Waterford Estuary and SSE Generation Ireland Limited P0606-03

Water quality of the Waterford Estuary

Date released: 22 May 2020

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The EPA has received complaints regarding poor water quality and foaming in the Waterford Estuary which have been attributed to discharges from the SSE Generation Ireland Limited (Great Island) power station. The EPA has assessed SSE Generation Ireland Ltd (Great Island)’s compliance with their licence (P0606-03) and has found no evidence that SSE Generation Ireland are the cause of poor water quality (other than foaming). There are foaming issues at the power station and this situation is described below.

Industrial Emissions licence P0606-03

An EPA licence (P0606-01) was first granted to the ESB in January 2003 for the operation of an oil-fired combustion installation with a rated thermal input equal to or greater than 50MW. The licence was reviewed twice, in January 2005 (P0606-02) to provide for participation in the National Emission Reduction Plan (NERP) and in March 2011 (P0606-03) to provide for the replacement of the oil-fired plant with a new gas-fired combined cycle gas turbine power plant.  
The licence was transferred to SSE Generation Ireland Limited in October 2012. In December 2013, the licence became an Industrial Emissions licence.
A copy of licence register no. P0606-03 including the application is available on the EPA website. You can also review annual environmental reports and other enforcement documentation such as site visit reports at this location.
SSE made a technical amendment request to the EPA on 13/02/2020 seeking authorisation to maintain discharges at SW7 and SW8. SW7 is a storm water discharge which is required for the discharge of rain water and SW8 isscreen wash water discharge. The request also identifies an error in the licence review application for P0606-03 in regard to the usage of sodium hypochlorite. In the licence application, it was submitted that 5 tonnes per year would be used. In actual fact, annual usage is up to 1,300 tonnes. The EPA’s Environmental Licensing Programme has refused this technical amendment request. All information relating to this technical amendment request is available on the EPA’s website and can be searched at the following link Licence search.


In 2016 the EPA first received complaints of foaming in the Waterford Estuary attributed to the SSE discharge of cooling water. Investigations concluded that the foam was due to mechanical action on the discharged cooling water at the outfall.  Booms were installed in 2019 to contain any foam generated at the outfall. After that, there were no complaints of foaming until the weekend of 18-19 April 2020. The licensee (SSE Generation Ireland Limited) is currently investigating further measures to prevent the discharge of foam.

The EPA will maintain close surveillance of the licensee’s preventative actions to achieve an early conclusion of the foaming problem.

Shellfish mortality

In 2016, and again in 2019, the EPA received reports of shell fish dieback and other marine life health issues in the Waterford Estuary. These reports alleged that the discharge of chlorinated cooling water at the SSE power station was, at least in part, a contributing factor. the EPA has investigated this allegation and has found that SSE are compliant with the licence limits on the concentration of chlorine in the discharged water and found no evidence that SSE’s discharge is having such an effect on shell fish and fish mortality.  Chlorine (in the form of sodium hypochlorite, NaOCl) is added to cooling water at intake to prevent fouling of pipes within the power station. This anti-fouling agent is added to the intake cooling water when the water temperature exceeds 10°C.
SSE are currently completing an ecological survey in the estuary and a sampling and modelling exercise to examine the potential for negative effects of discharges from the power station.

Chlorine concentration limits, as set out in licence register number P0606-03, are 0.3 mg/l at SW2 (the main cooling water discharge) and 0.5mg/l at SW8 (screen wash water discharge).

Water quality in the Waterford Estuary

It is evident that the power station at Great Island is not the only potential pressure on water quality in the Waterford Estuary.  The EPA has consulted with other State bodies and we note shellfish dieback has been occurring over many years, not just in the Waterford Estuary but around the whole coast.

Currently there is limited information on the nature and extent of shellfish dieback in Waterford Estuary or the reasons for such mortality. There is, consequently, insufficient evidence to conclude which individual pressures, if any, are contributing to the impacts on marine life in the estuary.

Data on water quality in the Waterford Estuary is available at https://www.catchments.ie 

Licence enforcement

The EPA is responsible for enforcing industrial and waste licensed activities.  Where the EPA forms the view that there are breaches of any licence that is not being addressed by the licensee, further enforcement action will be considered by the EPA in line with its enforcement policy.

Making Environmental Complaints

Make a complaint to the EPA.

