Toward home-brewed electricity with 'personalized solar energy' (hydrogen storage)

[OKIsItJustMe]

http://www.eurekalert.org/pub_releases/2009-11/acs-the110409.php

Public release date: 4-Nov-2009

Contact: Michael Bernstein
[e-mail]
202-872-6042
http://www.acs.org/">American Chemical Society

Toward home-brewed electricity with 'personalized solar energy'

New scientific discoveries are moving society toward the era of "personalized solar energy," in which the focus of electricity production shifts from huge central generating stations to individuals in their own homes and communities. That's the topic of a report by an international expert on solar energy scheduled for the November 2 issue of ACS' Inorganic Chemistry, a bi-weekly journal. It describes a long-awaited, inexpensive method for solar energy storage that could help power homes and plug-in cars in the future while helping keep the environment clean.

Daniel Nocera explains that the global energy need will double by mid-century and triple by 2100 due to rising standards of living world population growth. Personalized solar energy - the capture and storage of solar energy at the individual or home level - could meet that demand in a sustainable way, especially in poorer areas of the world.

The report describes development of a practical, inexpensive storage system for achieving personalized solar energy. At its heart is an innovative catalyst that splits water molecules into oxygen and hydrogen that become fuel for producing electricity in a fuel cell. The new oxygen-evolving catalyst works like photosynthesis, the method plants use to make energy, producing clean energy from sunlight and water. "Because energy use scales with wealth, point-of-use solar energy will put individuals, in the smallest village in the nonlegacy world and in the largest city of the legacy world, on a more level playing field," the report states.

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ARTICLE FOR IMMEDIATE RELEASE "Chemistry of Personalized Solar Energy"

DOWNLOAD FULL TEXT ARTICLE http://pubs.acs.org/stoken/presspac/presspac/full/10.1021/ic901328v

CONTACT:
Daniel Nocera, Ph.D.
Department of Chemistry
Massachusetts Institute of Technology (MIT)
Cambridge, Mass. 02139-4307
Phone: [phone]
Fax: [phone]
Email: [e-mail]

[The2ndWheel]

1. What's the cost?

We know what the profit might be. Increased demand met by inexpensive energy, limitless in scope, available to every individual on the planet, to be used without consequence.

So what's the downside? There has to be some kind of a price paid for that.

[OKIsItJustMe]

2. Good question

http://pubs.acs.org/stoken/presspac/presspac/full/10.1021/ic901328v#h22

…

Abstract

Personalized energy (PE) is a transformative idea that provides a new modality for the planet’s energy future. By providing solar energy to the individual, an energy supply becomes secure and available to people of both legacy and nonlegacy worlds and minimally contributes to an increase in the anthropogenic level of carbon dioxide. Because PE will be possible only if solar energy is available 24 h a day, 7 days a week, the key enabler for solar PE is an inexpensive storage mechanism. HY (Y = halide or OH−) splitting is a fuel-forming reaction of sufficient energy density for large-scale solar storage, but the reaction relies on chemical transformations that are not understood at the most basic science level. Critical among these are multielectron transfers that are proton-coupled and involve the activation of bonds in energy-poor substrates. The chemistry of these three italicized areas is developed, and from this platform, discovery paths leading to new hydrohalic acid- and water-splitting catalysts are delineated. The latter water-splitting catalyst captures many of the functional elements of photosynthesis. In doing so, a highly manufacturable and inexpensive method for solar PE storage has been discovered.

…

Concluding Remarks

PE is transformative in its scope to achieve a secure energy future, to provide economic equity to people of the nonlegacy world, and to stem the flow of nonanthropogenic sources of CO2 into our environment. However, downscaling current technologies to the personal level will not be economically feasible. Most energy systems are incommensurate with the very nature of PE because they have been designed to operate at large scale and high efficiency, and thus significant costs are associated with the balance of systems on a small scale. Hence, the solution to solar PE will be one that begins with a blank sheet on which the discovery of PE will be written. New materials, new reactions, and new processes such as those afforded by Co-OEC are needed to permit PE to be an attractive economic alternative. If the cost of solar PE through discovery can be decreased, then the development of the nonlegacy world can occur within an energy infrastructure that is of the future and not the past. Considering that it is the 6 billion nonlegacy users that are driving the enormous increase in the energy demand by midcentury, a research target of solar PE provides the global society its most direct path to providing a solution for its sustainable energy future.

…

[Statistical]

3. Well excluding equipment cost it requires roughly 3x the solar = 3x the cost.

Electrolysis of water (Electricity + H20 -> H2) is only about 60% efficient. Fuel cell stack for turning H2 back into electricity is about 50% efficient.

So the round trip efficiency

electricity from panel -> H2 -> fuel cell -> electricity is about 30%. So you even assuming the electrolysis equipment along with storage equipment, and fuel cell are completely free you could need a solar array roughly 3x as large to store energy as H2.

