Techno-economic assessment of a 100 kWp self-consumption photovoltaic system for underground coal mining in Colombia

Abstract

This study evaluates the technical and economic feasibility of implementing a 0.1 MWp (100 kWp) photovoltaic system for self-consumption in a small-scale underground coal mining operation located in the area of Sogamoso, Boyacá (Colombia). The main objective is to reduce energy costs a significant component of operational expenditures (OPEX) by integrating a renewable energy source capable of supplying between 30 % and 40 % of the mine's total electricity demand.

The methodology includes detailed electrical design of the photovoltaic system (PV array sizing, inverter selection, cabling, protection coordination and grounding under RETIE/NTC 2050 criteria), load profile modeling of the mining operation, and annual hourly energy simulation (8760 h) to accurately estimate generation, self-consumption, and surplus energy. Additionally, an economic evaluation was conducted based on CAPEX and OPEX broken down by cost items and key financial indicators.

The results indicate an annual energy generation of approximately 144 000 kWh, with a self-consumption rate of 94 % and an energy demand coverage close to 39 %. The economic analysis shows a net annual savings of approximately 98 million Colombian pesos (COP), with a payback period of less than five years (2.5–3 years when considering Law 1715 incentives) and a levelized cost of energy (LCOE) close to 200 COP/kWh, well below the current grid tariff (≈900 COP/kWh). It is concluded that the integration of photovoltaic systems in small-scale underground mining is a technically viable and economically profitable solution, with a significant impact on reducing energy costs and improving the sustainability of the sector.