Local Energy Systems and EV Fleets

Whilst UK business has more than halved greenhouse gas emissions between 1990 and 2017, transport emissions have remained stubbornly high, now accounting for the largest share of the UK’s emissions. Internal combustion engine (ICE) vehicle efficiency has improved in this time, but this has not been enough to offset the increase in road traffic1.

We therefore need an alternative technology, and vehicle manufacturers globally have largely settled on battery electric vehicles (EVs) for cars and inner city logistics vehicles. EVs emit no tail-pipe emissions and, with a decarbonising grid, EVs life-cycle greenhouse gas emissions could be 90% lower than an equivalent diesel/petrol car2. With battery costs falling rapidly, ranges extending, and the introduction of government incentives, EVs are becoming increasingly attractive and as a result businesses are scaling up their EV fleets.

EVs require charging and installation of charging infrastructure can be a major hurdle for fleets. UPS and UK Power Networks Services have been working together at UPS’ centre in Camden to develop and trial smart-grid technologies to overcome some of the hurdles involved. Through their work together they have demonstrated that:

  • Fleet electrification brings commercial, environmental and reputational benefits.
  • Smart-charging is key to minimising infrastructure CAPEX and disruptions. 
  • Smart-charging offers significant OPEX savings through reduced energy costs.
  • A strategic approach to infrastructure development is key to future-proofing and minimising regret costs.

This article describes some of UK Power Networks Services’ and UPS’ work to date to expand on these points.

An overview of UPS’ experience with EVs in London

UPS EV VanUPS is a global leader in logistics, employing 481,000 people globally, with a fleet of 123,000 vehicles, to deliver 20.7 million packages and documents a day (2018). The UPS Rolling Laboratory, where alternatively vehicle technologies are added into UPS’ real-world operations, has trialled electric, hybrid-electric vehicles, gas and other alternatively fuelled vehicles. By testing vehicles as a part of real-world operations, UPS can determine which technologies are practical and offer real-world sustainability benefits.

As a key service centre for central London, UPS Camden has led the way for fleet electrification, with the first 12 EVs added to the delivery vehicle fleet for the London Olympics in 2012. The next tranche of EVs were added to the fleet as part of the Freight Electric Vehicles in Urban Europe (FREVUE) project, where 15 Mercedes P80E vehicles were retrofitted with batteries and motors. To charge the growing EV fleet, UPS upgraded their electrical infrastructure at this point. This upgrade included a new 1,250kVA package substation on site, designed with capacity to supply the non-EV loads such as conveyor belts, and to charge up to 63 EVs. The cost and time required for this upgrade highlighted to UPS the challenge of installing EV infrastructure to supply a large vehicle fleet.

Further tranches of retrofit-EV vehicles were added to the UPS Camden fleet, bringing the total up to 42 by 2016. By incorporating a significant EV fleet into daily business-as-usual operations, UPS proved that EVs are practical, and offer real reductions in greenhouse gas emissions and tail-pipe emissions. UPS therefore increased their ambition for the Camden centre, aiming to reach a fully electric operation from the central-London site by bringing the total number of EVs to 170.

UPS were keen to avoid the cost and disruption of further electrical network upgrades. Using traditional methods to charge 170 EVs at UPS Camden would require a network connection of 2.5MVA. This connection capacity would have triggered significant reinforcements to the electrical network upstream to the UPS Camden site, adding further costs and impairing the business case for transitioning their fleet.

UK Power Networks Services were asked by UPS to assess alternative options to an electrical connection upgrade. A feasibility study identified that installation of a smart-charging system and energy storage system (ESS) would enable UPS to fully charge an all-electric fleet of 170 vehicles without upgrading their existing connection capacity. This system was developed, installed, and trialled during the Smart Electric Urban Logistics (SEUL) project.

The SEUL project was completed in September 2019 and demonstrated that the application of smart-charging and energy storage significantly reduces costs of charging EVs. As a result, the business case for transitioning entire fleets to EVs is improved, enabling UPS to further scale their EV operations. UPS recently announced a commitment to purchasing 10,000 electric vans from the UK based manufacturer Arrival3.

