See through solar cells to be applied to windows

Solar technology advancements are leading to thinner, more efficient and cheaper solar panels.  One of the most exciting developments may be invisible solar cells.  Applied to windows, the building integrated photovoltaic technology allows for see through solar power.

Just think – no bulky solar panels installed on the rooftop!  Solar windows may have a clear advantage over less aesthetically pleasing alternatives.

Invisible solar cells are still in development stages, but are showing great promise for the future.  Along with flexible solar cells that can be applied to a wide variety of surfaces, scientists at the National Renewable Energy Laboratory have been working on transparent solar cells.  These modules can be fixed to window panes, blending seamlessly into building facades.

While the efficiency of invisible solar cells is not yet to the level of traditional PV panels, the technology is so much less expensive than the alternative (as well as less visually intrusive) that these benefits outweigh the drawbacks of the developing solar technology.

Spray on solar cells

Spray on solar cells are one of the more exciting solar technologies that can be employed as building integrated photovoltaics.

Thin film solar is incorporated into solar inks that can literally be painted onto walls and windows of structures allowing the sides of buildings to function as solar collectors to generate enough electricity to power interior uses.

Unlike bulky photovoltaic (PV) solar panels, spray on solar cells use thin film nano particles instead of silicon as solar conductors.

Applied to the sides of structures that face the sun, the thin solar cells invisibly generate clean, green power.

Spray on solar is not limited to buildings, either.  Thin film solar technology is also used in clothing, and may one day be incorporated into automobile paint.

Advantages of Spray on Solar Cells

• More efficient than conventional solar panels
• Capable of generating ample electricity
• Hassle-free installation of solar technology
• Able to harness even infrared rays from the sun, allowing generation of solar power even on cloudy days

Parabolic mirrors used for concentrating solar power technology

The United States Department of Energy (USDOE) announced this week a commitment to invest $60 million in concentrating solar power (CSP) technology.  Used for utility scale solar power plants, CSP consists of large, parabolic reflective mirrors, which concentrate sunlight to superheat water, creating steam and turning turbines for electricity. CSP is also referred to as solar thermal energy.

Large scale solar power plants require a lot of land and are often quite expensive.  Concentrating solar power technology – for now – is more costly than photovoltaic (PV) solar panel plants, which create energy directly from sunlight absorbed by the solar panels.

The government investment in concentrating solar power technology is aimed at finding a way to reduce costs associated with CSP plants.  Sixty million dollars will be invested over the next three years in companies that are developing new solar technologies for CSP.  Funds will be distributed through the SunShot Initiative, DOE’s competitive program with the goal of reducing solar costs by 75%.  Among the various advancements the Department of Energy hopes to encourage are: new solar collectors, heat transfer technologies, power plant engineering approaches, and improvements in steam temperature ranges.

Solar energy grid integration

In 2007, the U.S. Department of Energy created the Solar Energy Grid Integration System, a competitive program that encouraged solar research that can better integrate solar energy generated by panels installed on rooftops or ground-mounted into the electrical grid.

Among several goals of the program were: (1) help encourage utilities to accept solar power; and (2) development of new solar commercial products.

The competitive solar program resulted in a number of solar technology submissions to the USDOE.  Out of more than 25 companies/organizations that applied, the Department of Energy selected 12 to advance to “Stage 1.”  These were then narrowed down to 5 finalist companies.

Among those included in the finalists was PV Powered, a local, Bend Oregon-based solar inverter company, now known as Advanced Energy Industries Renewables.  Its research was aimed at determining how to effectively transfer solar power, which can be intermittent – depending on cloud cover – to an electrical grid that is consistently loaded by constant energy from burning natural gas or coal at power plants.

The Solar Energy Grid Integration System finalists also included Portland General Electric, Northern Plains Power Technologies of South Dakota and Schweitzer Engineering Laboratories.

The results of the solar research for the Solar Energy Grid Integration System, published this week, should take some of the heat off the Obama Administration regarding the failure of Solyandra – a solar panel manufacturer that filed for bankruptcy recently, after receiving a $535 million government-backed loan from the government two years ago.

REC New Solar Technology

Renewable Energy Co. (REC) has recently developed new solar technology that allows its solar PV panels to achieve energy payback time in one year.

So-called energy payback time is the amount of time it takes for a photovoltaic (PV) solar module to produce as much energy as was used to manufacture it.  Efficient solar cells are just part of the equation.  REC’s solar technology uses a new method of producing silicon that requires much less energy and reduces the energy payback time to just one year.

What does this mean for solar PV panels?  Well, to start with, other solar manufacturers have only been able to produce cells with energy payback times of five years, or more.  REC, on the other hand, uses the Fluidized Bed Reactor (FBR) process that it developed to create granular silicon – a substance that uses much less energy to produce crystalline silicon.  The energy-saving manufacturing process requires only 10% of the energy required for traditional silicon processing.  This is because the FBR process does not use heating and cooling processes.

The FBR process was awarded the 2011 Solar Industry Award by Solar Industry Magazine on September 6, 2011.

Spray on solar power

Spray on solar power technology from Mitsubishi could transform everything from buildings, cars and clothing into energy-generating surfaces.  Thin solar cells – less than 1 millimeter thick, and which weigh 1/10th of similarly sized crystalline solar panels – are the latest in building integrated photovoltaics.

The Japanese-based company has been part of a clean tech revolution starting in March 2011 after the devastating tsunami and resulting nuclear power plant meltdowns.  Government has backed research and development of solar power and other green energy sources.

