SMART Frequency Control is smart by name – and by nature. It will deliver the fast frequency response that tomorrow’s low-carbon world will demand. And save National Grid and its customers up to a phenomenal £200m a year.
This blog is all about sharing the early breakthroughs we’ve made on the project. But before we do that, I’d like to recap what system frequency is – and why the project is so important and innovative.
System frequency is a measure of the balance between energy generated and consumed – a constantly shifting number that has to be managed and controlled. National Grid is duty-bound to keep it within plus or minus 1% of 50Hz – with Hz (or hertz) being the unit frequency is measured in.
Today, thermal power stations – such as gas and coal plants – are called upon when swift action is required to maintain frequency. These large plants, which use rotating synchronous (synchro) generators, actually provide a natural aid to achieving frequency stability because they provide inertia – the resistance of an object to a change in motion.
It’s a complicated concept to understand, but essentially this inertia can be released into the system – when needed – to keep it stable.
The problem we now face is that due to future carbon limits, more and more renewable sources of energy will come into the energy mix. This is great for the environment, but these sources don’t provide the inertia that today’s methods do. The resulting reduction is known to increase the risk of rapid changes to frequency – and the threat of severe faults or even blackout.
So we’ll require a greater volume and speed of frequency response to keep the system stable. However, relying on the standard, business-as-usual approach – with its normal response methods – isn’t a viable option. They’ll simply become too expensive to be sustainable.
Continuing on our current path of frequency response could cost up to £250m a year. So we’re fighting these figures head on with SMART Frequency Control.
Our project proposes a more sustainable and cost-effective way of doing things. We’ll trial newer technologies – such as wind farms, solar PV, energy (battery) storage and demand-side response (DSR) – to see how they can play a larger role in maintaining system frequency.
So where are we now? Well, let’s start with one of the areas that holds a lot of potential – battery storage.
We see battery storage as central to the mix of fast frequency response services that needs to be provided. A battery storage system can store the energy produced by solar, wind or hydro systems. And previous studies have shown it can play a key role in ensuring system reliability.
Our submission to Ofgem proposed we invest in a new battery storage unit. Costs were included for trials to be carried out at two locations, one of which would allow for combining battery storage with a solar PV plant. This hybrid approach is truly pioneering as it would be the first demonstration of such a concept in Britain.
However, to ensure the project provides the best value to our customers, Ofgem asked us to investigate existing battery storage sites within the UK, before they made a decision on whether we could go ahead and trial the new facility.
So we’ve been busy investigating existing sites. What we found was there’s actually a limited number that are suitable for providing the fast response that we’ll require. The main challenges of using these existing sites include significant delays in delivering the project and expensive costs to modify them to our needs.
So on the balance of cost, risk and value for money for our consumers, we recently submitted a report to Ofgem recommending the investment in a new battery storage unit.
As I write, we’re waiting for a decision, but we’re hoping to get this in the next month. If we do get the green light, the project will be able to proceed in the way we feel will be best for all our customers.
Monitoring and control
One of the project’s main goals is to develop a new monitoring and control system, which will collect accurate frequency data at a regional level, calculate the required rate and volume of very fast response, and then enable this required response to happen.
On this front, one of our project partners – power giant Alstom – has been busy developing the main control philosophy. In plain English, that means the way we’re going to be detecting the rate of change in frequency.
We’re currently involved in discussions around what level of central control there should be compared to regional control across the network. We want to be able to detect regional variations due to different levels of ‘non-synchro’ generation on the network. But we also need some sort of central supervisory element, which will enable us to do more high-level checks and provide an interface to the National Grid control room. It’s work in progress.
Alongside that, Alstom are developing a way of scheduling the different response providers. Once completed, this will do the job of co-ordinating proportionate frequency response where we need it.
We’ve also been taking significant steps with another aspect of the project – validating our findings. Academic partners at Manchester and Strathclyde Universities have started looking at how we’re going to be validating our work to ensure our results are accurate. Validation will be a combination of simulation modelling that represents the transmission system as well as testing control system hardware at Strathclyde Universities PNDC. This is important because it allows us to reduce the time, cost and risk associated with developing complex new systems.
Among the other frequency control resources we’ll be trialing is Demand Side Response (DSR). It’s another area we’ve made progress on. Partners Flexitricity have already shortlisted businesses from their customer base who expressed interest to participate, and produced an initial schedule of trials for these providers.
It’s no good doing ground-breaking work if you don’t share the progress you make and knowledge you build. We – and all our partners – are fully committed to this and Manchester University is submitting research papers and discussing the project at international industry forums. Meanwhile, back in May, National Grid presented alongside the institution at an important Institution of Engineering and Technology (IET) event, which was very well received.
We’ll be participating in important stakeholder meetings and industry conferences throughout the year. Most notably we’ll be exhibiting during the Low Carbon Networks and Innovation (LCNI) Conference on 24-26 November in Liverpool , and we’ll be carrying out lots of internal education about the project here at National Grid.
SMART Frequency Control has incredible potential and we’re busy planting the right seeds to allow it to flourish. It will provide us with an inspiring and cost-effective platform to manage system frequency in tomorrow’s world.
Read Charlotte’s previous blog about the project here.
And explore the finer details of SMART on the project’s microsite.