What Does Renewable Energy Look Like – Part II

10 Aug, 2009

[Approx. Read Time: 4 minutes]

Only 5,000,000 Wind Turbines?

Last week, I posted an article comparing the land areas required for Nuclear, wind and solar energies to produce an amount of energy equal to two 1600MW AREVA EPRs.   This week, I believe that it might provide valuable insight to show how much area these power sources need to power the entire United States.  It seems that public figure after public figure makes statements that lead the general public to believe that our entire country can be powered by renewables.

Democratic Presidential Primary Candidate Mike Gravel regularly stated during Primary Season that the entire United States could be powered by only 5 million 2.5 MW wind turbines.  Only 5 million wind turbines?  Although this isn’t at all possible because of issues with current technologies, and the Department of Energy states that no more than 20% of our electricity can possibly come from wind and solar, after hearing Mr. Gravel say this in all seriousness, I casually calculated the land area required to do this by using lower end figures for acreage required per wind turbine.  My calculations came out that over 40% of the continuous 48 states had to be covered.

Although it was unpopular for the pro-nuclear folks last time, I’m going to again give wind and solar a little benefit of a doubt.  I will use gross conservatism and assume that the United States has nothing in the way (i.e. houses, schools, roads, etc.) of putting these energy installations in place.  Although, I admit that this isn’t a realistic scenario.  I feel that, sadly enough, it is necessary to address since there exists a very serious discussion out there by some people that think this is a realistic solution.

(Like last time, calculations and references are at the end of the article.)

Energy Consumption in the United States

First off, the according to the Department of Energy, the United States consumes 100,000 quads (quadrillion BTUs) of energy per year.  This is equal to 29,000 TWh or 29,000,000,000 MWh.  Converting this to MW gives us that the United States consumes on average 3,310,502 MW (MWh per hour).

Nuclear Power

For Nuclear power, I am going to conservatively round up and assume that each reactor takes up 1 sq mile of land area.  This leads to a total land area required of 2,069 sq miles.  An area approximately equal to the size of Delaware.

us_nuclear

Land required (2,069 sq mi) for nuclear energy to power the entire United States (Green)

Solar Power

For solar power, I’m using the previously calculated 91 sq miles per 1000 MW.  This means that, in order to theoretically power our entire country with solar power, approximately 301,256 sq miles of land is required.  This is equal to the approximate area of the entire Southeast Region of the country. (Florida, Georgia, Alabama, Mississippi, South Carolina, North Carolina and half of Tennessee)

us_solar

Land required (301,256 sq mi) for solar energy to theoretically power the entire United States (Yellow)

Wind Power

Finally, for wind power I’m using the previously calculated 260 sq miles per 1000 MW.  Therefore, approximately 860,731 sq miles of land area is required for wind power to theoretically power our country.  This gives us a land area approximately equal to everything east of the Mississippi River.  But keep in mind, calculations for wind and solar don’t take into account already existing infrastructure that will increase these estimates even more.

us_wind

Land required (860,731 sq mi) for wind energy to theoretically power the entire United States (Blue)

Calculations and References

Nuclear

I used the commonly accepted <1 sq mi for Nuclear power plants and rounded up to 1 sq mile to be conservative.  This includes the average capacity factor for Nuclear power plants at 0.90.

3,310,502 MW/1,600 MW = 2,069 sq miles

Solar

11,000 acres / 0.19 capacity factor = 57,895 acres for 1,000 MW

57,895 acres = 91 sq mi for 1,000 MW

3,310,502 MW/1,000 MW = 3,310

3,310 x 91 sq mi = 301,256 sq mi

Wind

50,000 acres / 0.30 capacity factor = 166,667 acres for 1,000 MW

166,667 acres = 260 sq mi for 1,000 MW

3,310,502 MW/1,000 MW = 3,310

3,310 x 260 sq mi = 860,731 sq mi

References

1 – US Department of Energy, Office of Utility Technologies, Energy Efficiency and Renewable Energy & Electric Power Research Institute

2 – US Department of Energy, Energy Information Administration

3 – American Wind Energy Association

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17 Comments

  1. Deborah
    August 10, 2009

    Nuclear requires mining of uranium to fuel the plants.

