EV charging: 5 factors every business should consider

Tesla South Mimms Supercharger and PowerPack

As Electric Vehicle (EV) uptake accelerates and costs fall, more and more companies are exploring how to electrify their vehicle fleets and offer EV charging to employees and/or customers. Delivering sustainable transport solutions will cut carbon and improve air quality, but businesses need to think carefully about the impact on their electricity demand and how they manage EV charging as part of their wider energy strategy.

Dagoberto Cedillos, Strategy & Innovation Lead at Open Energi, explores five factors every business should consider, and how, with the right approach, EVs can be managed to deliver valuable savings and income.

1. Charging infrastructure

There are a large and growing number of EV models on the market with progressively faster charging speeds and bigger ranges. Charging set-ups differ across manufacturers, although two favoured options seem to be emerging; Type 1 and CHAdeMO or Type 2 and CCS (Zap Map offer a good overview of this).

In the UK Type 2 is by far the most commonly available chargepoint. Understanding fleet or workplace/customer charging requirements should inform what charging infrastructure is most appropriate, but of course fast or rapid connectors will have a larger impact in terms of electricity demand.

EV charging speeds

2. Connection size:

EVs can instantly draw a lot of power from the grid. Today’s rapid chargers typically charge at up to 50kW (although Tesla’s are faster), but newer models are expected to charge at 150kW and beyond.  If you are offering fast/rapid charging and expect to have many vehicles charging at once, you may need to expand your connection size. A larger connection will cost more but will enable you to meet higher demand without exceeding your import limits – assuming the local electricity network has the capacity. An alternative approach is to stagger the timing of vehicle charging so that you avoid creating a surge in power demand (‘smart queuing’), enabling a smaller, less expensive connection. Similarly, if you have on-site renewable generation or energy storage, these can be used alongside EV charging to manage demand and make the most of clean, cheap electricity when it is available.

3. Charging patterns

It’s really important to think about expected charging patterns. If it’s your own fleet will they all be charging overnight only, weekdays versus weekends, or on a rolling 24/7 basis? Similarly for employees or customer charging facilities, will charging be condensed into working or opening hours or could the facilities be used more widely? The more flexibility you have to manage and spread EV charging the better, but you have to start by focusing on the requirements and expectations of the driver. A supermarket customer might only connect for twenty minutes but won’t want their charging interrupted. Someone at work could plug their vehicle in for eight hours or more, so probably won’t mind if you delay or interrupt their charging as long as their vehicle is charged and ready to go when they finish work. Smart queuing, which automates optimal queuing and charge dispatch of EVs can manage this process to support local network needs and ensure vehicle charging is prioritised in the appropriate order.

EV value streams4. How many and where

If charging stations are dispersed in small numbers across multiple sites that will be much easier to manage and integrate with existing infrastructure than a large number all at one site. However, if your charging is concentrated in one place, this will make it easier to capture value from smart charging and EV flexibility. Local flexibility markets are emerging, and the ability to turn-down demand quickly and efficiently could provide a valuable service to local Distribution Network Operators. The business case for aggregating and delivering this kind of service from EVs becomes more compelling where there are economies of scale to be gained from connecting to many vehicles in one place.

5. Electricity bill

It’s important to assess the impact EVs will have on your electricity bill. Understanding this, and the nature of the tariff structure you have with your supplier, will help to identify where the opportunities for optimisation lie. Minimising charging during peak price periods and maximising charging when electricity is at its cheapest is an obvious first step, but the ability to manage the timing of EV charging also opens up potential revenue streams. For example, as renewable generation grows instances of negative pricing – when you get paid to consume electricity – are expected to occur more often. With the right technology in place, your EVs could respond to these price signals and get paid to charge your EV fleet. More generally, the ability to respond to fluctuations in electricity supply and demand and provide short-term balancing services – i.e. a few minutes – to the System Operator can be extremely valuable.

If you have any questions or would like to discuss your business’ EV charging strategy in more detail, please get in touch.

Electric Vehicle Charging Infrastructure Innovations Conference

South Mimms supercharger

Electric Vehicle Charging Infrastructure Innovations Conference is bringing together 10 leading EV chargepoint and technology businesses to showcase new hardware and software. These EV chargepoint innovations will improve the customer experience and contribute to the delivery of charging infrastructure across the UK.

Open Energi’s Strategy and Innovation Lead, Dagoberto Cedillos, will be speaking and sharing details of our project at South Mimms Motorway Services, where we have integrated a Tesla Powerpack with Tesla’s supercharger station to make sure that EV drivers can charge affordably without causing strain on the local network.

Date: 28th June 2018

Location: Nottingham

Topic: Battery storage integration with EV chargepoints: South Mimms case study

Speaker: Dagoberto Cedillos, Strategy and Innovation Lead

More information is available from the event website.

Faster Frequency Response: A Cost-effective Solution to Future System Balancing

open energi wind farm

Creating a sustainable energy future will take decades and the pace of technological development will lead to ideas and solutions that no one has even thought of yet. This innovation will come from the next generation of energy leaders, who are already conducting vital research at universities across the globe.

