The first historical records of using biogas for economic purposes occurred 3000 years ago in China [1–3]. Marco Polo also mentioned in his diary that biogas was produced in this area [4]. In 1895 biogas was used to power street lights in Exeter (UK) [5]. Many countries have been recently developing an energy sector based on biogas [6–9]. This has been influenced by both economic factors and care to protect the environment. High prices and limited resources of fossil fuels together with the technolo- gical progress and optimisation of the biogas production make biogas energy even cheaper. The use of biogas for energy production reduces the use of fossil fuels, the combustion of which contributes to the climate change [10,11]. The Polish energy sector has also noticed a possibility of biogas production, especially of agricultural biogas [12]. Agricultural biogas is at the moment a small fraction of Poland’s general energy balance. However, the importance of biogas as an energy resource in Poland is increasing every year since Poland has a great biogas potential, which is comparable to that of Germany Experts are forecasting a dynamic development of agricultural biogas plants till 2020 at a rate of a few tens per cent a year.
The actual realisation of agricultural biogas potential in Poland during this period of time will depend on the effectiveness of the implementation of Directive 2009/28/EC of the European Parlia- ment and of the Council of 23 April 2009 on the promotion of the use of energy from renewable sources [17]. The plan to implement the directive was presented in so called ‘‘National Renewable Energy Action Plan’’ [18]. It seems that in the coming years agricultural biogas will gain more significance on the green energy market and the growth rate will be among the highest in Europe.