European regulators should propose post-2020 CO2 emissions targets for passenger cars and light duty vehicles. To prepare the ground, OEMs are looking at options to comply with future standards. Electric vehicles will take a crucial role to achieve further emissions reduction but it is still not obvious which technology will take the lead (full electric, hybrid, plug-in hybrid, etc.). While hybrid vehicles are still more expensive than combustion engine vehicles, the recent developments of mild hybrid vehicles could offer a cheap and efficient alternative to quickly reduce fuel consumption and emissions.
The mild hybrid technology offers several advantages for OEMs. Firstly, they are cheaper (around 700€ per vehicle) and less complex than full-hybrid powertrains. In the first phase of the technology, a small 48-volt electric motor connects to the crankshaft to provide a low-cost power boost from a battery topped up with energy recovered during braking and deceleration. Furthermore, mild hybrid technology may be the most cost-effective way to meet stricter emissions standards and to deliver power to energy-consuming components and avoid costly high-voltage batteries. Besides, mild hybrid vehicle engines can be turned off whenever the car is coasting and braking, or it can be stopped and restart quickly. Regenerative braking is one of the key benefits of the technology compared to full hybrids. Its batteries and motor/generator are also smaller which allows OEMs to reduce cost and weight.
However, the technology also has some limitations and does not improve fuel consumption as much as a conventional hybrid system. Besides, some fear that their market uptake is mainly driven by tax incentives and sales would collapse when public incentives will end as it happened in the Netherlands. Finally, the implementation of real drive emissions test procedures may be detrimental to the deployment of mild hybrid vehicles. According to these new test procedures, thermal engines of mild hybrid engines would prove to emit more than conventional cars which would limit public incentives and ultimately affect their sales.
Some forecast that by 2025 mild hybrids will capture 18 percent of the European market, compared with 6 percent for plug-in hybrids, 3 percent for full hybrids and 3 percent for full-electric vehicles in the same time frame. Figures show that hybrid and plug-in hybrid sales already grew a 30 percent to over 400,000 in Europe last year. Hybrid vehicles were introduced in the market in 1997 and since then over 12 million of them have been sold worldwide. Japan has the world’s highest hybrid market penetration, with more than 5 million hybrids sold as of April 2017 followed by the United States (sales of over 4 million units since 1999), and Europe (about 1.5 million hybrids delivered since 2000).
Mild hybrids seem to be a cheaper and more efficient solution than full hybrids in the short-term. Volkswagen stressed that future consumers’ preference will go for petrol engines in combination with a mild hybrid. At present, there is no silver bullet in the field of electrification and the solution will rely on a variety of technologies in the coming years where mild hybrid will definitely play a role.