Carbon emission efficiency is key in sustainability development such as renewable energies and nuclear. To reach the zero-carbon emission all those levers should be activated. Carbon emission efficiency has some advantages over other levers. Renewable energies are inexhaustible resources, but they are not fully available everywhere (it depends on the geographical situation) and the storage of this energy is still to be developed. Nuclear is also an option for avoiding fossil fuels. Nevertheless, the treatment of nuclear waste is still an issue because they are still radioactive and therefore harmful for health. Moreover, in case of incident the consequences can be huge. This article discusses various best engineering practices for reducing carbon emissions. All those best practices have been selected among different practices because they have been successful experiences: tested, reproduced and important CO2 savings confirmed. The industrial site of this case study is a pharmaceutical manufacturing in France. Thanks to the implementation of the best carbon emission efficiency practices, site’s carbon emissions have been reduced by 48% in a decade (from 2010 to 2020).

Energy audit is one lever to reduce carbon emissions of an organization (industrial site, residential building etc.;). This paper explores the energy audit savings tendance, barriers, challenges, and opportunities through an extensive review of the literature. Different variant of the methodology can be found in the literature and one aim of this research is to make a synthesis (from the most relevant variant). Energy audit can be adapted to the size and context of the organization thanks to the different levels of audits. Different cases studies are also included in this article that highlights the benefits of the energy audit. Other aspects are studied such as tools to use during audit and competencies and experience of auditors. Several barriers should be removed progressively to add more benefits to this sustainable lever. A list of opportunities has been identified and should be subject to further research.

Greenhouse gases cause global warming of the earth. Carbon dioxide is one of those gases. There are different sources of carbon emission such as industrial activities and deforestation. The application of energy efficiency in industrial environment is one lever to reduce carbon emissions. "Waste" heat represents a significant energy saving potential for industrial companies. Thanks to recovery technologies, waste heat resulting from a process that is not used by it can be recovered for other uses within the same plant or outside. In addition to the economic interest, the recovery of fatal heat is very virtuous from an ecological point of view if the recovered energy avoids the consumption of fossil fuel. It thus improves the carbon footprint of an industrial installation. This article is a case study in an industrial pharmaceutical site in France and explains how a heat pump has been implemented. All the steps of the methodology are detailed: deep analysis of waste heat from the site, calculation and measurement of the reuse potential and research of the most suitable technology to carry out this recovery. This study has permits to reduce by 1/3 site's carbon emissions.