A more flexible grid

Flexibility is not a new concept: important volumes of flexibility are already used in France to balance the electric system at the national level. In the area of Smart Grids, electrical flexibility can enable the distribution grid to better adapt to the integration of renewable energy or the incorporation of electric vehicles. The distribution grid was of course not originally built to integrate such new uses.

In France, 95% of intermittent renewable energy is directly connected into the distribution network. When generation from renewables is significant yet its consumption is low for example, problems can occur across the electrical network..

In order to face this “variability,” flexibility allows a customer’s consumption or generation to be changed momentarily, depending on the needs of the electricity grid. For example, its consumption can be shifted during periods of high photovoltaic production in order to locally use up temporary surplus generation.

The flexibility is controlled directly by the aggregator if necessary. The aggregator is a new actor in the electrical system that puts in place and activates flexibilities to solve problems both on a national scale and within the local grid. For example, it can remotely trigger the hot water tank at a customer’s premises if it is equipped with a control system.

The NICE SMART VALLEY project will examine the following flexibility solutions:

> Smart charging for electric vehicles;

> Management of battery-based electricity storage systems;

> The remote control of the electricity usage for residential, commercial, industrial and corporate clients: this is known as demand side management;

> Gas/electricity flexibilities: gas/electricity flexibilities exploit the complementarity between gas and electricity grids. Hybrid boilers and motor-driven cogeneration modules are the main gas/electricity flexibilities involved in the project. They can modulate their energy consumption or production according to the needs of the distribution grid and the national electricity system.

Energy storage for local consumption

The progress made in the field of battery technology allows for the storage of increasingly larger quantities of electricity today. This is especially pertinent in terms of the energy produced by solar panels. This enables the overnight usage of the energy produced earlier during the day. Within 5 years, the cost of electric storage batteries is expected to decrease between 19% and 36%.1

NICE SMART VALLEY aims to test an even more ambitious idea: having several solar energy producers share the same battery in order to reduce infrastructure costs. NICE SMART VALLEY is developing a collective self-consumption experiment. Self-consumption is defined in Ordinance n°2016-1019 of 27 July 2016 relating to self-consumption of electricity as follows : “the fact that a producer, known as a self-producer, consumes all or part of the electricity produced by its installation itself”.

Based on the principle of “cloud storage” for digital data storage, the “cloud storage” of photovoltaic energy will allocate (virtual) shares of the battery for each producer connected to the grid.

NICE SMART VALLEY also wishes to test other possible energy storage services. For example, in cases of overloaded electricity grids, or in the case of maintenance, the distribution system operator can use these batteries to ensure the continued quality of their energy distribution. The batteries could also contribute toward balancing global production/consumption across the grid in order to achieve the same goal.

Finally, storage will be used for supply-demand balance needs at the national level. Nice Smart Valley’s challenge is also to contribute to the production/consumption balance of the national electricity system for example, in order to study the combination of services that storage can provide.

What is the function of islanding?

Within the NICE SMART VALLEY demonstration, islanding maintains the power supply to a low-voltage district disconnected from the main grid (because of maintenance works or grid incidents) for a limited duration of time thanks to a storage system and local renewable generation.

This emergency power supply lasts for the entire power outage or until the storage system is discharged. The presence of local generation within the islanding district allows for an increase of the maximum possible duration of islanding.

Islanding will involve several generators and storage systems including ENGIE and EDF and will be supervised remotely by Enedis’ operational teams. Islanding thus makes it possible to reinforce the resilience of areas where power supply is critical. It is a more environmentally friendly alternative.