Procurement Cost Volatility and Supplier Dynamics in Southern Leyte Electric Cooperative (SOLECO), Philippines: A Multi-Year Statistical Analysis of Electricity Sourcing in a Liberalized Market

Khorina O. Aguilar; Jonelle H. Tablada

doi:10.69650/rast.2026.263252

Authors

Khorina O. Aguilar Southern Leyte State University, Sogod, Southern Leyte 6606, Philippines https://orcid.org/0000-0002-7974-420X
Jonelle H. Tablada Southern Leyte State University, Sogod, Southern Leyte 6606, Philippines https://orcid.org/0000-0001-7359-3546

DOI:

https://doi.org/10.69650/rast.2026.263252

Keywords:

Electricity Procurement, Cost Volatility, SOLECO, Energy Economic, Strategic Sourcing

Abstract

Electric distribution utilities in liberalized power markets are increasingly exposed to procurement risks arising from supplier heterogeneity, contract discontinuities, and spot-market volatility. This study evaluates the electricity procurement profile of the Southern Leyte Electric Cooperative (SOLECO), Philippines, from 2020 to 2025 using supplier-disaggregated monthly disclosures for Mainland and SPUG service areas. Descriptive portfolio analytics, including annual purchased energy, weighted average generation cost, source shares, and volatility indicators, were integrated with inferential testing through one-way ANOVA and Tukey’s HSD to determine whether inter-source cost differences were statistically significant. Results show that annual purchased energy increased from 63.60 million kWh in 2020 to 165.92 million kWh in 2025. The weighted average generation cost sharply increased to ₱10.70/kWh in 2022 before partially declining to ₱7.91/kWh in 2023, ₱6.52/kWh in 2024, and ₱6.24/kWh in 2025, indicating a persistently higher post-transition cost baseline. The energy mix shifted from NPC-TSC/PSALM dominance in 2020, with a 70.45% share, toward IPP-led sourcing, with GNPD peaking at 67.56% in 2022, and later toward greater market exposure as WESM, net of SSLA, reached 35.86% in 2024. Portfolio fragmentation also increased, as reflected by the “Others” category reaching 56.94% in 2025. ANOVA confirmed significant mean cost differences across sources, while Tukey’s HSD identified WESM as significantly higher than multiple contracted sources and the portfolio benchmark. The findings position procurement as a smart-grid governance issue requiring volatility-aware benchmarking and digital decision support.

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