How much electricity can we really produce?

Engineers love numbers. They (the numbers, that is) generally bore people to death, but at times they are necessary for understanding. One of the biggest questions that has been asked is simply, "Can we really generate enough pollution-free electricity to power our businesses and homes?" The calculations below are presented to answer this very important question.

First, the "givens":

In the contiguous 48 states, there are over 25,000 square miles of impervious surfaces (roads, parking lots, driveways, sidewalks, etc.), not including actual buildings and structures. Continuing development adds another quarter of a million acres each year. If these impervious surfaces were replaced with Solar Road Panels™, how much electricity could we produce?

Let us make these very conservative assumptions:

·        We use solar cells that have a mere 15% efficiency (there is technology available that actually doubles this number)

·        We average only 4 hours of peak daylight hours per day (4 x 365 = 1460 hours per year)

A popular manufacturer of solar panels offers a 200 Watt model rated at 15% efficiency. Its surface area is 15.16 square feet. If we covered the entire 25,000 square miles of impervious surfaces with solar collection panels, we'd get:

((25,000 mi²) x (5280 ft / mi)²) / (200W/15.16 ft²) =

((25,000 mi²) x (27,878,400 ft² / mi²)) / (200W/15.16 ft²) =

(696960000000 ft²) / (200W/15.16 ft²) = 9194722955145.118733509234828496 Watts ≈ 9.19 Billion Kilowatts

If we average only 4 hours of peak daylight hours (1460 hours per year), this gives us: 9.19 Billion Kilowatts x 1460 hours = 13424295514511873.350923482849604 Billion Kilowatt-hours (or) ≈ 13,424 Billion Kilowatt-hours of electricity.

Now, keep in mind that this is a conservative estimate.

According to the Energy Information Administration, the United States (all 50) used just over 4,372 Billion Kilowatt-hours of electricity in 2003, while the entire world (including the U.S.) used approximately 14,768 Billion Kilowatt-hours of electricity total. It is easy to see that the Solar Roadways™ could produce over three times the electricity that we currently use in the United States. Slightly increasing the conservatively low 15% efficiency would allow the U.S. (the “lower 48”) to produce the entire world’s electricity needs.

About 40% of U.S. carbon dioxide emissions stem from the burning of fossil fuels for the purpose of electricity generation. Coal accounts for 93% of the emissions from the electric utility industry. US Emissions Inventory 2004
 

This is where some of the numbers become "fuzzy": as best we can tell, it is estimated that approximately half (different agencies provide different estimates, but the average is about 50%) of the greenhouse gases that are causing global warming come from the burning of fossil fuels (primarily coal) to generate electricity. The Solar Roadway™ will, therefore, eliminate half of the greenhouse gases currently being produced.

Summary: the Solar Roadway™ can cut the causes of global warming in half!

What is all this going to cost?

The average cost of asphalt roads in 2006 was roughly $16 per square foot. The cost does not include maintenance (pot hole repair, repainting lines, etc.) or snow/ice removal. The average lane width is 12 feet, so a 4 lane highway would be 12' (width per lane) x 4 (lanes) x 5280' (one mile) = 253440 square feet. Multiply this by $16 per square foot and your one-mile stretch of asphalt highway will cost $4,055,040.00 and will last an average of seven years.

We plan to design the Solar Roadways™to last at least 21 years (three times that of asphalt roads), at which time the panels would need to be refurbished. Adding no additional cost to the current asphalt system, this will allow us to invest about $48 ($16 x 3) per square foot. This means that if each individual panel can be made for no more than $6912.00, then the Solar Roadway™ can be built for the same cost as current asphalt roads. However, asphalt roads don't give you anything back.

Based on 15% efficiency, each Solar Road Panel™ can produce an average of 7.6kWh per day. Our hypothetical 4-lane, one-mile stretch of road would require 1760 Solar Road Panels™. That means that, each day, this stretch of Solar Roadway™ would produce at least 13,376 kWh of electricity. That's 4,882,240 kWh per year - enough to take 500 homes completely "off grid". You don't get that out of asphalt!

In addition, the Solar Roadway™ replaces our current aging power grid. The Solar Roadways™ carry power – not from a centralized point like a power station, but from the power-producing grid itself – along with data signals (cable TV, telephone, high-speed internet, etc.) to every home and business connected to the grid via their driveways and parking lots. In essence, the Solar Roadways™ becomes a conduit for all power and data signals.

For an accurate cost comparison between current systems and the Solar Roadways™ system, you’d have to combine the costs of asphalt roads, power plants, and power and data delivery systems (power poles and relay stations) to be compatible with the Solar Roadway™ system, which provides all three.

2003:  the US used just over 4,372 Billion kilo-Watt hours of electricity. This would require 14,574  300MW power stations (coal-fired, nuclear, etc.). For the sake of argument, let’s assume coal-fired power stations, which cost roughly $1B each for a 300MW plant.

Asphalt roads: 25,000 square miles in the “lower 48” states = 696960000000 square feet. At $16/square foot, this is a cost of $11,151,360,000,000 and the cost of asphalt is rising rapidly with the cost of petroleum. This does not include maintenance (pot hole repair, repainting of lines, snow/ice removal, etc.)

 4.84 billion (12’ by 12’) Solar Road Panels™ would be required to replace the current asphalt road system, parking lots, and driveways in the 48 contiguous states. This is enough to provide three times more electricity than the United States used in 2003 and almost enough to supply the entire world.

If the Solar Road Panels™last 21 years before needing to be refurbished (not replaced), then we can triple the amount of money spent on asphalt roads, which have to be replaced every seven years.

Adding the cost of the power plants and tripling the cost of the asphalt roads, we get a total cost of $48,059,670,000,000. Divide this amount by the 4.84 billion Solar Road Panels™ required to replace the asphalt, and we get a target cost of $9923.16 per panel. This number is considerably higher if you pad in the costs of utility poles and relay stations that will no longer be needed with the Solar Roadways™ system.

In addition, there is no way to calculate additional savings such as the reduction in costs of vehicle and health insurance (due to lighted night roads, wildlife avoidance systems, snow/ice removal, etc.). Accidents and the loss of life (both human and wildlife) will be drastically reduced upon the Solar Roadways™.

Then there is the whole environmental issue: elimination of the fossil fuel plants will take away about half of the CO2 emissions that are known to be contributing to Global Warming. Providing a means to recharge electric cars anywhere along the roadside will open the door for the elimination of the internal combustion engines, which account for most of the other half of the CO2 emissions.

Conclusion: for roughly the same cost of the current systems (asphalt roads and fossil fuel burning electricity generation plants), the Solar Roadways™ can be implemented. No more Global Warming. No more power outages (roaming or otherwise). Safer driving conditions. Far less pollution. A new secure highway infrastructure that pays for itself. A decentralized, self-healing, secure power grid.

The real question may be: what will be the cost if we don't solve the problem?