Minigrid Research Paper

Minigrids are electricity systems that combine electricity generation and distribution at the small-scale (usually below 10 MW). 99% of minigrids in small islands and remote areas in Indonesia which already have electricity still use diesel gensets (DG) as their source of power generation. Many of them are even smaller, less than 5 MW, minigrids. In these minigrids, coal power plants are simply not feasible. Gas turbine power plants which use LNG, are also not simple and may not even be the cheapest due to the scale and logistics. Since the people in these islands have to have electricities, the Indonesian government through PT Perusahaan Listrik Negara (PLN) provides the electricities by using DG. It’s fast, effective and getting things done.

So how do we mitigate this high cost and high pollution level of DG minigrids? The answer is that we have to turn the existing minigrids into renewable energy (mostly solar PV)-based minigrids, and when we have to make a new minigrid, we make it a renewable energy (mostly solar PV)-based minigrid in the first place. If we’re lucky enough, in a minigrid we may found a suitable river, enough cheap feedstock or a speedy enough wind speed, so we can build a mini-hydro power plant, a biomass/biogas power plant or a wind turbine power plant. But in the case those three are not available, in Indonesia we can almost always find a coordinate inside a minigrid which has a Global Horizontal Irradiance more than 1,600 kWh/m2/year, which is enough to make a feasible solar PV power

For example, in Sabu Island, Nusa Tenggara Timur, the DG-based minigrid day time peak is 840 kW, night time peak is around 1,200 kW. Without a Hybrid Controller and Battery Energy Storage System (BESS), we can only install 168 kWp PV without disrupting the stability of the grid. But with a proper Hybrid Controller and BESS, we can build a 1.5 MWp PV plant while maintaining the grid stability. The Specific Fuel Consumption (SFC) is ranging between 0.27 to 0.33 liter/kWh. The High Speed Diesel (HSD) cost is ranging between 50 to 90 cent USD, and the cost for Capex and O&M of the DG system is 2 cent