The electrical grid must always be supplied with as much electricity as is taken from it. However, the greater the share of fluctuating renewable energy sources, the more difficult it becomes to manage power supply. In order to help, interactive systems have been designed to encourage users in using renewable energy when there is plenty of it rather than when there is little (i.e. shifting energy supply). Most of these systems use ambient interfaces to represent forecast information on the availability of renewable energy. Yet, it is unclear which ambient interfaces are more effective in enhancing ambient awareness and maintaining new practices for shifting energy supply. We think that parameters such as perceptible artefacts (e.g., shape-changing, color-changing) influence the effectiveness of ambient interfaces. To answer this concern, we study shifting energy supply with laptops in the workplace. Because practices for shifting energy supply with laptops have yet to be identified, we introduce a tool for simulating and exploring such practices. Furthermore, we evoke the design of a dynamic bar chart for visualizing renewable energy forecasts. Using different ambient parameters, we will study how this design enhances ambient awareness and helps employees to shift energy supply with laptops in the workplace.