# How much installed capacity of wind or pv would be required to match the output of a 4GW nuclear power plant

I am trying to understand the challenge of decarbonising the power grid, and the equivalence between different generation technologies.

If a nuclear power plant has a capacity of 4GW and a capacity factor of 90%, how much installed capacity of wind turbines with a capacity factor of 40% would be required to match that output?

How about the same with solar pv with a capacity factor of 25%?

What area of land/sea would be required by that installed capacity of wind or pv to match that 4GW power output?

These are the numbers I get but I have been told they are ridiculously wrong. One of the worlds largest offshore sites is the London Array - 630 MW 122 sq km (47 sq mile) That works out to 194 sq km per GW installed capacity. (75 sq mile) The London Array capacity factor 36.8% So to produce 1GW average power you need to overbuild by a factor of nearly three, and would need about 200 sq miles. A large nuclear power station puts out 4GW, so equivalent power to about 800 square miles of offshore turbines.

• It's not clear what you're asking – is it really "percentages" that are a mathematical hurdle for you? As it is now, this feels like homework where you didn't even make the slightest attempt. – Marcus Müller Jun 24 '19 at 21:35
• I'm voting to close this question as off-topic because it appears to be a homework or study question with no effort to solve demonstrated. – Charles Cowie Jun 24 '19 at 21:41
• The answers to your questions can be found in David McKay's excellent and free to download Sustainable Energy - without the hot air. It is specific to the UK but the general numbers for wind farm land usage will be applicable anywhere. Most of your question you can answer yourself if you do the maths. – Transistor Jun 24 '19 at 21:42
• I've tried the maths myself but have been accused of being out by several orders of magnitude. David McKay is now somewhat out of date. I'm 67 years old and don't get homework any more. – Mike H Jun 24 '19 at 21:46
• This question may be a better fit on Sustainability.SE. – LShaver Jun 24 '19 at 21:57