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.

How 3M Ultra Barrier Solar Film Works

You probably know 3M for its Post-Its or tape products, but now the company is working to change the solar landscape with the help of a $4.4 million grant for development of its lightweight Ultra Barrier Solar Film.  The grant, awarded through the Department of Energy’s SunShot Initiative, will allow 3M to expand production of Ultra Barrier Solar Film at its Columbia, MO plant.  The Ultra Barrier laminate is produced with the company’s flexible copper indium gallium selenide (CIGS) and other solar energy surfacing.  It shields photovoltaic (PV) cells, offering protection in place of glass.

The lightweight material reduces the overall weight of solar panels, making them both lighter and more affordable.  By using Ultra Barrier on a conventionally-sized PV panel (4 x 6 feet), the panel’s weight would be only 1/8th of a typical 30-pound glass-covered solar panel.  This is important for rooftop solar installations on residences and commercial buildings where weight is a factor.

Through SunShot, solar energy development will be accelerated, while solar panel installation costs can be dramatically reduced from $7 to $1 per watt of solar capacity.

Beyond solar panels: can solar technology change the world?

If you didn’t already know, then let me be the first to tell you when and how solar technology will change the world.

OK, well maybe I won’t be the first to make the claim, but I can at least tell you that the Massachusetts Institute of Technology (MIT) has included solar tech in its annual list of 10 technologies that will save the world.

Technology Review is an MIT publication which publishes an annual list of 10 new technologies that are anticipated to change the world.  While solar power is certainly not “new,” in the sense that people have been using energy from the sun to cook food and dry clothes for hundreds of years, MIT has put stock in two solar power applications it believes will positively impact the future.

1.  Solar Fuels

There was some buzz about solar fuels last year.  We even blogged about it here, noting that:

Researchers are looking into the potential of reversing fossil fuel combustion with the use of sunlight to re-energize molecules from air.  Using solar chemical reactors “solar fuels” could one day be created from a variety of materials.  Already, the technology has been able to produce hundreds of gallons of clean, energy fuel per hour.

Technology Review reports that Noubar Afeyan of Joule Biotechnologies has genetically engineered microorganisms that can convert sunlight into ethanol or diesel.  This green innovation could help make biofuels competitive with conventional diesel, gasoline or natural gas.

New discoveries and developments are underway in solar technology

2.  Light Trapping Photovoltaics

Thin-film solar cells have been newsworthy of late, as well.  Their flexibility and slim profile allows for a multitude of applications.  With light-trapping photovoltaics, Kylie Catchpole of the Australian National University has discovered how to increase solar efficiency of thin film cells by depositing nanoparticles of silver onto the cell’s surface.  The nanoparticles trap the photons allowing for increased solar cell efficiency.  Of course, with solar panels gaining in efficiency, solar power rises in status as a desired alternative to coal or gas-based electricity.

So there you have it – two of 10 technologies that the wise people at MIT believe will change the world!  What do you think of these solar technologies?  Do you agree they have the potential to make a positive impact?

Check out the complete list of technologies to change the world at Earth Times.

How far can we push the solar efficiency envelope? (image from jhritz on Flickr)

There are two factors that every solar cell manufacturer considers: cost and efficiency.  Of course, we want the first factor to go down, and the other one to increase.

When companies improve the efficiency of solar panels, they can promise more bang for the buck.  Instead of 10 solar panels on your roof, perhaps 8 panels could generate the equivalent solar electricity!  In other words, when more efficient solar cells produce more power, you save money and get a quicker return on your solar investment.

One question that lingers, however, is how far can we push the solar efficiency envelope?

Is there a ceiling of maximum efficiency?

When weighing the two factors mentioned above – cost and efficiency – some companies are willing to sacrifice a bit of efficiency to keep prices down.  In order to maximize conversion rates of solar cells, expensive materials and/or technology is often required.

Suntech Power Holdings ran into issues last year with its highly efficient solar cell, dubbed “Pluto.”  Although it broke efficiency records, the company lowered production forecasts in part due to factory-based automation issues.

Solar efficiency hangs in the balance

Experts in the field believe that, no matter how much we push solar efficiency, current technology can only improve the existing watts/dollar ratio by a few percentage points.

With silicon-based solar panels, the upper limit is approximately 33%, and more realistically 28-30% efficiency.  Cadmium-telluride and CIGS cells also have a predicted limit of 28-30%.  Calculations are made using each semiconductor’s band gap, which refers to the amount of energy (photon) required to push electrons around, which determines a material’s ability to absorb and convert light to electricity.

Even with current limitations, researchers will continue trying to improve the efficiency of solar panels.  Consider the following record holders:

• USNW produced a multi-material solar cell with 43% efficiency
• USNW also produced a monocrystalline silicon cell with 25% efficiency
• The Fraunhofer Institute in Germany created a multicrystalline silicon cell with 20.4% efficiency
• The National Renewable Energy Laboratory (NREL) came up with a Cadmium-telluride cell, converting at 16.7% efficiency
• NREL also created a copper, indium, gallium and selenium (CIGS) cell with 19.4% efficiency

What new records will be shattered in 2010?  Stay tuned for more solar panel manufacturing news in the weeks and months ahead…

How to Calculate Solar Energy Production

Before you consider installing solar panels, you may want to calculate the solar energy production in your region.  That will help you determine the efficiency of solar panels in generating electricity for your home or business.  You’ll also be able to determine how many solar panels you’ll need for your energy demands.

Efficiency of solar panels depends in part on the angle of their positioning, but perhaps more importantly, the amount of solar irradiation in your area.  Overall solar energy production is influenced by the number of clear, sunny days, but also latitude and longitude.

If you want to learn how to calculate solar energy production where you live or work, there are several methods of doing so.

Perhaps the easiest approach is to use the tools from the National Renewable Energy Laboratory.  As stated on NREL’s PV Watts page:

The PVWatts calculator works by creating hour-by-hour performance simulations that provide estimated monthly and annual energy production in kilowatts and energy value. Users can select a location and choose to use default values or their own system parameters for size, electric cost, array type, tilt angle, and azimuth angle. In addition, the PVWatts calculator can provide hourly performance data for the selected location.

There are two versions of the NREL PVWatts calculator:

Version 1 allows users to select a location from a map or text list of pre-determined locations throughout the world. Version 2 allows users to select any location in the United States.

The calculations take into consideration several decades of recorded irradiance values.  You can pinpoint your area pretty well using its maps, which are developed based on local weather, sun angles and local microclimate cells.

There are some formulas to help you calculate solar radiation

Some believe that you can get a more accurate total energy production by using your own formula.  Engineers and scientists will enjoy putting pen to paper and crunching the numbers to calculate solar energy production.

Now, I’m not a scientist, but I did find this formula at SolarPanelTalk:

PV STC value *.8 (80% of STC) times hours of usable light (5 is a normal number) The sun may be up 12 hours a day in the summer, but the 3 morning and 3 evening hours, carry little power, so you can’t count them.
Figure in a number for clouds.

2KW array =(1600 *5) = 8000w day x 365 = 2,920,000 watts year, of sunny days, no clouds, no rain, perfect sun angle. You will NEVER exceed this #, and almost always fall short of it because of bad weather.

No matter how you do it – using the NREL links, or crunching your own numbers – calculation of solar energy production is an important step before you install solar panels.