This five-minute guide is a brief introduction to some of the key definitions, approaches, metrics, strategies, and essential items required to help achieve zero net energy and carbon.
Resource
Zero net energy (ZNE) has gained traction across the built environment with the conversation shifting from kilowatts to carbon, as the world addresses global warming and climate change.
This five-minute guide is a brief introduction to some of the key definitions, approaches, metrics, strategies, and essential items required to help achieve zero net energy and carbon. It showcases growth trends for ZNE buildings, policies around the globe, and highlights some of the notable projects that have achieved ZNE and carbon.
Definitions of zero net energy
A zero net energy (ZNE) building is an energy-efficient building that produces as much energy as it consumes over the course of a year, usually by incorporating solar PV on site. There are many different definitions of ZNE. In general, any nomenclature such as ZNE or net zero energy (NZE) refers to the same concept. The definition refers to operational energy use only.
Definitions of zero net carbon
The core distinction between zero net energy and zero net carbon (ZNC) is that ZNC or carbon-neutral buildings consume only carbon-free renewable energy, either produced on site or procured. A ZNE and ZNC building can consume natural gas and offset that consumption through carbon offsets, however a zero carbon building would not consume natural gas at all. The definitions of ZNC and zero carbon are associated with operational energy only. However, some carbon certifications and international definitions also include embodied energy associated with the materials used in construction or end-of-life phases of the building.
Growth trends
The adaptation of stricter policies has driven the exponential growth of ZNE+C buildings across the world since the early 2000s. Areas where policies have been passed see a higher number of ZNE+C buildings compared to areas with no policy. For example, in the US, California has one of the strictest building codes, and almost half of all ZNE+C buildings in the US are located there. As policies expand, ZNE+C buildings are encompassing a wider range of building types and sizes.
Pioneering policies around the world
A combination of prescriptive and performance codes, initiatives, and plans to reach goals set by countries, states, and cities has been driving the development of ZNE buildings across the globe. Each region has pilot policies that are the first to take aggressive steps towards ZNE. Most countries have made pledges to take these types of steps towards sustainable development. There are also many non-mandatory programmes available to certify buildings.
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