Approximately half of the energy produced by biogas combustion engines is in the form of low-grade heat. A plethora of initiatives have been undertaken to utilize this energy source. In commercial terms, only a few technologies have proven to be economically viable in practice. These include: 1) feedstock pre-treatment; 2) drying of agricultural commodities; and 3) low-temperature pyrolysis of the fermentation residues into charcoal or biochar. Whilst low-temperature pyrolysis appears to be the most profitable, current legislation and qualitative standards gives preference to the application of fermentation residues to arable soils. Analyses have shown that if current legislation is not updated, this significant energy source will remain unutilized, which can be interpreted as having a negative impact on the environment.