Evaluating the environmental footprint of a photovoltaic + storage system

Being able to say where and when to combine a photovoltaic system with battery storage from the environmental point of view

Research and innovation

Published on 07/07/2022

The ITE INES.2S is conducting research on life cycle analysis and is developing a tool for the analysis of the environmental impact of installations composed of photovoltaic (PV) panels and a battery storage system, in self-consumption. A guidance to make technological choices with regard to their environmental impacts.

Such systems combining renewable energies and batteries seem to be an interesting alternative to fossil fuels; however they also have their own environmental impacts. But technical and scientific literature often proposes very specific cases that do not allow to compare several scenarios easily nor to adapt the characteristics to the considered application. Moreover, the specific parameters of the different photovoltaic systems (efficiency, type of technology, location of the installation) and of the batteries (life span, energy density, ageing) can have a significant influence on the environmental results.

The tool developed by ITE INES.2S takes into account the different parameters of the installation and focuses on the different uses (countries of installation, modes of use, etc.) thus allowing a comparative analysis of the LCA in relation to a reference solution. It aims to help experts to optimize their models to ensure the environmental interest of a given storage solution.

First results have been obtained, that highlights the interest of photovoltaic coupled with a battery in the context of self-consumption at the local scale, for different locations.

These results use the conclusions of LCA of photovoltaic, obtained with the optimized parameters of the "Eco PV" tool, and the results of LCA of an NMC (Lithium nickel manganese cobalt) battery provided by a partner.

The approach compares 3 use cases:
Case 1: the installation is connected to the electrical grid
Case 2: the system is equipped with self-consumption photovoltaic panels and is connected to the grid
Case 3: the installation is equipped with photovoltaic panels and a battery for self-consumption and is connected to the grid

The functional unit used is the KWh of electricity consumed by the application for the chosen lifetime.

One can already observe that the PV + NMC battery installation in residential buildings is of more interest, from an environmental point of view, according to the more or less carbonated electrical mix of its location. In the case of a high Carbon mix, the environmental criteria will be favorable to such an installation. It will be less favorable, for some of these criteria, in countries with a low carbon mix.
For example, for an installation located in Germany, the results obtained tend to indicate that a photovoltaic + storage installation will be beneficial for almost all environmental impacts.

To allow the optimization of the installation from an environmental point of view, the tool calculates the environmental impacts by taking into account the characteristics of the system and the ageing and replacement of the equipment. It also enables to visualize the share of each impact due to each component of the system (PV, battery or grid mix). It is then easier to understand how a change in the usage criteria (a different location for example) will impact the results on the different environmental criteria. The tool can also be adapted for various studies and further enriched with battery life cycle analysis data. It will help guiding choices such as target markets, PV or battery technologies to be favored according to the targeted application

This work opens up various possibilities for valorization with actors such as stationary battery manufacturers or their integrators.

ITE INES.2S continues to develop its environmental analysis tools and will further improve its databases with LCA data from several types of batteries and photovoltaic systems, with improvements to better account for daily and seasonal variations in PV or battery aging. The institute also seeks to improve knowledge of second life batteries and impacts generated by the reconditioning phase for stationary applications.

Launched in 2019, INES.2S is an Institute for Energy Transition (ITE). Led by the CEA at INES, its mission is to develop an industrial sector for the integration of photovoltaic solar energy in France, in support of the French Multiannual Energy Programming Act. The ITE INES.2S is co-financed by the French government under the Programme d'Investissements d'Avenir (ANR-10-IEED-0014-01).

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