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Return home7.1. DNO connection scenarios
Compare different distribution network operator (DNO) connection scenarios and plan for the future development of your charging infrastructure. Consider the implications of larger electricity connections, increasing fleet demand and the installation of higher-powered charge points when designing a long-term charging strategy.
Assessing connection types
The way electricity connections are assessed varies between distribution network operators (DNOs). For Scottish and Southern Electricity Networks (SSEN), connection types are generally categorised as:
- Small connection: up to 70 kVA.
- Medium connection: 70 kVA to 200 kVA.
- Large connection: over 200 kVA.
Large electricity connections can bring additional requirements, such as transformer management, network reinforcement works and other regulatory considerations. These factors can increase project complexity and may extend delivery times.
As charging infrastructure expands and electricity demand increases, organisations should carefully consider the implications of larger network connections, higher-powered charge points and future fleet growth during the planning process.
The scenarios in Table 23 summarise the key considerations associated with different scales of charging infrastructure deployment.
Future-proofing
Most lower-powered charge points can be supplied using a building’s existing electricity connection.
Higher-powered charge points, typically rated at 50 kW or above, are becoming increasingly common and may become standard across parts of the public charging network. They are also expected to play an important role in supporting fleets of electric heavy-duty vehicles (HDVs).
Higher-powered charging infrastructure may require new electricity connections or upgrades to existing site electrical supplies.
It is important to consider future charging requirements during the planning stage. Taking account of anticipated fleet growth and future charging demand at an early stage can help avoid costly infrastructure upgrades and reduce disruption later.
Table 23 – Considerations when installing different types of infrastructure
| Charge point type and power per outlet | New energy supply capacity required per charge point now | New energy supply capacity per charge point for future-proofing |
|---|---|---|
| Slow or standard 2.4kW or 3kW | Generally not required | 80 or 100Amps AC single phase (for a faster charge point) |
| Fast 3.7kW AC | Generally not required | 80 or 100Amps AC single phase (for a faster charge point) |
| Fast 7kW AC | Generally not required | Three phase AC supply 80Amps per phase (for a faster or rapid charge point) |
| Fast 11kW AC | Three phase AC supply: 16Amps per phase | Three phase AC supply 80Amps per phase (for a faster or rapid charge point) |
| Fast 22kW AC | Three phase AC supply: 32Amps per phase | Three phase AC supply 80Amps per phase (for a faster or rapid charge point) |
| Rapid 20kW DC | Three phase AC supply: 32Amps per phase | Three phase AC supply 80Amps per phase |
| Rapid 43kW DC | Three phase AC supply: 100Amps per phase | Three phase AC supply 100Amps per phase |
| Rapid 50kW DC | Three phase AC supply: 100Amps per phase | Three phase AC supply 100Amps per phase |
| Supercharger 130kW DC* | Three phase AC supply: 200Amps per phase | Three phase AC supply 200Amps per phase |
*Higher power superchargers are currently under development and testing (Western Power Distribution, 2021)
