Dynamic Containment – a look into the crystal ball

After the excitement of January 2021, which saw Day-ahead prices of £1,500/MWh and Balancing Mechanism (BM) prices of £4,000/MWh, it feels strange to write about the comparatively mundane topic of Dynamic Containment (DC). However, it’s perhaps easy to forget that current prices of £17/MW/hr (resulting in battery revenues of £140+/kW/yr.) are just as exceptional and are going to be vastly more important to the returns from battery systems this year than value obtained through trading -something almost no one was saying would be the case in 2021 a few years ago when frequency response was old news.

The market is clearly in a phase of transition so the most important questions for investors and developers are: how long are these prices likely to last, and what will things look like afterwards?

What is Dynamic Containment?

Dynamic Containment is a new, fast-acting, dynamic post-fault frequency response service, the first of National Grid ESO’s (NGESO) new suite of frequency products. It is designed to stabilise grid frequency in case of large generation or consumption drop-outs, such as the interconnector trip on 28th Jan.

Dynamic Containment response from Open Energi unit during IFA2 trip on 28th January 2021.

Anyone who has been around the market for a while will know that trying to predict frequency response prices has bitten people badly in the past – we only need to look back to the crash of Firm Frequency Response (FFR) rates in 2018 and the current rates observed in DC. However, improved transparency from NGESO and the dominance of lithium-ion storage now makes it a little easier to understand the market and predict where things are heading (famous last words…).

So, let’s look back at the recent past and the three main frequency response markets to understand the dynamics at play.

Graph showing Frequency response prices from March 2020 to February 2021.

As expected, supply and demand volumes are the driving factor for prices, illustrating a competitive and functioning market. Price discovery varies by market based on the frequency of procurement – the monthly dynamic FFR market takes much longer to settle at a new price than the daily DC market, which found its cap within a few days. DC is more valuable to NGESO than Dynamic FFR meaning those who can have left FFR to provide DC. In turn this has reduced the competitive pressure in the FFR market and raised prices for the monthly tenders. Essentially, the additional 500MW requirement which arrived with DC implementation has massively unbalanced the market in favour of providers.

This means that for forecasting the price forwards in the near term, the most significant elements are: NGESO’s requirement for frequency response volumes, the volumes of storage competing for these services, and the relative price caps NGESO sets for each service.

Dynamic Containment requirement for 2021

On the demand side, luckily NGESO have published their forecast requirement for DC for the entirety of 2021, along with dynamic FFR requirement through to July 2021. Interestingly this shows a significantly higher requirement in the summer, which is perhaps to be expected given lower system inertia at this time.

Forecasting supply is a little more tricky. We know no other technology than storage looks able to meet the increased technical requirements of DC (namely speed and response) at scale and therefore we can use the pipeline of storage being developed over the next few years. Given the favourable investment environment and current sky-high DC prices, we can expect most of these to be bought forward to completion (this could see 500MW+ of storage being built this year!) and all of this capacity should be able to immediately enter the DC market. We expect a portion of dynamic FFR participants to continue to switch across to the higher value DC service. There are also some long-term FFR contracts coming to a close, along with EFR contracts doing the same towards the end of 2021.

Putting all of this together, and we start to get a picture of what things might look like in 2021.

Graph showing the supply imbalance up to Dec 2021.

As we can see, this current market oversupply looks likely to remain in place until at least Q4 2021. It is actually incredibly hard to create scenarios that brings this point forward, given the higher requirement across summer and capacity not expected to enter the market until the autumn. This leads to the current high prices being maintained until late 2021 (as long as the price cap remains the same). When market saturation does occur, we would expect DC prices to quickly fall towards those available in the weekly and monthly FFR markets, and track these downwards from that point on at a rate similar to what has been observed historically.

As we can see, this current market oversupply looks likely to remain in place until at least Q4 2021. It is actually incredibly hard to create scenarios that brings this point forward, given the higher requirement across summer and capacity not expected to enter the market until the autumn. This leads to the current high prices being maintained until late 2021 (as long as the price cap remains the same). When market saturation does occur, we would expect DC prices to quickly fall towards those available in the weekly and monthly FFR markets, and track these downwards from that point on at a rate similar to what has been observed historically.

