How do you effectively manage regulatory constraints while still achieving project sustainability goals?

I am currently working on public-sector projects where strict regulatory requirements limit certain technical solutions (for example, restrictions on specific mechanical systems). In such cases, achieving sustainability targets—such as energy efficiency, thermal comfort, or green certification—requires alternative strategies and careful stakeholder coordination.

I would like to learn from the community:

• How do you balance compliance with regulations and ambitious sustainability or performance goals?
• What project management practices or tools have helped you manage stakeholder expectations in similar constrained environments?
• Are there any lessons learned or best practices you would recommend for documenting trade-offs and decisions for future projects or certifications?

I appreciate any insights or real-world experiences you are willing to share.