DESIGNING NET ZERO BUILDINGS FOR AFRICA
By Marc Sherratt
Managing Director & Professional Architect at Marc Sherratt, Sustainable Architects (MSSA)
Net Zero-rated buildings are set to become the minimum global standard of sustainable architecture over the next 20 years. This will largely be led by cities, encouraged by programs such as C40. Cities in Africa that are currently set to participate in this ambitious vision are Johannesburg, Cape Town, Durban, Tshwane, Dar es Salaam, Nairobi, Addis Ababa, Lagos, Accra and Dakar.
City as leader
Today more than 50% of the world’s population lives in cities and this is projected to grow. Cities consume more than 66% of the world’s energy and account for more than 70% of global C02 emissions. African cities are set for explosive growth in the next twenty years and so the continent could see itself taking a leadership role in the pioneering of sustainable city design.
What is Net Zero?
We have used the Green Building Council of South Africa’s (GBCSA) definition for a Net Zero building. This is a new rating tool that will most likely become the objective, technical standard for Net Zero buildings across the continent.
Net Zero as per the GBCSA is divided into four categories, Carbon, Water, Waste and Ecology.
Net Zero Carbon – “A building that is highly energy-efficient, and the remaining energy use is from renewable energy, preferably on-site but also off-site where absolutely necessary, so that there are zero net carbon emissions on an annual basis.”
Net Zero Water – “A building that is designed, constructed and operated to greatly reduce total water consumption, and then use harvested, recycled and reused water such that the amount of water consumed is the same as the water that is produced.”
Net Zero Waste – “A building that reduces, reuses and recovers its waste streams to convert them to valuable resources with zero solid waste sent to landfills over the course of the year.”
Net Zero Ecology – “A building that does not reduce the ecological value of the site during development for greenfield (sites with minimal man-made disturbance usually in healthy ecological condition) sites.”
What is important to note is Net Zero does not necessarily mean “off the grid”. As your consumption is tracked over a year period, you could, for example, have a grid electrical connection that is used for part of the year as long as this is then offset with renewables so that your overall consumption is offset to equal zero.
Thankfully the GBCSA Net Zero-rating is one of the most forward-thinking in the world. C40 cities are required to have all their new buildings Net Zero Carbon by 2030 and all new and existing buildings Net Zero Carbon by 2050. There are no requirements in the program currently for Net Zero water, waste or ecology.
That said there are currently only a handful of projects that have achieved Net Zero ratings in South Africa. The goal of South African cities achieving Net Zero Carbon for new buildings by 2030 and all by 2050 is extremely ambitious.
To achieve that scale of implementation would require unwavering government support including radical, enabling policies, with associated projects. Most importantly there are few firms in the country that have the technical experience and skill to deliver such a change so quickly. Therefore it would require a public-private partnership of municipalities, engineers, sustainability consultants, architects and contractors with financial investment that has yet to be seen in South Africa’s building industry.
This is, however, the task that must be championed by us to begin to redress the effects of climate change created by the built environment. It is not a matter of hard it is but how necessary it is in a time where the building industry is under severe stress due to the lack of economic growth. Could this be the catalyst?
Designing Net Zero
Being the first architectural practice on the continent to achieve a triple Net Zero rating (Net Zero Carbon, Net Zero Water, Net Positive Ecology) on a project we feel obliged to share what we have learned in how to approach a Net Zero development.
- Do it for the right reasons
Our research has shown Net Zero buildings can cost up to 20% more than convention. That means at this stage it will make it a difficult financial decision. Additionally only doing a Net Zero building for corporate marketing will create blind spots for innovation. Be a leader rather than copying what the competition is doing. Understand you as a business, municipality or private citizen are responsible for your ecological footprint. Let that conviction guide your decision making to pursue a rating rather than a corporate or government agenda. Make the cost equal the ethics.
- Hire the right people
A Net Zero rating is not easy to achieve. It is highly technical and requires an experienced team to be successful. Make sure to hire competent professionals to ensure achievement and implementation.
- Leverage more than one rating
If the budget allows, attempt to pursue more than one rating. This creates creative opportunities where ratings start to strengthen each other through win-win solutions. For example on our Vleihuis Development (https://www.leadingarchitecture.co.za/the-vleihuis-development-achieves-net-zero-certification/) we were able to solve one of the most difficult problems with Net Zero Water, water storage. Our Net Zero Ecology mandate gave us the solution. We created an endemic wetland above which our buildings were designed. This single solution gave us the water storage capacity we needed to achieve Net Zero Water and Net Positive Ecology.
Beyond Net Zero
Net Zero in its nature can only ever be a minimum standard. Net Positive is the future.
Net Positive means you are producing at least 5% more energy, harvesting at least 5% more water and recycling/reusing at least 5% more waste from others than you are consuming. In Ecology you are increasing the ecology of a brownfield site (a site mainly of man-made structure and influence). What exciting opportunities would be created for new business, new partnerships, new collaborations with Net Positive buildings. This would truly create a more shared and democratic economy.
This is where our company mission statement comes from to “reverse local extinction through sustainable architecture”, we are talking about Net Positive, regenerative design. Join us in designing spaces that tangibly better the context they exist in, in every way, for all life.