Enhancing Power Distribution Efficiency in Central Kalimantan through Renewable Energy Integration and Grid Optimization

In areas with uneven development, many residents live far from the city center. The medium-voltage grid in Kuala Jelai, Sukamara Regency, Central Kalimantan, operates as an isolated system, resulting in poor voltage quality and high distribution losses. Annual fuel and lubricant costs exceed IDR 8 billion, with maintenance reaching IDR 2 billion. Despite this, the area has significant untapped solar energy potential. This study evaluates the impact of solar energy integration on reducing distribution losses and identifies the most cost-effective distribution options to support the government’s de-dieselization program. Time domain and load flow analyses are used to assess system reliability and measure hourly energy losses across diesel, solar, and hybrid scenarios. Results show that distribution losses in the combined solar-grid network are estimated at 7.21% per month, compared to 9.05% in the diesel system. With an average electricity tariff of Rp959/kWh, the integrated system is projected to generate 1,976,832 kWh annually valued at approximately Rp1.89 billion and save about Rp34.9 million per year through a 1.84% reduction in losses.