Methods
Complexity follows evidence.
The study uses the simplest transparent model that the available public evidence can support, then adds complexity only when the next question requires it.
Progressive evidence ladder
From source record to bounded inference.
Hourly demand reconstruction
Observed daily energy; reconstructed intraday shape.
Continuous public Kerala interval-load telemetry was not available in the admitted evidence. The model therefore fixes what is known and reconstructs only what is missing.
Σₕ Load(d,h) = observed SLDC daily energy(d)
Held-out intraday-extrema performance
January–March extrema were withheld from fitting. These errors measure intraday-shape reconstruction conditional on known daily energy, not day-ahead forecasting.
Chronological adequacy
Every hour is solved in sequence.
The statewide screen asks whether generation, storage and imports can meet demand in each of 8,760 hours.
Demand scenarios
Official future energy/peak trajectories from different studies remain separate rather than being averaged into a synthetic consensus.
Transfer scenarios
CEA's 4,455 MW ATC is the dated reference. 80% and 60% cases are transparent stress sensitivities.
Candidate resources
Renewable and storage ceilings are research scenario envelopes, not legal buildable capacity.
Stage 2: preserve Stage-1 adequacy, then minimize candidate investment + partial import cost
The lexicographic objective avoids inventing a Kerala-specific Value of Lost Load. It is an adequacy-first screen, not a total-system welfare optimum.
Hydropower hierarchy
Separate timing value from reservoir physics.
Daily hydro MWh fixed; hourly timing flexible within power limits.
Hydro energy conserved over 1/3/15/30-day windows.
Add storage state with reconstructed net-water forcing.
Require direct physical inflow/storage evidence before stronger claims.
State replay: Sₜ₊₁ = Sₜ + Bₜ − Gₜ/c
Because B is constructed from storage change and generation, historical storage closure is algebraic. It verifies implementation and date alignment, not hydrology.
Public transmission screen
A source-backed topology with explicit proxy layers.
Spatial inputs
- Public KSEBL topology and equipment evidence.
- Distribution-interface transformer MVA as a load-location proxy.
- Mapped generation where source location is resolved.
- Generic voltage-class reactance where source X is unavailable.
Interpretation boundary
Outputs are candidate stressed corridors and robustness to import-injection location. The model does not assess reactive power, voltage, transient behavior or N-1 security.
Verification & validation
Different checks answer different questions.
| Check | Purpose | What it establishes |
|---|---|---|
| Source provenance | Trace values to a named agency/document/date. | Evidence identity and accounting boundary. |
| Conservation / invariant checks | Verify energy/accounting transformations. | Arithmetic correctness, not physical truth. |
| Unit/integration tests | Check software guards and equations. | Implementation correctness. |
| PyPSA ↔ SciPy ↔ OSeMOSYS | Reproduce common mathematical formulations independently. | Reduced framework-specific implementation risk. |
| Held-out extrema | Evaluate demand-shape reconstruction on withheld observations. | Out-of-sample shape evidence. |
| CEA transmission plan comparison | Compare network-screen geography with independent planning evidence. | External corroboration of selected hotspot locations. |
Method selection
Why more complex methods were not used yet.
| Method | Why it was not the primary approach | Evidence needed to upgrade |
|---|---|---|
| Deep-learning hourly forecasting | No dense measured hourly target series. | Multi-year interval load + weather observations. |
| Full unit commitment | Plant-level ramping, startup, minimum-output, heat-rate and outage data incomplete. | Operator-grade fleet parameters. |
| Probabilistic LOLP / ELCC | Forced-outage, multi-weather-year and hydro uncertainty distributions unavailable. | Reliability datasets and stochastic scenarios. |
| AC / N-1 network study | Measured bus injections, complete impedances and reactive-power data unavailable. | Utility-grade electrical model and operating states. |
| Single least-cost 2040 optimization | Would collapse unresolved demand, transfer, spatial, ecological and cost uncertainty into one precise-looking answer. | Planning-grade physical, siting and economic inputs. |