A customer asked me the energy price in Belgium and I could find a document of the Belgian government, published end 2014. I also could find a study about the price of recycled glass. With both, we are able to estimate the production cost of cellular glass without labour cost.

The energy price depends strongly on consumption like shown in the following tables.

The study about the price of recycled glass gives 110€/ton recycled (collected, cleaned, …) glass. For 1m³ cellular glass, we need about 180 kg or 20€ glass. We need 1400 MJ primary energy for 1m³ cellular glass. For a plant of 100000 m³/year, we have a consumption of about 40 GWh/year or 0.045€/kWh. In that case, we have for 1m³ (1400/3.6=389) 389 kWh or 17.5€. In total, we get about 40€/m³ without foaming agents, belt protection and labor. It is clear that cellular glass with 1000 kPa compressive strength and 0.050 W/mK thermal conductivity is a competitor for high density mineral wool if the thermal conductivity measurement takes natural convection into account.