Email of the day - on battery powered flight:
Comment of the Day

May 21 2019

Commentary by Eoin Treacy

Email of the day - on battery powered flight:

I loved Lex’s tongue-in-cheek view of lithium-on batteries. A useful energy density chart that shows where lithium-ion batteries are - roughly in between lead batteries and liquid hydrogen.

Eoin Treacy's view

Thank you for this story and I also enjoyed the tongue and cheek nature of the energy density comparisons. I suppose it is no longer politically correct to point out that whale blubber has about 87% the specific density of kerosene which is better than lithium ion batteries. If that could be artificially replicated, we really could see whales fly.

Fun aside, the most important thing about the chart in this article is that both the x and y axes are depicted in log scale. It is orders of magnitude leap to get from where lithium ion batteries are today to the specific energy of kerosene. The reason SpaceX used LOX/RP-1 (rocket grade kerosene) as fuel for the Falcon Heavy is because it sits at the top of the specific energy table.

Cryogenic hydrogen is where the most ambitious renewable solutions are aiming. That is unlikely to be necessary to get small passenger electric aircraft into the market and we may see more hybrid solutions like Boeing pioneered with the Dreamliner. However purely electric long-haul flights are going to need new technology.

This article from Atlas highlights the fact that research into these kinds of solutions is ongoing but it is still early days. 

However, it is worth considering that clouds are insulators and the only time all air traffic was grounded in the USA was in the couple of days after 9/11. Without thousands of planes in the air and their associated contrails, the USA experienced some of the clearest weather in recorded history. That is something to ponder when people debate the priorities in terms of anti-warming measures and innovations that need to be funded.

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