Frederiksberg Forsyning has replaced ten of its vehicles with Nissan all-electric vans and has installed ten special “bi-directional” charging points. Its engineers unhook their vehicles in the morning, go off to their jobs around the city and return the vehicles to the charging point in the afternoon. After that the batteries are at the disposal of the grid.
Nuvve’s software, which was developed in the University of Delaware in the US, connects to the grid and constantly monitors its energy requirements. If there is a fluctuation in power it can call on the multiple batteries on its system, to smooth it out within seconds.
“We call this a virtual power plant” says Marc Trahand, chief operations officer for Nuvve in Europe. “All these small batteries put together .. become one big power plant that you can then activate onto the grid."
I don't quite get it. Why put the batteries on vehicles, where they won't always be available to the grid ? Surely it's better to have dedicated energy storage facilities rather than using cars that may or may not happen to be available ?
More interesting, I thought :
Ravi Manghani, director of energy storage at Greentech Media thinks other storage ideas are worth exploring: “Compressed air is an interesting technology,” he says. “It can be a form of bulk storage.”
One company that has investigated compressed cold air is Alacaes in Switzerland – it’s drilled a hole in the side of a mountain to store air that can be used to drive a turbine. “The downside is it has to rely on specific geological formations… It needs underground caverns which in itself is a limitation”, says Mr Manghani, of this technology.
But Highview Power Storage, founded in the UK in 2005, is convinced by the potential of cold air and is developing a technology that it says is a world first. Using refrigeration, the company cools air until it is liquid at minus 196 degrees Celsius, and stores it at a low pressure. Liquefaction is a tried and tested technology, but Highview has moved it on to a further level.
At the Pilsworth energy storage facility in Bury, near Manchester, the firm has built a prototype plant that uses heat generated by burning waste gas from landfill, to re-expand liquid nitrogen. It’s pushed through an expansion turbine which drives a generator and puts electricity back on to the grid. The plant is due to be connected to the UK grid in the next couple of months.
I seem to recall that both compressed air and liquid nitrogen being touted as alternative fuels some years back, but they never really went anywhere. We'll see.
http://www.bbc.co.uk/news/resources/idt-sh/disruptors_smart_power
On a small scale a fixed instalment would might be better, but the goal is to have this enabled on all EVs. en.wikipedia.org - Vehicle-to-grid - Wikipedia
ReplyDeleteWhy put the batteries on vehicles, where they won't always be available to the grid ?
ReplyDeleteIsn't the point that, if you've got battery vehicles, not using them to smooth out the grid when they're available is wasting an available resource. Imagine the situation where the entire country has battery powered vehicles. At any given time, a reasonable percentage of those vehicles are going to be plugged in. If the system's allowed to syphon off even just the top 10% of charge to smooth out grid spikes when needed, that's a huge resource that would otherwise be sitting idle.
I've also read a report that said V2G can actually extend the life of a battery. However, while searching for the reference I found another saying the opposite. I guess the jury is still out on that point...
ReplyDeleteThe problem with compressed air storage is that it is very inefficient. The base version is to compress ambient air in bottles, but compressed air heats up considerably - heat that is wasted energy. Then, when you release it, the expanding air becomes frigid, to the point it can freeze up the mechanism.
ReplyDeleteIt also has very bad power density and requires bulky, thick high-pressure bottles.
The cryogenic version is probably much more power-dense (I would be curious to see their numbers), but they most probably have the same problem of energy losses, in this case with energy spent cooling the gas.
It is not an option if energy generation is expensive. However, if you can get cheap but unreliable energy generation (that is, cheap renewable), it becomes an option to simply eat the inefficiencies.
Flywheel may be an interesting option in the future. The theoretical energy density is limited by chemical bound strength, the same as for superconductor solenoid batteries - I've read numbers in the 50 MW/kg range.
Without going to those extremes (bulk superdiamond flywheels may be a bit too far in the future, plus margin safeties), those could be a high-density option.
In addition, they could conceivably also be used as centrifuges, an option many developing nations will appreciate, I'm sure.
The downside is that they will probably be high-maintenance, require great care and precision, and failures will be spectacular - though at least without the chemical or radiological dangers of other spectacular failures. (Depending on what was in those centrifuges, that is.)
Elie Thorne here's something else gravitricity.com - Gravitricity
ReplyDeleteOliver Hamilton and there's ARES, doing the same thing with rails...
ReplyDeletevox.com - The train goes up, the train goes down: a simple new way to store energy
Oliver Hamilton That's interesting!
ReplyDeleteAs they say, the biggest cost would be digging the shaft, but it looks like a great idea for existing holes.
They say they expect the cost of digging to decrease significantly. What kind of technology is in development on that front?
Alun Jones That's a good one too!
I wonder what the maintenance cost is.
Alun Jones The description of ARES is a bit misleading, I think. It isn't the trains that store energy, it's the huge weights that are transported up the hill and stored there. It's like pumped hydro, with the weights being analogous to the water, and the motor generator trains being analogous to the pump/turbines. Motor generators are apparently very efficient.
ReplyDeleteKent Crispin yes - the article I linked to was the best description I could find on a quick search. I saw a good article about it a year back, but couldn't find it again...
ReplyDelete