Resource efficiency

FREE – Feasibility of Renewable Energy Integrated with Energy Storage in Buildings

The FREE project will carry out pilot feasibility of renewable energies integrated with energy storage into municipal, recreational, and industrial buildings.

Project manager at MDU

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Buildings and their energy infrastructure are designed and constructed for several decades. Therefore, the energy system solutions for buildings must take future developments into account to achieve both economic goals and sustainability. With increased concern on climate change and fast development of renewable energy, it is vital for energy suppliers including both electricity and heating to understand how distributed renewable energies will change the future energy profiles and market models. This will also call for new adaptation for a city planning and utility strategy to the new market conditions where the utility becomes a grid service provider more than an energy provider.

Previous studies

Since September 2015 a 12-­month pre-­study (Pre-­study of a Sustainable Energy Building) has been conducted, where Mälardalen University together with Wallenstam AB have investigated how renewable energy storage solutions can be applied in the building sector, in particular within residential buildings equipped with heat pump for heating and cooling. Since November 2016, Mälardalen University has extended the pre-­study in a larger project financed by KKS (iREST –Integrating renewable energies and storage technologies into residential, office and industry buildings: towards near zero energy targets) within the Future Energy Profile. The on-­going iREST project is in collaboration with the real estate building companies, Wallenstam AB and Castellum AB, the energy providers Mälarenergi AB and Göteborg Energi AB. The research group has also a further on-­going project financed by the Swedish Energy Agency (Soloptimerad stadsplanering) in collaboration with Eskilstuna municipality, and Eskilstuna Energi och Miljö to optimally design solar districts in Sweden. In those projects, the main focus are on the understanding of the fundamental knowledge when renewable energy and distributed energy are considered in the whole system and what are the potential technological innovations can be applied.

Project goals

The FREE project will carry out pilot feasibility of renewable energies integrated with energy storage into municipal, recreational, and industrial buildings. The primary goal is to provide a complete package solution, which can be used for the pilot or demonstration in a real application. The study will also investigate how existing district heating networks can be affected by the integration of renewables, storage system and micro-­grid at the end-­users. The project includes the following five main topics:

  • Characterization of building energy consumption and solar photovoltaic energy production profiles;
  • Configuration of a micro-­grid with considerations of selected building and district conditions;
  • Integration of energy storage and priority selection of type of storages (battery, hot water, hydrogen, phase change materials, and building thermal inertia);
  • Development of control strategies and control systems for photovoltaic systems equipped with different storage technologies, and combined with different heating and cooling options;
  • Recommendation of new business models by maximize the flexibility benefits of the whole systems when integrating renewables.


The novelties of the project consist of:

Cutting-­edge innovative technology solutions

Using the models and expertise gathered from the previous projects, the proposed project will tackle the integration of renewable and sustainable solutions from the perspective of end-­users, aggregators, and energy providers point of view through pilot/demonstration facilities of cutting-­edge technologies at the project case studies.

Implementation guidelines and tools

The results of the projects can be used for city planning activities and for electricity grid and district heating management. Recommendation guidelines will be formulated for future building projects with high integration of renewable and battery systems. These guidelines will be spread to the partners within the project and also through publications. Corresponding implementation tools including database and open source software will be developed.

Novel business model

The project will also provide new and innovative business models for policy makers and other market actors to stimulate the deployment of renewable energy technologies and energy efficiency measures into industrial and recreational buildings.

Strategic impacts on mitigation of climate change

Regarding the Swedish environmental objectives, the project is addressing the following:

  1. Reduce climate impact by more efficient utilization of renewable energy and thereby also enhancing the penetration of renewable energy;
  2. Local clean air quality can also be improved by enhanced penetration of renewables;
  3. The built environment is also enhanced by the more environmentally friendly building power production.