Monthly Archives: May 2012

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.

 

Generating electricity from water flowing through pipes

Think how much electricity could be generated if all of the kinetic energy of water running through pipes could be converted to electricity.  It boggles the mind – and someone is doing something about it.  Lucid Energy has developed an “in pipe” hydropower system designed to generate millions of megawatt hours of renewable electricity from the water already flowing through pipelines without interrupting flow.

According to their data sheet – “LucidPipe can operate across a wide range of flow conditions, volumes and velocities. The unique lift-based vertical axis spherical turbine design of LucidPipe generates electricity by extracting excess head pressure from large diameter (24”-96”), gravity-fed water pipelines and effluent streams. To maximize electricity generation, several LucidPipe systems can be rapidly and easily installed into a single pipeline, enabling operations to continue normally.

“The amount of electricity generated is a function of the rate of flow and the pressure inside the transmission pipe. For example, in a standard 60-inch-diameter pipeline, with flow velocity of seven feet per second and 12 feet of excess head pressure, a single LucidPipe unit can produce up to 100kW of power while extracting less than 1 PSI from the system. Adding multiple turbines in a pipeline with these characteristics has the potential to generate billions of megawatts of renewable energy without environmental impact.”

Because this system doesn’t disrupt the flow of water or require a dam, multiple units can be installed, one after another, along the entire pipeline.  So the amount of electricity generated from a flow of water is dependent upon how many LucidPipe systems are installed.

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.