How many offshore wind turbines would be needed to power each of the world’s major cities? One company has done the maths. 

UK-headquartered component supplier RS Components looked at the world’s major cities to determine how many (or how few) wind turbines would be needed to fully power them, the percentage of the city’s area that would be taken up by wind turbines, and how many square kilometres of turbines would be required. 

For example, Tokyo would need to install 10,310 offshore wind turbines to power itself completely, while just 238 turbines could power Milan.

New York City would need the next highest number of turbines – 3687 – while Barcelona could run on 307.

To power Tokyo, New York, Seoul, Shanghai and Los Angeles – the world’s most power-hungry cities – together would take a combined area of 23,445.7 square km filled with offshore wind turbines, according to the data.

It would take over six times more than Seoul’s area in offshore wind turbines – 3752.9 square km or 620 per cent of the space occupied by the city – to match its population’s electricity demand.

Meanwhile, just 286 offshore turbines covering 293.6 square km could fully power Kuala Lumpur.

RS Components said it had made the calculations to show how little space cities would need to allocate for offshore wind power in order to “start taking new approaches to generating electricity in more efficient ways”.

The firm said it had calculated each city’s power consumption using its population in conjunction with International Energy Agency (IEA) data on per capita consumption in its home country. It then calculated the city’s yearly power consumption and divided by the power one turbine can generate in a year to arrive at the number of turbines needed.  

An 8 MW Siemens SG 8.0-167 DD machine was used as an example turbine, and an assumed offshore wind turbine efficiency of 41 per cent was taken from data released by WindEurope, the wind sector trade group. Turbine spacing was calculated on the basis of having at least seven rotor diameters of space between each turbine, as per a recommendation from the UK government.

According to Bloomberg New Energy Finance, wind and solar power are predicted to supply 34 per cent of the world’s power by 2040. But the world still has a ways to go.

In London, which would need 1569 offshore wind turbines covering 1615 square km to cover its estimated annual power demand of 40,000 GWh, the massive 175-turbine, 100 square km London Array currently provides 630 MW. 

The full graphic, with thanks to RS Components: