Grid Connected Generation
Terminology to Start
Developer
You!
Distribution Network Owner/Operator (DNO)
Owns, maintains, develops and operates the physical network
SP Manweb, United Utilities in the North West
Not the slightest bit interested in selling or buying energy from you
Electricity Supplier
Party to contract with to buy & sell energy
Npower, PowerGen, Scottish Power, British Gas, etc
Not the slightest bit interested in the physical connection
Ofgem
Electricity and Gas Market regulator
Also administers the ROC process if your technology is eligible
Just Some of the Legal Issues
If grid connected, then it is a legal requirement to have permission to connect & operate any form of generation
Needs to have a DNO connection agreement
Needs to have correct electrical protection
Needs to have correct earthing
Needs to have an export meter (if exporting)
Needs to have a supplier contract (if exporting)
D-code : Distribution Code for UK Distribution Networks
G-code : Grid Code for UK Transmission Networks
Electricity at Work Regulations
Engineering Recommendations
Technical connection requirements are detailed in the Engineering Recommendations
DNOs view these as Rules rather than just Recommendations
G83: Less than 6kW (16A/phase)
No connection agreement required but must notify DNO once on
G59: Less than 5MW and less than 20kV connection
Must have a connection agreement
G75: Anything else up to 50MW or transmission connected
Must have a connection agreement
DNO Responsibilities
Statutory obligations under the terms of their licence
Secure operation and development of the network
Safe & reliable operation of the network
Ensure fair and equal access to the network
Least cost options for connection
Lifetime of network not just your connection
Must respond to a connection application within 90 days. Remember, theyre not out to get you, but they have responsibilities too!
Electrical Connection Issues
Technical issues to be considered during connection study/investigation
Thermal limits
Voltage limits & step change
Reverse power-flows through transformers
Short-circuit rating of switchgear
Protection arrangements & co-ordination
Harmonics & Power Quality
Transient stability (usually only for larger generators)
Energy Metering
There will be the need to provide a reasonable level of data on the generator and the site connections
The connection and protection will need to be witnessed and approved by the DNO in order to complete the connection process
Network Capacity Issues
The Distribution Network has real limits
Due to load growth and the drive towards maximising use of existing assets, available headroom is often quite limited
Cable ratings reached during peak load
Voltage drop/rise reached
Circuit breaker short-circuit limits reached
The Capacity Race
It is not just fiction it is unfortunately real in some locations
First-come, first-served & Interactive Applications
There are some solutions but most do add cost and complexity
Rule of Thumb Connection Capacities
< 6kW 240V
< 1MW 415V (3-phase)
< 1-10MW 11kV
< 30MW 33kV
< 50MW 66kV/132kV
> 50MW 132kV upwards & National Grid interfaces
As with any project, the bigger the project, it is important that you have the right level of advice or expertise to de-risk the project.
So, what do I do to get connected?
Contact your friendly neighbourhood consultant ☺
But seriously:
Start with a rough idea of what you want to do
Check that your site can fit it and you can afford it
Check that all other regulatory issues are okay
Have an informal chat about connection possibilities with DNO generator connections or knowledgeable person
Check that your initial idea still sounds sensible
When contacting the DNO
Contact DNO generation connections (NOT Demand)
The connection process will be more likely to be successful with good communication between the developer and the local DNO
Determine your connection route: G83, G59 or G75
This may have costs associated with it
Be prepared for a process not just rubber stamping
Planning & Information phase
Detailed Design phase
Installation phase
Testing & Commissioning phase
Working with the DNO
Seek an early meeting to discuss your project
Outline the scheme
Discuss the DNOs process for connections
Request an indicative connection design and budgetary cost estimate with a split between contestable & non-contestable works
Review your project
Submit the formal connection application
Remember to accept the connection offer!
Submission of data to DNO
Make sure that this is appropriate and timely to avoid delays
Testing and Commissioning
Plan in advance to avoid delays as staff will usually be quite busy
Connection Charges
Application Fees
These vary between DNO and size and voltage level of project
Complex projects may involve additional fees
Connection Assets
Developer will be expected to pay full costs for all sole-use assets
Generation Use of System Charges
Site dependent & in lieu of network reinforcement costs
Each DNO has own policy in-line with Ofgem guidance
Competition in Connections
Developer as two options:
Get the DNO to do all works necessary for the connection
3rd party to provide all contestable works which DNO then adopts
Contestable Works
Supply & installation of any new assets up to the point of connection to the existing network. Adoption agreement required.
Non-Contestable Works
Any studies, reinforcement or installation on existing network
Design & specification of any new assets, consents & way-leaves
Note: The DNO will not get involved in any on-site works
Finally, just when you thought it was too easy
Other non-electrical issues still need to be resolved
Planning Permission?
EIA, Emissions?
Health & Safety?
Commercial?
Installation & transport?
CDM?