What is a zero-energy building?
A zero-energy building has zero net energy. The total amount of energy used by the building on a yearly basis is nearly equal to the amount of energy generated on-site using renewable sources. Hence, these buildings release fewer greenhouse emissions into the atmosphere compared to equivalent non-ZNE (Zero Net Energy) buildings.
What are the factors affecting the net-zero energy concept?
- Building type, size, and way of construction
- Energy generation and storage systems
- Community characteristics like building density and layout
- HVAC and other building energy systems
- Smart operating and controlling strategies
What are the ways of achieving zero energy?
- Site Selection and orientation.
- Using Climate Responsive Design and Conservation Practices to Reduce Heating, Cooling, and Lighting Loads
- Making use of renewable or high-efficiency energy sources
Advantages of net-zero energy buildings
A fundamental advantage of net-zero energy buildings and communities is that they do not rely on non-renewable energy sources on an annual average basis. They often derive their energy from renewable sources (e.g., solar, and geothermal energy). As a result, such structures and communities make major contributions to energy sustainability and consequently to resource sustainability.
Naturally, this advantage must be weighed against the increased material resources often required to create net-zero energy buildings and communities and acquire the necessary technologies. However, the findings of multiple years of research into such technologies indicate that they will provide a considerable positive overall net contribution to resource sustainability through the usage of smart net-zero energy buildings and communities.
By not consuming energy, the processes and technology used in net-zero energy buildings and communities contribute indirectly to sustainability during their operational stages. Naturally, the processes utilized to construct net-zero energy buildings and communities must be sustainable as well, in order for the whole process to be sustainable over their entire lifespans (accounting for extraction of resources, manufacturing of technologies, and ultimate disposal).
That part of sustainable behavior is strongly dependent on the construction methods and technologies utilized to construct net-zero energy buildings and communities. Sustainable methods for planning, developing, and building net-zero energy buildings and communities are likely to be used because these structures and communities are being built with the goal of saving resources and reducing the amount of pollution they make.
Net-zero energy structures and communities often have a high level of efficiency, as all energy-derived services required in buildings and communities are provided with no net usage of energy resources. As a result, such structures and communities contribute significantly to the efficiency improvements required for engineering, particularly when compared to more typical means of providing energy services to buildings and communities.
Nonetheless, efforts to increase the efficiency of processes involved in net-zero energy buildings and communities are still worthwhile, particularly during the development and construction of the technologies and components of the systems. Exergy analysis can also aid in such efficiency improvement attempts. For example, some energy approaches make it easier to see how much material and resources are used to build systems like net-zero energy buildings and communities and how much they save when they’re used and how long they last.
Reduced environmental impact
Because the main benefit of net-zero energy buildings and communities is that they don’t use non-sustainable energy resources, they don’t have a lot of environmental emissions when they’re in use and don’t have a big impact on how much energy is taken from the environment when they’re in use. Environmental emissions and resource extractions are also caused by the full life cycle of buildings and communities.
These must be weighed against the environmental benefits that come from operating the buildings and communities. Because buildings and communities can last for more than 30 years, the environmental benefits of operating the technologies tend to outweigh the environmental costs during the non-operating phases of the technologies, which happen only once during their lives. Thus, the reduced environmental impact of net-zero energy buildings and communities could make a big difference in engineering sustainability.
Fulfillment of other aspects of sustainability
Smart net-zero energy buildings and communities aid in engineering sustainability’s non-technical features. For example, if energy prices rise, net-zero energy buildings and communities are expected to contribute to the economic affordability of energy resources now and in the future. Additionally, by consuming little or no energy, net-zero energy buildings and communities are intended to assist society in meeting its ever-increasing resource demands, particularly as populations grow and developing countries industrialize.
Additionally, because net-zero energy buildings and communities are intrinsically linked to their surrounding communities, they are likely to be implemented only where they are deemed socially acceptable by the communities in which they are located. There is a high probability of community involvement, which contributes to the sustainability of such engineered buildings and communities. Finally, net-zero energy buildings and communities should reduce some of the environmental constraints and strains on the planet’s carrying capacity. Naturally, further effort must be made to address the non-technical components of sustainability if the outcome is to be holistically sustainable.
Watch the video below, offered by Belfast Cohousing & Ecovillage, to obtain a better understanding of the zero energy concept.