09-21-2014, 03:11 AM
Everything I'm about to say is relevant to near-future, not OA tech levels.
First of all, the most commonly talked about renewables (wind and ground solar) have very similar problems; the main ones are low power density and unreliability. (Wind power also has environmental implications as well; the turbines are quite good at killing birds and bats.) Energy storage would be a solution, but very little work is being done on this. One possible skeleton of a solution would be to use spare wind/solar energy to produce some fuel that can use atmospheric components as feedstock, the most obvious being hydrogen.
Interestingly enough, one approach just in the beginnings of being investigated is a semi-biological one. As it happens, one of the things that happens during photosynthesis is production of hydrogen with the release of oxygen; in natural systems the H2 is then used to reduce CO2 and eventually to produce carbohydrates, but decoupling of this process is possible and is being worked on.
Another approach to producing liquid fuel directly is the cultivation of blue-green algae, some of which contain remarkably large amounts of oils that don't need much processing to put them in a diesel engine for example. The process can be set up not to require anything except a small amount of water and (of course!) air, most of the water and all the trace minerals required being recycled.
Unconventional fusion methods are worth investigating, too.
FWIW, my opinion is that humanity is probably going to have to do something like fracking to tide us over while advanced renewable options are developed. (Methane produces much less CO2 per kilojoule of energy than any other fossil fuel, because of its very high hydrogen content.)
Lastly, nowhere near enough attention has been paid to energy efficiency. District heat and power is one of the most obvious; the cooling water from power stations is easily hot enough for space heating, but nearly all of that energy is currently being wasted. On a political note aimed at Americans, maybe it smacks too much of socialism for their taste.
First of all, the most commonly talked about renewables (wind and ground solar) have very similar problems; the main ones are low power density and unreliability. (Wind power also has environmental implications as well; the turbines are quite good at killing birds and bats.) Energy storage would be a solution, but very little work is being done on this. One possible skeleton of a solution would be to use spare wind/solar energy to produce some fuel that can use atmospheric components as feedstock, the most obvious being hydrogen.
Interestingly enough, one approach just in the beginnings of being investigated is a semi-biological one. As it happens, one of the things that happens during photosynthesis is production of hydrogen with the release of oxygen; in natural systems the H2 is then used to reduce CO2 and eventually to produce carbohydrates, but decoupling of this process is possible and is being worked on.
Another approach to producing liquid fuel directly is the cultivation of blue-green algae, some of which contain remarkably large amounts of oils that don't need much processing to put them in a diesel engine for example. The process can be set up not to require anything except a small amount of water and (of course!) air, most of the water and all the trace minerals required being recycled.
Unconventional fusion methods are worth investigating, too.
FWIW, my opinion is that humanity is probably going to have to do something like fracking to tide us over while advanced renewable options are developed. (Methane produces much less CO2 per kilojoule of energy than any other fossil fuel, because of its very high hydrogen content.)
Lastly, nowhere near enough attention has been paid to energy efficiency. District heat and power is one of the most obvious; the cooling water from power stations is easily hot enough for space heating, but nearly all of that energy is currently being wasted. On a political note aimed at Americans, maybe it smacks too much of socialism for their taste.