How can decentralised photovoltaic production and energy storage increase the energy autonomy of buildings?  With collective self-consumption, we can now source locally, make energy more equitable and reduce the impact on the environment.  Here’s how the ABC Grenoble real estate programme has brought energy closer to home – for the benefit of everyone.

Soaring energy costs and the depletion of fossil fuels are shining a spotlight on sustainability and opening up energy inequalities all over the world.  In a bid to reduce our impact on the environment, we are all more conscious than ever of the need to preserve precious resources and to do more with less.  Sourcing the products and services that we consume more locally has become a critical element of all of our individual sustainability plans – but can this extend to the energy that we rely on to live and work?


Using technology to serve the environment

When designing the ABC (Autonomous Building for Citizens) Grenoble real estate programme, Bouygues Construction wanted technical innovation to serve the environment and enhance the well-being of its inhabitants. This brand new building comprising 62 dwellings has been equipped with impressive photovoltaic sails installed by Solstyce, as well as an innovative energy storage system from Socomec.  The aim is to strive for energy autonomy for all residents of the building.  How?  By maximising the self-consumption of energy production from a series of photovoltaic roof panels.


The challenges of residential buildings

Photovoltaic production is not typically correlated with consumption within residential buildings.  Household consumption usually peaks in the morning and evening when production is low or even zero, while production peaks during the day, on working days when the inhabitants are generally not at home. In this context, a storage system makes it possible to store excess production during the day - over a 24 hour cycle - for consumption that evening or the following morning.


How does self-consumption work in practice?

Collective self-consumption consists of uniting, at building or district scale, one or more sources of electricity production and individual and / or professional consumers. The producers and consumers are linked within an Organising Legal Person (PMO), which signs a collective self-consumption agreement with the operator of the distribution network, setting the key for the distribution of production to consumers.

The distribution network operator provides the information necessary for operation and invoicing. At each 30 minute interval, the distribution network manager monitors production injected into the network and the consumption of each participant.

The share of self-consumed production is calculated and allocated to each consumer.  The production surplus can then be transferred free of charge or allocated a market value.

Consumers participating in the collective self-consumption programme benefit from locally produced electricity free of charge or as contracted with the producer. For additional electricity, consumers are able to sign up with another supplier of their choice.


Equitable energy

The energy storage solution implemented in this project aims to increase energy autonomy - also called the self-production rate – for all consumers participating in the self-consumption operation. This involves judicious sizing of the photovoltaic production and storage system, so that decentralised production covers 24/7 consumption as far as possible – most importantly, independent of consumption and production curves.

Hubert Hoeltzel, Energy Storage Marketing Manager Socomec explains; “The main objective of collective self-consumption operations, governed by Article L315-2 of the French Energy Code, is to make consumers an active player in the energy transition. They are no longer simply passive consumers, but contributors responsible for an approach to help decentralise electricity production as closely as possible to its point of consumption.  Thanks to the photovoltaic plant and the storage system, local production can meet 70% of electricity needs in this case.

“Self-consumption, whether individual or collective, makes it possible to promote carbon-free production, and in particular, thanks to the simultaneous deployment of storage systems, to reduce the dependence on the electricity network and increase the security of the electricity supply.”


Photo credit: Bruno Lavit for GEG

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