Removals:
Buildings as
C sinks
With the "Global Construction C-Sink Standard", OPENLY as C-Sink Manager issues CO2 certificates for biogenic building materials used.
New construction & renovation
From 1.8.2025 and according to the valid EU Framework CRCF.
1% construction cost subsidy
Use of the certificates:
You can use the CO2 certificates yourself for insetting in your group or receive the building cost subsidy from milton.earth.
Costs of certification:
The costs are borne by milton.earth (funding figures in the chart are net). In the case of insetting, the costs amount to 15-20 euros per ton.
You will receive the funding commitment from milton.earth when you submit your building application with a provisional CO2 certificate from Openly.
This enables us to realize biogenic construction projects, which are currently more expensive to build than conventional construction.
The role
of
Openly as C-Sink Manager
The
standard:
Principle: The building is the C-sink
Creator & Owner: Ithaka Institute
C-Sink Manager: OPENLY (certification of construction projects)
Audit: CERES
C-Registry: Carbon Standard International
Content:
Standard is based on the principle of additionality and focuses on > 60 years (EU requirement 35 years) of structurally used, biogenic building materials such as structural timber, biochar concrete, hemp, cellulose, cork, straw, bamboo, grass and reed.
The C-Sink Manager carries out annual stock checks.
There is no baseline scenario, but the calculation is net, i.e. minus emissions from farming, processing, transportation and installation.
Certification by OPENLY takes place on the property (the building is the c-sink) for the benefit of the property owner.
Use case:
Credit: Construction Stored Carbon
The OPENLY VALLEY WIDNAU pilot project with 19 apartments has saved around 900 tons of CO2 (avoided emissions, not certifiable) and stored an additional 563 tons of CO2 (stored carbon)
78t from biochar in concrete
91t made of hempcrete from Cancret.com (exterior insulation and non-load-bearing interior walls)
361 tons of construction timber (446m3)
11t cellulose & 9t cork & 13t laminated veneer lumber
The C-sink of Valley Widnau is therefore approx. 375 kg per m2 net floor area or approx. 250 kg per m2 gross floor area above ground.
What is CDR?
Plants as CO2 vacuum cleaners:
1kg of hemp binds around 1.7kg of CO2 during growth (3 months). Photosynthesis removes CO2 from the atmosphere.(Carbon Dioxide Removal)
CO2 balances are based on Ökobaudat or KBOB (Switzerland).
We have prepared these for you in an understandable way:
Hempcrete: Net negative emissions approx. -100kg/m3
Please note:
A) The primary goal must be to avoid CO2 emissions.
OPENLY engineered buildings achieve up to 5.5kg CO2 per gross floor area, which means a reduction of > -50% and corresponds to the legal requirements of Denmark 2029.
B) If certificates from C sinks are used for insetting or transferred to milton.earth, they can no longer be included in the CO2 balance of the building construction. Such a building may then no longer be designated "net zero".
C) If you are building without OPENLY advice, make sure that your building material suppliers have not already sold the C sinks contained in the building materials themselves. In principle, the sink belongs to the builders who have paid for the building material.
The potential of buildings as C sinks
The annual C-sink potential is around 5 gigatons of CO2, which corresponds to a market value of USD 1 trillion.
Our roadmap envisages carrying out pilot certifications of 10,000 tons in 2025.
In 2026 we expect 100,000 tons of removals and from 2027 we want to certify 1 million C sinks from biogenic construction activities every year.