A lab at MIT, led by Dr. Daniel Nocera, have invented a new and novel form of storing energy that may prove to be an important milestone in the development of alternative energy. In fact, the obvious utility of the process has engendered a bit of excitement, but this excitement has also generated some misconceptions about the process that I would like to clear up, now that I have a more complete understanding of how it works.
In essence, what Nocera's group has developed is a method for splitting oxygen and hydrogen with far greater efficiency than the old electrolysis process. The process is essentially a catalytic one, and uses cobalt and phosphate compounds which react under a charge to form the final catalytic form, which splits the water into it's component parts using an electron transfer much like what occurs in photosynthesis. I don't want to rain on everyone's parade here, but I've been reading a lot of stories about this technology that miss the point about what the real breakthrough is here, and what it does. This is a vital development, but let's go through some misconceptions about what this technology is before I move on to what this technology promises.
1) This is not a leaf! A leaf is a highly complex organic structure that has many functions, including gathering light, converting it to a storable form, and water, gas and temperature regulation. This technology can only convert electricity into a more storable form; it's analogous to the process of gluconeogenesis (i.e. the production of sugars) in the leaf, not the leaf itself. You will still need to have some conventional photovoltaic system, and a fuel cell, to complete the 'leaf'. Part of the reason for this misconception is that the Nocera team did in fact show off a demo system that had all of those things together in one unit, but that demonstration of the value of the technology is not the story here; the water splitting process itself has so many other uses in the energy arena that it boggles the mind!
2) This is not a revolutionary solar product! This is a revolutionary way of storing free electricity. The source is irrelevant; it could be solar, sure! But it could be used to store energy produced from wind, tidal, or geothermal power. You could even use it to store power generated from fossil fuels, though I'm not sure how that would be useful, since fossil fuels themselves are already potent stored forms of energy.
3) This is not going to be on store shelves soon! New inexpensive compact systems will have to be developed to work with this catalyst to store gasses, and then convert them back into electricity in a closed loop, if the demo product that the Nocera group showed off is to become a reality. This will take time, as will durability testing of the catalyst itself. Catalysts are famously fragile, and it could be that under harsh conditions the catalyst will break down. If that is the case, then the unit that produces gases from electricity will have to be separated from the energy generation system in a separate, climate controlled unit, but this is not an insurmountable technical challenge by any means. However, in the research that the group has published, it does seem that the catalyst is pretty resistant to pH and temperature changes, which is a good sign that durability issues will not be a big headache.
What this technology represents is something even better than a mere power generation method; it's a way to put the methods that we currently have to generate clean energy to work for us in a huge way! Many people complain that they always see wind generators standing still, but this is because there is too much power available, and the grid can't handle the extra juice. Indeed, we wasted 25 TWh of potential electricity generation from windmills last year because we had no place to store the power! In the past, methods of storing this excess energy were terrible expensive (batteries) terribly inefficient (hydrolysis) or just terrible (complex and potentially dangerous spinning flywheels). Some estimates say that this new catalyst can break water at more than 10 times the efficiency of older hydrolysis methods, and this is an enormous leap in the right direction. This technology can level the load, and set aside the electricity output of these generators until it is needed. The result; we can run our wind generators 24/7, or as long as the wind holds out, and when it does stop we will still have flowing power! Similarly, we can store power from photovoltaic sources to use overnight, or on cloudy days. This technology will also make the production of gasses like hydrogen and oxygen for medical and welding uses far cheaper, and allow for the development of home 'fill up' stations for fuel cells and anything that could use a boost of oxygen! This is a huge development, but don't be mistaken; it is just one part of the puzzle, albeit a vital one. We will have to watch the development of the technology carefully, but for now I wish the best of luck to the Nocera team in developing this energy storage solution, because we need such things if we are to build a future of sustainable and uninterrupted power.
Crossposted at CleanTechnica