Site Planning Tool

Benefits and Limitations

The Optimise Prime project’s goal is to accelerate the transition of fleets to electric vehicles by removing barriers related to the electricity distribution networks. The Site Planning Tool is a key part of this process - its aim is to help fleet managers understand their capacity requirements while helping distribution network operators streamline their connection process and make better use of available capacity. Designing depots is a complex task, and we have had to simplify the tool to make it user friendly - this introduces a number of limitations and assumptions which are outlined on this page.

The Site Planning Tool lets site managers compare between three different scenarios to understand the potential impact of electrification on power requirements, and understand the benefits of smart charging technologies.

• A base case, which shows the potential capacity required if all installed chargers were used at their maximum speed simultaneously. This is traditionally how a connection is sized, but may significantly exceed the capacity that will actually be used, unless the chargers are used very intensively.

• An unmanaged case which, based on vehicle schedules and site load, estimates the likely actual electricity demand. Depending on the use patterns and infrastructure, this might be significantly lower than the base scenario, even without changing charging patterns. This will give a more accurate view of the amount of power that would be used by the site’s vehicles.

• A smart case - which implements a specific smart charging algorithm to reduce ‘peak’ load at the site, by spreading charging more evenly across the time that the vehicle is plugged in, rather than concentrating it in shorter peaks. If the site’s non-electric vehicle load is high when the vehicles return, charging might be delayed to a later time. This is an example of a smart load profile, and other smart optimisations could be considered with other aims, such as reducing electricity costs or avoiding charging at specific times.

All three cases are compared against the supply capacity (ASC) in order to demonstrate whether a connection upgrade is likely to be required. The Unmanaged and Smart cases display a weekly load pattern, which may help in re-designing routes to avoid peaks in power demand, and a downloadable daily profile that could be used in discussing connection options with a distribution network operator, or with a provider of smart charging solutions. In addition, the tool outputs predicted charging costs to help build a business case for electrification. We’ve created an example case to show how smart charging could reduce peak load and power costs.

As part of the Optimise Prime project UK Power Networks is developing a new ‘Profiled Connection’ product that may reduce costs for businesses that can plan and control when they will charge. This will also allow more businesses to connect electric vehicles through more efficient use of available capacity.

• The tool can create a better understanding of customer needs. As a result of this new connections are less likely to be oversized, and the distribution network operator can be flexible where customers don’t have consistent demand for power throughout the day, offering products such as the Profiled Connections being developed as part of Optimise Prime. This allows more customers to be connected to the existing infrastructure and reduces the need for costly and time consuming upgrades.

• Creating more informed customers, who understand the factors that impact upon connection requirements, and who have researched their charging options before applying for connections

In the wider Optimise Prime project we’re trialing the types of solutions that would be necessary to control smart charging on sites and ensure that connection agreements are not breached.

Your Feedback

We’d appreciate feedback regarding you use of the tool - for example if you found it helpful, experienced any problems or have suggestions for future developments - you can get in touch with us at siteplanningtool@ukpowernetworks.co.uk. Please don’t use this address for enquiries relating to connections upgrades - these need to be directed to your Distribution Network Operator or an independent connection provider. To ask questions to UK Power Networks regarding connections, please use the options on this page.

The site planning tool is a simplified analysis tool designed to let users estimate the power demand from implementing a fleet of electric vehicles. The output of the tool is based on the information entered by the user and a number of assumptions, so capacities and costs may differ from what is achievable on a specific site. Specific points to note include:

• Vehicle efficiency can vary depending on usage patterns (such as driving styles and use of heaters) and may impact upon energy requirements.

• The tool assumes vehicles will charge at a constant rate until they reach full charge. Vehicles may gradually reduce their charge speed as they approach full charge.

• If there are more vehicles than charge points the charging will be planned in shifts. To charge all vehicles and achieve the profile it will be necessary to swap batches of vehicles around. The tool minimises the number of batches of vehicles.

• Achieving the smart charging profile will require the use of a control system that can manage charging load. The profile presented is an example of a smart load profile based on the principle of reducing peak demand as far as possible. Other smart charging methods, such as optimising to reduce charging costs or to a pre-agreed profile may yield different results.

• The model assumes that vehicles start the week at 80% state of charge at 00:00 on Monday morning and end the week at least 80% charged by midnight on Sunday. Vehicles must not fall below 20% state of charge at any point in the week. As a result of this, some schedules operating late on Sunday nights, early on Monday mornings, or using close to the full range of the vehicle may be returned as unfeasible. In the unmanaged scenario there may also be a demand peak shown early on Monday morning that may not occur in actual operations. Estimated charging costs may be slightly higher for the unmanaged model in circumstances where the electric vehicles have sufficient time to charge to 100% by the end of the week.

• Historic electricity usage needs to be provided to accurately model the capacity available for charging on the site. Customers without comprehensive meter data need to be cautious when specifying connection requirements and should consider metering power usage.

• Load (real power) is converted to capacity (apparent power) at a power factor of 1 (ie. 1kW = 1kVA). The power factor may vary depending on the types of load at your site.

• Indicative costs are presented by the tool based on a limited set of inputs. When designing your site you need to consider a range of up front and recurring costs, such as purchase of devices, leases, installation costs and ongoing maintenance, software and support. These can be accounted for using the CAPEX and OPEX fields on a site, vehicle or charge point basis if required. Charging costs only take into account the cost per kWh of electricity consumed, other fixed costs, such as capacity and standing charges, and the potential cost of connection upgrades also need to be considered.

• The Site Planning Tool is primarily designed to model a site using AC charging - maximum charge rate of electric vehicles and charge points should normally be based on their AC capacity. The tool can be used for a DC only site, by specifying only DC capacities of assets, but AC and DC assets should not be mixed in a single scenario.

• The output of the tool considers the entire capacity of a site. If a site has multiple connections, phases or distribution boards, it may be necessary to consider the capacity of each connection or phase when planning your site or implementing smart charging.

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