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Statement of Works

WPD are required (under the Connection and Use of System Code) to make a request for a Statement of Works (“SoW”) to National Grid Electricity Transmission plc (“NGET”) in relation to the potential impact of connection of embedded generation on the National Electricity Transmission System (NETS). 

Please click here for our SoW Guidance Document giving further details of the process.

NGET will undertake an initial assessment of the significance of the embedded generator(s) on the NETS and inform WPD of this through a SoW response.

Recent SoW requests made by WPD to NGET have highlighted widespread issues on the NETS that require mitigation. This is due to the cumulative impact of connecting new generation to the distribution system. NGET often require WPD to impose conditions on generator sites in many areas to modify the operating characteristics of the generator units. This may include, without limitation, a requirement to operate at a specific power factor, to have the capability of operating within a power factor range and/or to constrain the export capability to zero at certain times.

In certain areas NGET have indicated through their SoW response that they will have to reinforce parts of the NETS prior to the connection of any further generation capacity. Where this arises WPD will need to make a formal Modification Application to identify the detail, scope and costs of these works. Customers who initiate these works will be required to fund the cost and may need to wait for NGET to complete the reinforcement. The costs will be significant and the associated construction timescales lengthy.

Where customers are required to fund the cost of NGET’s works they may be required to assume both attributable and wider system liabilities and also provide security to cover that liability. Click here for further information on WPD’s requirements for satisfying liability and security conditions.

NGET’s SOW responses covering the WPD distribution area are available to view here. More information on the SoW process can be found here and here.

To find further Statement of Works information please view our Network Capacity Map here.

As part of a trial change to the Statement of Works process through WPD Bilateral Connection Agreements with NGET, WPD will be providing to NGET a list of relevant embedded generation connected beneath each Grid Supply Point. This contains the list of historic and proposed generation sites including size and technology, attached as an “Appendix G” to our formal agreement with NGET.  Part 5 of this Appendix provides the summary information, redacted versions of which can be found here.

If a Customer is willing to temporarily reduce their export capacity at times of peak network usage then WPD have a range of "Alternative Connections" which may allow connection with reduced costs and/or improved connection timescales. Please click here for further information regarding the types of connection WPD can offer and the areas in which these are available.


South West update

On the 27th January 2016 WPD received Modification Offers from NGET, detailing the work and/or conditions that must be met prior to the connection of generation identified in our SoW submission. See the update below:

WPD South West Statement of Works Update March 2016


South Wales and West Midlands update

In May 2016 WPD received notification from NGET (National Grid Electricity Transmission) to advise that due to a significant increase in levels of embedded generation connecting in the South Wales region, NGET  studies were highlighting concern around capacity and system overloads at peak times.  This resulted in NGET imposing a restriction on all new thermal plant connecting at Grid Supply Points (GSPs) in the South Wales region. This NGET restriction did not apply to renewable types of generation such as solar and wind. The restriction was extended to Port Ham GSP (West Midlands) in May 2017.

On 28th September 2020, WPD received an update from NGESO (National Grid Electricity System Operator). The update confirmed that due to a combination of factors (changes to the contracted background, the formal closure of large thermal plant on the system, the embedding of the Capacity Mechanism and new information on the market behaviours and the role of batteries in providing both flexibility and a range of other grid services), NGESO are able to lift the restriction upon new thermal plant connections in South Wales and Port Ham GSP.

Whilst the restriction on thermal plant has been lifted, any new connections will be subject to assessment by WPD via their standard design process and by NGESO via the Statement of Works/Appendix G process.  These assessments could still highlight more local restrictions on both the WPD distribution network and NGET transmission system which could limit capacity availability in certain areas.  Any local capacity restriction will be communicated as necessary as part of the above assessment processes. 

For further information on this update, please contact WPD on 0800 096 3080 and ask for the Primary System Design team in Wales.