Batteries energy storage systems are being dispatched in the Balancing Mechanism more than ever before. And, of those batteries that are registered to provide Balancing Mechanism actions, Enderby has the highest dispatch rate - i.e. it is the most likely battery to be called upon (relative to the amount of time it’s available).
So, what is it about Enderby that makes it so useful to the Balancing Mechanism control room?
What is the Enderby battery?
Enderby is a 50 MW, one-hour battery. It is owned by Gresham House, and operated by Arenko - and it became operational in February 2023. Statera Energy developed and constructed the battery, before selling it to Gresham House in 2021.
It is distribution-connected and is located in Enderby, just southwest of Leicester. Somewhat confusingly, a second battery is coming later this year in Enderby - a 57 MW system owned by Gore Street.
What makes Enderby interesting?
Enderby started operations on 1st February 2023 - and has since seen consistently high activity in the Balancing Mechanism.
Our recent Deep Dive on Balancing Mechanism activity identified Enderby as having the highest dispatch rates of any battery in Britain. So, what’s driving this?
How is Enderby operated?
Enderby has earned most of its revenues (80%) from Dynamic Containment. However, 30% of its net revenues have come from the Balancing Mechanism. This is offset by wholesale trading costs to support (-10% of revenues).
In comparison, other Balancing Mechanism-registered batteries earn just 5% of their revenues from the Balancing Mechanism (on average).
This has led to heavy cycling on some days - including a high of 3.3 cycles on 22nd April.
However, the time it spends delivering Dynamic Containment results in far lower cycling - overall, the system is averaging 1 cycle per day.
What happened on 22nd April?
On 22nd April 2023, Enderby completed 3.3 cycles - with 2.6 of those cycles coming from its Balancing Mechanism dispatches.
- Across the morning, the control room dispatched Enderby several times for Offers (i.e. exporting/discharging). Enderby subsequently took wholesale actions to charge (and keep its energy topped up), ensuring further availability for more Offers across this period.
- Bids received before the evening peak then meant that Enderby had enough energy to sell into the wholesale market.
This example shows how wholesale trading can supplement Balancing Mechanism activity - and even lead to a greater number of dispatches than would have otherwise been received. Without charging from the wholesale market, Enderby would have run out of energy ahead of Settlement Period 18.
Why does Enderby get so many Balancing Mechanism dispatches?
So, we’ve looked at how Enderby has been used in the Balancing Mechanism - but why is it called upon so often?
There are five reasons why Enderby might get dispatched so much in the Balancing Mechanism:
- Pricing - does Enderby price itself more competitively to earn an advantage?
- Availability - does Enderby make itself more available to be called upon than other batteries?
- Operation - does the way Arenko operates the battery make it more appealing to the control room?
- Size - does Enderby’s relatively large (50 MW) size make it more useful to the control room?
- Location - does Enderby’s location mean it can solve issues on the grid that other batteries aren’t able to?
Price
Cheaper Balancing Mechanism actions should be more likely to be called upon by the control room. So, is this why Enderby receives more dispatches?
Overall, the answer appears to be no. Enderby has a slightly more aggressive Bid pricing strategy than average, but there are other sites that price Bids at a similar level and don’t see a corresponding increase in dispatches.
Meanwhile, Enderby tends to price Offers higher than the fleet average - and still receives the highest rate of dispatches.
If we look at the average price of accepted Bids and Offers - Enderby shows no real difference from the rest of the fleet.
Availability
So, is Enderby being dispatched because it’s more available than other batteries?
Well, there are systems providing a similar level of availability that do not receive the dispatch rate Enderby receives.
Although our dispatch rate calculation normalizes for how available a battery is, a higher rate of availability could lead the control room to become more comfortable in using a specific asset.
This is shown in the data - in general, higher availability means a higher dispatch rate.
However, there is a possible feedback loop here - the more dispatches a system is receiving, the more it is likely to make itself available.
Operation
So, perhaps there’s something in the way that Arenko operates the Enderby site that leads to it getting dispatched more? For example, we showed above (on the 22nd April) how using the wholesale market intelligently can enable a greater number of Balancing Mechanism dispatches than would otherwise have been possible.
However, two similar Arenko systems, Bloxwich and Byers Brae, do not receive the same sort of dispatch rate as Enderby - despite having similar availability and pricing patterns.
However, all three of these systems are in the top seven batteries for Balancing Mechanism dispatch rate. This suggests that the way Arenko operates these batteries is appealing to the control room - or otherwise optimized specifically for Balancing Mechanism dispatch.
Size
At 50 MW, Enderby is one of the larger battery systems available for use in the Balancing Mechanism. Because of this, it offers the control room the ability to achieve more with fewer actions.
In fact, the five batteries with the highest Balancing Mechanism dispatch rates are all 50 MW in size.
However, this does not explain everything. There are similarly sized systems, available for similar amounts of time, that receive much fewer dispatches.
Location
So, is Enderby’s dispatch rate down to its location? A key function of the Balancing Mechanism is to solve locational problems on the network - read more here.
When we explored the Whitelee battery, we discovered that a large proportion of its Balancing Mechanism actions are “system-flagged” - i.e. it is dispatched to manage specific, locational constraints. Therefore, we can reasonably assume that Whitelee’s location has a big impact on its high dispatch rate. Enderby does not receive system-flagged actions.
However, that doesn’t mean that its actions aren’t related to its location. We simply can’t tell.
Instead of managing constraints, Enderby may be being used for exactly the opposite reason. Since it is located in a relatively unconstrained location, it might be that Enderby can be called upon by the control room without adding to constraint problems. However, other batteries in the same GSP Group (East Midlands) aren’t called upon anywhere near as much.
That said, Enderby is located on a key north-south transmission line. This means that it could be being used to manage flows over this part of the system.
Though we can’t say for sure, it does appear as though Enderby’s location is a factor in its high dispatch rate.
So, what’s the answer?
A lack of transparency in Balancing Mechanism dispatch decisions means that there’s no definitive way of telling for sure why Enderby gets so many dispatches. However, we do know that:
- As a large 50 MW system, Enderby is definitely at an advantage - all five of the most dispatched batteries are the same size.
- It provides a lot of availability to the control room - which means more opportunities for dispatch.
- This availability is improved by trading activity - which allows Enderby to maintain its state of charge so that it can provide further Balancing Mechanism actions.
- It prices competitively, which increases the chance of being dispatched.
- And it is located in an area in which the control room might look to utilize the flexibility it offers.
It’s likely a combination of these five factors which leads to Enderby having the highest Balancing Mechanism dispatch rate of the whole fleet.
How else can you maximize your dispatches in the Balancing Mechanism?
The control room favors certainty - which means that data submitted should be as complete and as accurate as possible in order to maximize the likelihood of being dispatched.
This includes:
- Accurate submissions of physical data (FPNs, MELs and MILs).
- Dynamic data (ramp rates, non-minimum zero times, etc.).
Ultimately, there are some things that a battery cannot change (easily, anyway) - namely, its size and its location. However, operators can give their batteries the best chance of being dispatched in the Balancing Mechanism by ensuring that they are available as much as possible, and that they submit the correct data.