Off-grid PV mini-grids are providing an important source of electricity for rural communities in developing countries. However, researchers from Sweden's Chalmers University of Technology have found that many of these systems are experiencing serious reliability issues due to inaccurate initial demand assessments and under-sizing of the mini-grids. This can result in significant unmet demand and a lack of cost-effectiveness over the long-term.
In a recent paper published in Energy for Sustainable Development, the researchers presented a case study of an off-grid PV mini-grid operating in southern Ethiopia. The mini-grid had a capacity of 375 kW and consisted of a PV system, converters, MPPTs, a storage system, a diesel generator, a distribution board and loads. Customers in 2022 had a demand of 638.8 MWh, of which 250 MWh was unmet.
The researchers found that capacity expansion based solely on cost-minimization may result in significant reliability issues. Instead, capacity expansion planning should be based on both cost-effectiveness and reliability to ensure that the system can meet the demands of the community over the long-term.
One potential solution to this problem is to use dynamic load profiles and demand forecasting to accurately predict the future energy needs of the community. By doing so, mini-grid operators can design systems that are better suited for the actual demand and reduce the risk of unmet demand and reliability issues.
Another potential solution is to implement energy storage systems that can provide backup power during periods of high demand or when the PV system is not generating enough power. This can help ensure that the system can meet the needs of the community even during periods of high demand or when weather conditions are not optimal for PV generation.
Overall, the researchers' findings highlight the importance of accurate demand assessments and capacity planning for off-grid PV mini-grids. By taking a long-term view and considering both cost-effectiveness and reliability, mini-grid operators can design systems that provide reliable and cost-effective energy access for rural communities in developing countries.
