Sustainability | Renewable Energy

Environmentally Friendly and Efficient Mass Transit

Sustainable Public Transit


Sustainable mass transit reduces greenhouse gas emissions from the transportation sector, helps to produce numerous economic and environmental benefits, creates urban centers of productivity, and reduces dependence on foreign oil. As far as carbon-based transit, the amount of emissions per passenger-mile is greatly reduced with any type of sustainable mass transit compared to the use of conventional fossil fuel-dependent private cars.

Fuel and energy technologies that represent widely developed global trends in modern, cleaner, environmentally sound, cost-efficient, and energy-efficient mass public transit include:

  • electric transit, such as all-electric buses; as well as other mass transit vehicles
  • electric-biofuel hybrid vehicles, electric-diesel hybrids, as well as a wide range of other hybrid vehicles 
  • electric light rail  (streetcars, trolleys, and trams)
  • rapid transit rail and high-speed rail (also both electric transit technologies)
  • biofuel (biodiesel and ethanol) buses; and buses that run on other low-carbon fuel blends (such as compressed natural gas and biogas)
  • bus rapid transit (BRT)
  • hydrogen* fuel cell vehicles (*not widely developed, still mostly in research and development, with some limited deployment)

The higher the quantity and quality of sustainable public mass transit options, the greater becomes the opportunity and incentive for people to look beyond traditional internal combustion engine (ICE) vehicle use. In order to address climate and energy issues, such as transportation efficiency and emissions, there are a wide variety of sustainable mass transit options available today.

"Transportation (27% of 2020 U.S. greenhouse gas emissions) – Greenhouse gas emissions from transportation primarily come from burning fossil fuel for our cars, trucks, [buses], ships, trains, and planes."  From  -

"Transport accounts for around one-fifth of global carbon dioxide (CO2) emissions [24% if we only consider CO2 emissions from energy]."  From  -

Below are details on some cleaner, and greener transportation alternatives to conventional fossil fuel modes of transit>>>

Types of Modes/ Fuels for Sustainable Public Transit


Modern mass transit systems include vehicles using various clean energy technologies that are an ever-expanding part of the global mass transportation sector. 100%-electric and hybrid buseselectric light rail, private electric vehicles (EVs), and other cutting-edge electric mass transit technologies, are all exciting advances in sustainable transit globally.

Hybrid vehicles, plug-in hybrids, and 100% EVs are all transportation technologies that are revolutionizing transit, along with other new technologies in the sustainable transportation movement.

As far as a complete departure from oil dependency, the world must embrace sustainable mass transit technologies now available which run on electricity and renewable energy sources (biofuels). In the meantime, as the world transitions public mass transit away from fossil fuels, there are many clean, green, low emission transit options for public buses.

Biofuels (ethanol, biodiesel) are a cost-effective and environmentally cleaner alternative to petroleum and other fossil fuels used by ICE vehicles. Due to the large contributions made by fossil fuels to global warming, biofuels are an attractive alternative in order to lower GHGs from the transportation sector.

Biofuel blends, both ethanol and biodiesel blends, are some of the most common low-carbon fuel sources for sustainable buses worldwide. Biofuels are used in hybrids vehicles of many types globally. Biofuels are derived from biomass; plant and animal waste by-products, or simply from kitchen oil (in the case of biodiesel). Such organic materials can be replenished readily for use in sustainable mass transit.

Biofuel blends and bio-LNG blends are popular options for low-carbon sustainable mass transit worldwide. Alternative cleaner low-carbon mass transit options include buses that run on liquefied natural gas (LNG), compressed natural gas (CNG), diesel-electric hybrid buses, and LNG/ CNG-hybrid buses. 

Hydrogen is used in demonstration transit projects in several countries in Europe (please see CHIC; H2BusEurope), in the form of hydrogen fuel cells for buses. One great benefit of hydrogen fuel cells is that they produce absolutely zero emissions, with water vapor as the sole by-product. Nations of the entire world must embrace low and zero-emission sustainable transportation technology like hydrogen.

The use of hydrogen for transportation worldwide is rolling out little by little, with applications in places like California to Norway to Asia slowly being seen.

Hydrogen fuel cell buses remain in the research and development stage, with limited deployment for demonstration projects. Hydrogen fuel cell cars are expensive and have limited refueling options, but Japan plans to have 200,000 hydrogen cars on the road by 2025 (along with over 300 hydrogen filling stations).

It must be noted that electric vehicles, through their electric motors and drive systems, produce zero emissions.

As long as the energy source for the given electric transit option is based on renewable energy (whether it's mass transit like electric buses, trams, and light rail, or private transit like individual EVs), the transportation source is zero-emissions. When the electric transportation option is powered by a municipal grid with fossil fuels in the energy mix, the electric transit option is still responsible for emissions.

EVs are responsible for emissions from power plants that provide electricity to ultimately power the vehicles. This is why it remains essential for municipal grids to be powered by renewable energy sources like wind and solar, to the greatest extent possible.

