Duplicating MIT's artificial photosynthesis breakthrough

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OK on page two or three we find this: "So is the idea then to couple this to a photovoltaic and also couple it to a hydrogenproducing catalyst?

Interviewee - Daniel Nocera

Right. So here's how you would think about it. You take water plus these catalysts and

light from the photovoltaic and you make hydrogen and oxygen."

Is this gibberish clear to your? Now I ask , since when does a photovoltaic produce light? And that light goes to their catalysts? What? Did he say that?

I'm sorry but this makes zero sense.

I think they mean that it takes electricity from the photovoltaic, to produce the oxygen with their catalysts. Hydrogen is produced elsewhere, which I also don't understand.

In any case why is this not electrolysis? and their device an electrolyser?

It seems that even the so called science guys don't know what to ask or how to make it clear.

It's ELECTROLYSIS.

Graham

Not to mention all the usual problems associated with the storage of hydrogen (and if you don't klnow what they are you shouldn't be posting about it).

And from MIT of all places ! Science is going down the drain.

Graham

Isn't it incredible what the news people and science people will buy as "scientific breakthrough"

--
"I know no safe depository of the ultimate powers
of society but the people themselves; and
if we think them not enlightened enough to
exercise their control with a wholesome
discretion, the remedy is not to take it from
them, but to inform their discretion by
education." - Thomas Jefferson
http://GreaterVoice.org/extend

Sure. He misspoke. Or was misquoted. He meant apply PV output to his electrolysis cell, and make gasses.

IOW, take an already inefficient source, toss away perhaps

2/3rds of that output to make something that you'll later burn, tossing away yet another 50-60%. 12% x .5 x .5 = 3%. I'd be pleasantly surprised if the thing's overall efficiency exceeded 2%.

Cheers, James Arthur

Not only do thay ignore the hydrogen storage problem, they seem to think you can hop on over to Ace Hardware and pick up a convenient fuel cell system.

John

Scientists aren't engineers.

--James Arthur

Yes, I feel so sorry for them.

John

--
I are.

JF

James Arthur wrote: ...

Whether that is accurate or not, it misses the main point, which is the question of how you use solar energy when then sun goes down (or the equivalent: how you use wind energy when the wind stops blowing). Solar and wind will remain minor contributors to our energy supply until we have an inexpensive means of addressing that issue. Storing some of the energy for later use is one obvious approach. Efficiency is only one factor in the expense of storing energy. The lower the capital and operating costs are (as well as the environmental impact, if you include that as a "cost"), the less efficiency is required in order to be economically feasible. Whether the MIT discovery will eventually lead to a cost effective solution is unknown at this point, but its potential contribution appears to be the lowering of capital costs more than any increase in efficiency. I don't have access to the Nature paper, however, so it is a bit difficult to tell from the (as others have noted) rather poorly written press releases.

Regards, Bill Ghrist

A lot of energy breakthroughs devolve to bad calorimetry.

John

Is this not the same school that discovered Resonate Energy Tunneling (Marin Soljacic from the Massachusetts Institute of Technology). Big hat, no cattle! Harry

Around here, it's Big Hat, No Horse.

John

If it's 2% efficient, it's not economic.

Photovoltaic systems (including inverters, installation, wiring, battery, backup, etc.) aren't economic to the consumer above about $3/watt, or about $1.50-2.00/watt for the panels all by themselves. That's about 1/3rd the current price.

With this new-fangled innovation you'd have to quadruple your PV array, plus buy and maintain storage and generation-from-gas facilities to make up for the storage losses. These increase your system cost perhaps 6- to

10-fold. More for a fuel cell.

If you're going to use a very expensive power source, you can't afford to waste 3/4 of it.

Cheers, James Arthur

Interesting you should say that.

I'm convinced that the supposed efficiency of the 'water car' as promoted by Meyer was based on incorrect readings of pulse waveforms by primitive meters.

Graham

the

No, FORTUNATELY that is not the case. To directly split water to H2 gas and O2 gas would make an explosive gas mixture at the active site. With separated electrodes, one can collect H2 gas bubbling from one electrode, and collect (or discard) the O2 gas from the other electrode.

The 'use' of the catalyst doesn't use it up, so expense is low. Mainly, efficiency of the electrolysis is higher than with untreated electrodes, which is important if you want to scale the process up. It's extremely important if you want to scale the process 'way up'

It's disadvantageous, however, to form small bubbles (the surface tension makes a high back-pressure which translates to gas generation inefficiency). It would be good to find some way around that step entirely.

Then the vanadium redox flow battery seems to be a better way of storing electric energy. Energy density is low, so those batteries are useless for powering vehicles, but since they can be built very large, they seem ideally suited for fields of wind generators, solar panels and such.

Quoting the Wikipedia,

: Currently installed vanadium batteries include: : : * A 1.5MW UPS system in a semiconductor fabrication plant in Japan : : * A 275 kW output balancer in use on a wind power project in the Tomari Wind Hills of Hokkaido : : * A 200 kW, 800kWh output leveler in use at the Huxley Hill Wind Farm on King Island, Tasmania : : * A 250 kW, 2MWh load leveler in use at Castle Valley, Utah : : * A 12 MWh flow battery is also to be installed at the Sorne Hill wind farm, Donegal, Ireland

This is proven technology, currently in use (except for the projected last one). I think the numbers above speak for themselves.

S.

Not invented by Volta, used by the ancient Egyptians 2500 years ago. Do bother to learn your science history properly, please.