Cleaner energy, cleaner air

Writer: Tan Chui Hua

Clean air remains a global challenge due to fossil fuel pollution consumption. Advances in clean energy tech offer viable solutions, enabling cities to lower carbon emissions, adopt cleaner energy, and provide citizens with healthier air.

Cities mentioned in this article:
Shenzhen, Pune, Oslo, Warsaw, Beijing, Lucknow (Uttar Pradesh), Bristol

Once a polluted city, Shenzhen's air quality is among the top in China. © zhaojiankangphoto/123RF

As the world rapidly urbanises and city dwellers are estimated to comprise some 70% of the world population by 2050^1., one of the biggest ongoing challenges is to ensure clean air in urban environments. In a recent report by the World Health Organization, data from some 6,000 cities shows that 99% of the world’s population still breathes in unhealthy levels of air pollutants^2..

Factors that contribute to poor air quality in cities are wide-ranging: from vehicular traffic, industrial activity, and construction to the city’s heating and cooling systems. To tackle this urban challenge, cities have developed different strategies, largely centred on replacing pollutive sources of energy with cleaner sources.

By adopting clean energy, cities not only improve their air quality, but also benefit in other aspects. Clean energy help cities reduce their carbon emissions and contribute to mitigating the impact of climate change. These energy technologies often have lower operating and maintenance costs than fossil fuel-based power plants. Most importantly, improved air quality supports better health for the population and a more liveable environment.

"The goal is to cut emissions, which is why E.V.s (electric vehicles) are so important, but also to make the city better to live in." — Sirin Hellvin Stav (Vice Mayor for environment and transport, Oslo)

Pushing for electric vehicles

Emissions from internal combustion engine vehicles are a main source of air pollution in cities. In comparison, electric vehicles produce around 40 percent less carbon, do not release harmful pollutants, and cost less to maintain over time^3.. Increasingly, cities around the world are embracing electric vehicles despite high upfront costs needed for routing and charging infrastructure.

In 2017, Shenzhen, China became the first city in the world to fully electrify its bus fleet. The city began its pilot of electric vehicles in 2009 with substantial funding from the government. Over time, Shenzhen built more than 500 charging stations with some 8,000 outlets and ensured utility companies worked closely with bus companies to install charging outlets along bus routes. Today, the city has the world’s largest electric bus fleet — over 16,000 — as well as the largest electric taxi fleet^4.. Coupled with other pollution control measures, Shenzhen cut air pollution by 50 percent within the same period and is known as one of the cleanest cities in China^5.. Since then, more cities have been adopting electric buses. Pune, India, has converted some 20 percent of its fleet to electric buses in recent years while Santiago de Chile has converted 30 percent of its fleet with a goal of 100 percent electrification by 2035^6..

Oslo aims to fully electrify the city's vehicles by 2030. © mumemories/123RF

Oslo, Norway, has taken electrification further with its goal of becoming the world’s first capital city with an all-electric system^7.. The city has been converting its fleets of trains, trams, ferries, buses, construction machines and shared bicycles to electric ones. In 2022, 80 percent of Oslo’s new car sales were electric^8.. Furthermore, much of the electricity powering the grid comes from hydropower^9..

“The goal is to cut emissions, which is why E.V.s (electric vehicles) are so important, but also to make the city better to live in,” said Sirin Hellvin Stav, Vice Mayor for environment and transport^10.. Just over a decade ago, the air pollution caused by vehicular emissions in Oslo and other Norwegian cities was a growing concern as diesel car population grew^11.. With the switch to electric vehicles, pollutants such as nitrogen oxide and sulphur dioxide have decreased sharply, making for cleaner air^12..

Phasing out coal

Despite being highly pollutive^13. and the most carbon-intensive fossil fuel, coal is still used to generate one third of the world’s electricity¹⁴. Nonetheless, nations such as Sweden, Belgium, and Austria have successfully phased out coal while more cities worldwide are reducing reliance on the fuel.

Within the European Union, Poland is the largest consumer of coal with around 14.5 million tonnes per year^15.. Correspondingly, its cities have consistently been rated with the worst air quality in the region. Warsaw, however, has been making ambitious efforts to replace coal with cleaner energy. The city has decommissioned household coal stoves, installed solar panels on city infrastructure facilities^16., improved the efficiency of its district heating system^17., and undertaken thermal retrofits of buildings^18.. Warsaw has also banned burning coal for heating and installation of coal and wood boilers in new houses as of 2023^19.. Despite the ongoing energy crisis in Europe, mayor Rafal Trzaskowski says, “We’ve still managed to go from having 15,000 coal-powered furnaces in the city to just 4,500, so the shift has been pretty dramatic.”^20.

Beijing, China, also demonstrates how cities could dramatically improve their air quality by cutting back on coal use. Since the 1990s, the city had begun tackling air pollution with more stringent regulations on vehicular and industrial emissions. In 2013, the city began shutting down coal mines and plants. It built large gas-fired power plants, gradually replaced coal-fired boilers used in district heating with gas and electric systems and introduced programmes to incentivise households to switch from coal burners to electric. Over a decade from 2010 to 2020, Beijing cut down on coal use by 95 percent^21.. By 2022, the city had slashed PM 2.5 levels by two-thirds from 2012^22. while emissions of pollutants such as nitrogen oxides were reduced significantly^23..

Renewing cities with renewables

Advances in technology has made it increasingly viable for cities worldwide to switch from pollutive fossil fuels to cleaner, renewable energy. Conventionally, adoption of renewable energy used to be highly dependent on having the right geographical conditions such as geothermal activity.

India has been establishing solar parks such as this in Raichur, in a bid to combat air pollution and carbon emissions. © lakshmiprasad Sindhnur/123RF

With solar panels becoming more high-performance and cost-effective over time^24., countries have accelerated the building of solar parks with significant capacities, such as China’s Golmud Solar Park which generates over 2.8 gigawatts^25. and India’s Bhadla Solar Park, which is capable of powering 4.5 million homes^26.. Recognising that solar energy adopting would improve air quality, Indian cities have been pushing solar power adoption in recent years. Lucknow, capital of Uttar Pradesh, has set ambitious targets for electricity production through solar installations such as farms and rooftop systems. Since 2022, the city has provided substantial subsidies for households to install solar rooftops, organised public programmes to increase awareness of renewable energy solutions, and deployed solar systems on public buildings^27..

Progress in technologies to produce biogas from organic materials such as food waste, sewage, and municipal waste has led to a recent rise in cities adopting this renewable energy. Compared to fossil fuels, biogas produces 85 percent less greenhouse gases and much lower levels of air pollutants^28.. Bristol, United Kingdom, has an extensive fleet of buses fuelled by biogas generated from waste food and a sewage plant producing biomethane that powers a few thousand homes. At the launch of the biogas buses in 2020, Marvin Rees, the city’s mayor, said, “We welcome this significant investment in new, cleaner buses and infrastructure as part of our drive to reduce air pollution and achieve carbon neutrality.”^29.

While air pollution remains a chronic challenge in most cities worldwide, these case mentions show that by committing to clean energy strategies — pushing for electrification of vehicles, phasing out coal, and growing share of renewable energy — cities can effectively improve air quality, bringing about a more liveable, healthier environment for their citizens.