Other things which could affect the value in 2021 (likely in a positive way) would be the introduction of high response DC and moving to EFA block procurement, albeit neither of these is certain to happen this year.

2022, by contrast, is a whole lot more complicated. The biggest factor at play here is the possible introduction of the remaining two new frequency response services: Dynamic Moderation and Dynamic Regulation. Initially scheduled to be introduced by March 2022, we now expect this point could be delayed towards the end of 2022. This then brings a few questions which right now are difficult to answer: will this see additional volume as with DC? What price will NGESO be willing to pay for these services? What assets will even end up being able to provide the high utilisation regulation service? If these products are introduced along the published timescales, we would expect to see a similar distruption of the market as seen with the introduction of DC with high prices in the short-term, albeit perhaps one resolved quicker as there will be more storage online to meet the requirement.

Other big questions are: what state do the 200MW of EFR batteries emerge from their contracts? Will they be able to jump immediately into providing these new services? And finally, will we see another bumper year of newly built batteries as we expect in 2021?

To keep things simple, if we assume the new products won’t be introduced for much or all of 2022 then as long as dynamic FFR volumes are maintained this should lead to similar market dynamics being at play in 2022. All in all, this could see 100MW or so swing the market significantly one way or the other, depending on whether the higher summer requirement sees the supply imbalance returning and prices moving towards the cap again.

Graphs showing the energy supply type differences and pricing forecasts for 2021.

Frequency response prices have shown previously they have the potential to fall as low as £3/MW/hr in a saturated market, given the operational costs of providing frequency response are so low for batteries (a bit of efficiency losses and degradation). This time however arbitrage markets will provide significant opportunity cost – given the improved access to and consistent value demonstrated by trading and the Balancing Mechanism in particular. Batteries no longer have to accept rock bottom  revenues and become price makers in the frequency response market.

Beyond 2022, this optionality is going to be the main factor driving frequency response prices, as we expect storage capacity to start to significantly exceed the requirement for frequency response services. This will see prices starting to reflect the value available in these other markets, especially with EFA block (or even half-hourly) procurement. At this point, we would really hope to see price caps on frequency response prices removed or lifted to enable the market to function efficiently – otherwise next time prices of £1,000/MWh occur in the day-ahead expect to see much more volume exiting the market to chase this value. An example of a market functioning across multiple revenue streams can be found in Australia, where system operator AEMO manages procurement of both frequency response and energy, with price caps of $15,000. This sees prices vary significantly on a half-hourly (or even 5-minutely) basis in response to the requirements of the grid and value from arbitrage in the spot market.

Graph showing the Australian FCAS price fluctuations November 2019 to Jan 2020.

So, in summary: we can expect 2021 to be a very good year for storage assets capable of providing Dynamic Containment, but if anyone is telling you we will see the same in 2022 treat this with a huge pinch of salt. Be sure to engage system integrators and optimisers early to ensure assets are ready to go into DC on day 1. And ultimately, optimisers having the ability to seamlessly trade across 5+ potential markets whilst managing state of charge and warranty constraints will be vital to maximising battery returns.

Batteries in the Balancing Mechanism

The Balancing Mechanism (BM) is the primary flexibility market in the UK. In 2019 over 2TWh of flexibility was procured through the BM with a value worth over £800m. Batteries are only a recent (and small) participant – the vast majority of flexibility is provided by CCGTs and some through pumped storage such as Dinorwig.

Batteries have had over a year in this market and have steadily seen increases in activity, helped by the introduction of the Distributed Resources Desk, while upcoming Project TERRE could also help non-traditional providers receive dispatches. Hence, while batteries remain a niche player in the BM, compared to the dominant technologies of CCGT and pumped storage, there has been a steady increase in activity.

