Replacing Fossil Fuels for Generating Electricity

Part of the Green New Deal being introduced by Democrats is the elimination of fossil fuels for power generation. The Democratically controlled House of Representatives is considering a House rule change to initiate a select committee to pull together a plan for implementing the Green New Deal. You can read more about this in the post House Select Committee on Climate Change.

Total electricity usage in the U.S. in 2017 was 4034 billion kilowatt hours. Of this electricity usage 17% was generated by renewable energy sources. Fossil fuels produced 62% or 2536 billion kilowatt hours of electrical energy.

Renewable energy sources include solar, wind, hydroelectric, geothermal, and several different biomass methods. Of these hydroelectric power would require building damns and backing up river basins displacing people and potentially putting some forms of wildlife at risk. If you couple this with the need for specific land formations around the river being damned, hydroelectric power is not a method that could be accepted on a large scale basis. Geothermal also needs specific natural geological formations, so it isn't structured for large scale implementation. Biomass systems generate carbon dioxide which is deemed harmful to the environment, so it's out too. We are left with wind and solar power to replace the needed energy.

The cost for installing a commercial solar farms is approximately $1000 per kilowatt of installed capacity. The amount of energy obtained from this system varies due to a number of factors including location. In general, a commercial solar farm will generate between 1300 and 1500 kilowatt-hours (kWh) annually for each kilowatt of installed capacity (kWp). The largest solar farm currently existing in the U.S. is the Solar Star installation with an installed capacity of 579 megawatts. The installation itself covers 3200 acres of land.

I was unable to find the amount of kilowatt-hours of electricity and the costs of Solar Star or the total costs of the facility Using the number of 1500 for the amount of kilowatt hours of electricity generated, Solar Star would be able to produce approximately 868 MWh of electricity. Using the $1000 per installed kilowatt installed the costs of Solar Star would be $57.9 million dollars.

If a second Solar Star power plant was built producing 868MWh annually this would be 0.868 million kilowatt-hours or 0.000868 billion kilowatt-hours. To generate the 2536 billion kilowatt-hours needed to fulfill the desires of the Green New Deal to replace fossil fuel power generation would take over 2.9 million installations the size of Solar Star. The costs of such an endeavor would be around $168 trillion and would cover 9.3 billion acres. Other than the constraining difficulties of obtaining $168 trillion and fitting 9.3 billion acres of solar panels on the 1.9 billion acres in the contiguous 48 states, this plan should be workable. Right?

Let's look at wind power. Most of the commercial-scale turbines installed today are 2 MW in size and cost roughly $3-$4 million installed. Because of factors such as friction, these machines only have efficiency ratings of between 30 percent and 50 percent of rated power output. For purposes here, I'll use $1.75 million for each megawatt of installed power and 40% efficiency. I will also assume the wind blows consistently 24 hours a day, 365 days per year. For $1.75 million dollars we get just over 7,000 megawatt-hours or 7 million kilowatt-hours of electricity per year. Each 2 MW installed capacity will generate 0.007 billion kilowatt-hours of the needed 2536 billion kilowatt hours of electricity needed to replace fossil fuels. In other words we need 362,286 of these 2MW installations that would cost $634 billion.

Wind power would be much more reasonable than solar power. This is evident when you look at the fact that wind power in 2017 produced 6.3% of the nations power compared to 1.2% solar power. The trouble is, where are these locations that the wind blows consistently 24 hours a day, 365 days a year. Everywhere I've ever been has this thing called weather that screws that all up. There are also some parts of the country which are not suited for wind power.

One of the largest wind farm in the U.S. is the Roscoe Wind Farm located in Roscoe, Texas. The farm has 627 windmills with an installed capacity of 781.5 MW and is spread over 100,000 acres. Using the numbers above the Roscoe Wind Farm would produce 6.85 billion kilowatt-hours of electricity per year. To replace fossil fuels we would need 370 installations this size with perfect conditions covering 37 million acres of land which is about the size of either Illinois or Iowa. Large, but still doable.

If we're going to replace fossil fuels for electrical power generation these simple numbers suggest that wind power is the way to go in the areas of the country with prevailing winds that make it possible. Solar power may be able to work in some areas with plenty of sunshine and lots of open land, but if many people lived there the open land wouldn't be available. The Democrats don't want to only replace fossil fuels in generating electricity but also on our roads. Imagine the huge amount of additional electrical power that will be needed to replace gasoline and diesel fuel. We're going to have to start stacking windmills and electrical panels on top of each other.

Sources:
What is U.S. electricity generation by energy source?
Solar farms: what are they, and how do you start one?
How much do wind turbines cost?
How Much Power Does a Wind Turbine Generate?
The 11 Biggest Wind Farms and Wind Power Constructions That Reduce Carbon Footprint