Energy from Waste Grid Connections

Transcription

1 Energy from Waste Grid Connections Catherine Cleary Grid Connection Lead TNEI Services

2 Overview Introduction to the UK Electricity Network Key Grid Connection Issues for EfW Generation Connection Process Commercial Considerations

3 UK Electricity Network Topology Transmission Distribution Transmission in Scotland Source: SP Electrical Awareness

4 Distribution Network Made up of 12 license areas Operated by 7 Distribution Network Operators (DNOs) Distributes power from the transmission system to the various end users Complex networks with LOTS of assets Frequent changes to the network every week 2 license areas -North East -Yorkshire 4 license areas -East Midlands -West Midlands -South West -South Wales 3 license areas -London -Eastern -Southern

5 Key Grid Connection Issues for EfW Plants Reverse Power Flow at Substations When generation exceeds demand in a particular area of network, power flows back up towards the Transmission System. Transformers in particular may have limits on Reverse Power Flow.

6 Key Grid Connection Issues for EfW Plants Voltage Rise Mainly a problem on 11kV & 20kV Networks. OHLs in rural areas not designed for generation connections. Power flowing back along the circuits causes voltage rise at the end of the circuit Loads on a circuit pull the voltage down Generators prop the voltage up Images Source: WPD Equilibrium Project

7 Key Grid Connection Issues for EfW Plants Fault Level All rotating machinery connected the network contribute to the Fault Level. EfW plants may have a significant fault level contribution. Fault Levels must be managed by the DNO to ensure that they do not exceed the rating of switching equipment. Often high in Urban or Industrial areas, or where there is generation already connected. Performing targeted feasibility work upfront should help to de-risk the grid connection and manage the above issues

8 The Grid Connection Process Submit Application to DNO DNO Issues Connection Offer Applicant Accepts Offer Statement of Works (if impacts on Transmission Network) Studies and Design Build the Connection Test and Commission

9 Connection Applications Submit Application 90 days Receive Offer Up to 90 days Accept Offer Free Acceptance fee

10 Building the Connection GSP Substation Non-Contestable Works Primary Substation Contestable Works PoC EfW Plant

11 Interactive Offers Occurs if multiple generators apply for the same capacity DNO will issue interactive offers Wind EfW project Farm 1 (15MW) Applies is for 1 st in 15MW Queue Substation: 20 MW Wind Farm 2 (10 Applies MW) is for 2 nd in 10MW Queue DNO issues Offer 10 day Moratorium period starts DNO issues letter stating interactivity. DNO issues interactive Offer Priority depends on Queue position

12 Statement of Works Additional process required by National Grid if the generation is deemed to have a Significant impact on the Transmission System. Can delay grid connection Stage 1 (does my Generator cause a problem?) 28 days Stage 2 (how big is the problem and what will it cost?) 4 months Applies to any project over 1MW in Scotland Applies to any project over 1 MW in WPD at a Grid Supply Point where transmission constraints have already been identified. In other license areas thresholds are still subject to discussions with National Grid. ALL GENERATION PROJECTS SHOULD BE CONSIDERED AT RISK OF SoW PROCESS UNLESS THE DNO HAS CONFIRMED OTHERWISE

13 Reinforcement Costs Each DNO applies cost apportionment rules, as enforced by the regulator, to share the cost of reinforcement works between the customers that benefit from them. Cost apportionment is the same across ALL DNOs Cost apportionment applies for up to 5 years after works are completed OR Until the cost of the works has been recovered in full (whichever happens sooner)

14 Cost Apportionment Thermal Upgrades If upstream reinforcement is required, the connecting generator pays only for the proportion of the capacity of the new asset that they will use: Cost Apportionment Factor =Generator Capacity (MVA) / Capacity of New Asset (MVA) CAF = 10 MVA / 30 MVA = 33% Generator pays 33% of 3M cost Circuit upgraded to 30 MVA ( 3M) GSP Substation New 10MVA Generator

15 Cost Apportionment Fault Level The connecting customer must pay to upgrade all switchgear where fault level ratings are exceeded. CAF =3 x Generator FL Contribution (MVA) / Switchgear rating increase(mva) Apportionment costs penalise fault level exceedances.

16 Connection Risk Summary Is it interactive? Is it subject to a Statement of Works? Are reinforcement works required? Accurate Data Provided in the Application form? Target Date for Completion?