Solar canopies can put PV panels in some new and interesting places

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With the cost of solar panels falling through the floor (2020 solar module pricing is now below $0.25/watt) and projected to continue falling steadily, where are we going to put all those beautiful panels?

Rooftops are a great place. Open land can be good in some areas, but not when it competes with natural habitat or agriculture. What about parking lots, canals, train lines, highways, and other areas already being used for some other activity?

That seems like a great idea to a lot of people and a number of companies are working on this growing area for solar deployment. I’ll focus on just one company in this piece, P4P Energy, a small company founded by Stephen Conger and based in Boulder, Colorado.

(Disclosure: I have no financial interest in this company, though I did used to own and run a small company focused on solarizing trains, Solar Trains LLC, which is now defunct).

P4P has designed and installed a number of solar canopies in India over canals, one of the more promising use cases for this new technology. Their technology relies on an innovative design that significantly reduces the amount of racking required to support the panels. Basically, the designs rely on cables to support the panels, rather than fixed racking. And that reduces the costs substantially.

A major advantage of this design is the ability to string cables over a longer distance without the support needed in traditional racking approaches. They’re also kind of pretty because of the natural catenary curve the cabling system provides.

A P4P Energy parking lot solar canopy under construction in India (Source)

P4P has so far focused on parking lots and water ways. But what about train lines, both over train tracks and adjacent to train tracks? Could this technology power a new system of ultra-efficient electric trains in countries like the U.S. that don’t have a very efficient train system?

Electric trains are so efficient that a single 300 W solar panel can provide up to 7,000 miles of an individual’s commuting miles per year, or 5 miles to 20 miles per day. The national average, based on National Transportation Database data on the efficiency of the various U.S. electric train systems, is about 4,000 miles per year for each 300 W solar panel. One mile of train tracks can support 1 MW to 3 MW of solar panels, which can provide 2 million to 6 million passenger-miles of train travel. Yes, “million.”

The passenger-miles provide by solar or other renewables is practically emission free, even if we include the energy costs required for manufacture and shipping of the panels.

Miles of daily train travel per 300 watt solar panel (source: NTD data and NREL insolation data).

These numbers highlight just how efficient electric trains can be. The equivalent miles from one 300 W solar panel for a regular electric car — my Chevy Bolt, for example — would be just 1,600 miles per year or 4.5 miles per day, or about 40% of the national average for U.S. electric trains. So electric trains are about 2.5 times more efficient than most personal EVs, which are in turn about 2.5 to 3 times more efficient than a highly efficient internal combustion engine vehicle.

These numbers translate to the ability to supply a majority or even all of U.S. electric train systems from solar power next to or over their train tracks and parking lots.

Does anyone see a national economic recovery plan potential with this new technology and the vast potential over the nation’s carports, waterways, trains and highways?

The views and opinions expressed in this article are the author’s own, and do not necessarily reflect those held by pv magazine.