At first blush, this looks like a fabulous idea:
Turn roadways into an enormous solar cell and get lots of other advantages like better new infrastructure. A long while ago, I looked at making solar roadways (and parking lots and driveways and footpaths and….) under contract when I was at Squid-Labs : http://www.squid-labs.com/projects/cc.html
The very difficult thing about making a road is making it structurally sound enough to carry vehicles. That means it has to take very high loads, and be very durable for up to 50 years.
So putting a solar cell there is completely possible, but then you’ll need to put some protective material on top that has some texture (so the roads are not slippery) and enough resilience to last a long time. The problem is that that protective material uses A LOT of energy to produce. Perhaps the company pitching this idea has some magic special sauce up their [...]
Before embarking on some enormous exercise like converting America’s energy use to 100% renewable energy, you might like to get a 20000 foot view of the impact on other things like land area use. Here are some charts to put that in perspective:
1. Land Area of the US by state, (does not include water area in those states) – note the country has been reduced to a square where each stripe is the proportional area of that state, starting with the biggest (Alaska) to the smallest.
2. Land area by use category for the US:
3. Land area required for 1000GW (1TW) each of Solar, Wind, Biofuels, and Hydroelectric. These are “all in” estimates that include capacity factor and the whole hog. Think of it as a year-round average.
4. And now we overlay them all on each-other to get a sense of just how big this project is, and where the land [...]
When trying to imagine the new renewable energy infrastructure it is critical to consider land use. This is especially important with renewable energy technologies because the power density (measured in watts per square meter) is typically quite low.
Here is an excellent summary of land use in the United States in 2002 from the USDA – US Department of Agriculture.
This PDF document in particular has the data on land use.
We churned it through google spreadsheet to produce this chart:
And you can go here for the original spreadsheet. You can’t edit, but you can cut it and paste it somewhere useful.