This is the question we are asked most, and the honest answer is that it depends on your route, your depot and your timeframe rather than on which technology is best.

Full electric

Quiet, clean, and cheapest per kilometre to run once you are operating. The difficulty is everything that has to happen before that.

You need charging infrastructure at the depot, which means a grid connection that can carry it. In many depots that upgrade costs more than the first bus. You need to plan routes around range, which is manageable on a fixed urban route and difficult on charter work. And you need a plan for what happens when a charger fails.

For a metropolitan route operator with a depot that can take the connection, electric is increasingly the right answer. For a rural school contractor, it usually is not, yet.

Plug-in hybrid

A battery and an electric drive, with a small diesel engine that can charge the battery when needed. You can plug it in overnight if you have somewhere to plug it in, and you do not have to if you do not.

The advantage is that nothing about your operation has to change. No depot upgrade, no route redesign, no range anxiety, and no stranded vehicle if a charger is down. The disadvantage is that you are still buying and maintaining a diesel engine, and the per-kilometre running cost sits between electric and diesel rather than at the bottom.

Diesel

Still the right answer for a lot of operations, and anyone who tells you otherwise is selling something. Long distances, remote work, charter runs where the schedule changes daily, or any operation where the depot cannot support charging.

A Euro VI diesel is a far cleaner vehicle than one from ten years ago, and the running cost is predictable in a way that a new technology is not.

How to decide

Start with the depot, not the bus. If the depot cannot support charging and the upgrade is not funded, electric is off the table regardless of how good the vehicle is.

Then look at the route. Fixed daily kilometres with a predictable pattern suit electric. Variable work suits hybrid or diesel.

Then look at the contract term. If your contract has eight years to run, the answer may be different from an operator renewing next year.

For a lot of operators, full electric is the right answer eventually and the wrong answer this year. That is precisely the gap hybrid fills.