The built environment encompasses all the buildings, distribution systems, roads, bridges, and conveyance systems, accounting for around 40 percent of global CO2 emissions. The world is now looking up measures to reduce and control global warming, and meeting these goals is only possible by cutting CO2 emissions from the built environment on an urgent basis. Out of the 40 percent of global CO2 emissions, 28 percent comes from the operation of buildings, and the other 12 percent comes from building materials and construction.
Decarbonizing in Advanced economies is very different from that of developing countries. In Advanced economies, where most buildings are already standing, decarbonizing will require only retrofitting the existing buildings. In developing countries, there is potential for new buildings, and decarbonizing these economies involves designing new buildings with net-zero emissions.
These emissions, also known as Greenhouse Gas emissions, are generated through various human activities leading to climate change. The GHG emissions associated with the building operations come in 2 classifications: Category 1 refers to emissions generated on-site, which include the heating, cooling systems, and the backup generators. Category 2 refers to emissions from the electricity consumed on-site but generated at a different place. The reduction of the emissions generated by Category 1 is done by minimizing the need for heating or cooling or switching to devices using natural gases, propane, or oil to those using zero-carbon sources. The reduction of the emissions generated by Category 2 is done by installing energy-efficient electric systems or sourcing zero-carbon electricity.
A zero-carbon buildings sector, however, would allow for more flexibility among individual buildings while preserving net-zero emissions overall. It is essential to note the difference between net-zero carbon and net-zero energy—the latter refers to developing energy that exceeds annual demand but does not necessarily mean that energy is zero-carbon. In theory, a net-zero carbon economy could also allow for some variability in emissions levels across areas if harmful emission technologies are readily obtainable, but that is outside the spectrum of the area-specific brief.
Here are a few ways to Decarbonize Building Environment:
Energy efficiency is likely a pivotal part of decarbonizing the building sector. Efficiency measures in both power and other building energy uses like heating and cooling help lower demand for carbon-intensive in the near term and make it easier to reach net-zero emissions. Digitalization is an emerging solution allowing for creative new technologies to help increase energy efficiency and lower emissions.
Software systems integrated into buildings can help coordinate supply and demand and shift energy use. Structures also have an inherent ability to store heat, called thermal mass, and can take advantage of this property to balance out heating and cooling to lower costs and shift power demand during off-peak times.
Electrification helps in decarbonizing the building sectors as long as the power sector is eventually able to decarbonize too. The economics of electrifying heating and cooling is dependent on climate, energy needs, and whether the building is being constructed or retrofitted. Energy efficiency and policy interventions would change that calculus—a combination of efficiency advancements, financial inducements, and carbon pricing would bring that to 60 percent.
District Energy Systems
District energy systems yield heat to pump moisture or steam from a central source and cool multiple public spaces. If seen theoretically, providing heating and cooling more efficiently than individual heating and cooling systems, it can be ineffective in practice if not designed and managed efficiently. District energy systems can run on diverse sources, but zero-carbon thermal sources like geothermal or solar thermal would be essential for a net-zero system. Due to their size, district energy systems are capital-intensive schemes and require integration with the regions they serve.
Renewable Energy Heating
Renewable energy heating is an option for decarbonizing heating, especially solar heating, hydrogen, or biogas. Solar heating is used to heat water in a residential or commercial building. These heaters manage solar energy with collectors much like a photovoltaic system, but instead of developing electricity, they pump a heated fluid via pipes to heat water for the facility. Solar air heating is also available but is not a widespread technology, with only about one gigawatt-thermal installed at the end of 2018 out of almost 500 gigawatts for all solar thermal technologies.
Switching out natural gas for hydrogen or biogas is a potential strategy for heating that can take advantage of the existing transportation infrastructure. Hydrogen can be integrated with natural gas and carted in the extant gas grid at 20 percent concentrations. Biogas is a low-carbon source of methane, a substitution for natural gas in home heating. Of course, mixing low-carbon gases with natural gas at low volumes is not adequate to achieve net-zero emissions, but this approach can help further the transition.
Alternative Cooling Solutions
Alternative cooling solutions are also a critical aspect to decarbonize buildings. Air conditioners pose two problems from a decarbonization perspective: they use electricity, which on a carbon-intensive grid emits CO2, and usage of refrigerants, the most popular of which are powerful GHGs called hydrofluorocarbons (HFCs). Evaporative coolers can save money and energy but are only adequate in zones with low humidity because of the restricted ability of moist air to take on better water vapor. Some innovative new technology explanations are emerging as well. Solid-state cooling systems use the thermodynamics of solids rather than liquid refrigerants to transmit heat.
Passive design refers to the decisions made in the design process of a new building that takes advantage of the environment to control the temperature in a building without additional heating or cooling systems. This can include orienting the position of a building to increase or decrease the amount of sun heating it, using different building materials that will absorb or reflect heat, or developing spaces that maximize airflow to inherently cool a space. Buildings designed this way may also add on-site renewable power generation like solar panels to reduce reliance on grid electricity.
These solutions and systems will help in decarbonizing the built environment.
Works Cited –
- “Brick by Brick: A Guide to Decarbonizing the Built Environment.” World Economic Forum, www.weforum.org/agenda/2022/01/decarbonizing-the-built-environment/.
- “Built Environment Decarbonization.” World Business Council for Sustainable Development (WBCSD), www.wbcsd.org/Programs/Cities-and-Mobility/Sustainable-Cities/Transforming-the-Built-Environment/Decarbonization#:~:text=To%20meet%20the%20Paris%20Agreement
- “Climate Solutions Series: Decarbonizing the Built Environment.” Www.csis.org, www.csis.org/analysis/climate-solutions-series-decarbonizing-built-environment.