Compare to other fuels
The calculations given in the example are made for average daily load of 8 hours, 31 days a month for 6kW hour load sufficient to heat an average family house with 80m² living area (200m³ heated volume)..
The table above shows that heating with lignite and firewood is cheaper, but lignite excrete a large amount of ashes (on delivery, while loading the fireplace, after combustion) and the firewood has many additional operations (cutting, splitting, sorting, frequent refuelling of the fireplace).