Thursday, July 02, 2015

How Much Land Does Nuclear, Wind and Solar Really Need?

bellefonteNot too long ago, we reviewed a report that looked at nuclear energy (and other energy sources) as biodiversity agents. This had to do, in part, with the amount of land a facility needs to function. Nuclear energy and fossil fuel plants use relatively little, wind farms and solar arrays quite a lot of land.

Based on an objective and transparent analysis of our sustainable energy choices, we have come to the evidence-based conclusion that nuclear energy is a good option for biodiversity conservation (and society in general) and that other alternatives to fossil fuels should be subjected to the same cost–benefit analyses (in terms of biodiversity and climate outcomes, as well as sociopolitical imperatives) before accepting or dismissing them.
Writer Barry Brook, who collected 75 scientists to endorse his paper, is interested in land use as it impacts flora and fauna. Biodiversity concerns do not get as much play as they might – and, when they do, it annoys many when land is withdrawn due to a specific lizard or weed - but it’s an important factor in siting new buildings of any sort.
WindPower022415But what about land use as an issue in itself? It’s a fair argument that nuclear energy provides a lot of energy in a relatively small amount of space. But how much really? Is it potentially an important issue or just another argument to throw on the pile?
Jesse Jenkins takes a look at land use over at the Energy Collective and concludes, using Brook’s figures:
To fuel one-third of the United States’ 2050 electricity demand with nuclear power would require only 440 sq-km [169 square miles], according to the land use figures compiled by Brook.
If solar provided one-third of Americans’ electricity in 2050, it would require just 4,000-11,000 sq-km [1500-4250 square miles].
That’s – a pretty big range and at least 9 times the space used by a nuclear energy plant.
Wind (also using figures from Brook):
Powering one-third of the country's projected 2050 electricity demand with wind energy could take a land area spanning on the order of 66,000 sq-km… [25,480 square miles]
And that’s just gigantic, about the size of West Virginia
theparkhasapNEI has tried the same exercise recently. Instead of of Jenkins and Brook’s calculation of one-third of American electricity, NEI compares the space needed to supply 1000 megawatts, about the amount of a full-scale reactor. (A nuclear baseline makes sense for NEI, yes?)
NEI also takes into account capacity factor. This refers to the amount of electricity a plant actually puts out against its rated capacity, expressed as a percentage. Nuclear reactors achieve an average capacity factor of 90 percent, largely because they shut down occasionally for refueling.  Wind farms, depending on location and other factors, have a capacity factor between 32 and 47 percent, solar arrays between 17 and 28 percent. (See the charts at the link for a more visual comparison.)
Does this give nuclear energy an advantage? You bet it does. Is it fair to consider it? Yes, I think so. Renewable energy advocates often ignore the whole capacity factor thing because it drags numbers down, but that’s the nature of intermittent (solar, wind) versus baseload (nuclear, hydro) energy. If there’s a big  jump in battery technology (a big if), wind and solar will improve their capacity factors. Until then, the numbers are what the numbers are. And it will take more land to make up for them.
A 1,000-MW wind farm would require approximately 85,240 acres of land (approximately 133 square miles). Accounting for a range of capacity factors (32-47 percent), between 1,900 MW and 2,800 MW of wind capacity would be required to produce the same amount of electricity as a 1,000-MW nuclear plant in a year. The land needed for wind energy to produce the same amount of electricity in a year as a 1,000-MW nuclear plant is between 260 square miles and 360 square miles. A 1,000-MW solar photovoltaic (PV) facility would require about 8,900 acres (approximately 14 square miles).
Accounting for a range of capacity factors (17-28 percent), between 3,300 MW and 5,400 MW of solar PV capacity is required to produce the same amount of electricity as a 1,000-MW nuclear plant in a year. The amount of land needed by solar to produce the same generation as 1,000 MW of nuclear capacity in a year is between 45 and 75 square miles.
To be honest, if mischievous, you could make this comparison even better for nuclear energy. Consider that the five reactors now being built in Georgia, South Carolina and Tennessee are at existing facilities. They take up no more land than has already been committed to the facilities. Almost all new wind and solar installations are new builds – of course, mischievous wind and solar folks have distributed energy installations in their camps (roof-top solar and the like). But let’s just call this a minor factor withal – some proposed nuclear reactors could be in newly built facilities.
The conclusion however you look at it is almost foregone: if you want a lot of cleanly generated electricity in a (relatively) small space, then nuclear energy is the way to go. As Brook points out, this could be determinative in places where land is at a premium or when biodiversity concerns rise in importance. In places like the U.S., it is, or should be, a factor in considering the mix of energy types. These may have started as exercises, but they reveal real issues to consider in energy policy.