    Where is the footprint(acreage required for mining and milling and for the tailings and waste rock to be stored forever) of the mines and mills required to power all the nuclear plants that you think will take up the space of Rhode Island?

    What about the storage of the “spent” uranium rods that are used by the nuclear plants?

    As these are integral parts of the process they should be considered also.

  2. August 10, 2009

    Deborah,

    I think that maybe you meant to comment on the previous article I wrote about energy footprints. Here’s the link (http://www.cleanenergyinsight.org/energy-insights/what-does-renewable-energy-look-like/). Feel free to comment there as well.

    Take a look at the maps in the above article. Personally, I believe that you are entitled to your own opinion. But do you really think that a Uranium mine the size of 25 states will be needed to power two 1600 MW AREVA EPRs? Even if it even existed or was possible? That is the only way solar and wind will be able to compete with nuclear in the arena of environmental footprints. When it comes to comparing footprints, your point is trivial at best.

    I compared apples to apples. I also neglected to account for transmission lines and supporting facilities for solar and wind. I’m not trying to hide this from anyone. I even neglected to account for economies of scale type effects from building many nuclear power plants. This means that the more power you produce from nuclear power, the less unit area is needed per plant. Doing this, I could have used 60% of the area required for each nuclear power plant.

    If I used more realistic numbers (i.e. actual average capacity factors for solar and wind are lower than what I used) based on actual data in my calculation, the difference would have been even greater. Even by accounting for realistic placement of solar and wind installations (i.e. not on top of any houses and roads), I would be willing to bet that these figures would probably double.

    Also, the spent uranium rods are already stored on site at every nuclear plant in the United States. There is enough room for them there within the 1 sq mile figure I used. The storage is called ISFSI (Independent Spent Fuel Storage Installation) in case you want to do some research on them.

    Spent fuel from nuclear plants is a lot smaller than you would think. Actually, you could store all the spent fuel from nuclear plants in US history into a box the size of a football field up to the bottom of the goal posts. If we were allowed to reprocess our fuel, like the French, Japanese and British, we would be able to fit it into a much smaller area. All of France’s spent fuel is stored at La Hague.

    Thanks for your comment.

    Regards,
    Carrington Dillon

  3. Dr. Dan Ulseth
    August 10, 2009

    Deborah, Wind turbines are made of steel which requires iron ore, which requires mining – lots of it. Solar panels require aluminum framing, which requires mining to extract the aluminum and processing of excess dirt. All of these sources – wind, solar and nuclear – require concrete for foundations, footings and structures. In the end, it’s the actual generated power, not nameplate maximum, that counts to keeping your lights on, your A/C or heat making life comfortable and the use of electronic devices possible and reliable. BTW, it’s Delaware, not Rhode Island.

    Carrington: I think you meant to say, in responding to Deborah, that ALL of the nuclear-power-generating capacity to meet the electricity needs of the USA would comprise 2,069 square miles of nuclear reactor space (at 1 sq. mile per GWe generated). The land area mined to extract uranium to feed those nuclear reactors might be difficult to estimate since uranium exists in different areas of the world and in different concentrations.

    And you probably don’t even take into consideration the savings of transforming coal-fired plants into nuclear stations, either. The land is already there for storage of spent fuel (assuming you’re using LWRs and not PBMRs); the steam turbines are there; the high-voltage lines are in place with the rights-of-way established and (likely) paid-for; many other buildings, trained staff and logistical considerations are already in place. Just exchange the billions of tons of coal for hundreds of pounds of uranium (or better yet, kilograms of Thorium) and, viola’, you’ve got near-zero emission, 24x7x365 electric power. See http://www.coal2nuclear.com for all the calculations and concept. I don’t agree entirely with the AGW fears, but the goal of nuclear power for electricity is worth reading the whole site. And yes, I have done that.

