Energy

Networks

AssociationFlexible Connection Offers

15 September 2015

The Voice of the Networks

2 The Voice of the Networks

• Significant volumes of applications – often on the same parts of the network leading to interactive offers and queues

• Reinforcement required resulting in high connection costs and long lead times

• Reinforcement ahead of need generally not possible due to the risk of stranded asset cost falling onto domestic customers

• Interaction with National Grid – SoW process and total system concerns raised in their System Operability Statement are resulting in the need to add further conditions to connection offers

Background

3 The Voice of the Networks

• Expanding our offers to include flexible connections allows customers willing to be

constrained to be connected more quickly and cheaply whilst maintaining network security

for existing customers

• This will optimise our networks, increasing the utilisation level of existing assets

• It is also an important step in the transition from passive to active networks and will require

us to have greater visibility and wider control in order to undertake actions similar to a

System Operator

Flexible Connections - why bother?

4 The Voice of the Networks

Distribution Network Operators are looking at a range of

options to help mitigate the costs of reinforcement…

5 The Voice of the Networks

• Generation curtailed within specific seasons or time- of-day

• Generally best suited to smaller DG

• Modelled seasonal capacity variations

• Localised control only

• No communications link needed

• Non-optimised

Timed Connections

6 The Voice of the Networks

• Developers are required to keep their DG export levels within the Maximum Export Capacity

specified in their Connection Agreement

• The Developer may over install generation plant but cap the export in line with their

Connection Agreement

• Some DNOs will permit additional generation connections to be made to existing DG sites

subject to application and technical assessment

The Use of Export Capping Schemes

7 The Voice of the Networks

• DNOs working with the ENA to create some consistency

• Should shortly be in a position to issue some interim criteria which may include:

• Fail-safe

• Not rely on wireless comms

• Meet all relevant power quality requirements

• Act within a defined timescale

• Commissioning witnessed

• Additional relays at HV

Export Limiting Devices

8 The Voice of the Networks

• Releases pre-fault capacity with trip facility

• Triggers constraint in the event of minimum system demand coinciding with maximum export

• Suitable for small clusters of generation behind one simple pinch point

• Not suitable in areas with complex constraints

• 11kV and 33kV

• Real-time monitored values

• Existing monitoring with localised control

Intertrip

9 The Voice of the Networks

• Fully optimises capacity based on all constraints

• Variable connection offers depending on dynamic network conditions

• Management of generation using LIFO principles

• Real-time granular control of output

• Requires new Active Network Management control and monitoring systems

Active Network Management

10 The Voice of the Networks

• More complex networks, involving many generators across different circuits and voltage

levels require constant monitoring to ensure the capacity is available and is shared optimally

• In order to manage the risk effectively, the system must be secure, robust and encompass all

affected areas

• An advanced deployment of intelligent monitoring and distributed control systems will be

underpinned by a fail-safe communications network, allowing the network to accommodate

more connections, whilst maintaining the quality and security of supply for existing

customers

Active Network Management

11 The Voice of the Networks

• Utilise historic load and generation data, together with the assumed profiles of future

generation in the area to estimate the level of curtailment an application will receive

• The curtailment tools can provide a generation developer an indication of the level of

constraints a site will experience and the associated risk

• DNOs would expect developers to also do their own estimates as part of due diligence before

committing to an investment

Estimating Curtailment

12 The Voice of the Networks

Demand Side Management

13 The Voice of the Networks

Dynamic Circuit Thermal Rating

14 The Voice of the Networks

Dynamic Circuit Thermal Rating

15 The Voice of the Networks

• Flexible Connections are generally based on a Last In, First Out (LIFO) principle

• Your position in the stack is secured on receipt of the minimum application information

required

• Each customers calculated curtailment is based on all connected, committed and offered

capacity which sits ahead of them in the queue at that moment in time

• If generation ahead of you in the stack drops out, you will move up the stack and the

potential for curtailment will reduce

• Committed and offered capacity within the stack changes daily

Stack Management

16 The Voice of the Networks

• Financial incentives and reducing generator technology costs have resulted in a significant

increase in the applications for connection to the distribution network

• DNOs are focused on providing more publicly available information and better customer

service

• The use of consortiums is a method of sharing the costs of upstream reinforcement

• DNOs are introducing flexible connection offers and are developing other innovative

solutions to reduce reinforcement costs, but whole system issues need to be considered

Summary