Compressed air: a source of savings and decarbonization to be optimized

Nicolas Peignet, Director of Industrial Development for the Northeast Territory of ENGIE Solutions, analyzes the means and challenges for better production and distribution of compressed air in order to rationalize costs and thus participate in the decarbonization of sites.

A pillar of the industrial process to be revalued

Industrial sites rely heavily on utilities to power their equipment and production processes. The reliability and availability of these services are essential to avoid costly production interruptions. Compressed air, as both an energy and power vector, is a solution adopted by most industries as a means of drying, cooling, cleaning, waste ejection, transportation, and even lifting. It is therefore ubiquitous: 70% of manufacturers use this utility, according to ADEME. Simple to produce, flexible in its use, and practical to store, some equipment is now even designed from the outset to operate solely on this energy.

Although the real cost of compressed air consumption is often diluted in the overall costs of the manufacturer, this item of expenditure is not insignificant. Although little highlighted, compressed air can represent up to 30% of a site's electricity consumption[2]. This utility is therefore not negligible, both for its key role in the manufacturing process and for its weight in the final energy bill. However, experts now know how to maximize its value to unlock its full potential.

Produce better, waste less, decarbonize well

In addition to the energy benefits listed above, the economic benefits of compressed air must be emphasized. Reducing consumption can be achieved through careful infrastructure and cost management to optimize the profitability of industrial operations while contributing to decarbonization. To achieve this, three vectors can be identified for optimizing the use of compressed air by manufacturers.

Replace installations to boost their performance

It is essential to replace compressed air systems, which may be aging. This modernization means improved fuel consumption. While this represents a new investment, it will be recouped through lower consumption and, consequently, the savings generated. The technological advancements of these new-generation systems will ensure greater distribution stability and the production of better-quality air, all with significantly higher efficiency.

Recovering waste heat: an economic interest

The integration of systems for recovering the calories emitted by the compressors of compressed air plants makes it possible to benefit from free heat that can be reinjected to meet either the needs of the industrial process or those of heating and domestic hot water on the site. 70% of the energy consumed by compressors can generally be recovered in the form of hot air. So why deprive yourself of this energy that will be created in all cases? Another gain often ignored because it is invisible: the compressed air distribution network is often subject to leaks. In industry in Europe, the rate of energy that would be wasted by leaks is estimated at between 20 and 30% of the energy consumed by compressors. As a result, it is necessary to renovate it or at least regularly check its tightness using verification methods, whether automatic or not. In 2022, ADEME recommended regular leak detection and, if necessary, their sealing[3]. The cheapest compressed air is the one that doesn't have to be produced!

Decarbonize sustainably and commit to performance

To ensure ambitious results, a long-term commitment is necessary. The utility production contract offers manufacturers a turnkey solution with a fixed utility price for the duration of the contract. This price includes:

• Financing and installation of new equipment
• Operation and maintenance of installations
• A performance guarantee integrating the quality and availability of compressed air

This makes it possible to achieve a fixed, optimized yield over time and, consequently, better control of loads which involves a reduction in electricity consumption.

In addition to the sobriety achieved through energy savings, these commitments can also be more sophisticated in order to contribute more generally to the greening of the site's energy mix to accentuate its decarbonization. Electricity supply could notably be offered, either through the installation of self-consumption photovoltaic panels or through the use of green electrons.

Let's take the example of a construction company whose compressed air production amounts to 56.000 km3 per year. It was possible to generate financial savings of €275 per year, materialized by a 33% reduction in annual electricity consumption (i.e. 3,5 GWh/year), and thus avoid the release of 198 tonnes of CO2 equivalent.

Economic, industrial and territorial synergies: compressed air maximized

Manufacturers can benefit from financial assistance for these initiatives. Compressed air is particularly eligible for energy savings certificates (ESCs). This incentive mechanism makes it possible to finance all or part of energy efficiency work such as the use of more efficient equipment or the implementation of waste heat recovery.

For example, thanks to a 10-year commitment to renovate and supply compressed air, the Savoyard papermaker La Rochette Cartonboard has reduced its consumption by 9% and now recovers the compressor's waste heat. The project received financial support from the CEE scheme, resulting in more than 16 GWh cumac of CEE[4] recovered and savings of 63,5 million Nm3 of compressed air per year.

To go a step further, waste heat can also be a source of revenue by being redistributed to nearby communities or buildings. This virtuous circle between industry and local areas leads to a simultaneous acceleration of decarbonization locally. This notion of territorial industrial ecology is a pillar of the circular economy already identified in the energy transition law of August 17, 2015.

A final, less-used avenue is the pooling of facilities, made possible by grouping factories together in industrial zones. This would allow for increased savings with shared compressed air production and distribution infrastructure. This pooling of needs can lead to improved energy performance for the facility, as the larger the facility, the more efficient it is. By also sharing human resources and maintenance costs, the manufacturer can significantly reduce its costs.

Tribune by Nicolas Peignet, Director of Industrial Development for the Northeast Territory of ENGIE Solutions (LinkedIn).

[1] Industrial utilities refer to energy services such as electricity, water, steam, gas, air or even cold, which are essential to the production process and therefore crucial for industrial performance.

[2] Practical guide of the Chambers of Commerce and Industry Alsace Eurométropole and Grand Est within the framework of the regional Climaxion program in collaboration with ADEME, www.alsace-eurometropole.cci.fr.

[3] “How can companies mobilize for sobriety and energy efficiency?”, press release of September 1, 2022, www.ademe.fr.

[4] “Cumulated and Actualized” MWh is a unit created within the framework of the CEE system measuring the quantity of energy avoided over a given period.