Potential of clean propulsion technologies

Going-Electric's contribution to Question 2.1 of the European Commission's Consultation for a European strategy on Clean and Energy-efficient Vehicles.

Question 2.1: What is the potential of different clean automotive propulsion technologies (improved fuel efficiency, hybridisation and alternative powertrains) for contributing to decarbonisation objective in the short, medium and long term?

1. To clearly assess the potential of different clean automotive propulsion technologies, it is essential to realize that about 80% of daily car usage is for short trips (shorter than 60km), mainly in slow traffic with only one occupant.

As explained in question one, small Battery Electric Vehicles (BEVs) are ideal for this usage.

2. Well-to-Wheels, lithium BEVs are intrinsically far cleaner and more energy-efficient than equivalent Internal Combustion Vehicles (ICVs) having same weight and performances (excluding range):

• They consume 1.7 times less primary energy than equivalent gasoline vehicles and 1.4 times less than equivalent diesel vehicles.
   
• In Europe, they cause 2.4 times less CO2 emissions than equivalent gasoline vehicles and 2.2 times less than equivalent diesel vehicles (using JRC’s 2006 emission figures for the EU electricity mix = 443 g CO2/kWh).
   
• They are very silent and cause no urban pollution.
   
• They consume virtually no petrol products.
   
  (For more information, please read our scientific assessment of EV sustainability)

3. Small and ultra-light electric vehicles, such as electric scooters, motorcycles, quadricycles and “Ultra-Narrow Electric Cars”, can be up to twice as clean and energy-efficient as full size electric vehicles.

Obviously, a small and light vehicle consumes less energy than a large and heavy one. If the weight and drag coefficient of a vehicle is halved, so will its consumption and emission. This is the case for some lightweight scooters, as well as for some “Ultra-Narrow Electric Cars” which, as the Lumeneo Smera, are now entering the market.

Ultra-small vehicles present an additional advantage in urban environments: they occupy significantly less space in traffic and parking, thereby reducing traffic and parking congestion.

4. For cars having to cover long distances, the best solution is Extended Range Electric Vehicles (EREVs), which are nearly as clean and energy-efficient as BEVs.

Current car batteries usually take several hours to fully charge, so Battery Electric Vehicle (BEV) usage is limited by their battery charge to commuting and other short trips.

To extend the range, some manufacturers complement EVs with a Internal Combustion Engine powering a generator when batteries are low. Such vehicles are called Extended-Range Electric Vehicles (EREVs), as well as Range-extended Electric Vehicles (ReEVs) or Series Plug-in Hybrid Electric Vehicles (SPHEVs). Several models are to be commercialised as of 2011 (including GM's Chevy Volt and Opel Ampera).

For short distances, which represent about 80% of cars mileage, EREVs operate in electric mode and are therefore as clean and energy-efficient as BEVs.

For longer distances, which represent only about 20% of cars mileage, EREVs operate in generator mode, where they consume significantly less fuel than conventional Internal Combustion Vehicles (ICVs) because:

• EREV engines are significantly smaller than of equivalent ICVs, because they must only cover average power needs (peak power being delivered by the batteries), while ICV engines also must cover peak power surges (accelerations).
   
• EREV engines operate at a constant, highly efficient rotation speed, while ICV engines often operates at low or high rotation speeds at which efficiency is low.

5. Hydrogen Fuel Cell Vehicles (FCVs) have the potential of being clean and energy-efficient, but they are far from ready to enter the market: much more research is needed. Fuel cells may also have a large market in the power generation sector.

Our preliminary computations indicate that Fuel Cell Vehicles (FCVs) are about as clean and energy-efficient as BEVs when hydrogen is produced by steam reforming of natural gas, which is today the most energy-efficient method.

Unlike BEVs, whose 150 years old technology is ready for widespread commercialisation, FCVs are still in an experimental development stage. There are still several technical issues and cost is still far too high – today the fuel cell for a small car would cost around 100'000€. Also, a hydrogen distribution network should be created, which may be expensive.

FCVs could probably become a choice solution for vehicles having to cover long distances, such as buses, long-haul trucks and boats, which are not well suited for other electric technologies, and possibly as a substitute for EREVs.

Also, fuel cells may have a large market in other sectors than transport, notably in the power generation sector, with applications such as cogeneration plants, peak electric power generation and domestic generation of electricity and hot water.

6. Hydrogen powered ICVs are far less energy-efficient than petrol ICVs.

Since hydrogen combustion only produces water, hydrogen-powered ICVs could contribute to reducing urban pollution. However, the production, compression and transport of hydrogen and its transfer into the vehicle require a lot of energy: the Well-to-Wheel efficiency of hydrogen ICVs is about half of petrol ICVs.

Hence this technology should NOT be considered for the future European strategy on Clean and Energy-efficient Vehicles.

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