The 2017 ADEME study on the place of the electric vehicle in the ecological transition in France shows that these cars could have more advantages by developing services to the electric system ( “vehicle-to-grid” or V2G). What does this system consist of? How can it fit into the building? Is there a synergy between local energy production, electricity storage and buildings? Quick inventory of fixtures.
According to the monthly barometer of October 2019, conducted by AVERE France (Association pour le développement de la mobilité électrique), the French car fleet has more than 200,000 light electric vehicles in circulation, including 50,000 new units over the past 12 months. France aims to reach one million electric vehicles by 2022. The question arises as to the capacity of the electricity network to meet the massive demand for charging inherent in the introduction of these vehicles.
The objective is to smooth electricity demand over the day, reducing peak consumption to avoid the risk of overloading the grid. The idea would then be to be able to temporarily store electrical energy when demand is low (at night, for example) and to return it to the grid when it is heavily used (peak consumption in the early evening). Electric vehicle batteries can be moving storage units capable of meeting this demand. Why not use electric vehicles to supply the grid if necessary? This is the principle of the “Vehicle-to-grid” or V2G.
An energy reserve to reduce pressure on the electricity grid and supply a building
Electric vehicles remain immobilized for 95% of their time and daily trips use less than 80% of the battery’s capacity. With the V2G principle, the network can draw from vehicle batteries the electricity needed to meet high demand or to compensate for a specific lack of production (renewable energies that cannot be used because of weather conditions, for example). This synergy between electric vehicles and buildings makes it possible to secure the supply of local electricity to buildings by smoothing out peaks in consumption and limiting the risk of power cuts.
From the detached house to the neighbourhood: examples of how electric vehicles can be used with V2G
V2G also allows electricity from fluctuating renewable energies (solar or wind) to be stored during periods of high production in order to be reused later for building activities, or to be fed back into the grid during peak consumption periods. The grid is then more stable and the share of electricity from renewable energies in the energy mix increases.
An experiment, called Solar Camp, will be launched at the Aix-en-Provence TGV station in the coming weeks with a first Nissan V2G compatible vehicle and a bidirectional terminal. It combines photovoltaic production, electric vehicles and rail activity. Fabien Albert, project coordinator, considers this approach to be a “project to optimise locally produced renewable energy and raise users’ awareness of energy consumption through a remuneration system”. Indeed, owners of V2G-compatible electric cars will be able to be paid in virtual currency by leaving their vehicles parked in Aix-TGV. Travellers will indicate via a mobile application their return date and the desired recharging level upon their return. During their absence, their vehicle will serve as storage and distribution units for the photovoltaic energy produced on site or at The Camp… This system will make it possible, for example, to provide stability and standby services at the station or to avoid power outages. The final objective is for the Aix-TGV station to become self-sufficient in energy thanks to its photovoltaic production and the storage capacity available in electric vehicles.
The European SEEV4-city project is funding a series of pilot experiments in the United Kingdom (Leicester, Loughborough), Belgium (Kortrijk), the Netherlands (Amsterdam), Germany (Hamburg) and Norway (Oslo) to test different models of V2G: storage and restitution of photovoltaic production by a fleet of vehicles, at different scales – from the individual house to the neighbourhood. For example, the Loughborough’Living Lab’ project demonstrates the added value of V2G in storage for optimized energy production and consumption at the household level. When the electric vehicle is parked in the home, the V2G unit allows the electric vehicle to recharge itself by using excess solar energy produced by the photovoltaic panels on the roof. This electricity is returned to the house when necessary. The V2G charger can also vary the response to match household electricity demand and solar energy production forecasts. As a result, the distance travelled by electric cars using zero emission photovoltaic production is expected to increase while minimizing overall housing demand.
Source : SEEV4-City
The challenges facing V2G
In the construction and rehabilitation of new housing and offices, precautionary measures are taken to ensure that there are possible connections in new buildings, convertible parking spaces or bi-directional electrical terminals.
But the V2G principle is still at the experimental stage and still faces some challenges. This technology is based on the alternation between charging and discharging cycles of batteries. The existing infrastructure is not yet large enough. The economic model, adaptation to market mechanisms of the national network, user empowerment factors, data properties, technological obstacles to battery life related to mobility are other issues to be addressed.
The experiments are only at the beginning. Many other possibilities for using V2G are still to be explored, such as with smart city networks.
Article researched and written by Lauriane Debord for Urban Chronicles™
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