By Annelide Sherratt and edited by Karen Eicker
Regenerative buildings give more to the environment than they take during the process of their construction and operations. This extends to improving the quality of the surrounding environment – either by contributing water or energy to neighbouring developments, or by restoring natural ecosystems that have been damaged by previous developments.
The current South African market defines regenerative buildings as net-positive buildings, a concept that stems from the Green Star net-zero/net-positive certification, which awards projects that go beyond the partial reductions recognised in the Green Building Council of South Africa’s (GBCSA’s) green building tools. Net-zero looks at buildings that have zero impact on carbon emissions, water, waste and ecology. For example, net-zero carbon buildings aim to offset their entire annual carbon emissions so that, over the course of a year, their overall energy use is zero.
Net-positive buildings take this notion a step further by positively redressing their impacts through generating more energy and water than they use, and improving the ecology of the neighbourhood and surrounding area. Generating anything more than 5% in excess of what it uses allows a building to qualify as net-positive. This can be achieved through onsite renewables, offsite renewables and carbon offsets (as demonstrated in Figure 1).
Understanding the impact of net-zero buildings
Because net-zero and net-positive buildings use renewable energy, sustainable water harvesting and recycling to provide the building with what it needs in order to operate, the infrastructure for these renewable resources only bears a capital cost upfront. Once the payback period has been achieved, the building is able to generate income for the owner.
Most countries in the world have signed up for the COP 21 agreement, to hold the planet’s temperature increase to a maximum of 2°C (with a UN stretch goal of 1,5°C – see Figure 2). The World Green Building Council (WGBC) initiative, “Advancing net-zero”, was prompted by the COP 21 agreement, and works with Green Building Councils all around the world, with the aim of making all new buildings net-zero by 2030, and all buildings net-zero by 2050.
As a commitment to advancing net-zero, several Green Building Councils have committed to developing net-zero/net-positive verification programmes and tools. The GBCSA launched their rating tool in June 2017 and has since had over 15 pilot projects certified.
Achieving regenerative buildings
The most efficient way to achieve net-zero or net-positive goals, is to work with the project team to design buildings that are as efficient as possible from the outset. There are two steps in this process: The design of energy-, water- and waste-efficient building systems and services; and implementing onsite renewables such as photovoltaic solar panels, rainwater harvesting and onsite waste recycling. Additional methods include offsite renewables and purchasing carbon offsets.
Regenerative buildings not only contribute to a city’s ability to be climate resilient, but also provide exciting opportunities for, among others, urban agriculture, cradle-to-cradle waste management, recharging groundwater systems and recreating ecosystems for local species.
Net-zero and net-positive imply more conscious design choices that challenge conventional building practices to make the world a better place for future generations.
Solid Green Consulting
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