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Our Performance

Find out what we delivered so far in RIIO 1

Our Performance

Find out what we delivered so far in RIIO 1

Ofgem expects us to efficiently deliver outputs for the revenues they allow us, and our current outputs were set by a stakeholder consultation process at the start of RIIO-T1 (Revenue = Innovations + Incentives + Outputs). A summary of our performance against these outputs can be found below.

Since the start of RIIO-T1, we have invested £1.3 billion in operating and maintaining the network, while returning £207m for planned work where the changing needs of our Customers has meant it is no longer required. We keep our plans under review, and under RIIO T1 we expect to invest £300m more than the allowances agreed with Ofgem because we believe this is the right thing to do for our Customers and Stakeholders. 

You can find our Gas Transmission performance summary for the fifth year under RIIO-T1 by following this link. We produce this report annually so that we
can explain how we have performed to our customers, stakeholders and end consumers. Under the RIIO-T1 contract our performance is assessed against five main outputs: reliability and availability; environment; customer satisfaction; customer connections; and, most importantly, safety. We hope that you find it useful and we welcome your feedback on how we can improve our report in the future.



We have delivered strong safety performance which is crucial to our stakeholders, the communities we serve and to our business. We are on track to meet government requirements for protecting our assets that are essential for securing UK infrastructure.

100% compliance with HSE legislation.

Our Injury Frequency Rate (the number of injuries per 100,000 hours worked) has remained low throughout the period.


Reliability and availability

We have maintained very high levels of reliability and availability for our customers to input and offtake gas from our system as and when they want to.

Despite needing to be more active in constraint management, we’ve continually reduced the number of maintenance days requested over the period, which ensures that our customers can continue to supply gas to their customers. 



As one of our key outputs under RIIO-T1, minimising the impact our business has on the environment is important both to us, and to our stakeholders.

A large part of our carbon footprint is made up of our gas powered compressors that moves gas from entry point to where it’s needed. Changing supply patterns have therefore led to increasing emissions in recent years.

We have responded with investment in low emissions technology to meet customers' use of the network. We are working hard to make sure we comply with the latest emissions legislation.

Customer and Stakeholder Satisfaction

We continue to respond to the changing requirements of an evolving customer base. Our satisfaction scores are steadily improving since RIIO-T1 began, whilst using the feedback to create detailed action plans to help us improve even further.


Customer connections 

All our commitments to provide timely and efficient connections to the network have been met. We recognise that our customer needs are changing, so we are improving to meet our customers' expectations. 

You can find more details on our performance in our annual stakeholder reports