Life Cycle Analysis and Causal Modeling in Sustainable Energy Systems
Life Cycle Analyses and System Quality Characteristics
Life Cycle Analyses and Methods (Chapter 3)
1. Quality Characteristics (QCs)
- Define inherent qualities of products and systems.
- Produce nonfunctional requirements.
- Examples: Affordability, agility, HSI (Human Systems Integration), interoperability, logistics, producibility, RAM (Reliability, Availability, Maintainability), resilience, sustainability, safety, security.
2. Affordability
- Balances performance, cost, and schedule.
- Includes LCC (Life Cycle Cost): concept, development, production, support, and retirement phases.
- Cost Effectiveness (CE) Formula: System Effectiveness / (Initial + Sustainment Costs).
3. Agility Engineering
- Enables timely and cost-effective change.
- Metrics: Timely, affordable, predictable, comprehensive.
4. Human Systems Integration (HSI)
- Integrates human, organizational, and technical elements.
- Covers interfaces, workload, training, and safety.
5. Interoperability
- Ensures systems work together seamlessly.
- Achieved via standards or custom interfaces.
6. Logistics Engineering
- Ensures lifecycle support.
- Covers maintenance, spares, and supportability.
7. Manufacturability / Producibility
- Ensures efficient and cost-effective production.
8. RAM Engineering
- Focuses on Reliability, Availability, and Maintainability.
- Strongly influences design and verification processes.
9. Sustainability
- Supports the circular economy model.
- Considers environmental, social, and economic factors.
10. System Safety
- Mitigates hazards and risks throughout the system lifecycle.
11. System Security
Sustainability, Energy Systems, and Dynamics
1. Sustainability Basics
- Definition: Development that meets present needs without harming future generations.
- Three Pillars: Environmental, Social, Economic.
- Goal: A balanced, interdependent system.
2. Energy Sources and Systems
- Nonrenewable: Coal, natural gas, nuclear.
- Renewable: Wind, solar, geothermal, ocean current.
- Energy System: Converts raw source into usable energy; includes extraction, conversion, delivery, and waste management.
3. Challenges in Energy Systems
- Rising global energy demand (approximately 2% per year).
- Increasing CO2 emissions.
- Fuel import dependence.
- Energy-water nexus issues.
- Environmental impacts of renewables (e.g., wind: noise, bird strikes).
4. Energy System Sustainability
- Meets present energy needs without limiting future generations.
- Must consider environmental, economic, and social impacts comprehensively.
5. Systems Thinking and Dynamics
- Systems Thinking: Holistic understanding of complex systems.
- System Dynamics (Forrester): Focuses on feedback loops and causal models.
6. Causal Model Concepts
- Positive (+) Link: Factors move in the same direction (e.g., A increases, B increases).
- Negative (–) Link: Factors move in opposite directions (e.g., A increases, B decreases).
- Reinforcing Loop (R): Amplifies change (vicious or virtuous cycle).
- Balancing Loop (B): Stabilizes the system toward a goal.
7. Environmental Pillar Causal Loop (Balancing)
Energy installations $ ightarrow$ increased water footprint $ ightarrow$ increased ecological footprint $ ightarrow$ decreased social acceptance $ ightarrow$ decreased future installations.
8. Social Pillar Causal Loop (Reinforcing)
Installations $ ightarrow$ increased skilled personnel $ ightarrow$ increased employment $ ightarrow$ increased acceptance $ ightarrow$ increased installations.
9. Economic Pillar Causal Loop (Reinforcing with Balancing Effect)
Installed capacity $ ightarrow$ increased power $ ightarrow$ increased economic opportunity $ ightarrow$ increased investor commitment $ ightarrow$ increased installations.
Balancing effect: Market saturation eventually reduces installations.
10. Key Conclusions
- Sustainability requires a full lifecycle view of sources and systems.
- Causal patterns help create consistent, reusable models.
- A system-of-systems perspective is needed for comprehensive analysis.