The United States attained the position of a superpower to a very large degree by our ability to utilize fossil fuels. Our way of life requires burning massive amounts of those fossil fuels. The wastes released by burning these fuels is leading to global warming and ocean acidification. If we want to preserve any semblance of a natural environment on this planet we must stop.
To maintain our lifestyle we have to adopt energy production systems that are free from carbon pollution and have long term sustainability. Direct solar, wind, and biofuels derived from crops are three strategies being exploited on a small scale already.
These three energy sources all derive from the sun but are they of equal efficiency? The short answer is NO, in capital letters. Not only are biofuels very inefficient in terms of land use, but also compete with food crops for acreage, fertilizer, and water.
Although the direct tax credits for biofuels like Ethanol and Biodiesel have been discontinued, we continue to subsidize these energy sources by crop price supports and mandates for biofuel use. This is certainly good for agribusiness, but is it good for society?
Consider the productivity of Ethanol from corn. In the United States, we use about half the corn we grow for ethanol production, roughly 50 million acres per year. For this we get 3 billion gallons of gasoline equivalent from ethanol. The problem is that we use over 130 billion gallons of gasoline a year. If we put every arable acre of land in the country in corn (580 million acres), we still would only be able to produce less than half of the fuel we need.
And we would have nothing to eat! The problem with biofuel is that photosynthetic efficiency is very low. Thats why it took hundreds of millions of years to accumulate the fossil fuels were are now consuming.
Of course, there are alternatives to biofuel.If that same land area is used for wind turbines, solar thermal or photovoltaic applications, much more energy can be harvested. The 60 gallons gasoline equivalent per acre from corn ethanol represents less than 2000 kilowatt-hours per acre per year. Dedicate that same land mass to wind turbines with good winds and you get 130,000 kilowatt-hours per acre per year. And the land beneath the wind farm is still available for crops or pasture.
Photovoltaic systems are even more productive. Virtually anywhere in the US, 800,000 kilowatt-hours per acre per year is attainable with current technology, That is 400 times as efficient as corn ethanol. We dont need cropland, we can do it on our roofs. We get to eat.
In summary, photosynthesis is a very poor choice when it comes to energy production because it is so inefficient and it competes with food crops for land and water. Solar energy production methods such as photovoltaics and wind with current technology can sustainably power our future, now.