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.
Table of Contents
1. Introduction
1.1. Motivation
1.2. Aim
1.3. Objectives
2. Fundamentals of Biomass and Geothermal Energy Systems
2.1. Thermodynamics of Power Plants
2.2. State of the Art of Geothermal Energy Systems
2.3. State of the Art of Biomass Energy Systems
3. Combination of Geothermal and Biomass Energy Systems
3.1. Geothermal Part
3.2. Biomass Part
3.3. Thermodynamic Proposals
3.4. Economic Considerations
3.5. Risk Management
3.6 .Existing Hybrid Power Plants
4. Conclusion and Recommendation
5. Further Research
Research Objective and Core Themes
This thesis investigates the feasibility of combining geothermal and biomass energy sources into hybrid power plant concepts to increase electricity generation efficiency, particularly for low-enthalpy geothermal reservoirs. The research evaluates these hybrid systems through thermodynamic analysis, economic assessment, and risk management strategies to determine their viability as a sustainable alternative to conventional energy systems.
- Thermodynamic evaluation of geothermal and biomass hybrid plant concepts.
- Economic viability and capital cost structure of hybrid renewable power plants.
- Risk mitigation in geothermal projects via hybrid energy integration.
- Case studies of existing and projected hybrid power plant facilities.
- Assessment of renewable energy resource utilization for electricity generation.
Extract from the Book
3.3.1 Evaluation of Improvements by Hybrid Technologies
Considering the improvements of the ideal Rankine or the ideal reheat Rankine-Cycle as starting points geothermal and biomass resources are combined to a hybrid plant.
The comparison of the fluid enthalpies in biomass plants and of geothermal resources shown in figure 28 indicates that biomass cycles operate in enthalpy ranges well above the enthalpies supplied by low quality geothermal resources. However, enthalpies are also low and even lower than those of the geothermal resources. Consequently a combination of both processes seems to be theoretically possible. As higher enthalpies occur in biomass cycles this paper assumes that technology and characteristic of hybrid plants resemble the Rankine-Cycle used in biomass plants. The basic process is a power cycle externally fired with biomass.
Summary of Chapters
1. Introduction: Outlines the dependence on finite fossil fuels, the impact of climate change, and the potential of combining geothermal and biomass as a solution for efficient renewable electricity generation.
2. Fundamentals of Biomass and Geothermal Energy Systems: Provides the theoretical thermodynamic basis and reviews the current technological state of geothermal and biomass electricity generation.
3. Combination of Geothermal and Biomass Energy Systems: Analyzes specific hybrid proposals, economic costs, risk management factors, and examines existing implementations such as the Wendel and Neuried plants.
4. Conclusion and Recommendation: Summarizes the study's findings, noting that while the hybrid approach is thermodynamically advantageous and mitigates certain risks, it faces significant economic challenges.
5. Further Research: Suggests future directions, including the development of comprehensive models for economic optimization and the investigation of other hybrid combinations.
Keywords
Hybrid Power Plants, Geothermal Energy, Biomass, Rankine-Cycle, Renewable Energy, Low Enthalpy, Thermodynamics, Electricity Generation, Economic Analysis, Risk Management, Sustainability, Energy Efficiency, Cogeneration, Renewable Resources, Power Systems
Frequently Asked Questions
What is the core focus of this thesis?
The thesis explores the integration of low-enthalpy geothermal energy with biomass energy in hybrid power plants to improve the efficiency and reliability of electricity production.
What are the primary thematic areas explored?
The research covers thermodynamic cycles, current geothermal and biomass technologies, economic feasibility, project risk assessment, and specific hybrid plant case studies.
What is the main research question or goal?
The goal is to determine if hybrid power plants utilizing both geothermal and biomass resources are viable from thermodynamic, economic, and risk management perspectives.
Which scientific methods are applied?
The paper uses thermodynamic cycle modeling, comparative analysis of energy conversion paths, and evaluation of financial data for geothermal and biomass infrastructure.
What is covered in the main body of the work?
The main body details thermodynamic proposals for integrating geothermal heat into biomass cycles, calculates performance indicators like mass flow and thermal efficiency, and evaluates costs.
Which keywords best describe this research?
Keywords include Hybrid Power Plants, Geothermal Energy, Biomass, Rankine-Cycle, Thermodynamic Efficiency, and Renewable Energy.
Why is a low-enthalpy geothermal source considered inefficient on its own?
Standalone low-enthalpy geothermal sources often result in low power output and efficiency, making them less attractive compared to conventional fossil-fueled power cycles.
How does the hybrid approach mitigate risks in geothermal projects?
By adding biomass combustion to the power cycle, the system can ensure a consistent power output even if the geothermal reservoir quality or flow rate underperforms.
What are the main economic drawbacks of the proposed hybrid plants?
The hybrid plants require high initial capital investment because they essentially combine two complete power plant systems, which may not be offset by fuel cost savings alone.
- Quote paper
- Bastian Görke (Author), 2006, Hybrid Power Plants. A Combined Geothermal and Biomass Electricity Generation Approach, Munich, GRIN Verlag, https://www.grin.com/document/1030670
