The article introduces a method to compare different energy systems based on their overall energy yield. It looks at various scenarios like using wood for heating and power production through combustion. By evaluating the Energy Yield Factor, a ranking of energy systems can be made without bias towards renewable or non-renewable fuels. The study suggests that for a sustainable energy supply, renewable energy systems should achieve an energy yield of at least 2, preferably greater than 5. This evaluation can help in choosing the most efficient energy systems based on biomass combustion in the future.