Figure 1 – Activity by batteries in the Balancing Mechanism has been increasing over the last year

Batteries in the BM – The Basics

The Balancing Mechanism is manually dispatched by the ESO Control Room – providers submit prices and volumes but only deliver (and are paid) when selected. Dispatch decisions are made based on a number of operational criteria, of which volume and price are just two. For example, only certain technologies are able to meet certain needs: thermal plant provide inertia but batteries don’t.

However, battery storage does have its own unique benefits as batteries can respond extremely quickly and accurately in either direction. This quality is being exploited by the Control Room with batteries delivering short bursts of power of mostly under 10 minutes duration (see fig 2). Traditional thermal providers cannot do this, given their ramp rate restrictions.

The most obvious difficulty batteries bring is that they are duration limited, whereas a gas power station could increase its power indefinitely. This means, once a battery has discharged completely, it cannot sell any more energy and so must recharge, either through trading or by waiting to be dispatched in the other direction. Batteries can be dispatched in either direction throughout the day – even if the system is long, batteries may be offered up, and vice versa, so leaving the battery empty (or full) would result in missed dispatches and lost revenue.

Figure 2 – A day of BM actions for a battery, light area showing availability and dark bands are dispatches. Most dispatches are under 10 minutes in duration.


State of charge – The limiting factor?

State of charge (SoC) is, therefore, a massively important consideration for both operators and National Grid alike. However, unlike the physical restrictions of thermal plant (such as minimum output), SoC is not captured in the BM, given it is a novel issue. We can infer when SoC has drifted significantly, though, as batteries adjust their available power (MEL and MIL) to represent 15 minutes of storage. This means that when less than 15 minutes output is available in one direction, the system can only be dispatched at this reduced level.

For a two-hour system this only has a small impact – state of charge can drift significantly in either direction before this limit is hit. However, for a one-hour system the impact is much more significant, as the battery could potentially be offering up reduced availability 50% of the time.

Overall, taking a much more active role in managing SoC is necessary to maximise benefit, especially for more limited duration batteries.


Being Active

Market optimisation of batteries within the BM takes two forms: integration with other trading strategies, and through much more dynamic provision of bid and offer price. Both of these offer solutions to more actively managing SoC to reduce time spent offering reduced availability.


The most obvious route to managing SoC during the course of the day is through the intraday markets. If one or more offers in a row start to deplete SoC, energy can be bought on the intraday market to recharge the system. However, doing so may not always be the optimal solution – eg if the price is too high, or perhaps it is likely a bid will arrive soon anyway.

An advanced optimisation and forecasting solution combining manual and automated inputs is needed to effectively manage SoC through trading; system warranty is a constant consideration and confidence will be needed that any actions will increase profitability later in time.

For the example below, purchasing just 30 minutes of energy at the time shown would increase total daily returns by 13%.

Figure 3  – A day of BM actions for a battery, with energy purchased through intraday markets around 9am (green), and corresponding increase in availability and dispatches shown in grey



Although operators have no control over whether their assets are dispatched in the BM, they can influence the likelihood of being dispatched in either direction by adjusting their posted prices, or by providing stepped bids and offers.

Increasing bid price in response to low SoC could be provided to increase the chance of dispatch, in order to then capture higher revenues across the whole day. Meanwhile, stepped bids and offers provide the Control Room with two or more prices, which can be paid to access different levels of power output.

However, this route still has a limitation in being dependent upon being dispatched, even if the probability of being so can be influenced.



The BM has long been talked about as the holy grail for battery operation but there is still a lot of uncertainty over when (and indeed whether) that point will be reached as system balancing transitions from CCGTs (with infinite duration headroom and footroom) to fixed duration energy storage.

However, recent activity has provided good signs for batteries to be the principle candidate to take over from CCGTs as the UK moves towards net zero, and we expect to see further design aspects of the BM to be updated in favour of storage assets, to enable NG ESO to meet its target of zero carbon operation by 2025.

Meanwhile, value from the BM continues to increase and challenge frequency response revenues – Open Energi and Erova Energy will be launching our Balancing Mechanism offering in the coming months, so watch this space!


For a free consultation about trading in the Balancing Mechanism, call +44 (0)20 3051 0600