Overlapping metering standards hampering flexibility

Overlapping asset metering standards are hampering the ability of “behind-the-meter” assets to provide flexibility services, increasing costs and creating a risk of stranding, industry figures have warned.

Alistair Martin, chief strategy officer for flexibility aggregator Flexitricity, said under the current arrangements, “asset meters” embedded within devices such as car chargers and heat pumps cannot be used to provide flexibility services unless they meet the same standards as the “boundary meters” they sit behind.

Speaking to Utility Week, Martin said meeting these standards requires device manufacturers to add “a bunch of features, none of which are necessary in the asset metering role and all of which involve making the thing look like a normal electricity meter”. These include an external display, a flashing LED and particular communications ports.

“If you’re going to do that, don’t bother adapting the charge point, just buy another meter,” he remarked, adding that this would cost around £200 per site. On this basis, Martin said installing a separate asset meter for electric vehicle (EV) chargers for all 10 million of the UK’s homes with driveways would cost a total of £2 billion.

The requirements in questions come from the EU’s Measuring Instruments Directive, which sets out standards for the design, manufacture, and verification of measuring instruments used in trade, such as weighing scales, gas meters, and electricity meters. The directive was transposed into UK law through the Measuring Instruments Regulations (MIR) 2016.

Martin said none of the EV chargers currently on the market meet the MIR requirements, meaning in practice, parties using them to provide flexibility services effectively “throw away” the data from embedded asset meters and instead use data from the boundary meters for the sites.

The problem with this is the flexibility provided by the asset gets diluted among the households’ general consumption, meaning if people happen to turn on the oven or take a shower at the same time, “then your numbers go wrong”.

Martin said there is an exemption within the regulations for half-hourly meters measuring flows in excess of 100kW – the level at which half-hourly metering was required prior to the introduction of smart meters and the market-wide half-hourly settlement programme.

He said the government should extend this exemption to cover asset meters that are compliant with one of a series of codes of practices (CoPs) created by Elexon to define standards for different types of meters within the Balancing and Settlement Code (BSC).

Martin said the particular code in question – CoP11 – provides a “gold standard” for embedded asset meters that should be considered sufficient, although perhaps not necessary, for participation in most flexibility services.

In a document outlining its proposals, Flexitricity said CoP11 “echoes the accuracy requirements” of all the codes of practices created by Elexon, with meters measuring very large resources required to be more accurate than those measuring domestic-scale assets.

CoP11 requires that embedded asset meters have an error limit for power measurements of plus or minus 2% to 2.5%, depending on the frequency, voltage and current conditions.

As well as prescribing accuracy standards, CoP11 also requires a variety of performance assurance measures concerning certification, approval, commissioning, record-keeping, testing and life-cycle management.

Flexitricity said metering requirements vary between flexibility services, with the requirements for tenders by the six distribution network operators (DNOs) currently considered a “work in progress”.

William Goldsmith, head of grid and data services at ev.energy, said there has been a “range” of wording in DNOs’ previous contracts, with some saying meters must have an accuracy that is equivalent to the requirements of the Measuring Instruments Directive, “which we assume refers to plus or minus 2%,” and others referring to an “appropriate code of practice”, which is “really vague”.

Flexitricity’s proposal document said UK Power Networks and National Grid Electricity Distribution have now issued “tractable” standards that are consistent with the accuracy requirements of CoP11, although Martin said National Grid Electricity System Operator is “just waking up” to the issue.

Although it may not be necessary for embedded asset meters to meet all of the requirements of CoP11 to participate in all flexibility services, Martin said compliance with the code should be sufficient for most of them, with the exceptions being specialist services. He said the most important requirements concerning accuracy should certainly be “good enough” for most services.

Goldsmith noted that large fleets of thousands aggregated devices have a “big advantage” in terms of accuracy as the law of averages means errors in one direction tend to be offset by errors in the other. Flexitricity’s proposal document also noted that the accuracy of embedded asset meters can be cross-checked against boundary meters over many events using statistical analysis.

The company pointed to frequency response as an example of a specialist service for which the CoP11 requirements may not be sufficient. It said the newer frequency services require higher resolution data but are also valuable enough to justify investment in meters with very high sample rates.

Flexitricity said the current “confusion” around embedded asset metering is exacerbated by the Electric Vehicles (Smart Charge Points) Regulations 2021, which stipulate that EV chargers must have a metering accuracy of 10%. It said there is “a danger that this accuracy standard provides a false sense of security” as this will not be sufficient.

Goldsmith said the “whole reason” for the regulations was to prevent people installing chargers that are unable to provide flexibility services further down the line, but in fact they are increasing the risk of asset stranding. He said the accuracy requirement of plus or minus 10% seems to be completely arbitrary, adding that “no one know where it came from and it doesn’t align with any metering standards at all”.

As well as extending the exemption in the general metering regulations to embedded asset meters, Martin and Goldsmith said they would like to see the government align its requirements for smart devices, including the accuracy requirements in the smart charging regulations, with CoP11.

Martin said “there’s a lot of there’s a lot of industry push now, and it’s appeared quite quickly, to get this sorted out, because assets are going on walls. There are charge points out there in the hundreds of thousands. None of those are compliant with the asset metering requirements or the MIR or anything else so there’s already a massive cost burden that we’re accumulating”.

Thankfully, Goldsmith said most EV chargers currently being manufactured probably do at least meet the CoP11 accuracy requirements: “We’re semi optimistic that what is being installed today actually can and will meet this standard, but there’s a there’s a quite a big margin of uncertainty and it won’t be everything.”

He said none of them are currently CoP11 certified but Flexitricity and ev.energy are working with some manufacturers to demonstrate that “it can be done in a cost effective manner and therefore all manufacturers should be doing it.”

The Energy Networks Association declined to provide a response but did point out that it is working to harmonise flexibility standards as part of the Open Networks project. The ESO likewise declined to comment but said it is investigating the issue with industry partners through the Operational Metering Working Group for its Power Responsive programme.

The government had not responded to a request for comment at the time of publication.