Category Archives: Solar Energy

Beaming Solar Power from Space? Not so outrageous!

At first the idea seems far fetched – beaming solar power from space to help solve our renewable energy issues. However, intrepid  engineers at Strathclyde University in Glasgow are envisioning just that, and have put the first technical steps together for their project to build space-based solar energy systems that can send power back to the earth.

They are designing  a space-based power station that collects and concentrates the sun’s energy and beams the energy back using lasers and microwaves. The system will be able to beam the energy exactly where it is needed. Massimiliano Vasile, who is leading the project, says initially smaller satellites would be used to generate enough energy for a small village. This application would have special value in remote regions or to disaster areas where other power suppliers are cut off or non-existent.

The project makes extensive use of nano technology to make it possible to launch and assemble the station in space – they essentially launch a collapsed version of the station and blow it up in space using nano pumps.  While this sounds far fetched, it’s based on how plants build themselves – nature figured it out millions of years ago.

The aim is to eventually put a large enough structure in space that could gather energy that would be capable of powering a large city.  More from the University’s press release.

Creating low cost solar cells by using Titanium Dioxide

Nearly all solar cells today are  made of silicon, which is costly and difficult to produce. Now, however, a scientist in Switzerland has created solar cells from titanium dioxide molecules that react to photons to create electricity.  Titanium dioxide, while not as efficient as silicon, is inexpensive and is a common manufacturing chemical.

Professor Grätzel, of the Swiss Federal Institute of Technology of Lausanne, had used nano technology to create the cells and then sensitize them with a dye that captures the photons that land on the solar cell.  These cells are now called Grätzel cells, and we expect to be hearing a lot about them in the future.

 

Increasing Solar Panel efficiency by emiting light

This doesn’t sound logical, but it has been scientifically demonstrated that the efficiency of solar panels can be increased if the panels reflect back much of the light.  A team from the University of California, Berkeley, have shown that solar panels should be designed to be more like LEDs, able to emit light as well as absorb it.

Alta Devices high efficiency solar panels“What we demonstrated is that the better a solar cell is at emitting photons, the higher its voltage and the greater the efficiency it can produce,” says Eli Yablonovitch, team leader and UC Berkeley professor of electrical engineering.

In theory, the maximum efficiency of a solar panel is  33.5 percent conversion of incoming photons into electrical energy. Most panels today are around 26%.  Even a small improvement would significantly improve the ROI from installing solar panels, and bring the cost of solar closer to grid parity.  The Berkeley team has demonstrated an improvement to over 28% in their labs.

Yablonovitch, has founded Alta Devices in the San Francisco Bay Area to commercialize this concept.  They have created a prototype solar cell made of gallium arsenide (GaAs),that allows  light to escape from the cell by increasing the reflectivity of the rear mirror amongst other things.

More about this promising technology on the Alta Devices website, although they are still quite secretive.

Solar towers provide up to 20 times the electricity as standard panels

Live Science reports that a group at MIT have constructed solar panel towers that generate up to 20 times the power as regular installations, and have a much smaller footprint. The solar towers also collect much more sunlight during the mornings and evenings than standard panel installation.

“I think this concept could become an important part of the future of photovoltaics,” said Jeffrey Grossman, a professor of power engineering at MIT.

Liquid Metal Batteries – the missing renewable link?

Donald R. Sadoway, an MIT Professor, spent 6 years looking into how to radically change the cost equation for batteries, knowing that without wide-scale battery deployment sustainable power sources such as solar and wind will not reach their potential. Instead of trying to improve current battery technology, he changed the equation by looking for batteries that can literally be made from dirt.

He and a small team at MIT created a “liquid metal” battery, made from Magnesium and Antimony, that can be deployed at scale and is cost competitive with carbon fuels. They have since formed a company Liquid Metal Battery Corporation.

For more, see the LMBC website. Or listen to Dr Sadoway’s talk at the TED conference. It’s quite impressive

[ted id=1401]

Pythagoras Solar turns windows into solar electricty generators

It seems so logical – install photo voltaic cells in windows that are bombarded by light in order to both reduce the amount of heat that passes through and generate solar energy. Pythagoras Solar has done just this with their new Photovolatic Glass Unit (PVGU).  The double pane glass incorporate optical units, PV collectors and proprietary software to make insulated windows into power generators.  Per the company’s data sheet:

Structured as a standard insulated glass unit (IGU) Pythagoras Solar’s photovoltaic glass unit (PVGU) is the only glazing product that combines high density solar power generation with the energy efficiency benefits of an IGU, while providing quality daylighting and preventing direct solar radiation from entering the building. This delivers a new level of design flexibility to the architecture, construction and engineering industries, enabling the creation
of cost-efficient, aesthetically pleasing, self-powered buildings. Pythagoras Solar’s customers are able to realize the benefits of energy efficiency, generation and daylighting in a single, innovative product that meets today’s energy demands.

