When Julia Becker transitioned from renewable energy engineering to software development, she discovered an unexpected synergy between thermodynamics and functional programming. Her journey—from wrestling with MATLAB scripts in solar storage research to building production Haskell systems—exposes a critical gap in renewable energy software: the need for mathematically rigorous, fault-resistant code to manage inherently variable energy sources like wind and solar.

When Units Guide Logic: From Thermodynamics to Type Safety

During her energy systems studies at HTW Berlin, Becker’s thermodynamics professor offered pivotal advice: deeply understand SI base units to decompose complex formulas. This allowed her to solve problems structurally rather than through rote memorization—a precursor to type-driven development. Years later, as a Haskell developer, she recognized the same principle: compiler-enforced unit safety eliminates entire classes of runtime errors.

charge :: Power Double -> Time Double -> Energy Double -> Energy Double
charge power time energy = ...

This function signature—using Haskell’s dimensional library—ensures physical unit correctness at compile time. Attempt invalid operations (like adding power to time), and the compiler rejects it immediately.


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shows a real type error when units mismatch—catching mistakes that would fail silently in other languages. ## Why Traditional Approaches Fall Short Early in her career, Becker encountered two problematic patterns: 1. **Fragile Scripts**: MATLAB/Python scripts lacked type safety, allowing arbitrary inputs (even strings) for critical parameters like power values. Testing involved manual graph comparisons—error-prone and unscalable. 2. **OOP’s Hidden Traps**: Java improved type checking but couldn’t prevent semantic errors. Units lived in variable names (e.g., `double energyWh`), not the type system. Stateful objects also complicated concurrency and testing. ## The Haskell Advantage for Energy Systems Haskell’s functional paradigm solves these systematically: - **Type-Driven Design**: Encode domain rules (e.g., "energy = power × time") directly into types using libraries like `dimensional`. As Becker notes: "Once data is parsed into these types, you don’t need runtime checks—they’re compiler-guaranteed." - **Immutable State**: Functions transform inputs to outputs without hidden side effects, simplifying reasoning about distributed systems. - **Property-Based Testing**: Frameworks like QuickCheck auto-generate test cases to verify physical invariants (e.g., "battery charge never exceeds capacity") with minimal code: 
testProperty "does not exceed max capacity" \(Positive duration) -> 
  let newEnergy = charge power duration previousState 
  in newEnergy <= maxCapacity

A Sustainable Future Demands Better Tools

Renewable energy’s variability requires software that adapts flawlessly. Haskell’s emphasis on correctness—through expressive types and pure functions—makes it uniquely suited for modeling grid dynamics, storage optimization, and real-time control. While niche today, its adoption could accelerate the reliability of critical green infrastructure. As Becker concludes: "Unit safety and strong typing aren’t academic—they’re practical tools for building a maintainable energy transition."

Source: Julia Becker's personal blog