The Smart Electric Urban Logistics (SEUL) project

UPSFreight electric vehicles, like those used by UPS, can consume up to ten times as much power as a typical home when charging. This means that charging large numbers of trucks simultaneously puts significant demand on the electricity infrastructure supplying a depot. For example, increasing the number of EVs at UPS Camden from 42 to the full fleet of 170 would have increased peak demand to 2.5MVA. Due to capacity limitations, this would have triggered significant reinforcement works on the local electricity network.

Traditional network reinforcements could cost from £50,000 to £2 million, and often take more than six months to implement. To avoid this, UK Power Networks Services were appointed by UPS to design and deliver a smart-grid solution consisting of a dynamic smart-charging system and a 66kVA/150kWh battery ESS. The SEUL project was run by a consortium including UPS, Cross River Partnership, UK Power Networks and UK Power Networks Services and included further trials of large electric delivery vans.

The smart-grid solution was built and tested in three main stages:

  • Design and development of the smart-charging software, including integration testing with the ESS and EV chargers.
  • Installation of sub-second power meters, new smart charge-points, an Ethernet network and server to host the smart-charging software, and upgrading of all existing charge-points to enable communication and control.
  • Technology trials to test vehicle response, system dynamics, fail-safe measures, and long-term performance.

Design and development

Smart-charging and ESS technologies were assessed as part of a feasibility study conducted prior to the design stage. The key requirements were to avoid a grid upgrade, ensure the system installed is scalable and future-proof, avoid disruption to UPS’ business, minimise environmental impact, and optimise for cost.

This study considered the options described in the following paragraphs and concluded that a dynamic smart-charging system with an ESS was the optimal choice. A dynamic smart-charging system is able to fully utilise available power from the 1.25MVA grid connection while balancing EV charging demand against non-EV demand such as conveyor systems. An ESS was required to provide additional power during winter peak periods.

Further sophistication in smart-charging such as integration with fleet telematics systems to enable proactive scheduling of charging was not necessary at this stage but is discussed further later in this article.

Static smart-charging

In its simplest form, smart-charging divides the available power capacity between each connected EV charger. For example, a site may have 100kW of capacity available, with 20 chargers installed. If all 20 chargers are in use, each is provided with 5kW, if only 10 are in use then vehicles can charge at up to 10kW.

Static smart-charging at UPS Camden would only be able to charge 149 of the 170 vehicles.

Dynamic smart-charging

The next step in sophistication involves monitoring total site power demand to calculate the real-time power capacity available for charging. At this point the smart-charging system becomes dynamic. If the site has a 250kW connection, with non-EV load drawing up to a peak of 150kW, a static smart-charging system would only be able to use 100kW for EV charging at any time of day. However, non-EV load may reach a peak of 150kW only once a day, and during the rest of the day more than 100kW is available for EV charging. By installing a power meter at the site, and using dynamic smart-charging, the power made available for EV charging can be maximised at each point in time.

Dynamic smart-charging at UPS Camden would be able to charge 169 of the 170 vehicles.

ESS

With battery ESS costs still high, the business case for ESS must be built by stacking revenue streams such as shifting energy demand to cheaper tariff times, known as peak shaving, and providing grid services. For businesses with growing EV fleets, such as UPS, the re-use of old vehicle batteries in “second-life” stationary applications may reduce ESS costs.

An ESS was added to charge the last vehicle, bringing the total to 170. The ESS brings additional benefits of resilience and providing an opportunity to test the integration of ESS, and smart-charging for future sites with further constraints.

Installation

The smart-charging system and ESS was installed towards the end of 2017. The team were able to work around UPS’ operational schedules and so avoided disruption to UPS’ business. The key components of the installation are described below:

  • Sub-second power meter: This is required to measure real-time power demand of the site, and so enable the smart-charging software to balance load and maximise utilisation of the grid connection capacity.
  • Upgrading of old charge-points: Communication and control capabilities were added to each of the old charge-points to enable integration with the smart-charging system.
  • New smart charge-points: Additional smart-enabled charge-points were installed.
  • Onsite server: A server was installed onsite to host the smart-charging software, enabling isolation of the system from the internet for security.
  • ESS: A containerised 66kW/150kWh ESS was installed on site and connected to the in-depot electrical network.
  • Ethernet network: The power meter, charge-points and onsite server are connected with an Ethernet network to avoid ongoing mobile data costs.

