In order to offer Greenline House users transparency and an explanation of the quantification model used for estimating greenhouse gas emissions of wooden houses, a report was conducted to assess the method’s accordance with international standards. This report has been created according to requirements and recommendations set out in the international standard ISO 14064-1:2018 “Greenhouse gases – Part 1: Specification with guidance at the organization level for quantification and reporting of greenhouse gas emissions and removals.”.
When the report was conducted, the Greenline House database consisted of 57 unique construction material data sources and 13 average construction materials calculated based on unique materials in the database. The data has been acquired from construction material providers, business associations and scientific literature.
Two assumptions are made in this report:
· Transportation emissions are reported as a share of total emissions according to literature, based on the worst-case scenario.
· Assembly emissions were calculated based on the average of the construction of 8 wooden houses, with a value of 3.14 kgCO2/h.
The data used in the report falls into either scope 2 (indirect emissions caused by energy consumption of the assembly phase) or scope 3 emissions (indirect emissions caused by the purchase of assembly-related goods and services). Construction phase emissions arise from the use of electricity, district heat, lifters, tractor excavators, other drivable machines, chainsaws etc. and are considered same for all four types of houses: 4,4 tCO2e*. The construction phase emissions therefore account for 17.3% of total emissions.
The GHG assessment quantification model excludes employee commute, foundation, earthworks and other minor construction elements, such as paint, varnish, HVAC components, pipes etc.
The material budget of a product is listed along with the associated GHG emissions of each component and the quality of the data sources are evaluated. For the uncertainty assessment, a baseline scenario was created on the wooden house “Sanne”, with four additional scenarios, tying the building materials with their GHG emission factors.
The report showed that there was an acceptable level of uncertainty for all scenarios. The geometric standard deviation (GSD) for variability of source data uncertainty was calculated at 1.25 for baseline scenario “Sanne” and remained between 1.22 and 1.30 for the alternative scenarios, indicating a fairly significant variation of data source uncertainty.
The data sources were assessed on a scale of “poor”,” fair”,” good” and “very good”:
Active Data Reliability – very good
Active Data Completeness – fair
Active Data Temporal Representativeness – very good
Active Data Geographic Representativeness – very good
Active Data Technological Representativeness - fair
For access to the complete report, e-mail us at firstname.lastname@example.org.
* CO2e, carbon dioxide equivalent - this value represents the total production greenhouse gas emissions. Due to different greenhouse gases having different global warming impacts, then CO2e is a simple way to represent the impact of the total gaseous emissions in amount of CO2.