How can we harness renewable energy for operating electric buses — and why we should do so

Interlinking renewable energy strategy with electric bus operations holds significant potential for decarbonising the road transport sector and contributing to a greener future. Furthermore, it can assist bus operators, particularly State Transport Undertakings (STU), in offsetting operational costs and reducing dependence on conventional energy sources.

The renewable energy sector, in turn, offers economic opportunities. At a national level, this collaboration is vital for achieving Net Zero emissions and enhancing energy security.

Global electricity demand surged in the transport sector in 2022, especially in road transport, where electricity usage has increased by 60 per cent since 2019, according to the World Energy Outlook 2023 report. In 2023, electric vehicles accounted for nearly 15.8 per cent of vehicle sales worldwide.

Among road transport vehicles, heavy-duty vehicles and large fleet operators, including STUs, require high power supply and consume a significant amount of electricity.

The Government of India is actively deploying electric buses (e-buses) and plans to induct around 50,000 in its National Electric Bus Program, launched in 2022. This has the potential to markedly reduce emissions from heavy-duty vehicles while also contributing to meeting 26th Conference of Parties (COP26) to the United Nations Framework Convention on Climate Change commitments.

Current deployment of e-buses

As of July 25, 2024, the Union Minister for Road Transport and Highways (MoRTH) submitted a written response in the Lok Sabha stating that a total of 8,938 pure e-buses were operational in India, excluding Telangana and Lakshadweep,according to the Press Information Bureau. This total includes buses, omni buses and educational institution buses as of July 19, 2024.

The government plans the induction of over 24,000 e-buses to encourage further adoption of electric buses. This includes 14,028 e-buses through the Prime Minister Electric Drive Revolution in Innovative Vehicle Enhancement (PM E-DRIVE) scheme in cities with populations exceeding 4 million (namely Delhi, Mumbai, Kolkata, Chennai, Ahmedabad, Surat, Bangalore, Pune and Hyderabad) and 10,000 e-buses through the PM-eBus Sewa scheme in nearly 170 cities with populations under 4 million.

Analysing power consumption of e-buses

Currently, most STUs are deploying electric buses through gross cost modelling, participating in demand aggregation and agreeing to provide assured kilometres (km) on a daily or annual basis. For example, the Delhi Transport Corporation has committed to providing an annual assured distance of around 70,000 km, which translates to approximately 200 km per day.

Data from the Rajhat-II electric depot of the DTC indicates that around 615,000 kWh of power was consumed to charge 72 buses, which collectively covered 440,000 km in July 2024. This shows that each bus, on average, operated for over 200 km, consuming around 285 kWh of electricity per day, with an average consumption of 1.38 kilowatts-hour (kWh) per km.

Given the average consumption of 285 kWh per bus per day, approximately 14.25 million kWh will be required daily for the government’s ambitious deployment of 50,000 buses. This will lead to substantial power demand, increasing the load on the existing power grid, which primarily relies on thermal and hydroelectric sources.

Solar photovoltaic canopies as a sustainable solution

To drive the clean energy transition in the mobility sector, it is essential to explore emerging solutions. One promising avenue for reducing reliance on fossil-based energy sources in public transport is the adoption of renewable energy technology — specifically, the installation of solar photovoltaic (PV) canopies at depots and terminals.

The adoption of SPV canopy technology is gaining momentum in the transport sector globally.

Several cities, such as the San Francisco Municipal Transportation Agency in the United States, the Singapore Land Transport Authority and Rotterdam in the Netherlands, have installed SPV canopies at bus terminals and interchanges to generate electricity for lighting and other amenities. 

The Montgomery County Department of Transportation (DCDOT) in Maryland, US, developed the Brookville Bus Depot with SPV canopies and microgrid controls to generate power for charging buses in collaboration with industry-leading partners. 

Recently, Brihan Mumbai Electric Supply and Transport or BEST planned to install solar PV panels on the rooftops of 27 bus depots in collaboration with the C40 Cities Finance Facility to generate power for its electric fleet.

What are the advantages

The installation of Solar Photovoltaic (SPV) canopies at bus depots offers a range of financial, operational and environmental benefits, while also improving working conditions due to the shade provided. These canopies promote cleaner public transport systems by reducing dependency on conventional power grids supplied by DISCOMs. 

They help lower power consumption costs and avoid utility demand charges and time-of-use tariffs, contributing to more efficient energy use. Additionally, SPV canopies ensure a reliable, uninterrupted power supply during outages caused by severe weather conditions. 

The shade provided by the canopies not only protects buses but also enhances the working environment for employees, further improving overall depot operations.

What about limitations

The installation of Solar Photovoltaic (SPV) canopies, while offering numerous advantages, faces several limitations as an emerging technology. The power generated may not be sufficient to supply the entire bus fleet for full-day operations, particularly in large depots with a high number of operational buses. 

Additionally, the upfront cost of installing SPV canopies at bus depots can be significant, posing financial challenges. Adopting this technology may also encounter other operational and logistical hurdles as it is still in its early stages of development and implementation.

To overcome the limitations of SPV canopy installations and maximise power generation, STUs can adopt several strategies. One approach is to install SPV canopies not only in bus parking and charging areas but also on the rooftops of administrative and service buildings within the depot, thereby increasing the total area available for power generation. 

STUs can also explore financing mechanisms similar to those used by the DCDOT in Maryland for the Brookville Bus Depot, which utilised an Energy as a Service model through collaboration with industry partners. 

Additionally, working with public sector undertakings that promote renewable energy, such as the Rural Electrification Corporation, the Indian Renewable Energy Development Agency and the Solar Energy Corporation of India, can provide valuable financial assistance. Collaborations with organisations like the C40 Cities Finance Facility, which are willing to extend support for sustainable urban projects, can further aid in addressing these challenges.

Way forward

The installation of SPV canopies in bus depots and terminals is a direct step towards reducing emissions in the transport sector and supports India's net-zero emissions targets set at COP26. It also improves working conditions and provides financial, operational and environmental benefits. 

The limitations related to technology, financial models and regulatory compliance can be addressed as this technology evolves. The Government of India’s role is crucial in promoting the installation of SPV canopies at bus depots, which will pave the way for a cleaner public transport system. 

Linking SPV canopy installation to incentives for depot infrastructure development under the PM e-Seva Scheme can further foster collaboration between STUs, public sector undertakings and industry-leading partners.