Design of a reward-penalty cost for the promotion of net-zero energy buildings

The investment cost of renewable energy systems for achieving net-zero energy buildings (ZEB/NZEB) is a vital factor concerned by most building owners, which raises a requirement for a new financial scheme specifically designed considering the level of ZEB. This study thus focuses on the design of reward-penalty mechanism for promoting the target of net-zero energy balance in each building design, enabling that a cost-effective design option for buildings where high integration of renewable energy systems can be expected. The benefits for building owners are formulated into three scenarios (S0, S1, and S2), in which the effectiveness of the proposed three functions were investigated. The results show that a higher cost is required by a lower level of ZEB whilst considerable bonuses can be realized by owners opting for higher levels of ZEB. In addition, the boundary of building energy consumption level as well as zero energy level is identified and provided for the proposed three reward-penalty functions. Based on the case study, the proposed reward-penalty functions were verified to be effective for a building energy consumption level between 0.8 and 2.0, with an error index lower than 7.0%. This study can provide an efficient yet effective approach for developing a financial scheme to further boost zero energy buildings.