The first major point to observe is that the PV farm operator that is billing $40 per MWh to LADWP is able to bill that on every MWh they despatch, EVEN MWh's that go straight from the PV panels into the grid, bypassing the battery completely. The LADWP does not know whether the energy has flowed through the battery or not, and indeed does not care.
The amount of electrical energy that goes via the battery turns out to be only about 20% of the total - so for every 5 MWh of energy supplied 4 goes direct from the PV panels and only 1 goes via the battery, but the PV farm owner gets to bill $20 x 5MWh - so for each MWh that goes via the battery they get to collect $100, not $20.
The 'Solar+Storage' is a fully integrated offering, considered superior to a 'solar only' one and so gets rewarded with higher prices. The storage element can very effectively piggyback on the solar farm and does not have to try and justify itself in some sort of pricing vacuum.
So the big question is how you get from the capex cost of the batteries (perhaps $400 per KWh) to the $20 per MWh cost that is charged by the PV operator to the LADWP once it is up and running.
This Capex corresponds to $400,000 per MWh of battery purchased and installed. Naively it would seem that you would have to spread that over 20,000 charge-discharge cycles to seemingly get down to a cost of $20 for each MWh of electrical energy discharged. Are they using flow batteries, or amazing new Lithium-ion batteries that last 5 times as long as the conventional one - and if so how are they getting 20,000 charge-discharge cycles when even over 25 years the sun only rises and sets 9,125 times ?
The answer, of course, is that the naive way of looking at it is incorrect.
So the PPA bidders bid roughly $20 per MWh if their plant was a solar only one and $40 per MWh if the plant was a solar plus storage one. The people paying for the plant (Los Angeles District of Water and Power - LADWP) had requested the two options so that they could see the extra cost of adding the storage that would allow them to take energy later on in the day.
Note they were not asking to turn a PV system into a complete baseload source of energy - something, like a nuclear reactor, that delivers energy at a constant rate, day or night, whether us humans want it or not. Baseload is not what they, or the residents of Los Angeles want or need. An afternoon/evening peak of power consumption is what we generate, and very little at 3am in the morning. So forget about the fictional holy grail of baseload that is an irrelevant non-argument put out by the baseloadists.
So the cost of having that option - to have energy supplied more when humans need it rather than when the sun happens to be shining or the Uranium atoms happen to be splitting is only $20 for each MWh we use - roughly 1/4 of the extra cost of providing the electricity by Nuke, or roughly 1/9th of the extra cost of providing it with a conventional gas fired peaker plant ($200 per MWh of energy supplied.)
... part 2 after dinner
According to ( https://www.in2013dollars.com/uk/inflation/2012 ) GBP 92.50 in 2012 pounds is now equivalent to as near as dammit GBP 110 today.
So energy from UK offshore wind is only 36% of the cost of energy from a UK/French nuclear reactor. Impressive but of course the nuclear lobbyists and the climate deniers will be the first to point out that the wind doesn't blow all the time, and at night it is dark.
Hence the need for batteries.
'But batteries are sooooo expensive' they say. This article, and the USD 40/MWh PPA bids proves categorically that they are not.
Okay so the authors were trying to understand how some recent power purchase agreements (PPAs) in the US were able to come in at the amazing price of $40/MWh for PV generation (INCLUDING STORAGE)
As a reminder you may remember that last year the UK astounded everyone with offshore wind projects that came in at the previously unimaginably low price of £39.65/MWh (https://home.kpmg/uk/en/home/insights/2019/09/contract-for-difference-subsidiary-auction.html )
Another fixed point to remember is the £92.50 (2012 prices) that everyone in the UK will be paying EDF for electricity generated by Hinkley C, when it is eventually built ( https://www.gov.uk/government/collections/hinkley-point-c )
No questions anybody ? - Everyone understanding clearly how batteries that might have a capex of $300/kWh can only add $20 per MWh of solar plus storage ?
As a guideline a conventional peaker plant would cost around $200 for each MWh of energy supplied.
is covered in a great article here - https://www.energy-storage.news/blogs/battery-storage-at-us20-mwh-breaking-down-low-cost-solar-plus-storage-ppas
I will be around for a semi-interactive Q&A session on this paper at 6pm on the BMN forum later today - I expect there may be some of you guys who would be interested in that discussion.
Paul - it is not about BMN being more developed it is about the fact that the entire VRFB industry is more developed. It has been the largest game in town for the last 20 years+. There are dozens of manufacturers. It is a genuine industry segment not a fly-by-night company with a unique chemistry.
We will continue to hear of those hopeful startups and their American professors for years to come but in my opinion they will not make a serious commercial contribution to flow battery energy storage over the next 20 years, not now the Vanadium producers have teamed up with the VRFB manufacturers.
What is interesting is the configuration of flow battery and Lithium-ion bank of course.
I had originally assumed that the Lithium-ion battery was the short duration battery, dealing for example, with the FFR service provision (as most of the Lithium-ion battery projects in the UK have been) , whilst the flow battery would be the long duration battery dealing with the daily peak shifting. It turns out that in this demonstration project they are actually using the flow battery to do the rapid cycling for FFR balancing, as it can be cycled many times per day without degradation, thus saving the Lithium-ion batteries from heavy cycling and instead meaning that they only get exposed to perhaps only a single charge-discharge per day.
I believe that this combination was chosen so as to provide a degree of redundancy, so that all their eggs are not put into a single battery technology.
From an economics point of view it is cheaper to add energy storage to the VRFB than it is by adding Li-ion batteries - you simply make bigger electrolyte tanks and buy (or lease) more electrolyte. Having proven that VRFBs can do all the hard jobs - fast response, multiple cycles per day without degradation it will then be a simple matter to taper out the Li-ion component in future projects and displace them with VRFBs with larger electrolyte tanks. In fact that might be the expected plan when the Lithium-ion batteries inevitably die.
you are all missing the essential element that makes Vanadium flow batteries unique. They have the same electrolyte on both sides of the battery. EXACTLY the same, so the inevitable diffusion through the membrane ceases to be an issue.