of engineers and chemists have developed a new type of flexible solar panel that can absorb both the direct light of sunlight as well as the diffuse light of LED, fluorescent and incandescent lighting.

The super-thin solar module can be produced through a low-temperature, low-cost screen printing technique that churns out the panels in rolls.

The solar tiles, which resemble flexible versions of bathroom tiles, can be combined together to make window shades or wallpaper. Just a single tile, about the size of your hand, can produce 75 milliwatts of power. If you put a few together to equal the size of a sheet of paper, you have enough power to recharge a smartphone.

“There are several elements that make the technology very appealing,” said Priya. “First, it can be manufactured easily at low temperature, so the equipment to fabricate the panels is relatively inexpensive and easy to operate. Second, the scalability of being able to create the panels in sheet rolls means you could wallpaper your home in these panels to run everything from your alarm system, to recharging your devices, to powering your LED lights.”

The flexible panels at 10 percent efficiency are right behind conventional rigid silicon ones that usually come in around 15 percent efficiency and the researchers believe they'll not only catch up, but surpass their rigid counterparts soon. Of course, the list of potential applications already does.

The flexible panels can be made into any shape or design meaning that they could be used in a variety of ways both indoors and outdoors, like curtains, awnings, mobile charging stations, clothing and military gear. The flexible, lightweight design means that solar power doesn't have to be a fixed technology, but can be a fully mobile one, working outdoors and in.

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What's Next For Solar Energy? How About Space

Posted on November 5th, 2016 in solar by Spencer R.

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(www.smithsonianmag.com)

Think about what you know about clean sources of energy. What’s the greenest?

 

Hydroelectric, geothermal, wind and solar all probably spring to mind. Environmentally friendly though they may be, they all have significant limits on how much energy they can produce and where they can be used. To wit, despite some really cool advances in solar, solar panels still can only generate energy while the sun shines.

The solution, then, is obvious. Go where the sun never sets: in space.

That’s the vision of scientists, researchers and entrepreneurs both here in the United States as well as in Japan, China and Europe. Though the concept has been batted around at least since the 1970s, it’s been repeatedly revisited and abandoned because getting all the parts up there, and the people to put it all together, was impossibly expensive. Only with the advent of super small, mass-produced satellites and reusable booster rockets are some beginning to take a much harder look at making space solar a reality.

There are dozens upon dozens of ideas for how to build a space-based solar collection system, but the basic gist goes something like this: launch and robotically assemble several hundred or thousand identically sized modules in geosynchronous orbit. One part comprises mirrors to reflect and concentrate sunlight onto solar panels that convert the energy into electricity. Converters turn that electricity into low-intensity microwaves that are beamed to large, circular receivers on the ground. Those antennae re-convert the microwaves back into electricity, which can be fed into the existing grid.

John Mankins, who spent 25 years at NASA and Caltech’s Jet Propulsion Laboratory, received funding from NASA’s Institute of Advanced Concepts in 2011 to refine his space solar power plant concept in greater detail. The technology and engineering required to make space solar a reality already exists, he insists, but as with any expensive new idea, it comes down to greenbacks and gumption.

“It’s not like fusion—there’s no new physics involved,” Mankins says, referencing ITER, the 35-nation collaboration to build a fusion reactor in France. “There’s no secret sauce. It’s a financial hurdle to get funding to develop the elements and demonstrate the new architecture required to do this.”

Mankins and others estimate the total cost for developing, building, launching and assembling all the components of a space-based solar power plant is on the order of $4 to $5 billion—a fraction of the $28 billion price tag on China’s Three Gorges Dam. Mankins estimates a working scale model with full-sized components could be had for $100 million. By comparison, the Tennessee Valley Authority’s recently completed Watts Bar nuclear plant took 43 years to build, from start to stuttering finish, and cost $4.7 billion all told.

Critically, what consumers would pay—the price per kilowatt-hour—needs to be in the same ballpark as conventional sources of energy produced with coal, natural gas and nuclear, which range in price from 3 to 12 cents per kilowatt-hour. Hydroelectric can be staggeringly cheap, at less than one cent per kilowatt-hour—but only if you’re lucky enough to live in a region with abundant high-flow rivers, like in parts of Canada and Wisconsin. Geothermal is very economical too, checking in at 3 cents per kilowatt-hour, but you’ll need to ask the Icelanders how they like their power bills. And wind advocates trumpeted the news last year that costs for that renewable resource had plummeted to 2.5 cents per kilowatt-hour.

Getting the cost into the low double digits or even single digits of cents per kilowatt-hour is absolutely essential to make space solar a competitive utility, says Gary Spirnak, CEO of the California-based energy company Solaren.

Spirnak’s company is approved as a solar energy provider in California, and has had past supply arrangements with Pacific Gas and Electric, but its business model is completely based on generating their power from space-harvested solar. Solaren is in the process of negotiating new agreements with one or more utilities. The company has patents here in the U.S. for its design as well as in Europe, Russia, China, Japan and Canada, and has secured a first round of financing for a lab-based demonstration of its component technologies sometime in the next year. Spirnak hopes to convince investors to support a 250-megawatt pilot plant by the end of the development and testing phase, perhaps within five years.

Two keystone structures are required for space solar to work. First, solid-state power amplifiers that efficiently convert electricity from collected sunlight into radio-frequency waves, and receivers on the ground that re-convert the RF waves back into electricity.

Paul Jaffe, an engineer at the Naval Research Laboratory in Washington, D.C., worked on two prototypes of the collection module, which he refers to as a “sandwich” since the solar collector, power converter and RF emitter are all smashed together into a foot-square tile two inches thick. The weight of each individual module ultimately determines the pricing of the distributed electricity on the ground; in terms of watts per launched kilogram, Jaffe says the basic tile design came in at around 6 watts per kilogram.

Taking into account that power output, a 20-year solar power plant lifetime, a launch cost of $2,500 per kilo, and different cost levels of the components themselves, Jaffe calculates that if the mass decreased and wattage increased to 500 watts per kilo, that equates to a cost of 3 cents per kilowatt-hour.

“Doing even really simple things to reduce the mass gets us into the 100 watts per kilogram range, and 1,000 watts per kilogram isn’t crazy,” he says. “You get very good efficiencies with current solar technology that’s already commercially available, and we carry around these very efficient, lightweight RF converters in our pockets every day.”

RF converters are the very reason cell phones work—phones are basically glorified walkie-talkies whose signals are helped along by a network of signal relay stations. The converters in the phone translate radio waves into data that we understand—audio—and vice versa. This technology is central to research into space solar at Caltech, in a collaboration between scientists and engineers there and Northrop Grumman.  

Spirnak says the main thrust of Solaren’s work in recent months has been just that—reducing the weight of their modules. Though reusable rockets would knock the overall production cost down even further, Spirnak isn’t holding his breath in the near term; he’s figuring on using conventional heavy lift vehicles to get Solaren’s components into space.

“We spent a lot of time ruthlessly taking weight out of the system,” Spirnak says. “We can package individual large elements into single launchers, with some interesting feats of origami," though delivering the entire system into space will still require multiple super-heavy launchers.

Jaffe says the single most common question he gets when talking about space solar isn’t whether it can or should be done, but how dangerous that energy beam from space is. Won’t it flash-fry birds and planes in the sky when they pass through the beam?

“If you sit outside on a sunny afternoon for 15 minutes, you don’t get burned,” he explains. “Our radios, TVs and cell phones aren’t cooking us, and those are all at the same frequencies as what’s being proposed. There are already safety limits [on microwave transmissions] set by IEEE [Institute of Electrical and Electronics Engineers], so you design a system to make sure the power is spread over a large area. It won’t accidentally turn into a death ray.”

To get the best cost-to-weight ratios, efficiencies of scale, and have comparable electrical generation capacity of an average nuclear power plant (1 to 2 gigawatts), any solar collection array in space would need to be roughly a kilometer in diameter.

Collection receivers on the ground would need to be accordingly large—for a space-based solar plant to generate around one gigawatt of energy, a one-kilometer (.62 mile) solar collector would beam energy to a 3.5-wide kilometer (2 mile) receiver on the ground. That would require an area of around 900 acres. Compare that with the Solar Star solar panel plant in California, currently the United States’ largest solar utility, which occupies 3,200 acres.

Radio-frequency power transmission does have one significant drawback: the “safe” wavelengths that also won’t get refracted by something as simple as rain are already overcrowded, clogged up through regular radio transmissions, as well as military, industrial and satellite use.

Critics of space solar, prominent among them Tesla’s Elon Musk, say economy-scale efficiencies just can’t be achieved because of all the converting and reconverting of the power that is required.

But Jaffe is hopeful that the old crack on fusion won’t also become true of space solar: “It’s been 10 years away for the last 60 years,” he laughs.

Mankins stresses that with the global population forecast to explode to 11.3 billion by the end of the century, with almost all of that represented in the developing world, space solar deserves serious investment by public entities as well as private partners. He says abundant clean energy is necessary to fulfill basic human needs, as well as address the assured environmental destruction if all of that energy comes from conventional sources.

“If the mix of energy sources does not change radically, there is no way we’ll get to carbon neutral,” Mankins says. “You also can’t tell 800 million people in China that they must stay in abject poverty. There’s a need not just to offset today’s carbon use, but to look forward 70 years and to how we’ll offset three times today’s use. We really need big solutions.”

 

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Molten Silicon Offers Unprecedented Solar Energy Storage

Posted on October 11th, 2016 in solar by Spencer R.

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(designnews.com)

Researchers continue to make progress in large-scale storage of solar energy for use when the sun’s not shining. The latest comes out of the Universidad Politecnica de Madrid (UPM), where scientists have developed a thermal-based system that uses an abundant natural material, molten silicon, to store energy generated by the sun.

The system developed by researchers from the university’s Solar Energy Institute can store up to 10 times more than existing similar solutions, according to researchers, and it could one day be coming to a city near you. That’s because the team aims to develop a series of next-generation, low-cost solar thermal stations based on the system—which currently has patent-pending status in the United States—to store electricity in urban areas.

Solar thermal energy storage solutions store sunlight as heat molten salt, then convert the energy into electricity on demand using a thermal generator. The key difference in the solution developed by the UPM team from others is its use of molten silicon, the most abundant element in the Earth’s crust, researchers said. This makes it a plentiful, natural, low-cost, and safe resource for use in storing solar energy, they said.

The solution developed by the team takes solar energy and stores it in the form of heat in molten silicon at a very high temperature, around 1400°C (2552°F), said Alejandro Datas, the research promoter of the project.

“At such high temperatures, silicon intensely shines in the same way that the sun does, thus photovoltaic cells—thermophotovoltaic cells in this case—can be used to convert this incandescent radiation into electricity,” he explained. “The use of thermophotovoltaic cells is key in this system, since any other type of generator would hardly work at extreme temperatures.”

Indeed, silicon has properties that allow for storage of more than 1 mW per hour of energy in a cubic meter—10 times more than storage systems that uses salt, Datas said. The UPM system thermally isolates molten silicon from its environment until the energy is demanded and, when this occurs, the stored heat is converted into electricity.

The UPM team is manufacturing the first lab-scale prototype of the system and expect that the first application will be in the solar thermal energy sector. For future applications the system also is well suited to storing electricity in the housing sector and to provide and manage electricity and heating in urban areas.

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