A gas holder provided storage for the purified, metered gas. It acted as a buffer - removing the need for continuous gas production. The weight of the gasholder lift (cap) controlled the pressure of the gas in the mains, and provided back pressure for the gas making plant. A watered gasholder, consisted of two parts: a deep tank of water that was used to provide a seal, and a vessel that rose above the water as the gas volume increased.
- storage of biogas, methane, syngas
- holding CO2-rich off-gas from combustion (after purification with a biofilter) for subsequent use in a greenhouse or in the open field (CO2 Enrichment).