PV solar design example

To stop it going cold, of course.

There was a fad for big (as in many kilometer) superconductive rings that would store energy inductively. Don't know what happened. Pity, because efficiency would be almost 100%.

John

If it is from sugar cane you have more than enough bulk cellulose mass to burn for the distillation and generate some electricity too.

I can't find a free access summary but Reuters has paraphrased the key factors in one of their items. US Corn ethanol 1.1-1.7x inputs and Brazilian sugar cane ethanol currently >8x inputs and with room for improvement.

US ethanol is simply done to make farmers and their lobbyists rich by driving up food prices. And it has been very effective at this objective.

Brazil has an economic incentive to increase ethanol production when oil is more than about $40 /barrel (2004 prices). See for example:

Part of the gain is that the tropical sugar cane has a better conversion efficiency in C4 photosynthesis (most temperate plants are C3) and it has symbiotic nitrogen fixing bacteria in the roots. I doubt if any temperate growing crop can ever compete (although waste streams from some of them might if a decent industrial process cellulase became available).

Nothing is wasted in the Brazilian scheme but there are environmental problems and side effects too. It isn't all good. Tp tempting to nuke all the rainforest with oil prices so high and the stuff used in the boilers isn't altogether clean burning so lots of smoke.

Regards, Martin Brown

I wonder how much energy you could store in say 1km radius ring.

I wonder how much energy it takes to maintain superconductivity ?:-)

...Jim Thompson

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so as long as we are talking alternative energy... here's my idea for solar heating...

you use the sun to melt ice water, melted water holds a lot of heat....

at night you bring the moderatly warmed water inside and put it in a freezer, i.e. a heat pump.... the freezer (heat pump) pumps the heat out of the water and freezes it.... yes you need real electricity to run the freezer but you get something like 3x to 4x the amount of heat out of it compared to the elctrical energy you put in....

the next day you put the ice water back out in the sun to melt...

I calculated 4 to 5 gallons is enough to keep one room warm..

I just may try that next winter with a small fridge and 5 or so jugs of water.. see how it works...

obviously the above description is an experiment... you need to make it more practical ...

Mark

None, except for heat leaks. The superconductive magnets in NMR and MRI systems have to be topped off with liquid helium every few months. Lately, with the price of helium going up, people are starting to use small (shop-vac sized) refrigerators to re-condense the boiloff; and the helium comes out of their supplies budget, but the electricity is usually in the building's overhead.

Somebody recently discovered a "high-temp" superconductor that seems to hold up at very high field strengths. I'm guessing that some such invention might make superconductive energy storage feasible some day.

What I really want is surface-mount room-temp superconductive inductors.

John

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That's not bad. Multilayer superinsulators are amazing. MRI magnets only need a helium refill every couple of months. I think the scalings are favorable as the energy storage of a ring facility increases.

John

I'd like a MEMS cryogenic cooler, for those low-noise front ends. Best regards, Spehro Pefhany

The proposed "free trade" system would automatically take care of what's economically feasible and what isn't.

Not necessarily. If the instant electricity cost went up, many consumers (like ACs) could automatically turn off temporarily. If the grid would constantly tell both sources and sinks the current buy/sell price, the system would auto-regulate.

Indeed it doesn't. Germany has s similar system, and environmentalists rightfully criticize it for pretty much stopping innovation in solar systems because so much money can be made (by the mfgrs) with today's systms.

Note that my argument has nothing to do with any specific form of energy generation.

robert

Yes, but the load would instantly plummet as price goes up. A household washing machine could be programmed to only run if energy cost is below a certain level.

robert

In many other (non-U.S.) countries high-demand items such as water heaters run off of a second, switched power line that's only energized at night. The power company benefits from being able to even out their load whereas the consumer benefits from paying less per kWh than the "regular" power line.

Superconductors have a weird kind of kinetic inductance due to inertia of the paired electrons--for thin films, it can be orders of magnitude higher than the inductance of the same circuit above its critical temperature.

Cheers,

Phil Hobbs

Heating water with electricity is insane. That's rare in the US; most of us use gas.

John

What does that do to transmission lines?

John

We'll be hooking up to gas as soon as it makes it out to our part of the country. Right now it's about 15 miles away, so I'm not holding my breath. :-)

It raises their impedance amazingly, on account of the L/C ratio. It doesn't make such a big difference in wires, because it's a surface effect. Superconducting microwave stuff is surprisingly hard--I've just started working with a smart young guy from Cal Tech who's a specialist in that, on some interesting combinations of his stuff and my antenna stuff. It's been an eye-opener for me. If we get grant money (proposal in, fingers crossed) it ought to be a lot of fun.

Cheers,

Phil Hobbs

Most of "us" do not ;-)

Most of "us" don't have CA electric rates ;-)

Virtually all new-builds in AZ are all-electric homes.

CA should do "us" all a favor and fall off into the Pacific during the next earthquake... just delight yourself with the high-count loss of leftist-weenies ;-)

...Jim Thompson