Who’s the greenest? EV v Hybrid v Diesel…

Following on from my last post showing the financial benefits in running an EV vs diesel, I thought I’d show the CO2 savings based on the same figures, with some hybrid stats thrown in (as we are long term hybrid owners).

From personal experience owning and driving a hybrid (Toyota Auris), a diesel (VW Golf) and an EV (BMW i3) in Ireland.

By my calculations over approx. 2,500+km in comparable circumstances, the EV is emitting 46%/50% less CO2 at the power station than the diesel/petrol hybrid.

On cost alone, per 100 km the EV is by far the cheapest to run. Even at full price domestic electricity rates (€0.19/kWh), per km our EV is 69% cheaper than our hybrid, and 57% cheaper than the diesel to run (fuel only).  Here’s a summary of my findings;

What I find fascinating is that the mass of the EV is almost identical to the diesel and petrol hybrid (see table below).

All three are slippery vehicles at speed (a brick has Cd of 1.0, a 1930’s Citroen 2CV is 0.51 and a Tesla Model S is 0.24).

Furthermore, the EV is carrying an extra 120kg deadweight, due to its range extender – a small electric generator for emergency use i.e. without the range extender the EV would be the lightest, including batteries at 1245kg.

Full table of conversion factors and notes for those who want them:

Petrol Hybrid Vs Diesel

For those of you questioning the Hybrid Vs Diesel data, this screenshot, from Toyota.ie 19th July 2018, showing the Auris Hybrid (our car) at 4.3L/100km and the Auris diesel at 3.4L/100km with Focus / i30 diesels at 3.8L/100km: All are based on the NEDC test cycle, soon to change to WLTP for closer to real-world figures.

Toyota Hybrid has been a great car for my family and a pathfinder for us all, but it’s past it now when compared to the latest diesel and electric cars on real world performance, at least in my experience.

Toyota’s sustained investment in hydrogen may yet pay-off:  The ideal replacement for a range extender is a lightweight fuel cell fuelled by hydrogen.  At 90+% efficiency and emitting only water, the combination of Toyota’s gearboxes, a fuel cell range extender and smaller batteries could be an unbeatable combination (Smaller batteries? Most of us travel less than 50km per day most days).

BMW have invested heavily in hydrogen as well, whereas VW plumped for diesel, time will tell who got it right, but Tesla has succeeded in making them all accelerate their electric product roll-outs.

Despite “range anxiety” expect to see affordable shorter range electric city cars, and larger multi-seat vehicles, capable of all day range to support shared taxi services in the coming years; as users get used to the new dynamics of electric cars (where we “fill-up” every night at home).

What’s next in our house?  We’ve loans to pay off on these cars, so the hybrid will be there for some time yet, before it is traded in for a more electrified version (brand loyalty still counts, although Toyota service depts. may test ours to its limit).

The BMW i3 is a keeper, not just because of its performance; its built of carbon fibre on an aluminium chassis, so it will likely be with us as long as its mechanicals hold out.  I’ll discuss the BMW i3 construction in my next blog.

Notes and assumptions:

  • L/100km for hybrid and diesel from pump / odometer km i.e. it is real world.
  • kWh/100km from trip on EV and converted from L/100km for hybrid and diesel
  • CO2 at SEAI conversion factors including grid and generation losses for EV
  • €/kWh is day rate electricity vs forecourt price petrol and diesel (no excise on electricity)
  • €/100km is fuel / electricity only full price running cost
  • Mpg is provided for information only, the (e) stands for equivalent
  • ULW is unladen or kerb weight of vehicle i.e. the deadweight being pulled includes batteries for the EV and hybrid
  • Cd factor (co-efficient of drag) is an indication of how slippery (or draggy) a vehicle is; all these vehicles are relatively slippery