Seattle Council discusses renewable energy storage options for new building code

On March 7, 2025, the Building Code Council convened to discuss significant updates regarding renewable energy requirements for new buildings in Washington. A key focus of the meeting was the integration of energy storage systems into the existing solar energy mandates, which require all buildings over 5,000 square feet to incorporate renewable energy solutions.

The proposed changes aim to allow energy storage systems, such as batteries, to count towards a portion of the solar energy requirement. This initiative is designed to enhance the effectiveness of solar energy by addressing the mismatch between peak solar generation hours and peak energy demand times. As outlined in the discussions, simply installing solar panels without adequate storage can lead to increased carbon emissions during peak demand periods. By enabling energy storage, buildings can store excess solar energy generated during the day and utilize it during peak hours, thereby reducing overall carbon emissions.

The proposal suggests a ratio of one-third battery storage to two-thirds solar energy generation, which is intended to encourage the adoption of battery systems while ensuring that solar generation remains a primary focus. This ratio is seen as a way to incentivize building owners to invest in energy storage solutions, which are critical for maximizing the benefits of solar energy.

Council members raised questions about the operational aspects of these battery systems, including their potential use as backup power sources and their role in load management. While the proposal does not mandate how the batteries must be used, it allows for flexibility in their operation, which could be influenced by future utility pricing structures. The discussion highlighted the importance of aligning energy storage capabilities with utility needs, particularly as more utilities begin to implement time-of-use rates.

Additionally, the council addressed concerns regarding the longevity and technology of the batteries used. While lithium-ion batteries are commonly favored for their efficiency, the proposal allows for various energy storage technologies, ensuring that building owners can select the most suitable option for their needs.

In conclusion, the Building Code Council's discussions on integrating energy storage with solar energy requirements reflect a proactive approach to enhancing renewable energy use in Washington. By encouraging the adoption of battery systems, the council aims to not only meet energy demands more effectively but also to contribute to the state's broader environmental goals. The proposal is set to undergo further refinement before final approval, with ongoing discussions expected to address any remaining concerns.