In many cases, biogas is 100% saturated with moisture. When a temperature drop occurs, the moisture condensates and enters the utilisation system (boiler / gas engine / gas reprocessing). This is an undesirable situation because the operation is adversely affected and can lead to corrosion in the biogas fed systems. Forced condensate separation can be accomplished by cooling biogas in a heat exchanger which is cooled secondary by a chiller. In most cases a sufficient dew point can be reached with a chiller. If very low dew points (e.g. -5 ....- 10 grC) are required, one can use absorption dryers.