Having successfully achieved a Net-Zero Carbon Level 2 measured certification from the Green Building Council of South Africa (GBCSA) for its existing properties in Gauteng, real estate investment trust (REIT) Redefine Properties notes that the milestone marks the first time in South Africa that commercial buildings at scale have attained a ‘measured’ rating, based on performance data.

A net-zero carbon building operates with zero net carbon emissions over the span of a year. These buildings are highly energy efficient and, where feasible, use renewable energy for the remaining energy requirements, only relying on carbon offsets to balance energy use as a last resort.

Redefine Properties has achieved its measured rating through a combination of energy efficiency-enhancing projects, onsite renewable-energy installations, and carbon offsets traded through a voluntary carbon offset programme.

The GBCSA Net Zero and Net Positive Certification recognises projects that take the initiative to neutralise or positively address their environmental impacts going past partial reductions recognised in the current GBCSA suite of tools.

The certification scheme aligns with international best practices, offering projects a way to follow the prioritisation of energy efficiency, the use of on- and off-site renewable-energy production and employing carbon offsets.

The process of achieving net-zero carbon requires the yearly assessment of measured carbon emissions ratings, with the certification itself renewed every three years.

“Green building practices are a key milestone in the journey to net zero,” states Redefine Properties chief sustainability officer Anelisa Keke.

She explains that a sound climate change resilience strategy includes ensuring that capital investments are safeguarded against manageable climate risk exposure, thereby creating long-term value for stakeholders.

GBCSA offers two versions of the Net-Zero Carbon Ratings: ‘modelled’ and ‘measured’. Modelled ratings refer to predicted energy consumption over a 12-month period for buildings based on their designs.

In contrast, measured ratings are operational ratings for existing building based on verifiable performance data over the same period.

GBCSA technical head Georgina Smit explains that the majority of the net-zero carbon schemes GBCSA sees on the market tend to be based on modelled estimation of performance.

She adds that all measured net-zero schemes are required to be renewed every three years, therefore REITs that are “bold enough” to commit to this methodology and be externally verified, should be highly commended as it is the beginning of a journey requiring the demonstration of continuous performance.

“As REITs grapple with the environmental impacts of their portfolios, and take positive steps towards pursuing net zero, it’s important to understand the role of responsible offsetting within decarbonisation trajectories,” states Smit.

She points out that even with great design and management, and the use of the best technology available, many buildings still incur a significant carbon impact that can only be addressed through offsetting.

She reiterates that carbon offsets should be a last resort, once all other aggressive emission reduction strategies and effective, high performance building design initiatives have been implemented.

Therefore, it is critical for developers to understand that improving efficiency and exhausting on-site renewable supply has a return on investment, while offsets come with associated costs, says Smit.

She notes that until wheeling and procurement of renewable energy becomes easily accessible at a building-level scale, the market will require carbon offsets.

She explains: “The key is to understand the transitionary role of this within the greater net-zero journey of a building and its life cycle. Given the costs of offsets, building owners are inherently incentivised to move away from this option as quickly as possible.”

Keke adds that being certified as net-zero provides an objective confirmation to Redefine’s key stakeholders that its certified buildings have been benchmarked against global best practice efficiency standards.

She reiterates that Redefine will take the successes achieved from these three buildings to enhance energy efficiencies broadly across its portfolio, benefiting Redefine and its tenants.