How cities are focusing on renewable energy and buildings to provide cleaner air
To mark the second United Nations’ International Day of Clean Air for blue skies, we are highlighting the action being taken by cities around the world to ensure everyone, everywhere can breathe clean air.
Here we focus on three ways that cities can reach the goals set out in the C40 Clean Air Cities Declaration: cutting emissions from buildings, championing energy efficiency, and prioritising renewable energy sources.
From their iconic skylines to beautiful and historic architecture, buildings and infrastructure define cities. They protect, connect and create spaces for people to live, work, study, visit and play. However, our built environment is also one of the largest sources of greenhouse gas (GHG) emissions, and accounts for a significant amount of air pollution in our cities, threatening our health and the well-being of our communities. Specifically, building materials, construction, maintenance, buildings’ energy use, on-site fuel combustion, and demolition are responsible for a growing share of buildings’ carbon footprint, and they have an impact on our cities’ air quality.
“With every passing month, we learn about the countless ways that air pollution hurts our health — from our lungs, to our hearts and our mental well-being. Air pollution even worsens COVID-19 outcomes. The good news is that we have many opportunities to improve both our indoor and outdoor air quality, with just a few interventions capable of making a big difference. C40 cities are showing how it can be done, by increasing energy efficiency, shifting toward electric appliances, and designing buildings to use less energy from Day 1.” — Dr. Zoë Chafe, MPH, Technical Lead for Air Quality, C40 Cities.
Construction and Materials
The building and construction sector is a huge source of greenhouse gas emissions globally, producing about 39% of all energy related carbon dioxide, and construction equipment using diesel fuel are high emitters of harmful air pollutants, such as particulate matter and nitrogen dioxide.
In Oslo, where construction accounts for 7% of the city’s total emissions, the city has committed to eliminating emissions from construction machinery by using only zero emission mobile machinery on its construction sites. Starting with its 2019 budget, the city created measures to help the construction industry transition to emission free machinery and vehicles. In September that year, the city had its first 100% electric construction site and is intending for all municipal construction projects to be completely emission free by 2025.
Improving Energy Efficiency and Reducing Energy Use
Buildings are one of the biggest sources of greenhouse gas (GHG) emissions, accounting for over half of total city emissions on average, and a significant source of air pollution. Around half a million people die each year due to outdoor air pollution caused by energy used in buildings. Delivering on the science-based goals of the Paris Agreement requires urgent and dramatic action to cut emissions from buildings. Action is needed now, because most buildings will be standing for generations to come, and C40 cities are taking action to improve efficiency and energy consumption in buildings.
London is working towards more sustainable buildings, with the Mayor’s Business Climate Challenge pilot programme. The programme encourages commercial buildings to reduce their carbon footprint by cutting their building energy usage. The pilot will work with 15–20 businesses to reduce their energy consumption by 10 per cent within the first year. Following from the technical support they receive on the Challenge businesses will be encouraged to review and consider increasing their target to 30% over 3 years.
Working with C40 for technical assistance, as well as Lawrence Berkeley National Laboratory and the City of San Francisco, Mexico City created a roadmap to achieve net zero carbon municipal buildings by 2030 and private buildings by 2050. The roadmap was finalised in 2021 and puts forward a range of milestones and actions, from implementing policies to piloting projects and adopting new technologies. Mexico City is one of the first Latin American cities to develop a net zero carbon roadmap and it provides an important template for other cities on how to collect and analyse data to set net zero building targets.
Santiago is raising energy efficiency requirements for social housing projects by updating its procurement standards. This was made possible through a long running collaboration between many different departments within The Ministry of Housing and Urban Planning to deliver the sustainable construction policy, this included engagement with the private sector and international organisations. The result has been that the city has been able to demonstrate 40–50% better energy performance compared to the minimum standards for housing. C40 has calculated that this change could bring both social and environmental benefits, saving over 230,000 kilograms of carbon dioxide emissions per year and reducing energy bills for vulnerable households by $289 per year.
Focusing on buildings from a different angle, the city of Durban, with technical assistance from C40’s South Africa Buildings Programme, created Africa’s first net zero carbon buildings policy. The policy — adopted in April 2021, sets more stringent energy efficiency requirements for new buildings (and those undergoing major refurbishments) and provides guidance on net zero design for the public. C40 is now working with three fellow South African cities — Johannesburg, Cape Town and Tshwane — to develop similar policies and achieve net zero buildings by 2030 under the C40 Net Zero Carbon Buildings Declaration.
Expanding Renewable Energy
Cities have proven that they can make use of a wide range of renewable sources to supply energy for residential, commercial and municipal buildings. Prioritising and scaling up efforts to champion renewable energy can reduce emissions, improve air quality, save on cost, create jobs and contribute to energy efficiency and security..
Los Angeles is looking at how to achieve a 100% clean energy future and is aiming for a 100% renewable energy power system by 2035. Their LA100 study shows there are significant benefits from electrification in terms of improving GHG emissions, air quality, and health. Electrification of vehicles and buildings leads to substantial improvements in air quality and associated benefits to health — widespread across L.A.’s communities. LA100’s results indicate that reaching 100% renewable power will reduce NOx emissions by 86% and PM2.5 emissions by 26%, resulting in 100 avoided deaths annually and an estimated savings of $1 billion in avoided healthcare costs, with disadvantaged communities experiencing slightly greater reduction in PM2.5 and associated healthcare savings.
Taking a similar approach to Los Angeles, New York City is converting its biggest power plant by replacing the gas turbines with batteries that charge when demand is low. This will contribute to New York State’s ambitious policy of achieving a 100% carbon-free power supply by 2040.
Eliminating on-site fossil fuel combustion
Eliminating emissions from buildings requires solutions that look across all sources of fuel combustion, from how we get our electricity to how we cook our food. Cooking equipment using fossil fuels or biomass adds to the air pollution both in and outside our homes, increasing health risks among those who are exposed.
In the United States and elsewhere there has been growing concern about the role of natural gas in cooking, where recent research has indicated homes with gas stoves have up to 400% higher nitrogen dioxide (NO₂) concentrations than those with electric stoves. NO₂ is a powerful lung irritant, affecting all populations, particularly those most vulnerable, such as children; children living in homes with gas stoves have been found to be at up to 42% increased risk of having asthma.
In Seattle, buildings are one of the largest and fastest growing sources of climate pollution, responsible for more than a third of the city’s greenhouse gas emissions, with over 90% of these emissions resulting from burning fossil fuels like fracked gas for heat, hot water, and appliances. The city updated its buildings energy code in March this year, with the aim of decarbonising all new commercial and municipal buildings above three stories. The code now bans natural gas in new buildings, includes more stringent energy efficiency requirements, eliminates the use of fossil fuels for most space and water heating, and sets out improved access to onsite renewable energy.
No one should have to worry about the air they breathe harming their health. These initiatives demonstrate the diverse ways that C40 signatories are reducing air pollution and creating healthier, thriving communities for residents. What’s more, these examples also show that, no matter a city’s profile or economic background, collaboration and innovation can produce tangible and impactful results.
As the world feels the impacts of the climate crisis, reducing harmful emissions from across all sectors becomes more and more urgent. Working together means that we can accelerate achieving these goals, and at the same time push towards a more sustainable, equitable and inclusive future where everyone, everywhere can breathe clean air.