Louisville, KY, USA -- I was reading an article recently about mountaintop removal (MTR) coal mining and got to thinking: How many square miles have been cleared in Kentucky for MTR? And, if we covered that space with photovoltaic (PV) solar panels, how much electricity in kilowatt-hours (kWh) would be produced? Would it be enough to match the electricity consumed in Kentucky each year?
What about MTR in the U.S.? If we covered all the square miles that have been cleared for MTR in the U.S. with PV solar panels, what percentage of the national annual kWh consumption could be provided?
I decided to crunch the numbers and what I discovered was quite intriguing.
According to the Appalachian Voices (a non-profit committed to protecting the land, air and water of the central and southern Appalachian region), 574,000 acres (897 square miles) of land in Kentucky has been surface mined for coal and more than 293 mountains have been severely impacted or destroyed by MTR coal mining.
According to the U.S. Department of Energy, the total electricity consumption in Kentucky (residential, commercial and industrial) in 2005 was 89,351,000,000 kWh.
The following projection is based on experience from PV solar installations already in place here in Kentucky and from the fact that we get four and a half hours of sunlight per day on average, accounting for clouds. To produce that much electricity in one year from PV solar panels in this region, around 190 square miles of land would need to be covered by a 69.1 GW (gigawatt) solar array. And, 897 square miles of land has been has been flattened by MTR. Therefore, if we merely put PV solar panels on 1/5th of our already cleared land, we would supply ALL of the electricity needs for the entire Commonwealth of Kentucky!
If we covered the entire 897 square miles of cleared MTR space in Kentucky, we could supply nearly 10% of the electricity needs of the entire U.S.!
Additionally, according to Appalachian Voices, a total of 1,160,000 acres (1,813 square miles) of land has been surface mined for coal in the central and southern Appalachian region.
According to the Central Intelligence Agency, the United States consumed a total of 3.873 trillion kWh of electricity in 2008.
To produce that much electricity in one year from PV solar panels in this region, 8,225 square miles of land would need to be covered. Accordingly, roughly 22% of the electricity consumed in America could be provided by PV solar panels if the 1,813 square miles of land cleared by MTR in Appalachia were covered.
At this point, you're probably asking yourself: that's great, but how much would it cost? And, what about energy storage so we can use that electricity at night?
I'll admit that projecting the costs for a solar array of this size if pure conjecture, but I'll do my best.
Currently, large scale, megawatt PV solar panel arrays cost around $3 per watt to install without tax subsidies. A GW scale solar array might be closer to $2 per watt installed. Using this metric, it would cost about $138 billion to install the 69.1 GW solar array required to produce 100% of the electricity consumed in Kentucky per year. If the solar panels have the industry standard 25-year warranty, the cost of electricity comes to 6.2 cents per kWh. That's cheaper than what consumers in Kentucky pay for electricity right now (e.g. LG&E residential customers pay 7.9 cents/kWh).
There are many options available now for grid level energy storage, including, but not limited to: pumped hydro, compressed air energy storage (CAES), sodium-sulfur batteries, lead acid batteries, nickel-cadmium batteries, flywheels, and lithium ion batteries.
Germany is considering using empty, abandoned coal mines for pumped hydro energy storage for renewable energy systems. I would assume we have plenty of these in Kentucky.
Energy storage could cost an additional $1 per watt for each solar array. In Kentucky, this would increase the cost of the array to $207 billion with an electricity cost of around 9.3 cents per kWh. That price per kWh is a little above what LG&E customers are paying right now, but will soon be on par with current rates as LG&E recently requested the Kentucky Public Service Commission to allow rates to increase by 19 percent over the next five years.
Again, the cost projection is all conjecture and does not include grid transmission and maintenance. But it's a start.
This sounds like a lot of money until you consider that, according to a study by the Environmental Law Institute, the fossil fuel industry in the U.S. received $72 billion in subsidies from 2002 to 2008. Imagine using that money to fund a GW solar project in Kentucky.