Solution Reliability Evaluation Of Engineering Systems By Roy Billinton And May 2026

Roy Billinton is a leading authority in power system reliability and stochastic modelling for engineering systems. His work focuses on quantitative evaluation of system reliability, availability, and risk, particularly for electric power systems but broadly applicable across engineering domains. Key themes in his contributions include probabilistic modelling, component-level failure and repair data, system-level adequacy and security assessment, and methods to incorporate uncertainties and renewables.

A defining feature of Billinton and Allan’s work is the concept of Reliability Cost/Worth. They argue that "solution reliability" is not about achieving 100% reliability (which is impossible or infinitely expensive), but about finding the optimal point. Roy Billinton is a leading authority in power

Consider a small industrial power system: Two parallel gas turbines (20 MW each, failure rate 5/year, repair time 50 hours). Load = 25 MW. A defining feature of Billinton and Allan’s work

Deterministic Solution (N-1): System passes (one turbine fails, remaining 20 MW < 25 MW? Actually, that fails. So deterministic says "Unreliable – add a third turbine." Cost: $10M. Step 2: Calculate loss of load probability (LOLP)

Billinton Probabilistic Solution:

  • Step 2: Calculate loss of load probability (LOLP).
  • Step 3: Calculate EENS = 25MW * 0.0558 * 8760 hrs = ~12,200 MWh/year.
  • Step 4: If cost of unserved energy = $100/MWh, annual risk cost = $1.22M.

    • The Decision: Instead of a $10M turbine, spend $2M on a 5 MW battery to cover the single-turbine failure period. The probabilistic solution identified the optimal economic solution, not just the safe one.