Smart charging perpectives for optimal EV integration

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Defining smart charging

Smart charging is a broad term that captures methods of shifting or modifying EV charging based on grid and market conditions. All EV charging points, whether in public or private locations are concerned.

There are multiple definitions and concepts around smart charging. Here is the one proposed by IRENA[1], which defines 5 EV charging options to provide flexibility services.

Fig. EV51 – Example of smart charging options to provide flexibility services (source: IRENA[1])

There is an on-going debate on the hierarchical position of V2G vs smart charging: is V2G a specific, separate charging application, or just one option of the whole smart charging concept? The vision reflected above tends to include V2G as part of the smart charging.

Advanced smart charging: V1G, V2x options

While most home chargers offer basic on/off control, advanced chargers provide more sophisticated controls which provide benefits for multiple stakeholders.

V1G manages the power step-wise in a unidirectional manner.

V2x (including V2G) offers the same principle as V1G both in charging and discharging mode.

Fig. EV52 – Example of unidirectional (V1G) versus bidirectional (V2G) grid services provision (source: IRENA[1])

While V1G is not as popular as V2G in the media hype, it already offers interesting value for grid and building stakeholders and is not subject to the regulatory and grid code barriers applicable to the more disruptive V2G concept.

V2x : the most advanced form

Vehicle-to-Everything (V2X) is an umbrella term to explain the use of EV batteries to provide energy services and derive additional value from the battery asset during times of non-use.

V2X services aim to generate revenue from the battery asset through dynamic or bi-directional charge control to provide benefits to the electric grid or to reduce/flatten/shift peak energy consumption of buildings and homes

Microgrid operation is classified as a special use-case of the V2B Topology expressed by the color overlap of green shades.
Colored connections indicate interactions within the topology whereas black connections indicate connections/interactions with other grid elements.
We feature the Distribution System Operator (DSO) as a central figure due to the unique role of the distribution system in enabling much of V2X capability.
Fig. EV53 – V2X Topology Explained[2]

V2X can be classified in the following operating modes:

  • Vehicle-to-Grid (V2G): Using an EV battery to interact with/provide value to the electric grid (frequency control…)
  • Vehicle-to-Building (V2B): Operating EV batteries to optimize building energy consumption
  • Vehicle-to-Home (V2H): Optimizing home energy consumption or using EVs as emergency back-up power
  • Vehicle-to-Load (V2L): Any other instance of an EV battery providing energy to a load

EVs located ‘behind-the-meter’ in homes and buildings have a dual value: optimizing their own energy consumption as well as interacting with the grid.

V2G is seen as a ‘panacea’ by grid operators, since the EV battery offers the same functionality as a stationary battery for ancillary services such as frequency response.

Value of smart charging

Early forms of smart charging with Time-Of-Use pricing offer limited benefits in utility peak load reduction.

Advanced forms (V1G, V2x) reveal a much stronger value for all grid stakeholders.

For utility distribution network operators: more hosting capacity, faster implementation, less costs

  • Differ or avoid grid reinforcements, at a cost of 10% of the total cost of reinforcing the grid
  • Enable a much greater EV hosting capacity at local level without distribution network reinforcements

For utility transmission system operators:

  • Limitation in system peak load, avoid construction of generation capacities (peaker plants)

For building managers: EV flexibility ideally complements other energy resources such as rooftop solar PV, CHP, stationary batteries, flexible loads to optimize building own energy costs and monetize flexibility in utility demand response programs.

  • Time Of Use tariff optimization: shifting building consumption to off-peak periods
  • PV balancing/optimization , maximizing self-consumption
  • Demand Charge Management & Demand Limitation
  • Load Balancing, reduction of connection fee

Strong barriers for smart charging

While many recent studies at regional or country level reveal strong benefits in EV hosting capacity and system cost reductions, the concept still faces many barriers at various levels.

Here are some of these limitations captured in the studies:

  • First and above all: is the EV driver himself readiness to allow control over his critical charging process ?
  • Many regulatory and legal barriers
  • Dynamic pricing needs smart meters in place, dedicated rates for EV charging
  • No obligation for smart EV charger due to cost burden: many new chargers are still ‘dumb’.
  • Lack of standards: mainly in communications infrastructure, billing/roaming, data semantics…
  • Cybersecurity compliance
  • Data privacy in some regions
  • Charges applicable to V2G (‘double charging’), grid code limitations
  • High cost of bidirectional chargers for V2G
  • Space for aggregators managing fleets of EVs, ability to stack revenue of EV flexibility

Finally, smart charging is about an incredibly complex interaction between stakeholders from different industries: Grid stakeholders (incumbent utility companies, new aggregators…), IT/communications, services providers, automotive OEM. Each of them with specific culture and interests

Fig. EV54 – A complex ecosystem ...

Smart charging will be about a system-wide orchestration of this ecosystem, with clear rules and responsibilities for each stakeholder.

How soon will smart charging happen ?

It all depends on policy mandates at state or country level for mass EV roll-out.

For instance, some European policy makers stress the need to accelerate EV adoption to meet decarbonization targets, imposing conventional vehicle ban on a rather short-term horizon: originally 2040 in many member states, sometimes 2035 or even earlier.

As the policy pressure mounts, interest for defining a local smart charging frameworks grows. It’s about scaling the right infrastructure at the right time and the right cost to generate EV driver satisfaction in his new e-mobility experience.

A big challenge ahead for the whole EV ecosystem, including building managers.

Notes

  1. ^ 1 2 3 Innovation Outlook: Smart charging for electric vehicles, IRENA
  2. ^ Andrew W. Thompson, Yannick Perez (2020), Vehicle-to-Everything (V2X) energy services, value streams, and regulatory policy implications
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