Financial metrics such as LCOE, NPV, and IRR are widely used in evaluating energy projects.
They are often presented as definitive indicators of project viability.
However, in practice, these metrics are frequently misunderstood, misapplied, or interpreted without sufficient technical context.
Understanding the Metrics
LCOE (Levelised Cost of Energy)
LCOE represents the average cost of generating electricity over the lifetime of a system.
It is typically expressed as:
Total lifetime cost ÷ Total energy generated
This allows comparison between technologies such as:
• solar
• diesel
• grid supply
However, LCOE alone does not capture operational realities.
NPV (Net Present Value)
NPV reflects the total value of a project after accounting for:
• capital cost
• operating cost
• future cash flows
• discount rate
A positive NPV indicates a financially attractive project.
IRR (Internal Rate of Return)
IRR represents the effective return on investment.
It is often used by investors to compare projects across sectors.
Where These Metrics Go Wrong
In many projects, these metrics are calculated correctly — but based on incorrect assumptions.
Common issues include:
• Unrealistic energy generation estimates
• Incorrect load assumptions
• Ignoring system degradation
• Simplified operating cost models
• Failure to account for downtime or outages
As a result, financial outputs may appear strong, but are not achievable in practice.
The Missing Link: Engineering Reality
Financial models are only as good as the engineering assumptions behind them.
For example:
• Overestimating solar generation leads to artificially low LCOE
• Underestimating generator runtime inflates projected savings
• Ignoring battery degradation distorts lifecycle cost
In hybrid systems, this becomes even more critical due to system interactions.
Why LCOE Alone Is Not Enough
LCOE is useful for comparing technologies, but it does not account for:
• reliability requirements
• operational flexibility
• system integration complexity
• backup power needs
Two systems may have similar LCOE values but perform very differently in practice.
A More Practical Approach
A more robust financial evaluation should:
• integrate realistic load profiles
• reflect actual operating scenarios
• include system constraints
• consider reliability and downtime
• align with technical system design
This requires close alignment between engineering analysis and financial modelling.
Linking Technical and Financial Performance
Effective decision-making requires combining:
• power system studies
• hybrid system modelling
• financial analysis
Rather than treating them as separate exercises.
This ensures that financial outcomes reflect real system behaviour.
Conclusion
LCOE, NPV, and IRR are powerful tools — but only when used correctly.
They should not be treated as standalone indicators.
Instead, they must be grounded in:
• realistic engineering assumptions
• operational understanding
• system-level thinking
In energy projects, the strongest decisions are those where technical and financial analysis are fully aligned.
