Carbon neutral buildings are a sub-category of low-carbon buildings. Carbon neutral buildings are buildings which through a series of processes detailed in this article achieve net-zero GHG emissions during their lifetime. Template:TOCleft
Buildings and Climate ChangeEdit
Buildings alone are responsible for 38%  of all human GHG emissions (20% residential, 18% commercial). It is the industrial sector which contributes the most to Climate Change.
But according to the IPCC, it is also the sector which presents the most cost effective opportunities for GHG reductions .
What Are Carbon Neutral Buildings?Edit
Carbon neutral buildings are buildings which are specifically engineered to release no GHG at all or to balance the GHG emissions they produce using GHG trades.
Carbon Neutral Buildings TechnologyEdit
Buildings release GHG in the atmosphere during:
- Construction (incl. renovation and deconstruction)
GHG emissions associated with buildings construction are mainly coming from:
- Materials manufacturing (e.g., concrete)
- Materials transport
- Demolition wastes transport
- Demolition wastes treatment
The construction, renovation, and deconstruction of a typical building are on average responsible for the emissions of 1,000-1,500 kgCO2e/m2 (around 500 kgCO2e/m2 for construction only).
Strategies adopted by carbon-neutral buildings to reduce GHG emissions during construction include:
- Reduce quantity of materials used
- Select materials with low emissions factors associated (e.g., recycled materials)
- Select materials suppliers as close as possible from the construction site to reduce transport distances
- Divert demolition wastes to recycling instead of landfills or incineration
GHG emissions associated with buildings operation are mainly coming from:
- Electricity consumption
- Consumption of fossil fuels on-site for the production of electricity, hot water, heat, etc.
- On-site waste water treatment
- On-site solid wastes treatment
- Industrial processes housed in the buildings
Fossil fuels include for example: natural gas, propane, etc.
Depending on the region where the building is located and the building energy mix, operation emissions can typically vary from 0 to over 100 kgCO2e/m2 per year.
Strategies adopted by carbon-neutral buildings to reduce GHG emissions during operation include:
- Reduce energy consumption
- Use 100% renewable energy sources
Renewable energy sources include:
- Low-impact hydro
- Biofuels (under certain conditions)
- Wave and tidal
Indirect GHG reductions (GHG Trades)Edit
There are three main sources of indirect GHG reductions available for buildings:
- Green power
- Carbon offsets
- GHG reductions from the selling to the grid of clean electricity produced on-site
These GHG reductions can be used by buildings Owners to offset the emissions which can not be reduced otherwise.
Note: Buildings emissions should always be reported in GHG inventories prior to and independent of any indirect GHG reductions. GHG emissions trades should be reported separately in a different section of GHG inventories.
For this reason, it is recommended to reduce buildings emissions by adopting the strategies listed in previous paragraphs rather than using GHG emissions trades.
Low-Carbon Buildings TodayEdit
Carbon-neutral buildings, as part of “green buildings”, are developing very rapidly. Recent examples include:
- Aldo Leopold Foundation Headquarters, Fairfield (WI)
- Kroon Hall, Yale University’s School of Forestry & Environmental Studies
- Sustainable Energy Technology Center, The University of Nottingham, NingBo (China)
Existing Carbon Neutral Buildings StandardsEdit
The Low-Carbon Buildings Standard TM 2010, Construction, Operation, Reporting ‘’A Method for Estimating Buildings Lifetime GHG Emissions and Emissions Reduction Performance’’