Study on the Implementation of the Hybrid Annuity Model Financing Scheme in Drinking Water Supply Systems (SPAM) in Indonesia

Klara Nala Rita (Civil Engineering Study Program, Faculty of Engineering, Universitas Lampung, Indonesia)
Ahmad Zakaria (Civil Engineering Study Program, Faculty of Engineering, Universitas Lampung, Indonesia)
Ahmad Herison (Civil Engineering Study Program, Faculty of Engineering, Universitas Lampung, Indonesia)
Ofik Taufik Purwadi (Civil Engineering Study Program, Faculty of Engineering, Universitas Lampung, Indonesia)
Yuda Romdania (Civil Engineering Study Program, Faculty of Engineering, Universitas Lampung, Indonesia)

RESWARA: Jurnal Riset Ilmu Teknik
Vol. 4 No. 3 (2026): RESWARA: Jurnal Riset Ilmu Teknik, July 2026

This study examines the implementation of the Hybrid Annuity Model (HAM) financing scheme in the Public-Private Partnership (PPP) project of the Lombok Regional Water Supply System (SPAM) in West Nusa Tenggara. The project service area covers Mataram, West Lombok Regency, and North Lombok Regency with a 20-year concession period. This research employed a quantitative approach using descriptive analysis and discounted cash flow-based financial modelling to evaluate the financial feasibility and sensitivity of the HAM scheme. The study utilized secondary data obtained from pre-feasibility study documents, SPAM technical and operational data, macroeconomic data, and infrastructure financing regulations. Financial feasibility  assessed by Net Present Value (NPV), Internal Rate of Return (IRR), Debt Service Coverage Ratio (DSCR), and Payback Period (PBP). The results point out that both the unsupported PPP scheme and the HAM scheme are financially feasible. The PPP scheme generated a higher NPV of IDR 132.673 billion and a faster payback period compared to the HAM scheme, which produced an NPV of IDR 55.527 billion. However, the HAM scheme demonstrated a stronger DSCR value of 1.5. Sensitivity analysis revealed that the project is highly sensitive to revenue reductions and increases in investment and operational costs.