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New solar storage solution could be the key to home-brewed electricity

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November 4, 2009

The system developed by Professor Nocera to store energy gathered from solar panels could ...

The system developed by Professor Nocera to store energy gathered from solar panels could usher in an era of personalized solar energy (Photo: Lasigro via Wikipedia Commons)

Reports of new developments in the area of solar power are an almost daily event here at Gizmag. The main focus of research seems to be on improving the efficiency of solar cells, but others are working at developing an inexpensive method of locally storing the energy generated by solar systems. Because society relies on a continuous energy supply and solar energy is diurnal, storage systems are integral to what some see as an inevitable move towards 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.

A new paper by Massachusetts Institute of Technology (MIT) professor Daniel Nocera describes the 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.

Nocera says that low-energy densities characterize most current methods of solar storage, including batteries. Consequently they present formidable challenges for large-scale solar personalized energy implementation. Though considerable efforts are currently being devoted to battery development, most advances have little to do with the energy density, but rather they are concerned with the power density (i.e., the rate at which charge can flow in and out of the battery) and lifetime. Energy densities of batteries are not only low (~0.1−0.5 MJ/kg), but there is little room for improvement because the electron is stored at a metal center of an inorganic network juxtaposed to an electrolyte.

However, because the energy density of liquid fuels (~50 MJ/kg) is greater than or equal to 100 times larger than the best of the current methods of solar storage, Nocera’s approach of using the solar energy to produce fuel for a fuel cell could be the key to offering affordable personalized solar energy in the not-too-distant future. Nocera also sees his solar storage solution as being a great leveler between the developed and developing world.

"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," states the report entitled "Chemistry of Personalized Solar Energy", which appears in the American Chemical Society’s journal Inorganic Chemistry.

About the Author
Darren Quick Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag.   All articles by Darren Quick
11 Comments

Just not true. Lead batteries cost about $100/kwhr for storage and easily pay for themselves by charging at night and sell at peak, even making money. So no net cost.

Solar happens mostly at peak so far more valuable than steady power in most places.

Nor are H2 systems energy dense. They take up much space, far more than batteries or their cost, containment makes them not viable. Fuel cells are far too costly and have short lives. Nor are they eff, only 25% as eff as batteries.

Just another H2 hype press release looking for fool's money.

jerryd
5th November, 2009 @ 06:03 am PST

Has this guy heard of the idea of putting electricity back into the grid? (effectively, your meter runs backwards) Withdraw as you require.

windykites1
5th November, 2009 @ 09:41 am PST

I believe he is describing generating electricity in off-grid locations (such as Africa). In the US, it makes sense to put the excess on the grid. It's easy money.

Rich Hessler Solar
5th November, 2009 @ 04:18 pm PST

Batteries and H2 are not the answer. What we need is more research in high-density, nano-scale supper capacitors. They charge almost instantly, they can hold the charge as long as the plates don't short, and they can be drained at a controlled rate to work like a battery.

EE_Tim
5th November, 2009 @ 07:35 pm PST

does the water used have to be distilled or can it be just used from unpurified water?

in some countries in africa people (or children) have to walk for 5 hours or more just to get water, and nearly always it is definetly not safe.

bio-power jeff
5th November, 2009 @ 09:23 pm PST

but the "new oxygen-evolving catalyst" which splits water into oxygen and hydrogen could mean a new method for generating hydrogen gas, from greener sources then coal.

bio-power jeff
5th November, 2009 @ 09:31 pm PST

Professor Nocera has the right idea but the wrong technology. The reason for bundling the solar with storage is to reduce installation costs. Flooded lead acid batteries used correctly are already 90% efficient. Fuel cells are more like 50% efficient. You cannot afford to waste expensive photovoltaic-generated power on inefficient storage technologies. Specific energy density is not that great an issue for stationary power generating installations because they can be relatively large and heavy since they do not have to be moved after installation. The problem is that because of this size, they cannot be mounted on the panels themselves, increasing installation costs. What is needed is a no maintenance, 90 % efficient battery with 15,000 deep cycles. Just such a battery is already claimed to exist at Altairnano.com. However, the company seems to be in decline due to deficient management or lack of capital.

Jonathan Cole
6th November, 2009 @ 08:15 am PST

There is a use when considering H-based vehicles. In the USA you may be lucky enough to travel on one battery-load but in Australia you can have up to 320kms or 200mls between service stations. I reckon Africa would be the same. On this basis anything that is going to stretch the distance a vehicle can travel would be of use.

Considering the distances & population of Oz the numbers of servos is unlikely to change by any great amount, especially across the desert.

Rex Alfie Lee
9th November, 2009 @ 04:19 am PST

By developing the rooftop solar hot water system to produce

super heated hp steam during the day and storing it overnight

for the continuous generation of power may also be a way forward?

Pommie
9th November, 2009 @ 02:40 pm PST

Any source of heat at 50F can generate energy. Just look at Rasser technology. the working medium is a refrigerant namely butane. The New Zealand Dsir had a thermal plant that produced 300 watts at their Antarctic research station 30 years ago but gave up development. Typical.

Hydrogen gas when burnt produces more thermal energy than the energy used to make it. Is it not about time some-one or group got there act together to produce a cheap source of reliable energy for home use. The rest will follow.

cheers John M. kiwi

John M
25th November, 2009 @ 09:19 am PST

Jonathan Cole. That 50% efficiency is only if you count its electricity production. If you use it as part of a Combined Heat & Power system (CHP), efficiencies are then lifted to around 75%-90%. Use the "waste" heat for you hot-water & to heat your home during winter, & use so-called Tri-Generation to generate cool air for Summer. Just FYI.

Aussie_Renewable
26th November, 2009 @ 08:56 pm PST
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