| Summary: | In our paper we examine the economics of a technological process which utilizes the separated biogas plant digestate as the primary material and, as auxiliary material, the waste heat produced by the cogeneration process, to produce a marketable pellet which can be used in two ways (to supply soil nutrients and heat energy). Using multivariate linear regression model we developed an equation for the biogas yield from the modelled production recipe and expected nutrient pellet prices, and sensitivity analysis were also performed for the substrate dry matter content. We found that pellets can be produced at a cost of 88–90 EUR/ton with a 6 to 10% dry matter substrate content and that, primarily, sales of pellets for heating justify pelleting; producer’s own use and use for nutrient purposes can only be justified in exceptional cases. In the case of dry solid content above 5%, the process does not require the total amount of waste heat; some of this can be used to cover other heat requirements.
|
|---|