Member Info for Alfacomp

Ophidian, well a stirling engine is just one form of thermodynamic heat pump that turns a temperature difference into useful work. There's other subtly different cycles that you can take a working fluid around that allows work to be extracted - see for example:- http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heaeng.html#c3 . If you have a source of heat, and also a source of cooling then you can extract useful work from the heat on the high side as you pass it out to the cool side. The thermoelectric effect gives you the same thing but in that situation the species that are actively carrying the entropy are electrons and not atoms of a gas or liquid.

Those will have to be on their own 3-phase supplies no doubt - have a read of this:- https://pod-point.com/guides/driver/charging-electric-car-at-home

faramog - home eV chargers have a rate of no more than 8kW

Larky, yes I am most definitely considering getting a company eV. With economics like those described in this video https://www.youtube.com/watch?v=g6r5SRM2H3A , and the changes in company tax rules it is quite compelling.

Vauxhall Viva - there is the cost of energy stored (typically quoted per MWh) and the cost of building the energy storage plant (typically quoted per kWh).

They are quite different things - the first is cost of energy (COE) for each time you get 1MWh out of the plant whilst the second cost is the Capex you would need to build a plant, per kWh of storage energy capacity.

To go from a CAPEX cost to the COE cost you need to know how many times you expect the battery to be cycled, and over what period. Eg if it was a very bad battery and could only be cycled 10 times the COE cost would work out around 1/10th of the CAPEX cost. Similarly if the 'battery' can only be used once a year, eg when a lake is refilled or the moon and sun are in perfect alignment then your going to be getting hit by the finance costs on your CAPEX and it doesn't matter that the battery is going to run for 100,000 cycles the COE is not going to be 1/100,000 th of the CAPEX

The point I'm getting at is unless you know what the assumed duty cycle and financing costs are then you cannot work out the COE even though you may know the CAPEX perfectly. Another way of putting this is if you are a manufacturer of said plants then there is always the potential to 'tweak' these numbers so as to get a headline grabbing COE number.

RichKen and CowboyInvestor - there is some mention of this in the article here:- https://www.thebushveldperspective.com/blog/public-articles-1/post/energy-storage-europe-2019-415 - this describes the UK national grid's Future Energy Scenarios (FES) in 2018 (http://fes.nationalgrid.com/media/1363/fes-interactive-version-final.pdf when the reduction in emissions was meant to be only 80% in 2050, not the 100% it is now mandated). This considers multiple different projected scenarios with Community Renewables (CR) and Two Degrees (TD) having similar amounts of eVs takeup assumed, vis:-

"The Government’s aspiration
to end sales of conventional petrol and
diesel powered cars and vans by 2040
is met. EVs become the most popular
personal mode of transport. "

The effects that this has on total grid storage capacity is estimated as 50 GW for CR and 35 GW for TD, of this they are assuming that 20.6 GW (CR) and 17.9 GW (TD) would be provided by Vehicle-to-grid (V2G) energy storage. Pretty hopeful I would say given that only a single eV manufacturer is offering V2G capability on their cars, and it ain't Tesla.

This leaves 18-30 GW of true grid battery energy storage that will be required. Very conservatively this was assumed as 1 hour storage, but it is becoming increasingly clear that the average storage duration in the future is heading towards 4 hours, and that all the low hanging fruit of 30 minute and 1 hour storage for frequency firming will have been dealt with (no problem its only a very small fraction of the long term storage you could use for peak shifting/peaker replacement.) The amount of long term storage increases as the amount of renewables generation increases, especially PV with it's obvious daily cycle which does not match the peaks in demand.

Vauxhall Viva - my doctorate is in cryogenics so I should like these things.

However I don't - the reason for this is that compressing gas to make liquid cryogen liberates very large amounts of heat. Normally this is a problem and you simply chuck it away, because it s the cryogenic liquid that you want as you want to do something at the low temperatures that it provides. If you are using cryogenic liquids as a store of energy then you cannot afford to through the heat away as that would massively hurt your round trip efficiency - thus the problem becomes one of not just cryogenic storage but also heat storage, typically in some low cost material, like rocks.

