Company Poised to Blanket Former Sears Tower With 2 MW of Solar Panels

One argument (or excuse) against implementing solar power is that there isn't enough area - open space or rooftops - to make a difference.  This innovative company is proposing using semi-transparent panels to cover the south-facing windows of the former Sears Tower - of which there is plenty of area.  Not only will they generate power, but by reducing the amount of sunlight entering the building, lower the cooling costs too.

From Daily Tech:

Alternative energy startup Pythagoras Solar is dreaming big and it has sold the owners of one of America's most iconic skyscrapers on its vision.

Chicago's Willis Tower (formerly known as the Sears Tower) is among the most recognizable man-made landmarks in the country.  Towering over local high-rises, its 108 stories make it the tallest building in the U.S. and the fifth-tallest freestanding structure in the world.

During summer months solar heating contributes to energy costs and sun glare can be an issue at times.

Pythagoras Solar power has cooked up a novel solution -- transforming the building into the nation's largest vertical solar farm.  The farm will produce up to 2 MW of solar energy, reducing the building's reliance on the power grid.

Its panels -- to be installed on the building's southern-facing windows that get the highest sun exposure -- will help remedy both issues, while preserving the view and producing electricity.

The company's pane design is dubbed high-density photovoltaic glass units (HD-PVGUs).  The device acts similar to louvered windows (think slat blinds).  It contains a thin layer of monocrystalline silicon, sandwiched between glass, which acts as a cell.  An internal plastic prism directs angled (direct) sunlight onto the cell, while allowing diffuse daylight and horizontal (less intense) sunlight through.

The result is that you still have attractive views out the window, without the glare or heating.  Meanwhile your panel produces electricity that Pythagoras Solar claims is on par with rooftop panels.

If the installation is a success, it could set a precedent for high-rises across America.  The Willis Tower installation alone is expected to produce as much power as a 10-acre ground installation would.

Conserving land, particularly in a city, is obviously a tremendous concern.  The Willis Tower project could serve as a blueprint for skyscraper owners to reduce their energy costs and improve their buildings' sustainability in years to come.

Cost and maintainability are obvious concerns in the long run for solar window panels from companies like Pythagoras Power.  Indeed, Pythagoras Power offered little insight into how it would handle the extra maintenance burden or what the cost-per-window might be.  

That said, even if the company did provide such metrics, it'd be hard to fairly judge them, as this project is the first of its kind on this kind of magnitude.  Initial implementations of any technology typically start off high in terms of maintainability problems and cost, but eventually bring down both metrics.  

And the cost must not be overly exorbitant.  After all, the panels are good PR for the Willis Tower's owners, but they are in business to make money.  If the panels were overly expensive, the project likely wouldn't have received the green light to begin.