Overall rating: 4/5
With the rate of diesel ownership slowing, the swing back towards petrol power could be catalysed by the likes of BMW's forthcoming new plug-in hybrid model, which offers more performance, lower emissions and a usable electric-only range.
In the Metal:
Keeping away from the stand-out styling of the BMW i models, the 3 Series plug-in hybrid promises to look little different to its more conventionally-powered brethren. In fact, the only real tell-tale sign that this is different is the addition of a flap on the wing just behind the front left wheel arch, which is the access point for the battery charging inlet. Still in prototype guise as tested here, the finished car is likely to gain additional 'eDrive' badging on the wings and boot lid while aerodynamically-enhanced alloy wheels shod in low-rolling resistance tyres may also be fitted.
BMW has been reasonably smart with its packaging too. The 95hp electric motor is located directly behind the engine, while the lithium-ion battery that powers it is fitted directly over the rear axle in order to get as close to BMW's usual 50:50 weight distribution as possible - and it makes only a minimal impact on boot space, which remains very useable. The rear seats can also still be folded down should additional space be required.
As for the rest of the cabin it is a familiar affair with an added 'eDrive' button located at the gear selector's base being the only noticeable addition. The free-standing infotainment screen can display the current driving mode selected as well as the power source being used, while the animation also indicates when energy recuperation is occurring under deceleration. The driver can also see a more basic display of what the drive systems and the battery levels are doing at the base of the main instrument binnacle.
Each time the car starts its default drive mode is eDrive - providing there is some charge in the lithium-ion battery. When fully charged, the hybrid is capable of driving up to 35 kilometres using only electric power and with 250Nm of torque it lacks no performance at town speeds. On open roads it can travel up to a top speed of 120km/h without the need for the combustion engine to come into play. Its acceleration doesn't quite have the urgency of the BMW i3, for example, but the 3 Series is a larger, heavier car. What does warrant credit is how quiet the cabin is when driving in all-electric mode. Even under heavy acceleration there is a muted hum rather than the typical higher-pitched whine that can be heard in some electric vehicles.
Moving into 'Eco Pro' mode the car's driving range can be extended as the throttle sensitivity is reduced and the air conditioning system is altered in order to reduce the draw on the battery. When lifting off the throttle the transmission also disconnects the motors to give the car a coasting function allowing it to travel further with less power.
As the battery charge levels decrease, or should you switch to 'Sport' mode via the usual BMW Driving Experience Control button, the turbocharged four-cylinder petrol engine sparks into life in what is quite a smooth - though not completely seamless - manner. In this driving mode both motors work in tandem to provide the full 245hp and 400Nm. In either mode the eight-speed automatic gearbox works very well, though in this particular prototype the power delivery when the petrol engine is being used lacked the finesse one would expect from a BMW saloon - an issue that the accompanying engineer was keen to explain would be eliminated before the car reaches series production.
Even so, the level of composure from the chassis, particularly during high-speed cornering, is excellent and despite the plug-in hybrid carrying an additional 165kg of weight it remains very surefooted.
What you get for your Money:
With it likely to be the middle of 2016 before a production version of the 3 Series eDrive appears on sale it is hard to speculate on exactly how much it will cost. Given the shared costs of some of the electronic components across a wider range of models and a growing appetite amongst the buying public there is a stronger business case for making this a more affordable car than previously considered. Its price will decide its success in Ireland if it has a hope of competing with the best-selling diesels.
You can already purchase a hybrid BMW 3 Series right now in the shape of the ActiveHybrid 3. It is powered by a turbocharged 3.0-litre six-cylinder engine combined with a battery system then enables just four kilometres of electric-only driving while its emissions of 139g/km can't compete with the best-selling 318d and it also carries a significant price premium.
Apart from some small areas that need further developmental fine-tuning, the BMW 3 Series plug-in hybrid is a highly impressive package that, if priced correctly, could prove to be a huge success for the Bavarian brand. The very low emissions will also be a big draw for the Irish market.