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Engineering transit solutions to advance climate action goals

October 6, 2021

By Gregory Mirabella

Engineering transit solution

A public transportation project in Delhi uses regenerative braking technology to reduce emissions

Caption: ©

From local recycling programs to federal solar tax credits, there are many ways to encourage sustainable practices and clean energy sources. But to pursue the UN Sustainable Development Goalsopens in new tab/window of Clean Energy (SDG7) and Climate Action (SDG13) in earnest, we have to think big. A massive problem like the climate crisis demands large-scale solutions, so when considering solutions that would have a major impact, infrastructure must be a prime target.

Conservation opportunities in transit

Public transportation is a form of infrastructure that clean energy advocates have been focusing on in recent years. Improving the quality and availability of public transit options is a boost for the environment because it results in fewer people driving individual vehicles. Meanwhile, making major changes to existing transportation systems, such as replacing diesel powered trains with electric ones, is very important in the transition to green technologies.

There are also less obvious changes that can make a difference if you know where to look. That is why it’s important to have savvy, sustainability-minded engineers examine all aspects of transportation and discover the unexpected areas where changes or replacements can be made to create more sustainable systems.

Delhi Metro hits the brakes on emissions

Consider the case of the Delhi Metro Rail Corporation (DMRC)opens in new tab/window, which spearheaded a project adopting regenerative braking technology rather than the conventional electrodynamic rheostatic braking technology. Delhi, India’s capital, is one of the largest cities in the world, with a population of nearly 19 million. It is also a city with significant pollution problems and therefore a great candidate for an emissions-reduction project.

The average person riding a commuter train might never consider that the way the train slows down and stops would have environmental implications, but the very act of frictional braking converts the train’s kinetic energy into thermal energy that goes into the atmosphere as waste heat. Automotive engineers have been working on this problem of wasted energy, developing ways to convert it to something useful and not harmful.

From waste to haste

Regenerative braking has proven to be a good solution because it converts that kinetic energy into electricity that can be reused to help power the vehicle. This technology is mostly found in hybrid and electric cars, but DMRC has demonstrated that it can also be used in a major metro system.

DMRC is in fact the first railway and metro rail project in the world to be registered with the UN Framework Convention on Climate Changeopens in new tab/window for reduction of greenhouse gas emissions. Their choice of regenerative braking technology has reduced the demand for electricity by up to 33% over electrodynamic rheostatic braking technology, providing the twin benefits of energy conservation and emissions reduction.

Engineers can lead the way on achieving SDGs

Climate action and clean energy successes like this one result from the vision of multiple parties: the UN provided a framework, DMRC management committed to creating energy efficiencies and resource conservation in their system, and innovative engineers developed the regenerative braking technology that gave them a more environmentally friendly alternative to use.

Knovel can support engineers who want to do more to meet sustainability goals. There is an abundance of knowledge in Knovel to help engineers learn more about the new and developing technologies that can transform our infrastructure and transportation systems.


Portrait photo of Gregory Mirabella


Gregory Mirabella

Senior Manager for Portfolio Marketing - Engineering portfolio