Comparative life cycle assessment of different vacuum insulation panel core materials for cryogenic storage tanks – with a focus on glass bubbles as a novel core material

Developing a sustainable hydrogen supply chain is important in facilitating the energy transition towards climate neutrality. Hydrogen in its free form can be stored and transported either as a gas or a liquid. Due to gaseous hydrogen's comparatively low energy density, liquefied hydrogen (LH 2) is often preferred, especially with regard to long-distance transportation and storage in bulk. A notable challenge associated with LH2 is the inherent requirement to preserve it at a low temperature of -253°C. Consequently, the utilisation of thermally insulated tanks is necessary to minimise LH 2 evaporation. There is a lack of literature on the environmental impacts of insulation materials and concepts for cryogenic storage tank applications in the hydrogen supply chain. Hence, this study investigates a novel concept, namely vacuum insulation panels (VIPs), focusing on their core materials, with a view to assessing their environmental sustainability and circularity. A cradle-to-grave life cycle assessment (LCA) model is employed to investigate six distinct VIP core materials, namely, silica aerogel, rigid polyurethane foam, expanded perlite, glass fibre, fumed silica, and glass bubbles (hollow glass microspheres), with a special focus on the latter. The LCA results show that polyurethane foam and silica aerogel rank low in environmental performance, making them less suitable as primary choice. Expanded perlite is the most environmentally friendly material option, followed by glass fibre, glass bubbles, and fumed silica. Improvements to the environmental impact of glass bubbles can be achieved via the implementation of closed-loop recycling in their life cycle.