The hybrid EV imperative

General Studies Paper 3

Introduction

• With their higher fuel economy and reduced carbon emissions, hybrid EVs offer an opportunity for economically developing countries to kick start the shift towards sustainable transportation while addressing infrastructure and cost challenges associated with full EV adoption.

Different types of EVs

• Any vehicle propelled by an electric drivetrain, taking electric power from a portable, electrical energy source, is called an Electric vehicle (EV).
• In a hybrid EV, an internal combustion engine (ICE) is used to produce electricity with an electrical generator. A small battery, typically 1-5kWh, is used in a hybrid EV as an energy buffer to store the electricity.
• A full EV – a.k.a. a battery EV or a plug-in EV – has no ICE and hence no tailpipe emissions. The battery typically is much larger at 20-120 kWh. And it can only be charged from the grid.
• A plug-in hybrid EV is still a hybrid EV with a much larger battery, typically 5-15 kWh. This larger battery can also be charged from the grid. This means a plug-in hybrid operates like a fully electric vehicle as long as there is energy in the battery.
• A fuel-cell EV uses a fuel cell to produce electricity for the drivetrain together with a small battery buffer to manage variations.

Fuel economy of hybrid and fully electric EVs

• The use of an ICE in combination with a generator and battery in a hybrid EV results in the fuel economy of these vehicles being 1.5-2x times higher than in conventional ICE vehicles for city driving and 1-1.5x times higher for highway driving.
• A plug-in hybrid EV combines the best of both hybrid and full EVs. Using a small battery (5-15kWh) that can be charged from the grid, it can cover 80-90% of all short, day-to-day commutes in a fully electric mode with 3-4x higher fuel economy than conventional vehicles.

Net emissions of hybrid EVs

• Apart from fuel economy, an important metric is the net emissions of a vehicle.
• Well-to-wheel emissions include both tailpipe emissions and emissions due to fuel production – electricity or fossil fuels.
• The life-cycle emissions is a more comprehensive index that includes well-to-wheel emissions and emissions due to vehicle and battery production, maintenance, and end-of-life recycling.
• The grids of different countries are decarbonised to different extents at present
• In the case of full EVs: the lower the emissions from power production, the lower the vehicle’s well-to-wheel and life-cycle emissions.

EVs’ life-cycle emissions compared  to ICE vehicles

• According to an analysis, switching to full EVs will result in 19-34% lower emissions by sedans and 38-49% by SUVs – even with the fossil-fuel-dominated energy mix in India.
• By 2030, when renewables account for a greater share in the grid, emissions are expected to be 30-56% lower..

Challenges to transitioning to electric mobility

• Successful transition to full EVs requires fast-charging infrastructure along highways.
• This is vital because people generally want to own one affordable car serving both short and long-distance travel needs over 5-15 years, and want to drive without range anxiety.
• Second, many parts of the world, especially economically developing nations, don’t yet have access to a grid or the grid isn’t 100% reliable.
• The relatively high charging power for slow-charging (<22kW) and fast-charging (<350kW) make the problem more prominent vis-à-vis generation and transmission capacities.
• Third, mass-market price points of cars in the economically developing world are much lower, ~$12,000 – whereas EVs with a range of 300-400 km will reach at a price of $25,000-35,000 in the short term.
• This is due to the high battery costs. Vs with higher range will need larger battery packs and thus be more expensive.

Help in decarbonising

• The current focus in the industry is on full EVs, which isn’t practical for the immediate future, given grid reliability, state of highway charging infrastructure, and prohibitive vehicle costs.
• Hybrid EVs – either full or plug-in hybrids – present a big opportunity to lower emissions in the interim.
• The 1.5-2x higher fuel economy of hybrids and 3-4x higher fuel economy of plug-in hybrids in electric mode drastically reduces fuel costs, emissions, and oil imports.
• Regenerative braking in hybrid EVs – i.e. recovering the kinetic energy of the vehicle while slowing down instead of dissipating it as heat in the braking system – can improve fuel economy esp. in urban areas with frequent stop-go conditions and in hilly conditions.

Conclusion

• In an ideal future, all our electricity comes from renewable sources and we power our EVs using solar energy during the day and with wind energy at night. For countries that can already work towards this goal now, our priority must be to realise this vision. In places where transitioning to renewables for power and building fast-charging infrastructure will take a decade or more, we need to switch to hybrid EVs as a short-term solution due to the fuel-economy and emissions benefits.