Environmental considerations are an important part of any project, and can have wide ranging effects on the design. Therefore they need to be addressed early on as an inherent part of the architecture, and not just left as an afterthought tack on.
While there are minimum requirements that all buildings must meet, there are numerous environmental features and initiatives that can be considered. Energy efficiency, carbon footprint, usability, comfort level, future adaptability, and durability all interact to inform the most suitable solutions for each project. It comes down to what can be provided efficiently and cost effectively, not only as a capital cost but as a life cycle cost for the operation of the building.
For instance, we installed the first commercial sea water heat recovery system at the VUW Coastal Ecology Laboratory on Wellington's south coast. There sea water is used to heat the building. This was cost effective because sea water was already being pumped to the site and used in experiments.
In another project it was identified that cooling the building had a greater energy cost than heating the building. Therefore design features were adjusted, and included, to reduce the heat load.
With numerous technologies available it is a matter of identifying and selecting what is most appropriate to your project.