Agrotechnologie

Abstrait

Determination of Energy Thresholds Based on Energy Equivalent in Crop Production for Economic Return on Biogas Production

Vaclav Voltr, Martin Hru�?¡ka, Petr Derenik

The article evaluates the economics of electricity generation in biogas plants based on the analysis of gross annual rental effect and energy yield of crops. The evaluation of the database of crops has shown that the crop most suitable as biogas plant substrate both in terms of economics and energy generation is the fodder sorrel. Ranking among other suitable crops is sugar beet, extensively grown grass, clovers, rye and silage maize. Because of the maximum energy yield, the most suitable is fodder sorrel and silage maize since they generate maximum yield per hectare. The economic analysis of the operation of biogas plants indicates that the guaranteed feed-in tariff for electricity is currently above the minimum 10% profit in biogas plants with the capacity above 200 kW. When sorrel is used as a substrate and its growing technology is well managed, the guaranteed price for 1 kWh may be reduced by almost 50% while maintaining the 10% profit. The technology of sorrel growing, however, has not been well managed in practice. The existing feed-in tariff of electricity is reflected in better economic results of farms with biogas plants, the net added value of which has increased by up to 200 EUR per hectare. Higher subsidies of electricity feed-in tariffs lead are accompanied also by higher price of inputs which is taken advantage of by non-agricultural suppliers and customers. Small biogas plants with the capacity below 200 kW are not competitive with regard to the use of substrates from agricultural crops, but it is assumed that they can better utilize the biological wastes from farming and thus achieve lower prices of inputs.