UKH

Anyone with knowledge of grid level batteries. Have 425Kw Hydro scheme looking info on:

Store power from low peak to high and use spare capicity on grid connection when not generating full power

Get better power pricing ie reak time spot intead of PPA

Reduce DUoS charges.

Set up battery in community for EV charging via virtual metering

We looked into battery storage for our 490kW bio-gas system but it was uneconomic, we increased the gas storage and installed an extra 500kW generating capacity instead.

Have you thought about storing surplus water in the head pond rather than surplus electricity in a battery? There may be good (space/cost/environmental/regulatory) reasons why you can't of course.

jk

Run of river scheme unfortunately and a flashy burn so after heavy rain 0 to full power 20 mins,  

Going to be difficult financially, we priced using Tesla Powerpacks which are 236kWh so we needed 2 per hours output and they come in around $116,000 each so for 24hrs generation (the contracted shut-down time) a cool $5.6million. Plus all the junk around them probably another couple of million. Then there's the efficiency which might be 80% on a good day. Ten year guarantee means selling a lot of electricity at 13c/kWh before they need replacing.

€380.000 for another generator plus the same for the installation looked cheap!

WHA??  Why Tesla powerpacks? was minimising weight a consideration?
You know that forklift (reachlift) traction batteries are about £500 each 2nd hand (24v 450Ah - 5h). Wouldn't 10 of those do the job for £5k?

The downside is you need to top up the distilled water now and again depending on how much you use them

oops just read you needed 24 hours not the 2 I thought you said, so maybe much more than £5k, but definitely less than millions!

Buying new ( the things have to last 20 years or so about 1.5-2m for traction batteries, if they can take the charge/discharge rates that is. Plus maybe .5m for the chargers/inverters.

Batteries in terms of energy storage/cost are still pathetic especially when you are only talking cents/kWh (the current feed-in for off-peak demand is 6c and it costs us 5c to produce).

I can't speak for the economics, but in terms of the overall efficiency of the system you can't beat using the grid as a battery.

So you're looking to store 24 * 425Kw? That's over 10MWh! 😯

You say it's a 425kW scheme, I presume that's peak generator capacity? What's the peak export capacity? How much surplus energy per flood do you think you could store in an ideal world, I presume you've modeled this?

Even assuming you're only looking to store a small fraction of that peak output the storage and conversion cost is going to be significant. You describe a flashy burn, if a flood allowing peak generation lasts say 6H and, guessing you're at about 50% peak capacity under normal flow conditions (because why oversize the machinery much more than necessary) that's: 6*0.5*425=1,275kWH of storage needed. Ignoring conversion losses if you sell all of the stored surplus at 20p/kWH to the community that's ~£250/flood, maybe £5-10k/year extra income from an investment that at a *very* rough £150/kWH would cost you at least £200k, quite likely 2-4x that all in with little hope even considering the long term increased flexibility it would give you over when to sell of recouping the investment before the battery needed replacement. How far would that sort of money go toward increasing your export capacity? Maybe that's the sort of budget and return you had in mind or maybe some of my numbers are miles of but it sounds to me like a problem that potentially isn't worth solving at current prices.

How close is your community, how big and convenient for local housing/amenities is your parking lot, how good are your flow forecasts... could you dump it directly into other people's EV batteries parked on site for a more modest supplemental income?

Could you sell the surplus directly as heat instead? Most of the surplus is presumably available in the cooler months (assuming northern Europe).

Can the flashiness be reduced? That seems to be generally desirable anyway from a flood alleviation perspective so an opportunity maybe to leverage your investment by engaging other stakeholders. How many saplings and beavers would your £200k get you

jk

The typical problem with renewables, the amount of storage required is brutal and with batteries kinda uneconomic. We have loads of solar in our area (you can't feed into the grid with a new installation) and a sunny weekend we get taken off the grid, we used to store the gas but have to start burning it off after 24hrs. Now we get a premium for supplying the back-up power at night and were allowed to increase the maximum we can generate. The next step is start producing hydrogen which makes more economic sense than battery storage.

So you now have nigh on 1MW of generation capacity - What on earth are you using it for?! Or are you simply ensuring you can use up your excess biogas?

Sounds like digging a 'millpond' would be a good idea.

As someone with a small, flashy burn I’ve been watching the thread with interest.  

Mill ponds are not a high density store of energy.  If you can build one with a ten meter head (say a wide shallow pond above a run of the river system), one measly little kWH needs 37 m³ of water.

The volumetric energy density of water in a pond is atrocious.  I guess milling didn’t need that much power; our mill pond is long gone but I gather it would be trickle charged all week and used up over several hours.

Here’s my maths in case I’ve made a stupid mistake in the volume estimate:

• E = 1 kWH = 1 KJ/s x 3,600 s = 3,600,000 J 
• E = mgh
• m = E / (gh)
• m = 3.6e6 / (9.81 x 10) = 36,697 kg

Err it replaces a bit of the power our local nuclear power station doesn't produce any more (thanks Greens!). The CO2 certificates go to greenwash German railways coal produced power.

Oh Crikey!  Showing my age as I read this thread title as Grid Bias Battery. 

I did a quick price up with LiFePO4 cells from China and I think it'd be about £2M just for the cells for that amount of storage. It would be a lot cheaper than Tesla but building a battery that size is no mean feat!