[dlcarrier]

Lithium cobalt batteries have great specific power and energy, at a reasonable price per watt-hour, but there's a lot of trade-offs. It's been around a long time, so it's easy to manufacture.

Lithium iron phosphate batteries have lower specific power and energy, often making them too heavy for automotive use, but they have a great price per watt-hour, so they're getting enough use that they're becoming easier to manufacture, which is making them even more affordable and increasing the specific power and energy as new variations are developed.

Public transit busses are very large, don't carry a lot of weight, and need to charge and operate in cold areas, so sodium ion batteries are the best option, despite their low specific power and energy. They also theoretically have an even lower price per watt-hour, but they have so little adoption that there isn't any cost optimized manufacturing. They're absolutely what's needed for busses, and are also great for battery backup in cold climates, but as with lithium iron phosphate, it will take some time for them to be viable.

Early adopters are what makes technology happen, but they have to deal with under-performance and high costs. We may have to wait for the technology to mature, before it is practical for public infrastructure.