Diesel bus emissions pose environmental and health risks
The transportation industry is one of the largest contributors to greenhouse gas emissions. That’s predicted to get even worse over the 30 years. Diesel buses, the most widely used form of public transportation, are a major offender. These heavy polluters are responsible for 25 percent of the black carbon emitted by the transportation sector, which is harmful to both people and the environment.
Converting municipal diesel bus fleets to 100% electric buses, or eBuses, as they’re better known, can turn the climate-change tide by reducing vehicle emissions and eliminating air pollution. While the transition to passenger electric vehicles (EV) has been underway for several years, now eBuses are stepping into the spotlight as a way for cities, local governments, and transit authorities to meet their urban transportation sustainability goals.
In contrast, a single eBus can save 60 tons of CO2 per year
What makes eBuses such a green solution? A single eBus running 200km per day saves 60 tons of CO2 in one year compared to a diesel bus.
There are already nearly 600,000 e-buses on the road globally with plans for more on the way. For example, the European Commission’s ZeEUS (Zero Emission Urban Bus System) project is testing eBuses in over 90 urban bus system networks across Europe, which has added up to more than 20 million kilometers driven in pure electric mode.
eBuses also help cities meet environmental regulations
Urban transportation decisions tend to be made a city level. By moving from diesel to eBuses, cities enjoy benefits that include:
- Improving sustainability: Transitioning to eBuses make cities greener and healthier. They reduce diesel exhaust emissions and air and noise pollution, which improves people’s health and helps cities meet their sustainability targets, especially when eBuses are fueled by electricity that comes from renewable sources.
- Meeting passengers’ demands: The public wants greener transportation, if the rise in EV is any indication. Cities can meet this need with eBuses, which provide the environmental benefits passengers want while also improving passengers’ experience because eBuses they are reliable and quieter.
- Complying with regulations: Cities that use eBuses are future-ready because they meet existing stringent city- and country-level requirements and are prepared for new ones. For example, the European Union requires a quarter of new buses purchased by public authorities to be zero-emission by 2025. In addition, the EU’s “Fit for 55” legislation brings the transportation industry, which is responsible for roughly 20 percent of total EU greenhouse gas emissions, fully into the EU decarbonization process. It proposes to rapidly increase the use of electric vehicles by banning new fossil-fuel passenger vehicles by 2035.
eBus fleets are only as reliable as their electrical infrastructure
Transitioning from diesel-fueled buses to electric is just the first step toward greener transportation. Cities must also focus on end-to-end electrical distribution solutions that ensure reliable and resilient power for bus depots’ charging stations. This could be crucial in some geographies facing grid reliability issues that lead to outages.
To understand the best approach, and whether a microgrid is part of the ideal solution for eBus electrical infrastructure, consulting services play an important role. These services help set a strategy for success by right sizing electrical distribution and EV based on fleet usage, such as kilometers per day and time to charge, as well as right sizing a microgrid for on-site renewable consumption and resiliency. Consulting services can define an energy-sourcing strategy based on grid capacity, tariffs, sustainability requirements, and resiliency challenges, including PPA and carbon offset.
There are 3 main types of solutions for eBus electrification infrastructure for different cases:
- Bus depot electrification tied to the grid using MV-LV power distribution and power monitoring and control solutions with the option to procure green energy for end-to-end sustainability goals.
- Bus depot electrification and microgrid using the grid and an on-site microgrid for when grid capacity is not sufficient, grid tariff needs optimization, or to self-consume and increase sustainability.
- Depot electrification and microgrid tied to the grid that can be islanded for 100% of the critical charging needs in case of unstable grid with risk of downtime.
While the first approach above is the most common and is regularly met with success, let’s look at an interesting example of the third approach in the list.
Montgomery County aims to save 155,000 tons of GHG with its fleet electrification infrastructure project
Maryland’s Montgomery County is creating a green, electric future with its first-of-a-kind public bus fleet electrification infrastructure project. The project advances the county’s sustainability goals with a resilient system that improves its transit operations’ reliability while decarbonizing public mobility using fleet electrification and microgrid technology that integrates solar PV, on-site power generation, battery energy storage.
The Brookville bus depot has been electrified and powered by a microgrid able to run in islanded mode. Its microgrid is sized to meet peak demand and ensures power resilience for continuous operations — even during service disruptions to the main grid, such as extreme weather and power outages. Montgomery County is planning for the future with its new cloud-based infrastructure because it can accommodate additional DER assets or EV charging infrastructure as the fleet grows.
Once the fleet transitions to electricity, it will save an estimated 155,000 tons of greenhouse gas emissions over the microgrids’ lifetime.
Want to learn more? Read our white paper with Guidehouse: Linking Clean Energy and Clean Mobility via Resilient Microgrids: How Energy as a Service Business Models Foster Sustainability Solutions.
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