Farming is a crucial sector to support the transformation towards a net zero energy system as they have space for renewable energy installations and important resources such as manure. Multiple simulations have been carried out, assessing potentials for renewable energy integration on dairy farms. However, a thorough validation of those simulations is lacking. This study examines how closely the presented simulation tool can represent the reality for a case study based on a Northern German farm and further advances the simulation regarding possible expansions. The PV simulation with PVlib is based on strongly localised weather data, leading to differing cloud covers and thereby a deviation between simulation and measurement data. The deviations are much smaller for the biogas production compared to the deviation of the PV simulation, as the biogas production is very steady, and closely related to the manure availability. The possibilities for future, further usage of the biogas / the PV produced energy are simulated, including, direct biogas usage as fuel, hydrogen production though electrolysis and biogas reforming. The simulation shows, that all three options assessed are possible for the self-sufficient fuel production. However, the option of biogas as fuel accounts for the best energy usage with little losses.