6. Conclusion

In the 21st century, we have entered a period where energy expenditure, and the need to limit consumption in order to act on climate change, are increasingly driving industrial production strategies. We can see that industry is taking a more virtuous approach to energy, raw materials and waste, by reducing their volume or recycling them. To this end, two major leverage effects are worth mentioning:

• rising energy prices and scarcity of raw materials;

• higher, tougher standards.

These levers have totally "fed" the development of CO ₂ technology in the fields of materials processing, accompanying production methods and their evolution. It took almost two centuries, for an observation made on a compressed liquid by a French engineer...