Mitsubishi Chemical Corp has developed spray-on solar power technology with solar cells that use carbon compounds that operate semiconductors when dried and solidified, which means they can generating electricity when exposed to UV light.  Thin film solar, like this spray on solar technology can save space and cut down on weight normally associated with conventional solar panels.

Mitsubishi Chemical’s spray-on power technology promise a potential light-to-electricity conversion rate of over 10%. Traditional crystalline silicon solar panels provide an efficiency of as much as 20%, but – as noted above – less space and less weight of the spray on solar cells gives the technology an advantage.  Moreover,  Mitsubishi hopes to improve efficiency to 15%  by 2015.

Solar Parking Lot using Photovoltaics

Using solar technology that is being researched with solar roadways, incorporating PV cells and other electronic devices into pavement is no longer a far-fetched idea.  Along these lines, Solar Roadways received generous grant money in 2009 to develop a 12′ x 12′ solar pavement prototype.

The solar pavement prototype was so impressive that additional grant money has been awarded to Solar Roadways to develop a solar parking lot using photovoltaics.  Not only can this technology generate clean, free solar electricity, but solar pavement will also be able to melt snow and ice from its own energy to keep parking lots clear and safe.  Solar power generated by a layer of embedded LEDs can illuminate traffic signals, and excess energy generated can even be used for charging electric vehicles parked at the lot.

All surface areas covered by asphalt or pavement could eventually be “solarized.”  Beyond roadways and parking lots, why not bike paths, recreational blacktop surfaces, and even driveways?

The potential is exciting, but likely years away.  A single 12′ x 12′ solar pavement square costs about $100,000.  Yet, covering these surfaces with solar cells could generate three times more than the amount of electricity we currently consume as a nation.  With continued solar technology advancements, increased efficiencies and decreased materials costs, it might not be too long before we’re driving, parking and playing on sunshine!

Solar power growth is sweeping across the nation

Just a decade ago, solar panels on rooftops of homes were a rare sight.  These days, you can probably see solar power growth throughout your town, if not in your very own neighborhood.  You might even be considering installing solar panels yourself.  And why not?  With generous governmental rebates and incentives, you can save up to 80% on the upfront cost of solar panels and then immediately slash monthly power bills.  Your home value will increase, as well, by $20 for every $1 saved in electricity bills annually.

One of the biggest factors fueling solar power growth is the increase in fossil fuel prices for gasoline and oil.  Many experts agree that we are approaching grid parity, at which it is not any more expensive to go solar than to use traditional electricity power sources.

With solar technology improving each and every day, some experts say that getting on board with solar power is critical now, or you will risk being left behind.  Today’s solar panels will still generate ample solar electricity, even if efficiency improves in the near future.  Even better, the power is cleaner and cheaper than the alternative!

Paper solar cells from MIT (photo credit: MIT)

Currently, the paper solar cells can generate enough power to run an LCD clock and are flexible enough to be folded and stuck in a pocket!  Solar paper cells will best be used to power electronic devices like cell phones, iPads and cameras.  But some expect paper solar to be incorporated into clothing and outdoor products like tents, boating equipment and sun shields.

Unlike crystalline PV panels, the paper solar cells do not require silicon or heavy glass as a substrate.  Manufacturing solar paper will be more environmentally friendly too, as it will not need damaging high temperatures and corrosive liquids.  Impressively, paper substrate is 1000 times cheaper than glass (accounting for 40% of the cost of traditional solar panels).

Don’t look for paper solar cells on the market just yet.  Researchers are working to improve their efficiency from 2-8%.  When that happens – most likely within the next 2 years – solar technology will include another flexible thin solar cell option.

Solar energy is all around us - can we capture it without solar cells?

What if it was possible to generate solar energy without solar cells?  In other words, could we harness the power of the sun for our use without having to pay for bulky PV solar panels?  According to a recent Forbes Blog post by Alex Knapp, solar technology could take a big step forward relying on breakthrough research at the University of Michigan.  Using magnetic properties of light at just the right intensity, Professor Stephen Rand and his associate, William Fisher, have discovered electrical voltage can be generated without needing solar cells.

Light has electric and magnetic components. Until now, scientists thought the effects of the magnetic field were so weak that they could be ignored. What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not conduct electricity, the light field can generate magnetic effects that are 100 million times stronger than previously expected. Under these circumstances, the magnetic effects develop strength equivalent to a strong electric effect.

“This could lead to a new kind of solar cell without semiconductors and without absorption to produce charge separation,” Rand said. “In solar cells, the light goes into a material, gets absorbed and creates heat. Here, we expect to have a very low heat load. Instead of the light being absorbed, energy is stored in the magnetic moment. Intense magnetization can be induced by intense light and then it is ultimately capable of providing a capacitive power source.”

What makes this possible is a previously undetected brand of “optical rectification,” says William Fisher, a doctoral student in applied physics. In traditional optical rectification, light’s electric field causes a charge separation, or a pulling apart of the positive and negative charges in a material. This sets up a voltage, similar to that in a battery. This electric effect had previously been detected only in crystalline materials that possessed a certain symmetry.

What this all means is that one day we may not need expensive semiconductors to capture solar energy.  Instead, solar manufacturers could simply use ubiquitous, cheap materials like glass or transparent ceramics.

This solar technology is still in the conceptual stage, and may take years before it can be reliably used for everyday applications.  But perhaps the promise of cheaper solar power is worth the wait.