EDITOR'S NOTE: The NEI paper, "Land Requirements for Carbon-Free Technologies," is available on NEI's website.


Energysprawl said...

You didn't mention how much land area is required for 1,000 MW of nuclear capacity. The NEI report says approximately 1.3 square miles are required.

That means solar requires 34 to 57 times (or 3,400% to 5,700%) more land than nuclear. Wind requires 200 to 276 times (or 20,000% to 27,600%) more land than nuclear.

Solar can be good on rooftops but even if we covered all the rooftops it would generate 5-15% of annual demand according to some studies. Also a lot of environmentalists want to put green roofs or cool roofs on the rooftops instead. Also people like shady trees around their houses.

Solar on natural land kills everything underneath the panels and needs water for maintenance.

Wind turbines have to be spaced out, that's why they need so much land. The space between the turbines can be used for farming and ranching. Wind turbines in forests, mountain ridges, jungles etc. have a worse environmental impact. Some people don't like living with the noise, views, lights of turbines.

Another thing some of these studies aren't taking into account is all the land cleared for roads to each turbine, power lines, substations, etc. Solar needs the same things. More environmental destruction.

Joris van Dorp said...

One could take the comparison even further. Wind turbines and solar panels not only require more land, but they also use far more materials in their construction, per kWh delivered. These materials are taken out of the ground by mining. So I suspect one could also make a 'mining footprint' comparison which is expected to yield a similar advantage for nuclear versus wind/solar.

Quite apart from the land-use difference, materials used in nuclear are utilised far more effectively. While a generator driven by wind will only be working less than half the time, the same generator powered by nuclear will work almost twice as much. These means only half the number of generators will need to built. A clear advantage.

Similarly for solar farms. The power electronics equipment needed to deliver solar electricity is being utilized only about 1/4th as much as the same equipment powered by nuclear would be. In other words, we would need four times as much power electronics to deliver solar electricity as we would need to deliver nuclear electricity.

All of this illustrates the contradiction between the popular green goal of 'reducing our consumption of resources' and 'getting more of our energy from renewable sources'. Achieving the second goal conflicts with achieving the first goal.

Anonymous said...

Very good article. One of the things that is not discuss about nuclear is heat pollution. About two thirds of the energy generated has to be discharged to envirnoment as heat. Think a we need to keep balanced profile of all energy sources.

Anonymous said...

I think we need to be careful discounting the idea of rooftop solar. When we make the argument that new nuclear plants on existing sites does not require more land then we also need to accept that adding solar on rooftops also does not require more land. There are a lot of rooftops in the US and in the world and I'm seeing a lot of ordinary people making economic decisions to put panels on their roofs. The recent announcement from Elon Musk of his wall mounted battery makes such installations more practical and if you watched his announcement you would see he has big plans for solar with a convincing argument that the land use requirement is really quite small when compared to the space available. I've worked in the nuclear industry for 30+ years and I remain a strong nuclear advocate but I think we need to accept that solar and nuclear may end up coexisting and that might be a good thing.

Leslie Corrice said...

This also fails to mention that the land area calculated for nukes is largely due to political machinations, based on the linear/no threshold assumption used to model public exposure limits. Without LNT, the nuke land area number would be many, many times less.

Anonymous said...

Some folks assume pumped storage on networks can be used to make wind and solar energy usefully dispatchable and more economic. Most pumped storage schemes have been designed to accumulate their stored energy from the most economic steam turbines and combustion turbine plant at off-peak and weekend periods, so it can be used at peak times. The pumped storage schemes seldom have much capacity to make available to improve availability of renewable energy. Also, energy recovered from storage is not 100% of what was stored, a fact made worse if the electricity storage involves long transmission lines, which themselves can add energy losses of five or more per cent. And while solar and wind energy plant is storing energy in its own dedicated storage, the electricity stored is not available to grid customers, and is also subject to energy losses. Which all adds to worse real-estate numbers for renewables.