I think there will be a growing algae-oil industry, but I’m not optimistic about it being cost-competitive against fossil oils anytime soon or for it scaling up quickly. It would need many thousands of square miles of artificial growing ponds with good liners and a ready supply of water and more thousands of square miles of drying pans, plus all the infrastructure needed to maintain water, distribute nutrients, to move the algae from the ponds to the pans, and to harvest the dried algae. It’s not technically difficult in principle, but figuring out how to do it all on the cheap seems to be the sticking point that has killed the most algae-oil ventures so far. My suspicion is that much of the early production will go for higher-value applications, like foods, cosmetics and lotions.
“I’ve seen numbers as low as 2% for CO2 from aviation.”
That sounds like the figure for total greenhouse gas impact from all human activity. It’s closing in on a billion tons of CO2 per year (about the same as total global CO2 emissions back in 1920) which is more like 7 or 8 percent of total fossil fuel CO2 emissions. It’s not our largest emissions problem right now, but it has one of the fastest growth rates–roughly doubling each 15 years.
“I don’t think it’s that bad an answer to use fossil fuel for another 50 years assuming we cut out everything else which has easier technical solutions.”
After you factor in growth, it eats up a major chunk of our remaining carbon budget in 30 years, and we are not likely to have good alternatives which could even help to slow growth for another 10 years anyway.
“I agree batteries will probably never work for most person flight miles. Not only is the mass energy density terrible for a plane but now you are limited to the speed of a propeller aircraft”
I’ve seen some electric ducted fans, but increased speed would probably reduce the range.
I’d be interested to see how the Russian nuclear-powered cruise missile engine works. It seems to be capable of both great speed and range.
“What are your favorite aviation syn fuels? I believe they’ve tried hydrogen which works ok but can’t be stored in the wings effectively.”
As I understand it, the Navy research team started with hydrocarbon starter molecules which were then combined into larger molecules, and their end-product fuel was a liquid with a mix of molecules having from nine to sixteen carbon atoms. They were even able to fly a model airplane with a 2-stroke piston engine on this liquid fuel. It looks like fuel transport and storage infrastructure could remain basically unchanged and that there would be minimal need to modify aircraft or change the way they operate.
“So for large boats I’m sure you favor these new small Gen IV reactors.”
Also intrigued by the possibility of doing ocean traverses in large, nuclear-powered ekranoplans.
“What about smaller boats?”
Generally, it is heavy boats that cover the long distance routes, and smaller boats go shorter distances. The smaller the boat and especially the shorter the distance traveled, the more feasible it becomes to cover that with batteries. I gather electric ferries are already starting to enter service, and I expect that will expand into other kinds of short-haul ships as batteries gradually improve. I suspect there aren’t that many smaller boats that traverse large distances, and some of those could be covered by hybrid solutions including battery, solar, sail, and kite, mixed with synfuels.
“Do you see autos as going primary BEV or do you see synfuels in plug in hybrids for a while?”
I think hybrids will dominate in the mid-range to larger passenger vehicle class for quite some time. The full-BEV’s will first take hold in the smaller, lighter, metro-class cars, but even there, I think hybrids will the the preferred choice for people who have longer commutes, and those who occasionally have to do road trips. I’ve seen small range-extender trailer generators, so that you could effectively convert a BEV into a hybrid for longer trips and not have to haul the motor around the rest of the time, but I think the trailering option would be more bother than most people (in the U.S. at least) would care to put up with.
“(I’m a bit embarrassed to admit I’m leaning towards a Honda Clarity lease now that my Nissan Leaf lease is up - hopefully I can limit my yearly gas use to under 100 gallons but the Leaf has been a bit limiting).”
I’m guessing this would not be so much of a quandary if we had widely-available synfuels that it could run on.