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  •  Phase 1                                                                                                                                                                                                   



    The purpose of the PARCA window is to encourage those customers considering applying for a PARCA to submit their application at this time, so that we can assess how to meet their capacity need alongside other potential projects.

    For any PARCA application deemed competent outside a relevant PARCA window, within 10 business days of the initiation of the Phase 1 works of that PARCA we will open (where a window is not already open) either a PARCA entry or exit window.

    We guarantee to consider together all PARCA applications submitted and deemed competent within this window. However, it is important to note that if you wish to be considered for capacity alongside other PARCA applications, in order to ensure we can conduct our competency check within the PARCA window timescales, please endeavour to submit your application as early as practically possible.

     PARCA Period                                                                                                                                                                                            

    The PARCA window is open for a maximum of 40 consecutive business days but will close after 20 consecutive business days if no further PARCA applications have been received within that time. There are two types of PARCA window:

    • Entry window - triggered if a PARCA requests NTS entry capacity
    • Exit window - triggered if a PARCA requests NTS exit capacity  

    Only one entry and/or exit PARCA window can be open at any one time. So if a PARCA application requesting entry/exit capacity is deemed competent within an open entry/exit PARCA window, an additional PARCA window will not be triggered.


    Should you wish to progress to Phase 2, you will need to sign and return a PARCA contract within 28 days of us issuing it to you. You will also need to provide the first annual instalment of the security (detailed as a Phase 1 output).

    On receipt of the signed contract and the financial security, National Grid will countersign and return the contract to you within two business days. Phase 2 of the PARCA process will start and we will reserve the capacity for you. 

    To ensure consistency, fairness and transparency, the terms of the PARCA contract are generic and non-negotiable. 

     Phase 2                                                                                                                                                 

    PHASE 2                                                                                                                                                                  

    During Phase 2  of the PARCA process, where investment in the NTS is likely to be required, we will initiate the relevant statutory planning activities (either the Planning Act or Town & Country Planning.) The timescales associated with this phase are specific to your PARCA and will be included as an output from Phase 1. We currently consider that the maximum timeframe for this phase will be 60 months, depending on the complexity of the works to be carried out. While going through this process, National Grid encourages working closely, particularly where both parties need to progress their projects through the planning process.


    We will reserve the capacity on your behalf from the date specified in the Phase 1 output report. Irrespective of whether investment in the NTS is required to deliver your capacity, we will reserve the capacity exclusively for your project until the PARCA is terminated and/or the capacity is formally allocated, in line with the capacity allocation date provided in the Phase 1 output report.

    Within 10 business days of the capacity being reserved, we will publish appropriate information to the industry.