Review and validation of EnergyPLAN

Energy systems analyses are integrated elements in planning the transition towards renewable energy-based energy systems. This is due to a growing complexity arising from the wider exploitation of variable renewable energy sources (VRES) and an increasing reliance on sector integration as an enabler of temporal energy system integration, but it calls for consideration to the validity of modelling tools. This article synthesises EnergyPLAN applications through an analysis of its use both from a bibliometric and a case-geographical point of view and through a review of the evolution in the issues addressed and the results obtained using EnergyPLAN. This synthesis is provided with a view to addressing the validity and contribution of EnergyPLAN-based research. As of July 1st, 2022, EnergyPLAN has been applied in 315 peer-reviewed articles, and we see the very high application as an inferred internal validation. In addition, the review shows how the complexity of energy systems analyses has increased over time with early studies focusing on the role of wind power and the cogeneration of heat and power and later studies addressing contemporarily novel issues like the sector integration offered by using power-to-x in fully integrated renewable energy systems. Important findings developed through the application of EnergyPLAN includes the value of district heating in energy systems, the value of district heating for integration of VRES and more generally the importance of sector integration for resource-efficient renewable energy-based energy systems. The wide application across systems and development stages is interpreted as inferred validation through distributed stepwise replication.