The term “Net Zero” often creates some confusion as its now widely used but not that well understood. This post lists out how this term “Net Zero” is commonly used in various contexts to describe different types of resources and emissions. This highlights that whenever we see this term used, we should find out what it exactly refers to.

1. Net Zero Energy Buildings/Developments:

This refers to a building or larger collections of buildings (e.g. a neighbourhood) that generate as much energy from renewable sources as they consume over a specified time period ( usually annual basis ). These buildings are designed to be highly energy-efficient and often incorporate renewable energy systems such as solar panels or geothermal heat pumps etc. Depending on the sun availability and weather most of these buildings today in urban areas use the concept of net metering for e.g. in rainy months they may produce less than required renewable energy so they possibly use some electricity from the national grid. However, in other months they may produce more than required renewable energy, so the additional energy is returned to the grid. Overall, on an annual basis the sum of total renewable energy given back to grid minus the electricity taken form the grid should be Zero. Hence the term ‘Net-Zero’ Energy on Site.

2. Net Zero Carbon:

This term is commonly used in the context of carbon emissions. It’s a bit more complex to understand as it refers to achieving a balance between the amount of carbon dioxide emitted into the atmosphere and the amount removed or offset. CO2 is main source of global warming but there are other gases as well like methane which cause warming. Different sources of energy like Electricity ( Hydro / Coal ), Gas, Petrol, Diesel, Wood etc produce different amount of C02 and other global warming gases. Hence the concept of CO2 equivalence is used for such other gases to convert to Kg’s of C02 equivalent. Net Zero carbon may involve using technologies that may capture and remove carbon from atmosphere. Many such technologies are in early stages of development. So very often low-carbon is more realistically achieved.

Net zero carbon goals can be set for, buildings, countries, cities, organizations, or specific sectors. Presently common AEC industry usage of this term for buildings refers to nullifying the carbon footprint from operations ( AC, lights, equipment etc ) of the buildings but may ignore the carbon emitted during construction and also embodied in the materials.

3. Net Zero Transportation:

This refers to efforts to eliminate or offset carbon emissions from transportation systems, including cars, trucks, ships, airplanes, and trains. It involves transitioning to electric vehicles, improving fuel efficiency, and developing sustainable fuels or alternative transportation modes.

4. Net Zero Waste:

This term is used to describe initiatives that aim to minimize waste generation and maximize recycling and composting. It involves strategies such as waste reduction, recycling programs, nature-centric design solutions and waste-to-energy technologies to reduce the amount of waste sent to landfills. A net-zero waste building or development would be such that sends Zero waste to landfills. This is a very challenging concept in real life execution and may refer to building during construction as well as operations.

5. Net Zero Water:

This concept focuses on reducing water consumption inside and outside buildings, optimizing water management practices, and implementing strategies for water reuse and recycling. The aim is to achieve a balance between water use and the amount of water replenished or restored. A net zero water use building or development by definition would have its total annual water consumption ( indoor and outdoor ) equal to alternate water sources used ( rain water, recycled grey and black water ) and treated storm water returned to original source.

Net-Zero water buildings would have the benefit of decreasing costs of pumping municipal water, reducing storm water drains which take back rain, dirty water and will also increase resilience of the developments to water shortages. Net -Zero water concept is usually used for buildings but can be extended to large neighbourhoods, cities or manufacturing processes of products.

6. Net Zero Deforestation:

In context of forestry this term relates to efforts to halt deforestation and achieve a balance between the amount of forest area lost and the amount of afforestation or reforestation carried out. It involves sustainable land management practices and forest conservation measures. It may be applied to large projects or regions.

Above are a few examples of how the term “Net Zero” is used across different domains. While its main usage is in context of energy and carbon, the concept is broad and can be applied to various resources and sectors to address sustainability and climate change challenges.