Understanding the RHI: Keeping Your Payments on Track

The RHI Is Closed — But Existing Participants Continue

The Domestic Renewable Heat Incentive closed to new applications in March 2022. The Non-Domestic RHI closed in March 2021. No new installations can now join either scheme.

However, if your biomass boiler was registered before those closing dates, your payments continue for the full 20-year term of your accreditation. For many participants, that means payments running well into the 2040s. The total value of those payments — spread across two decades — is significant, and protecting that income stream is worth understanding properly.

This article focuses on what Ofgem requires from existing participants, what puts payments at risk, and what you can do to stay compliant.

How RHI Payments Work

Payments are made quarterly by Ofgem (the Office of Gas and Electricity Markets, which administers both schemes) based on the amount of heat generated. For the Domestic RHI, the payment rate is applied to deemed or metered heat output depending on the system type and size. For the Non-Domestic RHI, metering is generally required for larger systems.

Payment rates were set at accreditation and are adjusted each quarter in line with the Retail Prices Index (RPI). This means your tariff rate increases slightly each year in line with inflation — but only if your accreditation remains active and in good standing.

What Ofgem Requires

Ofgem's Participant Obligations are set out in the RHI regulations and your accreditation terms. The core requirements for biomass systems are:

Maintain the system properly

Your boiler must be maintained in accordance with the manufacturer's recommendations. In practice, this means:

• Annual servicing at a minimum, carried out by a competent and ideally manufacturer-trained engineer
• Keeping dated service records, including what was done and by whom
• Acting on any faults or advisory notes promptly

There is no specific requirement to use an Ofgem-approved engineer, but using a HETAS-registered engineer or manufacturer-approved service agent is good evidence of competent maintenance if your installation is ever audited.

Use an eligible fuel

Biomass boilers must use eligible solid biomass fuel — wood pellets, wood chip, or logs from sustainable sources. Fossil fuels cannot be used in the boiler at all. The sustainability of your fuel supply may need to be evidenced; for most domestic participants using ENplus-certified pellets or Woodsure Ready to Burn logs, this is straightforward. For non-domestic participants using large volumes of chip, you may need to demonstrate compliance with sustainability criteria under the applicable threshold rules.

Meet metering requirements where applicable

From August 2018, Ofgem introduced the Domestic RHI Metering and Monitoring Service Provider (MMSP) scheme for certain system types and payment tiers. If your accreditation includes a metering obligation, you must:

• Have a functioning heat meter installed and calibrated
• Ensure meter readings are submitted accurately and on time
• Notify Ofgem if the meter develops a fault

Non-domestic systems above certain sizes have been subject to mandatory metering from earlier in the scheme. Meters must be MID-compliant (Measuring Instruments Directive) and calibrated at the intervals specified in your accreditation conditions.

Report changes to your installation

If you modify the system — changing the boiler, adding or removing heat emitters, changing the fuel type, or making changes to the property — you must notify Ofgem. Failure to report material changes is a compliance breach.

Submit accurate periodic declarations

The Domestic RHI requires annual declarations confirming your system is in use and maintained. The Non-Domestic RHI requires quarterly declarations alongside meter readings. Missed declarations can result in payment suspension.

Suspension Risk

Ofgem has the power to suspend payments while investigating a compliance concern, and to reduce or recover payments if a breach is found. Common triggers for investigation include:

• Missed or late declarations
• Meter readings that appear inconsistent with the installation details
• Third-party complaints or tip-offs
• Changes reported by network operators or energy suppliers

Suspension does not automatically mean permanent loss of payments, but it does mean an income stream that may have significant remaining value is interrupted, potentially for months, while Ofgem investigates. Getting the basic obligations right costs very little. The consequences of not doing so can be severe.

Practical Steps to Protect Your Payments

1. Keep a service folder — store every service report, fault report, and engineer invoice in a single place. If Ofgem audits you, you need to be able to produce these quickly.

2. Book your annual service before the anniversary date — do not let it drift. A service that is even a few weeks overdue can put you technically outside your maintenance obligation.

3. Check your meter regularly — if your installation has a heat meter, verify it is reading correctly. A stuck or faulty meter is a problem you want to find and report yourself, not have flagged by Ofgem.

4. Read your accreditation terms — the specific conditions vary between accreditations. Know what yours say. If you have lost the original documentation, Ofgem's participant portal (ROES) holds your accreditation record.

5. Notify before making changes — if you are considering any modification to the system, contact Ofgem or take specialist advice before proceeding. Making changes without notification is a compliance breach even if the changes themselves are perfectly reasonable.

6. Keep contact details updated — Ofgem sends compliance notices and correspondence by post and email. If you have moved or changed email address since accreditation, update your participant portal details.

The Value at Stake

It is worth pausing to consider the financial context. A domestic biomass boiler with a 12.2 p/kWh tariff generating 20,000 kWh annually receives around £2,440 per year, rising slightly with RPI each quarter. Over a 20-year term, the total payment could exceed £50,000 before RPI uplift. For larger non-domestic systems, the values are multiples of this.

Protecting payments of this magnitude is simply good financial management. The administrative burden of compliance is modest. The risk of not taking it seriously is not.