Modern Architecture

Decarbonization planning

 A decarbonization plan is a roadmap for how a building can transition from fossil fuel-based energy to renewable energy sources. The process combines building energy efficiency measures with electrification of the mechanical systems. Full decarbonization is achieved once the building's electricity is provided from carbon-free sources such as renewable energy credits, or on-site generation.

The graphic below summarizes an example decarbonization plan. Recommended projects, upgrades, and replacements are grouped into three categories: weatherization, mechanical systems, and building systems. Arrows show the order in which certain projects should be completed. For example, the electrical meter must be replaced before the boiler or the water heater can be replaced. The building owner can initiate projects over an extended timeline, coordinated with equipment failures, budgets, and other building renovations. The decarbonization plan guides and coordinates the projects to transition from the existing mechanical systems to a preferred electric systems.

Construction work planning
Example summary of a decarbonization plan from a mechanical engineer

Selecting an initial project

The green highlighted tasks above show the projects that the owner chose to combine for an initial project. Here is a simplified version of the project description the owner would use when hiring a design team:

  • Air Sealing

  • In-room HVAC Equipment (Floors 1 and 3)

  • Lighting Upgrades (All floors except basement)

  • Controls Upgrades (Floors 1 and 3)

Typical architectural and architectural-engineering projects are broken into six phases: Pre-design, Schematic Design (SD), Design Development (DD), Contract Documents (CD), Bidding, and Construction Administration (CA). Read more about the typical project design phases. With the scope selected above, the project would be ready to start in the Design Development phase since the decarbonization plan covers the pre-design and schematic design work. Projects with large, complicated scopes would start in the schematic design phase. Small projects often combine design phases and adjust the number of deliverables.

Small Buildings

Small buildings with aging mechanical systems benefit from a simplified process where decarbonization planning is combined into the design of a replacement system. The project starts with imagining what an ideal future, electrified, building would look like and any considering any obstacles to the transition. Once a schematic level design is completed for the whole building, detailed design proceeds for only the items that will be constructed in the initial phase. High impact weatherization tasks may also be included in the initial project scope with other recommendations for future improvements included in a report.

Consider a small building with four stand-alone pieces of mechanical equipment such as residential style furnaces or rooftop units. Two of the four are twenty years old and the owner would like to replace them with electrified equipment. Our design would start by considering a future, cohesive, electrified system for the whole building. Then we would produce design documents with completed details for the replacement of the two older units. The documents would include notes and sketches capturing how the remaining units would be replaced in the future with notations so that contractor knows not to price these in the current project.