8 Can renewables power the world?
Can renewable energy provide enough energy to power the world?
One study demonstrating that this is possible was published in popular form in Scientific American in 2009 by two scientists from Stanford University in California (Jacobson and Delucchi, 2009).
In the following year they backed up their arguments in two detailed papers in the refereed journal Energy Policy (Jacobson and Delucchi, 2010a and 2010b), Their research suggests that the world’s total power demand for electricity and other purposes, which they estimate will reach between 11.5 and 16.9 TW by 2030, could be supplied by large numbers of wind turbines, solar power plants, water wave, hydro and geothermal installations, as detailed in Table 3 below.
|Energy technology||Rated power of one plant or device/MW||Per cent of 2030 power demand met by plant/device %||Number of plants or devices needed for world energy demand||Footprint area (% of global land area)|
(% of global land area)
|Wind Turbine||5||50||3.8 million||0.000033||1.17|
|Wave device||0.75||1||720 000||0.00026||0.013|
|Hydroelectric plant||1300||4||900 Footnotes a||0.407 Footnotes a||0|
|Tidal turbine||1||1||490 000||0.000098||0.0013|
|Roof PV system||0.003||6||1.7 billion||0.042 Footnotes b||0|
|Solar PV plant||300||14||40 000||0.097||0|
|CSP plant||300||20||49 000||0.192||0|
|Total new land||0.41 Footnotes c||0.59 Footnotes c|
FootnotesFootnotes a About 70% of the hydroelectric plants are already in place Back to main text
FootnotesFootnotes b The footprint area for rooftop PV does not represent an increase in land since the rooftops already exist and are not used for other purposes Back to main text
FootnotesFootnotes c Assumes 50% of the wind is over water, wave and tidal are in water, 70% of hydroelectric is already in place, and rooftop solar does not require new land. Back to main text
FootnotesSource: Derived from Jacobson and Delucchi, 2010a. Back to main text
The figures shown above assume a given partitioning of the demand among plants or devices. They also show the footprint and spacing areas required to meet the world demand, as percentages of the total global land area (1.446 x 108 km2).
Jacobson and Delucchi acknowledge that the numbers in Table 3 above may seem daunting, but as they point out, installation would be spread over two decades, and since the world currently produces some 73 million cars and light trucks every year, for example, this could suggest that the world’s industrial production capacity is probably sufficient – if we chose to harness it in this way.
You’ll now look at another study, showing how the world could supply nearly all of its energy from renewables by 2050, if combined with major energy saving measures.