For the techies among you, here’s how it works (taken from their data sheet):

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The windows can generate 120 Wp/m2, per their data sheet.

The one thing you do lose is a clear view out the window. which is why we believe that these are ideally designed for skylights.

See the Pythagoras Website for more information.

Advance in Nanocrystalline-silicon “nanoshells” promises to increase efficiency of solar films

A report out of Stanford University gives hope for significant improvement in efficiency of solar collectors.   Co-team leader Shanhui Fan, a professor of electrical engineering, said of the research “Nanocrystalline-silicon is a great photovoltaic material. It has a high electrical efficiency and is durable in the harsh sun. Both have been challenges for other types of thin solar films.”
Nanocrystalline-silicon’s major drawback, however, has been its relative poor absorption of light, making them inefficient.

The Stanford team developed what they call nanoshells from tiny balls of silica coated with silicon.  They then remove thee glass center with acid that does not affect the silicon, leaving behind the light-sensitive shell. These shells form optical “whispering galleries” (similar to those that trap sound in buildings such as the US capitol) that capture and recirculate the light.

“The light gets trapped inside the nanoshells,” said Yi Cui, associate professor of materials science engineering at Stanford. “It circulates round and round rather than passing through and this is very desirable for solar applications.”

This is purely research at this time, and will take years to make commercially viable product, but a promising advance in solar technology.

This online store has every solar gadget you can imagine

We came across a site that has literally hundreds of fun gadgets that are solar powered. From solar spotlights to battery chargers to toy cars to desk lights to lanterns, this site seems to have dug up literally every gadget powered by the sun. The most practical products we saw were solar phone chargers and outdoor lights.Check out EarthProducts.com (http://www.earthtechproducts.com/) and we’re pretty sure you’ll find something you take a shine to (sorry, we couldn’t avoid the obvious pun).(Full disclosure note – we haven’t purchased anythng from the site so can’t attest to their reliability, but they have been approved by the BBB and use McAffee Secure Processing, so they certainly are serious about their business)

Next time you paint your house, maybe it will make solar energy too!

Sounds like science fiction, but so did talking to a device and getting an intelligent answer a few years ago. Imagine if the paint on everyone’s house, and the roofing materials, all incorporated photovoltaic materials so that exposure to sunlight would create electricity. Yes, you would essentially be able to use your entire house to generate electricity, instead of just a few square feet on your roof.Scientists at several research instituations, including Swansea University and the University of Texas, are working on different versions of this idea, and are at the stage where the basic concept can be made to work, although they are quite far from making it cost effective or manufacturable. But they certainly are on an amazing path, which we will watch closely on this blog. Thanks to eco20-20.comfor their interesting article.

Smart Windows that block heat when needed, reducing air conditioning costs

We’re strong believers that Small Businesses with big ideas will lead many of the technological innovations that will move us to a more intelligent use of energy and resources in the future.  There are millions of great ideas out there percolating in the minds of entrepreneurs who combine their vision with a profit motive.

One such company we came across is RavenBrick. This Denver-based company specialises in thromochromic technology that blocks or stores heat, depending on the situation. They will be launching the RavenBrick Smart Window technology. In their words:

This adaptive smart-window for use in commercial, residential and industrial buildings uses RavenBrick’s thermochromic technology. It reflects the sun’s heat outside when it’s hot, and lets the sunshine in when it’s cool.  It saves up to 30% on heating and cooling year round, without using electricity or hard-wired control systems.  Besides reducing energy consumption and costs, RavenWindow is easy-to-install, can be retrofitted to fit existing frames and improves the temperate and light-glare comfort for people inside the building.

The product will be available in 2012.

They also have announced additional products that help to make homes more eco-friendly One that caught our eye is RavenSkin, which will absorb, store and release heat during th winter, and keep buildings cooler in the summer – reducing the need for heat and air conditioning. This will be available in 2013.

More about these products on the RavenBrick web site.