Donald Trump spoke to his supporters this week (21st June 2017), once again saying that he would build a wall on the US-Mexico border, but that he had a new idea.
He would build it with solar panels, so it would create energy and it would pay for itself.
The President took credit for the idea, saying “Pretty good imagination, right? Good? My idea.”
Well, the idea has been around for a while before that. Jigar Shah wrote a detailed article on 3rd January 2017 analysing the business case for a solar panel covered wall. The full article is here https://www.linkedin.com/pulse/giving-mainstream-media-credit-getting-things-right-solar-jigar-shah.
In a nutshell, the wall would run for 2,000 miles or 3,200 kilometres and be 65 feet or 19.8m high.
Each solar pane is 2 metres high by one metre wide, so you could have 10 stacked on the wall.
As the wall runs for 3,200 kilometres, then you could have 3.2 million panels side by side, or 320 million panels if they were really squeezed together.
At an output of 200W per square metre, you could install 0.64 GW of solar panels on each row. If you had 5 rows, that would be 3.2 GW of output. That would generate around 9.3 GWhs of energy operating 8 hours a day, 365 days a year.
That would collect over $500 million a year at 6 cents per kWh or $20 billion over the 40 year lifetime of the wall.
The cost of the wall is estimated at $12 billion – so the panels could actually pay for the wall to be built.
Jigar Shah’s analysis works it out at 5 GW of panels producing 6.6 GWhs and bringing in nearly $400 million a year or nearly $16 billion over the life of the project.
Putting aside the various concerns about the wall, from what it means to create such a barrier to what it means for the environment and fauna along the border, there appears to be a business case that could finance the project.