So your solar costs are roughly tripled compared to a grid-tie in system which efficiently sends excess energy back to grid (spins meter backwards) and draws from grid at night. Factor in standing loss from H2 (some H2 is lost) plus compression costs, plus all the equipment and it is likely more like 4x the cost of grid tie system.

[OKIsItJustMe]

4. 60% efficiency for electrolysis of water is not some sort of physical constant

Nocera is talking about a radically new (catalytic) process:

http://www.rsc.org/delivery/_ArticleLinking/ArticleLinking.cfm?JournalCode=CS&Year=2009&ManuscriptID=b802885k&Iss=1

…

Oxygen catalysis

Electrodeposition of the film is accompanied by vigorous effervescence of O2, as confirmed by mass spectrometric analysis. Mass spectrometric detection of O2 in real-time from ¹⁸OH2 enriched Pi and MePi indicate an isotopic ratio of ^16,16O2, ^18,16O2 and ^18,18O2 in agreement with the predicted statistical ratio, indicating that water is the source of the O-atoms in the evolved O2. The data shown in http://www.rsc.org/delivery/_ArticleLinking/ArticleLinking.cfm?JournalCode=CS&Year=2009&ManuscriptID=b802885k&Iss=1#fig2">Fig. 2a for films prepared in Co²⁺/Pi solutions is exemplary. Signals for all three isotopes of O2 rise from their baseline levels minutes after the onset of electrolysis and then they slowly decay after electrolysis is terminated and O2 is purged from the head space. The O2 isotopic ratios are invariant over hours (http://www.rsc.org/delivery/_ArticleLinking/ArticleLinking.cfm?JournalCode=CS&Year=2009&ManuscriptID=b802885k&Iss=1#fig2">Fig. 2b). The Faradaic efficiency of the catalyst is most conveniently measured by a fluorescence-based O2 sensor. http://www.rsc.org/delivery/_ArticleLinking/ArticleLinking.cfm?JournalCode=CS&Year=2009&ManuscriptID=b802885k&Iss=1#fig2">Fig. 2c shows the current passed during an electrolysis performed at 1.3 V (blue line) is completely accounted for by the quantity of O2 produced (red line). Moreover, the amount of O2 produced (95 moles, 3.0 mg) greatly exceeds the amount of catalyst (0.2 mg), which shows no perceptible decomposition over the course of the experiment. Thus, all current passed through the catalyst is used for O2 production.

…

[dpbrown]

5. Who would unrecommend this?

When I clicked on the link, it had six votes, when I read it, only four.

[OKIsItJustMe]

6. Another good question

Apparently, some people don’t want others to read about this technology.

[unc70]

7. Perhaps by those for more-centralized alternative energy

Those who want to spend huge amounts for infrastructure rquired for a centralized top-down implementation of alternative entery? That would be my guess.

Ever wander why we need all the new transmission lines and such if we are going to a distributed model of energy production -- micro generation at the same places it is being used?

[dpbrown]

8. People need to become their own flowers

Blooming little energy plants free of being shackled to the heroin line of forced power.

[excess_3]

9. just go do it

you don't need the permission of me or the US gov't

[hunter]

10. Residential energy use is the ugly canard of the power industry.

It diverts one's attention from the actual problem.

A residence doesn't really require any industrial scale energy sources at all. Our immediate ancestors lived without electricity, without air conditioning, without central heating. The Amish and lots of other people still do. I had great grandparents who only bought into Rural Electrification because purchasing and maintaining batteries for their radio was a nuisance. Having electric lights was handy too, but that wasn't the deal maker, they were comfortable enough with their Aladdin kerosene lamps which were the miracle technology of the time. And these lights didn't go out whenever winter storms knocked out the electric power provided you kept enough kerosene on hand.

The actual problem is industrial power. How do we make, fabricate, and recycle steel, aluminum, and concrete? Powering these energy intensive industries with wind or solar power is entirely unrealistic; the expense of doing that would cause in economic contraction so intense there would be little demand for steel, aluminum, or concrete in the first place -- no new cars, no new roads or road repairs, not even canned soda and beer. We'd be very much back in the world of my great grandparents, except maybe if our society didn't fall apart entirely, their radio would be replaced with a laptop, cellphone, and iPod. A solar panel might keep those charged.

I always think of it this way: If I want to cut my residential electricity use to zero I can do it any time I want to. All I have to do is walk out to the main circuit breaker, the one that says " 90 " on it, and flip it off. This would have some adverse impact on my family's comfort (washing clothes by hand is not fun...) but would in no way threaten our survival.

[OKIsItJustMe]

11. Out of sight, out of mind

The typical US electrical customer just has to plug in and pay the bills when they come. The bills may make them somewhat conscious of how much they're using, but just imagine if they had to shovel their own coal into a (hypothetical) home steam-generating plant…