 Over the last year, we’re delighted to have been supporting Yifu Ding, who is studying for an MSc in Sustainable Energy Futures at Imperial College. Yifu has been assessing the value of faster frequency response times in power systems, and Open Energi’s Dagoberto Cedillos has been one of her supervisors. Yifu’s project was recognized as the Best MSc Research Project in the cohort, and we’re pleased to share a post from Yifu about her work.
Y_Ding_Headshot

What is System Inertia?

In a stable power system operating with a fixed nominal frequency (50 Hz in the UK) electricity supplies must closely match loads on a continuous, second-by-second basis. This is especially difficult during some special cases such as the power pick-ups after big football games or a royal wedding.

Undoubtedly, achieving such a real-time balance is not a simple thing, but there are many approaches. Large power systems have an inherent property which provides the quickest response for contingencies. In a conventional power plant like coal, gas and even nuclear, electricity is generated by a turbine, basically a large spinning mass of metal. The inertia stored in these rotating turbines provides an energy store which automatically stabilises the system and insulates it from sudden shocks. In an event of a generation outage or surge in demand, inertial energy is released which prevents the frequency from falling. Equally the inverse happens in the case of a sharp increase in electricity supply or decrease in demand.

After that, the system operator begins to manipulate power assets through an array of automated measures already in place (like different frequency response products) and by sending out manual notifications. In response to these, large-scale power stations adjust their outputs. Hydroelectric reservoirs release or pump water. Aggregators control loads or battery assets they manage to provide a response.

Challenges for System Balancing

In light of the decarbonisation trend, great changes have been undertaken in the UK power system. Old methods relying on fossil-fueled power plants to balance the system are challenged and we need to explore new options.

As a rule of thumb, we are losing the system inertia. According to the National Grid System Operator Framework (SOF) 2016, approximately 70% of the UK system inertia is provided by thermal power plants. Unfortunately, the rapidly increasing volume of renewable generation units with power electronics interfaces, including solar PV and wind turbines, are not synchronized with the Grid. Therefore they don’t contribute to the system inertia.

Fig1a synchronous coupling

Figure 1: Generators contributing (or not) to the system inertia (From National Grid SOF 2016)
Figure 1: Generators contributing (or not) to the system inertia (From National Grid SOF 2016)

In our research, we considered ‘Gone Green’ and ‘Steady State’ scenarios from National Grid Future Energy Scenarios (FES) 2017, to compare and contrast what could happen in the near-term future. We found out that the inertia of the UK system will fall from 198 GVAs in 2015 to 132 -155 GVAs by 2025, as large numbers of thermal power plants are closed to meet carbon reduction targets.

Figure 2: The future scenarios considered in this research according to National Grid FES 2017
Figure 2: The future scenarios considered in this research according to National Grid FES 2017

Why Faster Frequency Response?

From this point of view, our power system will become more ‘erratic’ than before due to lack of this self-stabilization property. To counter this we could use more Frequency Response (FR) services, or perhaps something else?

We can envisage a power system with a stable frequency as a large tank with a stable level of water. The current inlet and outlet represent the generation and demand respectively. If a sudden imbalance occurs between inlet and outlet, we need to respond quickly in case the water level becomes too low or overflows.

In this fashion, one of the effective solutions is delivering faster-acting response. In July 2016, National Grid launched and tendered a sub-second FR service called Enhanced Frequency Response (EFR). Currently it is provided by batteries which can respond fast enough to provide a similar level of security to the inertial response from conventional power generators.

Value of Enhanced Frequency Responses

A few statistics from our research and other documents give you an idea of the exact economic benefit from delivering this new FR service.

By developing an optimization mathematical model to simulate power generation, dispatch and balancing in a row, we estimated the economic benefits of EFR will reach £564 to £992 per kW by 2020. National Grid has already contracted 201 MW of EFR, therefore the total economic benefit is estimated to be up to £200 million. This result conforms to the estimation published by National Grid on 26 Aug 2016.

Figure 3: A screenshot of the daily power generation and dispatch outcomes from the optimization model.
Figure 3: A screenshot of the daily power generation and dispatch outcomes from the optimization model.

But this isn’t the whole story. Although the fast-acting FR service demonstrates many advantages, there are still obstacles when it comes to the implementation.  For the system operator, an issue which might arise is how to determine the optimal mix of those FR products. Otherwise some of them could be undersubscribed or oversubscribed as mentioned in System Needs and Product Strategy (SNAP) report from National Grid.

Stakeholders in the balancing markets, such as electricity storage operators, can make themselves invaluable by providing such a service. However, we should note that it is designed to be fulfilled continuously, meaning it’s unlikely to be delivered in combination with other network services. In this case, the operator can only obtain the single revenue from the asset, risky from an investor perspective. Providing such a service is technically challenging since it requires a sophisticated state of charge (SoC) control to meet the service specifications and manage battery throughput.

As we look into the future balancing markets, fast-acting FR services indeed provide a cost-effective solution towards the low-carbon power system. Planned streamlining of  procurement mechanisms and ongoing technology development will help to fully unlock its potential.