This project aims to examine the demands of the new NollCO2-certification from a practicalpoint of view and to identify what it would mean for a real estate company to certify newconstructions according to NollCO2. Through investigation of a case-study object, a newbuilding at ICA Fastigheter, both climate impact and possible climate compensation measuresare analyzed in order to investigate how net-zero balance can be reached by 2045. By executing life cycle assessments and sensitivity analyses, both performed using MicrosoftExcel, the carbon footprint of the case-study building is evaluated within the NollCO2-certification framework. The project examines climate compensation measures related to bothenergy efficiency measures, and grid delivered renewable electricity. In the investigation,climate compensation measures are put in relation to both the NollCO2-framwork and ongoingsustainability work at ICA Fastigheter. The results show that there are many possibilities to decrease a building’s carbon footprint. Thegreatest decrease is retrieved by choosing materials with less carbon emissions such as greenconcrete or fiberglass insulation. In comparison to the case-study building’s original 512 tonsCO2eq, effective energy usage supplied from a green energy source can reduce the climateimpact further to approximately 415 tons CO2eq. To reach net-zero balance, offsite energyproduction can be installed. A solar park would need to produce 505 – 657 MWh which woulddemand approximately 15 000 - 20 000 square meters and cost 3.8 – 4.7 million Swedishcrowns. If ICA Fastigheter instead chooses to invest in wind power, the energy productionneeded would be 486 – 634 MWh, approximately 3% of the total production of an averagewindmill in Sweden. By investing in efficiency measures in existing buildings net-zero balancewould be reached with the expected expenses being a minimum of 7.6 million Swedish crowns. When analyzing the result of this case-study it is evident that an implementation of the NollCO2-certification is possible for ICA Fastigheter. However as of now, there are too many estimatesfor the result to be reliable. When taking ICA Fastigheter’s current long-term plans into accountit is evident that the most suitable climate compensation measure is to develop their energyefficiency projects in existing buildings. Efforts to increase energy efficiency in the real estateportfolio currently has a functioning workflow but must be improved to work as a sufficientclimate compensation measure when the number of new constructions aiming for the NollCO2-certification increases.