Update 08 October 2020

SSE submitted the revised Sodium Hypochlorite Modelling Report and Marine Ecological Survey on the 19th of July 2020 as requested and the Agency is currently reviewing these documents.

OEE Inspectors visited the site on 23/07/2020 and 10/09/2020 in order to observe discharges of cooling water. During the site visit, free chlorine monitoring was undertaken at SW2 & SW8 using a HACH DR300 Pocket Colorimetric. The results of the monitoring undertaken during the site visits were compliant with the emission limit values set down in P0606-03.

SSE Great Island submitted a licence review application to the Agency on 29th of September 2020. This application is being assessed by the Environmental Licensing Programme and information regarding the application can be found via our license search page. Interested parties can make a submission to the EPA– click on the “Make a Submission” button at the link.

The EPA has an open compliance investigation in relation to the foaming issue at the SW2 discharge from the facility. Further mitigation infrastructure is planned to be installed by the licensee in October.

Update 18 December 2020

On 30/09/2020 the Agency carried out a site visit in response to an incident reported by the licensee under condition 9.3 of their licence.  The incident involved the accidental activation of the firefighting deluge system during maintenance resulting in a discharge to the storm water system.  There was a small discharge of water and firefighting foam to the area immediately around SW4 before the storm water system was isolated.  This area was immediately cleaned by the licensee to remove foam from the foreshore. The licensee has confirmed that the firefighting foam does not contain per- and polyfluoroalkyl substances (PFAS) and is fully biodegradable. Our inspection concluded that the licensee had taken appropriate measures to minimise the impact of the incident on the environment. 

On 27/10/2020 the licensee installed further mitigation measures to prevent foam generation at the cooling water outfall at SW2. The installation of rock bags means, on low tide, the water percolates through the rock bags and prevents the waterfall effect which can contribute to foam generation. The licensee is monitoring the effectiveness of the rock bags and will provide periodic reports to the Agency.

Update 14 April 2021

SSE (Great Island) have stated that the usage of sodium hypochlorite in 2019 was 1128 tonnes and in 2020 was 525 tonnes. Under IE licence P0606-03, the EPA regulates the emission of chlorine in the used cooling water discharged to the Waterford Estuary. No non-compliant emissions have been recorded at the discharge (SW2) during monitoring undertaken by both the Agency and the licensee in the period January2019 to date.

Update 12 May 2021

The EPA has received five complaints regarding foam at the outfall from SSE Great Island since 06/05/2021. SSE Great Island informed the Agency that the floating boom (foam abatement) installed at the outfall in September 2019 has been submerged under water and inoperable since Friday 6th May. SSE verbally informed the Agency that this occurred as a result of a build-up of seaweed on the barrier which caused the barrier to be submerged. SSE Great Island further informed the Agency that they have contacted the appropriate contactors to repair and rectify this issue, which will be completed by Friday 21st May 2021.

Update 20/05/2021

SSE Great Island notified the Agency on 18th May 2021 that the floating boom (foam mitigation) across the outfall had been repaired as of 14:30 on the 17th May 2021. A further complaint relating to foam discharges from SSE Great Island was received on the 19th of May 2021. The Agency is currently assessing the performance of the floating boom as foam mitigation. 

The Agency have been informed by the SSE Great Island that following further investigations, sodium hypochlorite is now added to the intake cooling water only when the water temperature exceeds 12°C.

Update 09 March 2022

The Waterford harbour has been identified as a Priority Area for Action as part of the River Basin Management Plan. Information regarding the Waterford Harbour as an Area for Action is available from https://www.catchments.ie/data/#/areaforaction?_k=qzppod

Update 07/06/2023

SSE (Great Island) have stated that the usage of sodium hypochlorite in 2021 was 529.1 tonnes and 161.3 tonnes in 2022. The 2022 usage is lower than previous years as the site was on a major outage from 20th March 2022 to 27th August 2022. Under IE licence P0606-03, the EPA regulates the emission the concentration of chlorine in the used cooling water discharged to the Waterford Estuary. No non-compliant emissions have been recorded at the discharge (SW2) during monitoring undertaken in the period January 2021 to date.

Further information regarding SSE Great Island’s compliance & enforcement correspondence with the Agency is available via the LEAP online portal (https://leap.epa.ie/).