This outcome summary is available as a bilingual English/Welsh document in the 'Files' section below.

NNB Generation Company (Hinkley Point C) Limited applied to the Environment Agency to change its water discharge activity permit in December 2022.

The water discharge activity permit is a permit to discharge returned abstracted seawater from the cooling water system, fish recovery and return system, and other liquid trade effluents (including treated sewage effluent) to the Bristol Channel.

We asked for your comments during a consultation on the application from 24 January to 2 March 2023 (see Consultation), and on our proposed decision and draft permit from 25 April to 25 May 2023.

When we consulted, we explained that the consultations were not about the need for nuclear power, UK energy policy or policy relating to the siting of nuclear power stations.

During the consultations we shared information and explained our proposed decision. We emphasised that we would not make any final decisions until we had considered all relevant responses to the consultation.

We received 245 responses from organisations and members of the public

• For our consultation on the permit application, we received 50 responses
• For our consultation on the proposed decision and draft permit, we received 193 responses

All responses to our consultation (if the respondent gave permission) are published on this page.

Information about which organisations responded and how each response has been considered is included in our final decision document.

The Hinkley C project team would like to thank everyone who responded to the consultations and attended the online engagement meetings.

We have assessed the permit application, reviewed the evidence and carefully considered the responses we received from both consultations.

Our final decision is that we should grant the permit variation the operator has requested. We have added new limits and conditions in the permit to protect people and the environment.

The previous permit version (EPR/HP3228XT/V004) regulated the operational water discharge activities from Hinkley Point C – they are discharges of these non-radioactive liquid effluents:

• returned cooling water from the turbine condensers
• trade process effluents from the various plant systems (including those that maintain water purity and chemistry to keep the best operating conditions and maximise efficiency)
• treated sewage effluent (from staff welfare facilities)

The final varied permit will also now regulate the returned seawater through a fish recovery and return system.

As a result of our assessment on the impact of the fish recovery and return system discharge, we have included limits on volume, rate and the total biomass discharged from the fish recovery and return system outlet.

We have removed all conditions (or parts of conditions) relating to the acoustic fish deterrent (AFD).

We have concluded that there would be no adverse effect on the integrity of the relevant European designated sites (in relation to pollution from regulated discharges to waters) if there is no AFD in place. This includes those sites functionally linked to the Severn Estuary. The discharges will not result in the condition of relevant SSSIs deteriorating or prevent them from improving or recovering.

We have also concluded that the permit variation will not cause the current status of the water bodies to deteriorate or prevent them from achieving their objectives. 

The final varied permit includes the requirement to use an additional operating technique and an improvement condition. It also includes 2 pre-operational conditions which need Environment Agency approval before the proposed power station can be commissioned or begin to operate. These are included to make sure that NNB Generation Company (Hinkley Point C) Limited builds and operates the proposed power station according to the commitments made in its permit variation application.

The final permit, decision document and public summary are published below and on GOV.UK

Read more about our work regulating Hinkley.