It’s certainly an ambitious plan. The Advancing Net Zero project aims to dramatically reduce the impact on the environment by ensuring 100% net zero carbon buildings by 2050. But considering there are currently just 500 net zero commercial buildings and ‘several thousand’ net zero homes and residential units worldwide, the World Green Building Council’s (WGBC) plan is as important as it is necessary.
A net zero building is defined as being highly energy-efficient, with all remaining operational power use from renewable energy – preferably on-site but also off-site production – to achieve net zero carbon emissions in operation. Central to the concept are two objectives, firstly that by 2030, all new buildings must operate at net zero carbon; and secondly, that by 2050, all existing buildings must operate at net zero carbon.
‘Net zero carbon buildings must become standard business practice as soon as possible. So we build right from the start; avoid the need for future major retrofits; and prevent the lock-in of carbon-emitting systems for decades to come,’ the WGBC states in a report titled From Thousands to Billions.
‘Existing buildings require not only an acceleration of current renovation rates, but these renovations must be completed to a net zero carbon standard so that all buildings are net zero carbon in operation by 2050.’ The report also outlines a plan of action that it hopes will meaningfully influence the way in which buildings are designed, built, maintained and operated over the next several decades.
According to International Energy Agency estimates, global building stock currently stands at 223 billion m2, a figure that is forecast to almost double to 415 billion m2 by 2050.
‘Since the building and construction sector is responsible for around 30% of global energy consumption and the associated greenhouse gases, this sector will play a significant role in finding the solutions,’ states the WGBC.
‘What that means for the building and construction sector is nothing short of a dramatic and ambitious transformation towards a completely zero carbon built environment.’
In July last year, the Green Building Council of South Africa (GBCSA) became the 14th international body to join the WGBC project. While the SA council is well known for its Green Star rating system (which is about doing ‘less bad’), net zero focuses on providing the ‘ultimate’ built environment goal, says executive director and chief technical officer Manfred Braune.
Net zero certification is awarded over and above any Green Star certification that a project may already have. The GBCSA stresses the importance of energy efficiency as well as the reuse of resources within the building itself prior to investigating off-site sources of, for example, electricity. Its net zero certification scheme rewards projects for completely neutralising (net zero) or positively redressing (net positive) their environmental impacts under four categories, namely carbon, water, waste and ecology.
‘Independent certification is possible under each of these, and they can be certified as part of a Green Star, Edge or Energy Water Performance certification,’ says Braune, who adds that they can also be certified independently.
‘As far as we know, this goes beyond net zero schemes in other countries’ green building councils, which at this stage recognise net zero carbon only. The GBCSA believes all four are critical elements that need to be addressed in the South African context, and will recognise and reward property owners that excel in any of these areas.’
Until recently, projects could only be certified retroactively. However, the first phase of the pilot certification scheme is now complete. ‘From now on, projects can only be certified based on current consumption or new construction,’ says Braune. He explains that, over the next year, the focus will be on increasing the level of awareness around the scheme as well as the number of property owners willing to commit to the 2030 and 2050 targets, as opposed to merely certifying as many net zero buildings as possible.
The council also conducts training that forms the basis of the accredited professional programme. The response to the programme has thus far been very positive, says Braune, with large SA corporates, including Nedbank, Woolworths and Virgin Active, having already outlined organisational net zero targets.
According to the GBCSA, SA’s ‘first four projects to be certified as net zero under the pilot programme are Two Dam Sustainable (carbon); the Vodafone Site Solution Innova-tion Centre (carbon and ecology); the Estuaries Plaza (water) and the Greenfields Industrial Park (carbon). Each project demonstrates the feasibility of the multi-decade initiative across various development types, including industrial, commercial and agricultural. The aim of the pilot, adds Braune, was to acknowledge working examples of what is already being done towards ensuring a net zero built environment future.
The Two Dam Sustainable project is a ‘responsibly operated’ trout farm outside Montagu in the Western Cape that has been accredited by the GBCSA as carbon neutral. In addition to producing ethically made trout products, it’s almost entirely powered by renewable energy.
According to sustainability firm Ecolution Consulting, which worked on the project, the bulk of energy is provided by a 31 kW PV panel array and a ‘high pressure, low water volume’ micro-hydro turbine that generates up to 1 kW of continuous electricity. A small percentage of energy use that is supported by the back-up liquid petroleum gas-powered generator is offset through Carbon Green Africa’s Kariba REDD+ project.
The farm is also home to a ‘hyper-efficient’ recirculating aquaculture system – the first of its kind in Africa, according to Ecolution Consulting founder and sustainability engineer André Harms, who adds that it requires comparatively little electricity.
What’s more, the farm also has its own water catchment for drinking water. The filter, through its self-cleaning centrifugal action, releases at least 10% of the water to continue downstream.
The Vodafone Site Solution Innovation Centre (SSIC), in Midrand, is also net zero carbon-rated, in addition to being accredited as net zero ecology. In 2011, it became the first 6-star Green Star SA-certified building in SA. Alison Groves, regional director of building services at WSP Africa and sustainability consultant on the project, attributes this to the telco’s willingness to push boundaries on sustainability solutions.
Carbon-neutrality was achieved through a solar PV panel system comprising thin film tubes that allow flat, non-directional placement on a roof. These convert diffused as well as direct light into electrical energy. Meanwhile, the ecology rating was achieved by converting the site’s former tarred parking lot into an indigenous garden, reintroducing biodiversity.
Another net zero carbon-rated development is Cape Town’s Greenfield Industrial Park, which in 2016 became the first industrial property to be awarded GBCSA 4-star custom industrial as built certification. Located near Cape Town International Airport, it has a 21 000 m2 footprint and features solar PV panels, water-wise landscaping, waterless urinals, a recycling system and low-energy light fittings.
‘Setting new benchmarks for sustainability in the South African industrial sector, Greenfield achieved full scores for energy efficiency in its rating,’ according to the GBCSA. ‘It [is] a key pilot project for net zero energy buildings in the country because the base building produces as much of its own energy as is consumed by it over the course of a year.’
Then there’s the Estuaries Plaza, a commercial office development located in Century City, Cape Town, with its net zero water rating. However, the 4 132 m2 development was completed in 2013 – four years before the certification programme was introduced. Terramanzi founder and sustainability consultant Fabio Venturi, who joined the project after construction had already commenced, explains that each category requires an ‘all-or-nothing’ approach.
‘We selected water and effluent,’ he says. ‘The building is thus completely off-grid and future-proofed in terms of water.’
The Estuaries Plaza is almost entirely removed from the potable water supply of the City of Cape Town thanks to a purpose-designed on-site blackwater treatment facility. Reducing municipal demand by 88.5%, the treatment plant provides 2 189 litres of potable water per day.
That’s a significant amount, especially considering the water woes besieging the Western Cape. It’s testament that, however ambitious it may appear, the net zero project is so much more than a mere ideal. It should be considered an essential.