Ratemaking under indexation: How policy clauses compound into retail electricity tariffs

This study investigates how indexation and adjustment clauses within Pakistan's power sector ratemaking architecture compound to determine the structure and magnitude of retail electricity tariffs. Employing an explanatory sequential mixed-methods design, it integrates summative content analysis of policy instruments issued between 1998 and 2024 with systematic clause-to-component mapping based on statistically identified textual patterns. Four principal clause families are identified as central to tariff formation: capacity remuneration, energy charges, tariff adjustment mechanisms, and circular debt provisions. A final analytical stage applies slab-threshold discontinuity computations to quantify bill-level effects at predefined consumption thresholds. By translating tariff instruments into discrete changes in monthly bills immediately below and above kilowatt-hour cutoffs, the analysis links contractual design to category-specific affordability outcomes. The findings demonstrate that tariff volatility arises from identifiable transmission channels embedded within the contractual architecture. Foreign exchange indexation embedded in energy and capacity components amplifies depreciation shocks; benchmark-rate and financing provisions transmit monetary tightening; prior year adjustments generate compounding through reconciliation lags; and loss monetization, distribution recoveries, and surcharges introduce additional scaling and recovery layers. The results support a phased and clause-specific reform strategy for legacy Power Purchase Agreements, including transition from take-or-pay to take-and-pay structures, recalibration of return on equity, moderation of foreign currency exposure, and alignment of financing benchmarks with domestic reference rates. Transparent and rule-based implementation can enhance tariff stability while preserving contractual credibility in macroeconomically volatile environments.