Technology trial

The system was extensively tested during site-acceptance tests (SATs) and a long-term trial over one year. The SATs demonstrated the functionality of the system to UPS before commissioning.

System response: Non-EV and EV power demand was increased at the site to test the system response to curtailment under two alternative modes. The first mode curtailed EV charging first, bringing the ESS in later, and the second deployed the ESS first curtailing the EV charging later.

Fail-safe modes: The system must fail safe, ensuring the grid connection capacity is not exceeded whilst providing maximum power to each vehicle for charging. Each charge-point has a fail-safe limit individually set; under any error event each charge-point reverts down to this fail-safe limit. 

Long-term data collection: During the system trial period UPS would not reach a fully electric fleet and so a system model was developed and fed with data collected over the year to assess the suitability of the smart-charging and ESS.

SEUL project findings

Extensive data collected throughout the SEUL project was used to build a detailed profile of the UPS’ Camden fleet and centre operations. With this profile we demonstrated the suitability of the smart charging solution installed, proving it could significantly reduce capital costs (CAPEX), and ongoing operational costs (OPEX) for a depot-based EV fleet.

Smart-charging reduces fleet charging infrastructure CAPEX by up to 70%.

Capital cost reductions are achieved by minimising peak power demand to avoid triggering grid infrastructure reinforcements. Peak demand at the Camden centre was reduced from 2.5MVA to 1.25MVA, avoiding a major upgrade to the electrical network. Cost savings will vary from site to site as the cost of grid connection upgrades can vary significantly. However, for sites similar to UPS Camden, CAPEX cost savings of up to 70% are expected.

Smart-charging reduces EV fleet charging OPEX by 10% to 35%.

Ongoing energy cost savings can be achieved by charging at times with cheaper energy costs. In order to understand the potential for reducing ongoing energy costs, the UPS Camden fleet was modelled, and a flexibility profile was developed. This was used to estimate how the centre’s energy demand profile can be shaped. Energy purchase cost was then modelled, firstly assuming fixed two-tier energy tariffs, and secondly by including access to energy flexibility markets such as the Balancing Mechanism used to ensure that supply matches demand in real-time. 

It was found that a 10% energy cost reduction could be achieved by using the smart-charging system to charge vehicles during cheaper overnight tariff periods. Further to this, if the existing 1.25MVA grid connection was increased to 1.5MVA (which would require no changes to UPS’ onsite infrastructure), energy cost reductions could be increased to 15%. Alternatively, through participation in the Balancing Mechanism, energy costs could be reduced by 19%. In summer, when vehicles do not need heating and batteries perform better, energy cost reductions could reach up to 35%.

It should be noted that this energy saving from access to flexibility markets is purely from providing flexibility in when the vehicle is charged, and so does not require the use of bi-directional “vehicle-to-grid” (V2G) chargers. Whilst V2G may stack up for personal vehicles with lower daily usage, the operational fleet profiles we have collected from both the logistics and public transport sectors do not currently show a positive business case for the technology.

Next steps

Whole-life-cost parity for electric vans in inner-city logistics operations is expected this year, and so the roll-out of electric vans across UK businesses is expected to accelerate in 2020. The technologies demonstrated as part of the SEUL project will be key to keeping the business case for this transition viable by minimising electrical infrastructure costs.

A key benefit of EVs is that lower fuel costs and smart-charging can be used to maximise this benefit. The SEUL project identified EV charging OPEX savings of between 10% and 35% are possible for a fleet like UPS’. Achieving this OPEX saving requires delaying charging of EVs, and so potentially puts UPS’ operations at risk. Technology can be used to mitigate this risk; analysis of real-time telematics data can be used to regularly update the charging flexibility profile of the fleet. This charging profile can be used to flag constraints, prioritise charging of certain vehicles, and minimise energy costs for charging the fleet.

Author’s profile:

Jonathan BassettJon Bassett is a senior consultant at UK Power Networks Services, with a background in decentralised energy technologies including EV charging. Jon works with fleet clients such as UPS, councils and bus operators to develop EV infrastructure solutions and strategies. 

  • 1Office for National Statistics, Road transport and air emissions, 16 September 2019.
  • 2Electric Vehicles from life cycle and circular economy perspectives, EEA Report 13/2018.
  • 3UPS press release on investment in Arrival

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