Burning Buried Sunshine (2003) [pdf]
www-legacy.dge.carnegiescience.edu
www-legacy.dge.carnegiescience.edu
This has interesting implications for those who suggest biofuels as a fossil fuel alternative. These can be considered on an energy per unit area basis. Sparing some maths: for the US, about 3/4 of all present agricultural land would have to be devoted to fuel production to meet present energy needs under the most optimistic fuel-crop estimates. Most scenarios would require multiples of present crop land area, if not of the landmass of the country as a whole.
Electricity generation from photovoltaics is far more viable, though even this would require an immense land area devoted to electricity production. Plus additional provisions for energy storage.
It's helpful to remember that humans switched to nonrenewable fossil fuels in the first place because utilisation was exceeding replacement rates for biomass energy sources such as fuelwood and charcoal, prior to the 20th century with a small fraction of both the present population and per-capita energy usage.
Wind and hydro are largely derivatives of solar energy (as is wave energy). That is: the original energy source is the sun, here creating energy potential through kinetic wind energy (created by heating and cooling of the atmosphere), or of falling water (initially evaporated by solar energy). The total amount of available power is a fraction of incident sunlight, though the capital and maintenance costs may be lower where wind and hydroelectric potential are concentrated.
Geothermal represents an independent power stream, though high-potential sites are limited (and surprisingly highly utilised) over much the Earth, with Africa's Rift Valley being a notable exception.
Tidal and nuclear energy are also independent of solar power. The first seems to offer de minimas actual potential and at high costs. The second already provides ~4% of humans' net energy, with risks and fuel abundance posing grave concerns.
But yes, wind is also a viable significant contribution. It's being rapidly built out on land and in some offshor locations.
We let the dead veteran season for a year in the sun it could no longer use, and then on a crisp winter’s day we laid a newly filed saw to its bastioned base. Fragrant little chips of history spewed from the saw cut, and accumulated on the snow before each kneeling sawyer. We sensed that these two piles of sawdust were something more than wood: that they were the integrated transect of a century; that our saw was biting its way, stroke by stroke, decade by decade, into the chronology of a lifetime, written in concentric annual rings of good oak."
-Aldo Leopold, A Sand County Almanac
The transformation Leopold and his family accomplished on their Sand County property is a self-evident testiment and demonstration as well.