resLoadSIM – Residential Load Simulator

The energy transition, or Energiewende, is one of the greatest challenges of our time. A major issue is that today’s electrical grids were not designed for the increasing and fluctuating demand of modern energy systems. A simple but costly approach would be to reinforce all grid connections by excavating streets and installing larger cables. However, this is disruptive, expensive, and often unnecessary when smarter solutions are available.

The Joint Research Centre (JRC) has developed resLoadSIM, a simulation tool that helps estimate future electrical loads and evaluate strategies for intelligent energy management — including smart grids, demand-side flexibility, and smart home solutions. These simulations can support a more efficient and sustainable energy transition while minimising costly infrastructure upgrades.

The Residential Electric Load Simulator (resLoadSIM) is an open-source software tool developed by the JRC within the Smart Electricity Systems and Interoperability project. It predicts residential electricity demand with a time resolution as fine as one minute, using a probabilistic modelling approach based on real household statistics. By aggregating the simulated consumption of individual household appliances, resLoadSIM produces realistic and statistically consistent electrical load profiles for households or groups of households.

Beyond predicting energy consumption, resLoadSIM can be used to explore load shifting potential — for example, through flexible tariffs or automated control strategies. The goal is not to model specific technologies in detail, but to assess the potential impact of concepts such as demand-side management, energy efficiency improvements, and renewable integration on the power system.

resLoadSIM includes detailed and modular models for:

• Electricity demand of household appliances (based on energy efficiency classes)
• Heat demand (space heating, hot water, cooking) supplied by gas, district heating, or electricity (including heat pumps)
• Electric vehicle (EV) charging
• Photovoltaic (PV) generation, representing households as prosumers rather than only consumers
• Battery storage, at individual or community level
• Low-voltage distribution grid simulation

Through its comprehensive modelling capabilities, resLoadSIM provides a flexible environment to study residential electricity consumption patterns, the integration of renewable energy sources, and the potential for flexible demand and storage.

resLoadSIM can be applied in a wide range of contexts, including:

1. Energy system analysis and scenario development
2. Assessment of smart grid and smart home strategies
3. Evaluation of demand-side management and flexibility potential
4. Education and training on energy efficiency and load dynamics
5. Comparative studies on energy efficiency policies and appliance standards

Its open and transparent design makes resLoadSIM suitable for research institutions, utilities, technology developers, and anyone exploring future energy system scenarios.

You can:

• Try a Web-based version of resLoadSIM with limited functionality for demonstration purposes – detailed input files and result data for further investigation can be downloaded as a zip file. 
• Access the open-source code of resLoadSIM here. This will allow you to run simulations locally to access the full functionality of resLoadSIM and allows you to run larger simulations.