Sustainable Energy Use in Agriculture : A Case Study of a Swedish Farm

Abstract: The aim of this study is to find possibilities for a more sustainable energy consumption inSwedish agriculture with Rådde Gård as a case farm. The study assesses the current situationand evaluates possible future measures that could help Rådde Gård become more sustainable.To find effective measures, a model of the energy system is constructed in MATLAB whichsimulates different scenarios.The study is delimited to the direct energy usage in the on-farm processes at Rådde Gård.Indirect energy usage as a result of off-farm processes and transportation is not included.The three main energy sources used at Rådde Gård was shown to be wooden pellets forheating, diesel for engines in vehicles and equipment, and electricity used for lighting, airconditioning, among other things.The total annual energy consumption at Rådde Gård was estimated at 443.1 MWh, of which115.2 MWh diesel, 184.7 MWh electricity, and 143.2 MWh wooden pellets. The fossil part of theenergy consumption at the farm is due to combustion engines in vehicles and equipment, andgenerates 31.5 tonnes of CO2 emissions annually. Two measures were suggested to remedythis. A fuel change to HVO or a change of engines from combustion to electric. At Rådde Gård,a fuel change to HVO would result in a reduction of CO2 emissions to 8.5 tonne per year. Since,electrification of agricultural vehicles is still in early stages, technologically, HVO could be seenas a transition step between fossil use and electrification.Other suggested measures were related to a change of heating system. Either by electrificationthrough an installation of an air-water heat pump, or through a biochar pyrolysis boiler which,although it generates less heat than conventional boilers, coproduces both heat and biochar.These two heating systems can also be combined.The study also found that roof-top solar panels could be an important future aspect of anelectrification of agriculture. For example, since harvesting and grain drying consumes muchenergy during the summer, the seasonal variation of solar production could be utilized.A sensitivity analysis was also performed which indicated that sensitive parameters were to alarger extent related to current electricity consumption and solar electricity production than tothe efficiencies of engines, boilers, and a heat pump.