Zero Emissions Tree

The Zero Emissions Tree (ZET) is a sustainable charging point for electric bikes in the shape of a tree. The Microsystems Technology research group at Hogeschool Utrecht University of Applied Sciences developed this sustainable charging point for electric bikes in collaboration with Enexis Unplugged. The tree itself generates energy with its ‘canopy’ of solar cells. The energy is then also stored in the tree. Users of electric bikes can charge their bikes using the energy stored in the tree. Incidentally, you can also charge your laptop or mobile phone.


Goals and approach

Hogeschool Utrecht University of Applied Sciences is putting ‘Going Green in Business, Education and Research’ into practice through this tree. It will really encourage the use of electric bicycles by employees at the university and other institutions in the Utrecht Science Park (USP). This should mean that more employees will be tempted to cycle to work more often, instead of by car.

The ZET is a practical implementation of the research group’s Smart Storage project. The goal of this project is to increase knowledge of how to store renewable energy. What is unique about this ‘tree’ charging point is that it stores the solar energy in batteries from electric cars, which are given a second lease of life in its trunk. The development of knowledge about the storage of renewable energy is vital to be able to charge and discharge the batteries. In a test setup, the SoC (state of charge) of the batteries of electric cars can be measured.


The first prototype, designed to evaluate and improve the design concept, was put into operation in June 2013. Since July 2013, the first charging tree in the Netherlands has been standing at the entrance to the Botanical Gardens in the USP. Any excess energy is used for the Botanical Gardens. The tree incorporates as many natural-looking materials and organic forms as possible. As a result, it blends into a green area and it also looks like it has an association with sustainability.

The second charging tree is located in the parking lot of HU University of Applied Sciences, at Oudenoord 700. A third tree has being developed for a location in Zwolle. The research group is in discussions with various parties who would like to help bring the tree into production and onto the market.

Partner institutions

Hogeschool Utrecht University of Applied Sciences, Microsystems Technology research group, Enexis Unplugged, Ontwerpbureau Moorgen, Utrecht University.


Utrecht University, HU University of Applied Sciences, Enexis Unplugged.



Systems Technology/ Embedded Systems

Microsystems Technology/ Embedded Systems

About the Research Group