This is a long piece by the great Dave Roberts in Vox, worth scanning at the very least, but the upshot is that as battery technology has leaped forward the market for electric buses is on the way to exploding.

Cities are going to be replacing their entire diesel fleets.  But these BEBs are better than the natural gas powered buses too.  Air pollution kills 6.5 million people a year around the world, with particulates from diesel engines being the largest offender.  The world is urbanizing and those urban managers have caught onto mass transit as a defining asset of the better places to live.  Quiet buses with no tail emissions are just what cities need, everywhere!

Finally, electric buses are also just a much, much nicer experience — lower to the ground, roomier (diesel engines take up lots of space), not choked with the smell of fuel, and quieter, indeed close to silent. It is difficult to quantify the impacts of noise pollution in urban areas, but, well, imagine a dense urban area without big diesel engines roaring to life every few seconds. It would be nice.

More than nice.  Kind of essential.