Hybrid Power Plants. A Combined Geothermal and Biomass Electricity Generation Approach (PDF)

Master's Thesis from the year 2006 in the subject Engineering - Power Engineering, grade: 1,0, Bochum University of Applied Sciences, language: English, abstract: This research draws conclusions from existing biomass and geothermal electricity generation systems and combines these to a hybrid plant concept which is subsequently evaluated thermodynamically, economically and in concerns of risk management.

Using a hybrid power plant concept based on geothermal and biomass energy input, low enthalpy geothermal reservoirs can be utilised more efficiently for electricity generation then it was up to now possible with ordinary binary cycles. By passing the geothermal fluid through a heat exchanger to preheat the biomass boiler feedwater a classical Rankine-Cycle generates electricity with an ideal efficiency of 34%. Due to the geothermal contribution biomass is saved by the amount of 6%.

This thermodynamically desirable process, however, raises economic problems as all components of conventional biomass plants as well as the source-side components of geothermal power plants become necessary. Costs for these parts accumulating at the development's beginning only are compensated by reduced fuel costs and higher efficiencies.

For geothermal exploration failure and the underachievement of the geothermal reservoir the proposed hybrid technology opens up an additional alternative. Having to have to abandon projects with inadequate qualities in former times, it is now possible to produce electricity efficiently and sustainably by the new hybrid power plant. Moreover, the dependence on the fluctuation in terms of biomass quality and prices decrease as the contribution of biomass itself is reduced.

Although delivering first findings concerning these hybrid plants, this paper highlights the future research demand and suggests a list of worthwhile research topics.