  4. August 10, 2009

    Dr. Dan,

    Thanks for the comment! I guess I got mixed up between thinking whether Deborah meant to comment on this post or Part I from August 3rd. I probably made the mistake of not re-establishing my assumptions from Part I. I will take note for the future.

    We really are getting bombarded by Californians on this site, and we don’t mind at all. I did some work on the Reactor Head Replacement Project out at Diablo Canyon recently. It was a fun and unique project accounting for all of the seismic considerations. It’s really nice out there. You all are lucky. Thanks for stopping by and adding to the discussion. We really appreciate it.

    Best,
    Carrington

  5. Adam Johnson
    August 11, 2009

    Just thought I would add a couple more things to consider on this issue:

    - I’m going to go out on a limb here and say I’m pretty sure there is got to be some regulation prohibiting the large, 2.5 MW wind turbines from being installed within city limits. That would affect the amount of available land to be used for wind power generation.

    - Another fact to consider that affects the available land for power generation is that roughly 300,000 sq. mi. of the United States are national forests. That’s approximately 8.5% of the land area of the US (Basically the size of Texas, thanks Wikipedia!).

    - These land requirements are based on current power consumption. How much more land will be required to accomodate the estimated 30-40% increase in power over the next 20 years?

    - Also, one that is near and dear to my heart. How many resources would be needed to perform routine maintenance on all of these wind turbines? That’s a lot of fuel. Hopefully we can equip a Prius to carry a ladder and toolbox.

    • August 11, 2009

      Alright, Adam. You made me do it. I took your points into consideration with a rough calculation. Here is how I did it:

      Solar land area calculated was 301,256 sq mi. This is approximately 10% of the lower 48 states. Multiply this percentage by the area for the top 145 cities in the US (50,000 sq mi) plus the national parks land area (300,000 sq mi). You get that approximately 35,000 sq miles can’t possibly be covered because it is either in the city limits or national park limits. Then I increased this area by 36% (the projected energy demand increase over the next 20 years). This brings you to a more realistic number for solar at 445,000 sq miles.

      http://www.cleanenergyinsight.org/wp-content/uploads/2009/05/usa_solar2.jpg

      Then I did the same for wind energy. I end up with 1,409,000 sq miles required for wind energy after accounting for national parks, cities, and increased energy demand. This is what it looks like.

      http://www.cleanenergyinsight.org/wp-content/uploads/2009/05/usa_wind2.jpg

      Hopefully, this tickled your fancy.

      Carrington

      Dr. Dan,

      Thanks for the compliment and insight into California’s issues. It seems as though California is going to need something soon to fix their economy. We will see if they can come up with anything like you described.

      Carrington

  6. Dr. Dan Ulseth
    August 11, 2009

    Carrington,

    I really appreciate your blog, particularly the well-reasoned and fair numerical comparisons of the past two “Renewable Energy” posts. Having a visual representation certainly helps give the debate some much needed perspective.

    California is a basket-case in so many ways. I’ve been here since 1981 and am routinely disappointed by the lack of preparation or planning for an expanding population, increasing energy and water needs and other infrastructure. We have “environmentalists” who favor the Delta smelt over water for farm production – and a resulting 40% unemployment rate in the Central Valley – the nation’s bread/vegetable basket.

    We could, if the smelt and other fish are so important, use nuclear power plants to desalinate ocean water and provide for all the farmers and the public consumption in Southern Cal; create plenty of near-zero emission electricity in-state so we never come close to a brown-out; and develop hydrogen fuels when/if that type of engine becomes economically viable. Plus, the excess electricity could be used for all those plug-in hybrids just around the corner (right!).

    Not to mention, the vast resources of crude and natural gas off the Coast that would release the pressure from natural seeps that foul the Santa Barbara beaches. The thousands of jobs, economic activity and innovations spawned by these would bring California back from the brink of collapse. But the radical environmentalists and their pawns in the Legislature refuse to examine the science undergirding these suggestions. So we whistle past the graveyard, keeping an eye out for a banana peel.

