2018 has been a milestone year for the renewables industry. In the UK, renewables’ share of electricity generation reached a record of 31.7% in Q2, and overall capacity has now exceeded 40GW, nearly half of which is due to new offshore wind facilities. The era of fossil-fuel generation is drawing to a close, and with it we leave behind the high carbon emissions and rising energy bills caused by this outdated system.

As part of this transition, electric vehicles are becoming increasingly prominent. By 2040, the UK government will ban the sale of all new diesel and petrol cars under plans to tackle air pollution and some predict there could be as many as 36 million electric vehicles (EVs) on British roads.

However, with the growth of the EV industry, a rising concern is how the grid will cope with extra demand from EV charging. In addition, as we transition away from burning hydrocarbons as our primary source of energy, we’re faced with new challenges as our grid infrastructure struggles to cope with the increased variability of renewable energy supply. Compared with the straightforward paradigm of “x fuel burned equals y power generated” (particularly for gas), renewable energy production is highly variable, and the current grid infrastructure doesn’t have the capacity to absorb peaks in production.

With the advent of mass EV adoption almost upon us, the last thing a grid operator wants to see is everybody plugging in their EV at 6pm when they return home from work, exacerbating the existing peak load issues on the grid. To ensure a smooth transition to EVs and renewable energy, the challenge lies in ensuring the grid can meet the flexibility requirements of increasing electricity demands, while simultaneously balancing the greater variability of renewable production.

Distributing the capacity of the grid through VPP and V2G

One way to increase the storage capacity of the grid is to distribute energy capacity among consumers. Through creating a virtual power plant (VPP) network of interconnected domestic and car battery units, energy storage systems can be distributed throughout the grid to where it is most needed, and the total storage capacity scaled incrementally to meet future requirements — more consumers, more capacity.

An integral part of the VPP, vehicle-to-grid (V2G) charging utilises the additional storage made available by electric vehicles as more hit the roads by responding to demand from the grid. For between 90 and 95% of the time, domestic electric vehicles are stationary, and their batteries go unused. Bi-directional V2G chargers can harness the potential of these idle batteries to provide additional flexibility to the grid, charging up at off-peak when demand is low (and tariffs are cheap) or to absorb peaks of renewable generation, then discharging to the home, or grid, in response to peak demand.

Although it is inevitable that over the next 10-20 years we will see a significant increase in demand for electricity as heat and transport becomes electrified, the beauty of this increasing demand is that, like electric vehicles, it will comprise of primarily “flexible” or controllable loads. Often referred to as flexibility assets, each one of these individual storage batteries is capable of absorbing power from, or feeding it back into the grid.

In order to create the VPP, these units are aggregated to create a dynamic and interconnected network. Using intelligent operating systems, each asset can become responsive to the demand and supply side pressures on the grid, spreading electricity consumption more evenly throughout the day and balancing out the load on the grid.

Vehicle charging is a moving target

Implementing a V2G system is not without its own challenges, the most significant of which is that a vehicle is a mobile asset. A car’s battery isn’t necessarily available at all times, which makes scheduling charge and discharge cycles more difficult than a stationary asset such as a domestic battery. To overcome this, a delicate balancing act must be maintained between delivering services to grid operators and managing energy demand and also reserving sufficient capacity in the EV battery for vehicle owners to travel where they need to go — all while predicting when the vehicle will actually be plugged into the V2G charger at home!

Most importantly, the EV owner’s preferences must always take priority. By allowing members of the V2G network to define the parameters in which their car can be used, intelligent algorithms can be applied to ensure the battery charge will never be below a predefined level at certain times of day. If they require 60% battery capacity at 8am for their morning commute, for example, this will be prioritised, and the remaining 40% can be used throughout the night to deliver whatever services are needed in order to keep the grid in check.

Digitalisation of the grid is imminent

The key to these systems working in practice is the intelligent software behind them. Universal smart metering is one of the fundamental components required to complete the picture, as domestic consumers play an increasingly important role in the digitalisation and decarbonisation of the energy system. This requires almost real-time visibility of their consumption (and generation) patterns. Aggregators, system operators and the energy markets will require this level of data resolution in order to operate a secure and reliable electricity system, while also ensuring fair and transparent pricing for end-users.

The smart meter roll-out has already commenced in the UK. This allows for half-hourly market settlement right down at a residential level, which is critical for mass adoption of VPP networks. Thankfully, smart meter uptake has increased right across the EU and other mature energy markets across the globe, albeit with varying rates of adoption.

Another welcome proposal in the UK market is that made by Elexon, which describes amendments to the balancing and settlement code that would enable customers to buy power from multiple providers, including their neighbours. Progressive regulatory changes such as this are opening up the market to innovative new business models that address the challenges of an energy revolution head-on.

Increased renewable production must be met by the ability to integrate it into the system, and the combination of progressive regulation with intelligent new software platforms are making the creation of the virtual power plant possible. With renewable energy continuing to break records and electric vehicles on the rise, the vision of a renewable-powered future is looking increasingly hopeful.

Killian O’Connor is co-Founder of Solo Energy, an Irish start-up working on virtual power plants based on residential and EV battery storage and V2G technology.

Transition

'VPPs and vehicle-to-grid will help drive renewables growth'