Putting a battery with a wind farm in the US is more or less unheard of, because even battery backed wind is typically only able to bid for a fraction of its output in capacity and wholesale markets. So when Glidepath sent us a release about it this week, whereby it plans to buy up 149 MW of wind farms in North Texas and pair them with batteries, we took note.
Glidepath’s idea seems to be putting the same capacity in MWh as the wind capacity itself has in peak capacity, in batteries – so 149 MWh of battery for 149 MW of turbines. That would likely give it 25% of that capacity for four hours (37 MW) to support a wholesale bid.
The calculation of how much battery you need to achieve dispatchable power for any given resources is a complex calculation, but typically it is the amount by which the output can vary, in any given day, for the duration that the output varies. Wind is not straightforward – it can run at capacity, or go so slow as to be a fraction of capacity, say 15%. Anyone who has tested wind for two years in order to develop an output forecast for a turbine knows all too well how much it can vary. The battery should be enough to guarantee that can be turned that into a constant stream of energy.
But this really doesn’t seem to be what Glidepath is chasing, and according to its statement this is more about throwing in the battery, generating excess wind power, then using energy arbitrage to sell it at a higher rate, timeshifting the energy if you like, in order to get back the capex and running cost of the battery.
When batteries are used with solar, we know there is a period called night time, when the battery will be called upon, so it is easy to calculate the hours of darkness, and the call on the battery, and know what can be reliably offered. The solar also has to have spare unsold output during the day to fill the battery and that’s on its shortest and most cloudy day. It is a set of minimum calculations.
Now it is all well and good saying that batteries tied to wind farms are tougher to create a viable business plan around, but Glidepath, because it has sufficient cash reserves through its parent, Quinbrook Infrastructure Partners, can afford to be the pioneer here that will find out how best to make money out of this. Someone has to do it, then once accepted practice comes into the market, everyone else can rely on copying the model, to the extent to which it is public.
GlidePath uses Lithium iron phosphate battery (LFP) cathodes in its Lithium Ion batteries, which makes them cheaper than those built around other cathodes that use rare earth metals such as Cobalt, and this may be one of the keys to it specializing in battery technology. Even so most Lithium Ion batteries will last 10 years at best and need replenishing, so when working alongside 25 year assets, they get to be replaced a couple of times, which is why there is considerable pipeline in the rival Vanadium flow technology, which will usually last a project length.
Many of GlidePath’s operating portfolio is based around solar plus battery, although it claims it already knows how to optimize wind farms with energy storage.
By buying these wind farms, GlidePath’s now has 445 MW of live projects, and says it has a pipeline of over 1 GW of energy storage projects across the United States – we’d be surprised if anyone has much more than that – our own forecast for North American energy storage only suggests that 7.2 GW of battery will be installed over the next 3 years.
The Texas wind farms were acquired from Exelon Generation and include eight distributed wind energy projects north of Amarillo which serve the Southwest Power Pool (SPP) market. Terms of the sale were not disclosed.
One key instrument making all of this possible is the Federal Energy Regulation Commission (FERC) Order 841 which directed regional grid operators to remove barriers to the participation of electric storage in all wholesale markets – capacity, energy, and ancillary services. The Southwest Power Pool enacted it in May this year and this may be one of the key reasons that GlidePath has made this move now, although like any other market energy storage is subject to meeting the markets “adequacy requirements” for how long a wholesale service can run – usually at least 4 continuous hours.
This acquisition follows GlidePath’s recent announcement of the Prospect Storage project, a 10 MW/MWh standalone battery project located in the ERCOT market about 50 miles south of Houston. Prospect Storage is currently in advanced construction.
GlidePath’s pipeline of 1 GW of battery projects include deals in New York, Texas and throughout the PJM grid operator’s service territory.