  7. Larry Lix
    August 12, 2009

    People forget that solar thermal is a lot more efficient than solar PV technology. A major player in the consumption of electrical grid energy is thermal usage, especially hot water.

    Solar thermal is a viable technology that has a quick payback. Thermal uses for electrical energy is supreme wasting of an energy that is so expensive to create, and useful elsewhere quite easily.

    With this in mind, I believe the solar area calculations are way off and should look about 5-10% of the indicated area. For PV applications (solar electrical) grid power is still a fraction of the cost in dollars and probably ecological costs to produce.

  8. August 12, 2009

    Larry,

    Thanks for your comment. Although, I think you should give some justification instead of just haphazardly throwing out arbitrary numbers like that. I will give you credit if you can prove that I was 95% off in my conservative calculations. I could have used actually reported data from solar photovoltaic plants like 16% capacity factors that would have increased the area even more.

    Also, I didn’t use solar thermal, I used solar photovoltaic. How can you say that solar thermal is viable and has a quick payback when a large commercial plant has yet to be built and proven? But yes, solar thermal has been reported to be cheaper and more efficient than solar photovoltaic. Yet the reported costs for solar thermal is around 6 cents/kWh. Nuclear power costs about 1.7 cents/kWh. Additionally, solar thermal only has a reported capacity factor from the Department of Energy of 0.31 while nuclear is at 0.90.

    There really is no comparison.

    Regards,
    Carrington Dillon

  9. August 29, 2009

    Here is another size comparison of a coal mine to a uranium mine in Australia:
    http://enochthered.wordpress.com/2009/01/09/the-environmental-footprints-of-coal-and-uranium-mining/

    The uranium mine is about one quarter the size in land area but produces almost 9 times more energy and without all the CO2 emissions during electricity production. So the coal mine would have to be 9 times larger to produce the same amount of energy.

    Here is another insightful article written about a uranium mine with allegedly unsafe releases to the environment:
    http://uvdiv.blogspot.com/2009/07/catastrophic-effects-of-ranger-uranium.html

    Both of these sources can give people a better idea of what’s involved in the front end of nuclear power and hopefully realize what a very small environmental footprint it has.

  10. April 13, 2010

    I like the visuals. My brother had told me to visit this particular post and I can see why. I would think that the land required for fueling America is probably a little considered fact, and while some may love the idea of receiving all energy from renewable sources like wind are solar, it is just not feasible…

    Nuclear really seems like the immediate way to go.

  11. Brian
    October 06, 2011

    Your numbers seem total off.
    Supplying the total USA electricity, which is what I would use solar for, would require only .5% of the area.
    550 GW average total US electrical power delivered.
    15% panels
    93MW average per sq mile
    151KW average per acre
    7k acres per GW
    11 square miles per GW
    5500 squares miles needed for all USA electricity.
    USA 3.8M sq miles.
    or .5%

    This is easily accomplished on the existing roof area of homes and buildings, and if necessary parking lots, and road ways can be covered as well.

    rooftop solar uses Zero land. nukes use a lot. 20k acres for the Clinton plant for only 1GW. 50KW per acre. It’s not safe just to pack them in together.

  12. Heinrich Ernst
    February 05, 2012

    Hey folks, never thought on the huge amount of energy which is wasted in the US with unefficient technology? Sorry, but over here in Germany we need some 600TWh per year to feed an industrial society of 80 Mio people. (even too much for my opinion) So that 29000TWh in the US still has some potential to reduce. Meanwhile we us already >15% of renewables (and rapidly increasing), to melt that problem down. So sorry again – nuclear thinking is science fiction from the sixties. Even Areva (respectively the former co-owner Siemens / KWU has officially turned away from nuclear power) and modern photovoltaics and windpower is cheaper per installed kWp than any other source on the planet – little wonder, as all our energy comes from the sun! Look up from your paperwork into the sky! Sunny greets from Germany ! Heinrich.

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