By now, you may have heard of the Ofgem initiative Market-wide Half-Hourly Settlement – or MHHS for short. It’s billed as the biggest change to impact the energy system since privatisation, and aims to bring far greater insight to how electricity is generated, consumed and understood.
As part of MHHS, any electricity supply which isn’t currently ‘settled’ on a half-hourly basis – that is where consumption is mapped every 30 minutes over each 24-hour period – will become so.
This not only impacts existing supplies served by Non-Half-Hourly (NHH) meters, but also unmetered supplies (UMS) that don’t have a Half-Hourly (HH) meter attached – for example, the electricity that powers traffic lights, street lights or CCTV.
P434 spotlights unmetered supplies
Changes to these unmetered supplies is set out in a new industry modification designed to support MHHS called P434 Half Hourly Settlement for UMS Metering Systems. This requires all existing UMS to become settled on a half-hourly basis.
It’s important to note that P434 and MHHS aren’t going to trigger a mass upgrade of all the UK’s electricity supplies without HH meters or automated-meter-reading (AMR) technology attached. Imagine the scale of that.
What P434 will do is prepare UMS sites for MHHS by profiling consumption data in a far more granular way, with the aim of accurately reflecting how much electricity is being used in every half-hour period.
However, there are changes that will impact you if you have any UMS in your portfolio.
Important changes to be aware of
Changes being introduced as part of P434 include:
- New information on your invoices: for example, the top line of your supply number will change, which includes changing your Profile Class to "00" to align with HH-settlement arrangements
- Meter point administration number (MPAN) consolidation: if your UMS inventory covers multiple MPANs, these will be consolidated into one MPAN under the transition from NHH to HH supply. Your existing Unmetered Supply Operator (UMSO) will be in touch to agree any necessary changes to facilitate this change
- The appointment of a Meter Administrator (MA): a MA is required to calculate your HH consumption data using details from your UMS inventory. This data is then provided to a HH Data Collector for settlement (and billing) purposes. If you are an npower Business Solutions (nBS) customer, we will appoint an MA on your behalf unless you tell us otherwise
- A HH Data Collector (DC) and Data Aggregator (DA) will also be required: to manage and process your HH data. Again, we will appoint a DC/DA on your behalf
Changes start in October 2024
For all nBS customers with existing NHH UMS, we will migrate you to HH UMS between October 2024 and 31 March 2025.
This will happen automatically – and we'll be in touch once your migration is complete.
Important action for now
If you think there may be any discrepancies within your existing UMS portfolio, it’s worth looking into this now.
Once the switch from NHH to HH has been completed, your UMSO may no longer be able to retrospectively adjust any charges associated with your NHH inventory. So we recommend you investigate any issues with your UMSO as soon as possible.
Finally, if you have any queries about P434, do reach out to your usual nBS account contact (existing customers). Or get in touch directly.
And if you want to learn more about MHHS, you can watch a replay of our recent webinar here. Or, you can take a look at our updated FAQs.
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