Electric Rail |   

SkyTrain (automated electric urban rapid transit rail) in Vancouver

In addition to biofuel buses, another sustainable mode of public mass transit is rail. Particularly clean and efficient are electric urban light rail, electric urban rapid transit rail, and other electric commuter rail. Light rail is energy-efficient and cost-efficient; and has low maintenance needs and low energy demands.

Electric vehicles as public mass transit options in world cities often come in the form of electric and electric-hybrid buses.

Another popular electrified mode of mass public transit globally is electric light rail (tram, streetcar, trolley, or other light rail). EVs for sustainable mass transit can also be in the form of electric commuter rail, electric rapid transit rail, electric high-speed rail, electric taxis/ shuttles/ vans/ other private cars (and even some electric ferries/ ships).

All forms of electric transit will get more sustainable as municipal and national grids continue to be supplied with increasing shares of renewable energy. In fact, greater shares of renewable energy are absolutely needed on grids worldwide in order to ensure the sustainability of electric transit.

Environmental benefits of electric rail (and other electric mass transit) include the reduction of carbon dioxide, as well as the reduction of other pollutants/ GHGs caused by ICE vehicle traffic. Traffic congestion is greatly reduced in any urban environment with light rail, and ultimately light rail systems can replace highways.

Electric rail creates jobs both by producing a new source of capital, using new technologies, and creating employment opportunities with the mass transit itself and also by creating new, busy economic urban centers. Not only does electric rail effectively replace the use of fossil fuels, but the development cost of light rail systems is about half that of building freeways.

Please see:

Benefits of Hybrids, Plug-in Hybrids, and Electric Vehicles

Please also see:

Solutions to Fossil Fuels

high-speed rail line in Spain

Another form of sustainable mass transit that can (optimistically) dominate the world's future market for low carbon transit options is high-speed rail. High-speed rail runs on electricity and is an excellent eco-friendly alternative to flying to travel long distances.

High-speed rail greatly reduces GHGs per passenger-mile compared to planes.

With pioneering high-speed rail lines in Japan, as well as more recent additions throughout Asia and Europe, there is every reason to hope that high-speed rail can gain momentum to serve transit needs globally.

If the on-again, off-again, extremely slow roll-out of high-speed rail in California is any indication, however, the world might just have to make due for now with the many various Asian and European high-speed rail lines.

Bus rapid transit in Curitiba, Brazil
Bus rapid transit in Curitiba, Brazil

Bus Rapid Transit (BRT), and Public Transit in Curitiba and London


An exciting sign of progress in clean, low emissions, sustainable mass public transportation is the further development of electric, alternative low-carbon, biodiesel/ ethanol-fueled, and hybrid buses (especially those that run on bus rapid transit - BRT - networks).

BRT networks represent remarkably high-quality transit developments. BRT represents a revolutionary global trend in mass transportation, streamlining bus transit networks to increase the efficiency of bus systems.

BRT networks have features such as dedicated express lanes, innovative methods for passengers to easily purchase bus fares off-board, traffic signal priority, and efficient loading/ unloading passenger platforms in high-quality stations. These advanced features of BRT networks also serve to increase transit quality, traffic safety, as well as reliability and convenience of public transit. Some BRT networks also have trip-planning features such as live arrival and departure times with live schedules.

BRT buses also have advanced features such as highly efficient, high-capacity, longer buses, and a large share of low emission vehicles, with frequent and on-time service. BRT networks reduce travel time and reduce GHGs and other local pollutants from public transit (especially when run on alternative low-carbon fuels).

Electric, biofuel, and other low-carbon hybrid buses are effective means to reduce GHGs in public transit. The positive sustainable impact of these bus systems is improved markedly when bus routes are developed to be widely accessible throughout a city and are incorporated in BRT networks.

Examples of successful, highly efficient mass public transit, particularly in terms of clean, green bus utilization with high rates of ridership, are in London; and another is Curitiba. Curitiba has its fair share of biofuel and hybrid buses in the city's bus fleet, and also has one of the world's best examples of a successful BRT network in a metropolis.

Curitiba, Brazil represents an early adopter of BRT systems and a pre-eminent success story in public mass transit. Curitiba exemplifies the ideal use of a bus system to maximize sustainable public transit options for a city; a successful BRT system. 

The Curitiba BRT system is one of the greatest examples of successful mass transit in the Southern Hemisphere. The bus system in London is another great example of successful mass transit in a metropolis, this time in the Northern Hemisphere.

Today, a significant number of London buses are all-electric, run on low-carbon fuels, are hybrid diesel-electric, or other low-carbon hybrids. All new double-decker buses in London will be electric, or low-carbon hybrids, and will focus on only running the greenest, cleanest buses. In central London, all single-deck buses will generate zero exhaust emissions. By 2037 at the latest, all 9,200 buses across London will be zero-emission buses.

Please see>>> 

Vancouver: alternative transit capital of North America

Green city: bus rapid transit and urban planning in Curitiba

Green city: London [and Mass Transit in London]

please also see:

Clean Hydrogen in European Cities (CHIC); H2BusEurope

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