The idea is that you bring the hot rocks back into contact with cryogenic liquid, generate high pressure gas which turns a turbine and you get your energy back. One concern is that this process ultimately causes great thermal stress on the rocks, making them break down, not in itself a major problem but it is powdered dust generated from this that would get carried to your turbines and which may end up wrecking them. The other concern that I have is the essential inefficiency in all cryogenic liquification systems - there is significant thermodynamic irreversibility in all liquification processes which ultimately will affect the round trip efficiency of any energy storage system that utilises such a gas-liquid phase transition. Thermodynamic efficiency is never really considered a priority in conventional liquifaction systems so I would be very wary about basing an energy storage revolution upon such an approach.

Finally I was discussing flow batteries with one of my contacts in the industry a few weeks ago - it seems that there was an InnovateUK competition a few years back that they had put together a GBP 15M flow battery application for but that this ultimately got trumped by the Highview power cryobattery. I had understood that these research grant competitions were meant to avoid civil servants having to 'pick winners', something that they have been loathe to do in the UK since the 1960's - however it seems that they have simply outsourced the picking of winners to someone else - in this case the innovateUK judging committee, however this is comprised.

Larky - I take it your are referring to the 200MW battery referred to here:- https://www.drax.com/press_release/drax-starts-planning-process-battery-storage-gas-options/

We have had some direct interactions with their public relations team on Twitter, but there was zero information transfer in that process. They were holding up their purchase of a 1960's built pumped hydro station as evidence of their commitment to energy storage, oh that and funding a couple of PhD projects on batteries...

So whilst the UK goes about it's business like this, with bluster about past achievements and sticking plaster investments in new technologies Germany has multiple Fraunhofer institutes actively developing VRFB battery technology - eg Fraunhofer UMSICHT near dusseldorf developed the fully edge welded flow battery stack that Volterion (German company) is now selling to Voltstorage (German company), Visblue (Danish) and quite possibly H2 (S. Korea) in future.

??? - does any have any for me ?

Halespur - it has become clear this weekend what Coffeecups true colours are. You say profit he says worry. You say plans ahead he says why hasn't it happened already. You say black he says white. All in the interests of 'balance' no doubt.

It is clear that he will now say anything to bash the company and has no real interest in the truth. I won't be engaging with this sort of time-wasting leach in future as I have a useful job to do in covering the ongoing energy transition for all those who are genuinely interested and invested here.

I think that we have established reasonably conclusively here that the profitability of the business will not depend solely on Tin prices but Tantalum recovery rates.

is coming. Read this:- https://www.nrel.gov/docs/fy19osti/74184.pdf

Sorry I thought you had posted it to the wrong board.

I think that is somewhat off-topic Liion

playing silly games on the closing Auction - trade of 1 share offered

It would appear that this is a mechanism for converting kinetic motion of the aqueous solution into electrical energy. This is essentially the same thing that a water wheel does, with the associated issues of being able to supply sufficient flow of water in order to get any serious amounts of energy out.

Hamil - like submarines and high rise buildings there is nowhere to easily run to if a fire does break out so safety is definitely another key point in VRFB's favour. Do we know anyone who builds ships ?

That ferry uses a 4.3MWh battery (from Leclanche not Lechanche as stated in the article) - compare this with our 450kWh battery at Eskom - that is a 20 foot container size. So roughly 4.5 container sizes if you use VRFBs. Obviously it would be smaller if you built it into the ship instead of packaged it within containers. I'm not sure the same approach can be used with Lithium-ion batteries, not without risking that a fire might not be containable.

Personally I don't think that many mobile applications suit VRFBs (historical golf carts excepted). The weight is not the issue per se, as if you use regenerative braking then the extra energy you have to put into getting the battery moving is offset by the extra energy you can put back into it when you slow down. Also the size is not so much the issue, in eg the train situation, as having to have 1 full carriage stuck on the back of the train is not significantly worse than having to put half an extra carriage on the back of the train. No I think it is actually the vibration that is the VRFB killer for trains.

Ships however, that's another matter:- https://www.euronews.com/2019/08/20/world-s-largest-all-electric-ferry-sets-sail-in-denmark

dubmaskullanga - the problem with wind is that the sails don't fit under the bridges