<i>"It’s fundamentally impossible to improve on jet fuel because it would break the laws of physics", pronounced Laughlin. "You can’t have airplanes unless you make hydrocarbon fuel."</i><p>If electrical energy was cheap but hydrocarbons were expensive, it would be cost-effective to electrolyze water into hydrogen and oxygen. By mass, hydrogen is the most efficient way to store chemical energy. By volume, it's not so efficient, and currently storage is difficult. Still, 200 years from now I think materials technology will have advanced a little.<p>Another option is nuclear-powered aircraft. (<a href="http://en.wikipedia.org/wiki/Nuclear_aircraft" rel="nofollow">http://en.wikipedia.org/wiki/Nuclear_aircraft</a>)<p>Yet another pie-in-the-sky option would be to beam power to the airplane (either from satellites or ground stations).<p>I'm no physicist, but I think I just listed three ways airplanes can exist without hydrocarbons.
>"It’s fundamentally impossible to improve on jet fuel because it would break the laws of physics", pronounced Laughlin. "You can’t have airplanes unless you make hydrocarbon fuel."<p>This guy's a physicist? The claim is absurd, unless he's rolling economics into the bucket - especially as he's talking decades or centuries from now.
By the time we've burned all coal, global warming will be way out of control unless CCS systems are ubiquitous. All studies I've seen point to coal reserves being far, far larger than the atmosphere can handle.
The challenge is definitely liquid fuels for transportation, especially aviation. Stationary applications can easily go electric, and conceivably maritime transport could go to electric powered by nuclear or bulky non-hydrocarbon fuels, but aviation is weight and volume limited.<p>The US Air Force has a goal of qualifying all of their aircraft to fly on biofuels by 2011; they've flown B-52s and other aircraft on 50-100% biofuel mixtures. Currently, most biofuels for aviation use cost several times what petrochemicals cost, but I could definitely see this changing. It's actually pretty easy to get a jet turbine to run on anything, but the difficulty is more with qualifying the entire storage/supply chain to be stable, and stability at temperature extremes. If the Air Force can transition to biofuels, it will be relatively easy for scheduled commercial flights to transition.<p>Given relatively cheap electricity to input, there are plenty of processes to make liquid hydrocarbon fuels -- algae biodiesel, some forms of intensive agriculture, and CO2 sequestration from the air, as are pointed out in the article. These would be "carbon neutral" in terms of atmospheric CO2 as well.
I think coal will last us for a while and we should over time be diversify our energy sources. Which America is looking to do more now. For instance, some of the power generated from coal should be generated with nuclear, solar, etc. This should bring down the rate of coal consumption and allow us to extend our usage of coal in producing energy for a longer period of time.<p>So I think energy diversification is the key.<p>Also, I think nuclear is a great alternative to coal,but for it to be a global option there has to be a lot of stuff done foreign policy wise and in the global security space.
There are huge seams of coal in China that have been burning for hundreds of years. In Centralia, PA there is still a lot of coal around even though the coal fire there has been burning for some 40 years. We are not going to run out of coal for hundreds of years...