Skyllas-Kazacos is a genuine unknown to the Australian public. Yes if you Google her plenty comes up, but even amongst my friends not one seems to have heard of her, and that’s pretty much a collection of environmentalists and science enthusiasts. Yet her work stands a fair chance of transforming the electricity sector, and with it the whole issue of climate change.
Renewable energy suffers from the problem of being intermittant. The only form you can turn on and turn off are hydro power – which comes with pretty big environmental problems, and has limited sites. Geothermal also fits the bill; technically it’s not renewable, although it’s usually placed there and is similarly low on carbon emissions. However, so far geothermal isn’t cost-effective at most locations so we’re stuck with various forms of solar, wind and maybe wave, all of which don’t run all the time.
Opponents of renewables, and even some supporters, see this as an insurmountable problem for powering most of society on clean energy. You don’t have to hang around forums discussing the issue for long before you find people saying this. It’s almost as if batteries didn’t exist.
Nevertheless, there are plenty of problems with the batteries we do have. Either they don’t store that much electricity, or they’re hellish expensive or both. Many also leak toxic chemicals, don’t store well for long periods, take long times to charge up or only survive a limited number of charges before their performance degrades.
Which is why the vanadium redox batteries, Skyllas-Kazacos’ invention, are pretty damn cool. At the moment they’re expensive, but that’s because they’re manufactured using inefficient, labor-intensive techniques. As demand grows – and demand certainly is growing – manufacturing will improve and the prices will come down. There’s nothing inherently expensive about the technology. The only essential ingredient is the vanadium, and there are huge reserves of that. Prices spiked briefly when demand for top-quality construction steel steel went up before the Bejing Olympics, but now that more mines have come on line they’re back down to reasonable levels.
The chemistry involved is very neat, even to someone who finds chemistry the least interesting of the sciences. Vanadium has four charge states. So one one side of the battery you can have V2+ ions turning to V3+, and losing an electron in the process. The electron crosses a membrane and turns V5+ ions to V4+. By having vanadium on both sides the problems of damage to the battery when the electrolytes mix is removed, a major reason these batteries have a much longer lifespan than the alternatives.
Another neat thing is that the electrolytes are a different colour for each charge state, (see image) so you can measure how much charge is left in the battery by eye. Vanadium batteries are not damaged by overcharging of overdraining, and you can access all the energy stored in them.
Ok obviously there is a catch or we’d all be using them right now. Actually, on their invention there we a lot of catches. When Skyllas-Kazacos first demonstrated the idea worked the membranes available were bad and limited performance. That’s largely been fixed. Other problems remain, like the fact that the energy density is quite low so the batteries are large and bulky. Some people think they have an answer to that, but Skyllas-Kazacos is not convinced they’ve nailed it yet. Another problem, possibly also solved by the same research, is that the batteries only work well at a limited range of temperatures. This is a problem, but nothing that can’t be fixed with some good insulation, at least when you are talking about a back-up for standing energy.
Some have proposed vanadium batteries for cars, and they do offer a lot of potential there. If you run out of juice you wouldn’t need to spend hours charging your battery up, or replacing the whole thing on the Better Place model, you’d just roll into a power station, change over the electrolyte in minutes and leave the used electrolyte behind to be recharged by the station.
To get there we’re going to have to make a lot of improvements – energy density and temperature range in particular. However, if you’re talking about providing storage for wind or solar systems such developments aren’t needed, it’s just about getting the cost down through more efficient manufacturing processes.
All of this didn’t count for much in the days when solar and wind were really expensive. However, wind in many locations is now cheaper per kilowhat hour than coal, even without properly pricing carbon dioxide or more local pollutants. Solar costs a lot more, but as I regularly note, the price is falling so fast this won’t be the case for long.
Obviously it’s never going to be free to provide the back-up solar and wind need, but we’ve reached the point where all that is needed to bring the price of renewables plus storage into the same ballpark as coal is economies of scale from greater production. New technological breakthroughs would be nice, but they’re icing on the cake. Factor in a price on carbon and any location with a reasonable amount of sun and wind compared to the demand can be run this way. It’ll be harder where only one form of renewable energy is abundantly available, because the back-up will have to last a lot longer, but that’s certainly not Australia’s problem.