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Skeleton Technologies’ next-generation high-energy ultracapacitors to power Wrightbus’ hydrogen buses

Skeleton Technologies is partnering with Wrightbus to supply its next-generation high-energy ultracapacitor modules to power fuel-cell buses in the UK. The ultracapacitors’ two-times higher energy density is enabled by Skeleton’s latest material technology innovation, making them a valuable addition to hydrogen fuel cells in emissions-free transportation.

Since fuel cells are not able to recuperate the braking energy and re-use it for acceleration, they need efficient energy storage devices to improve overall system efficiency and total cost of ownership. Combining ultracapacitors and fuel cells will speed up the market adoption of hydrogen fuel cell vehicles.

Wrightbus is at the forefront of development of hydrogen vehicles and we are very excited to work with one of the most ambitious companies in the sector. We see a clear potential of 1000 buses in the next 5 years. Based on the technology and its underlying economics, we have reason to believe that all hydrogen powered trucks and buses could eventually adopt our products.

—Taavi Madiberk, CEO and co-founder of Skeleton Technologies

This is the first commercial release of Skeleton’s next-generation high-energy ultracapacitors, based on material technology innovation, which allows to combine the highest power density in the market with an energy density 2 times higher than the closest competitors, including Tesla.

Hybridization of fuel cell vehicles with ultracapacitors reduces the stress on fuel cells and benefits the vehicles’ fuel economy, allowing them to function more efficiently and increasing the overall range of the system. Wrightbus initial pilot testing is planned to be completed in 2021.

Wrightbus is a founding member of the H2Bus Consortium, announced in June 2019 and focused on deployment of at least 1,000 zero-emission Fuel Cell Electric Buses and related infrastructure in European cities at commercially competitive rates.

Earlier this year, the UK Government’s Department for Transport (DfT) announced a 5-year, £5-billion (US$6.4 billion) plan to enhance bus and bicycle infrastructure in the UK.



Why not use batteries for E buses. You can predict the range and work out the charging schedule.
Using H2 looks like green flag waving.
If they just wanted to reduce pollution and CO2, battery buses would have been just as good and probably cheaper.


Caps last and now FCs do too.
Lots of stop/go and miles requires longevity.

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The real value to the Skeleton Technologies Hybrid Ultracap will be in 12-volt electrical systems that run the air conditioner, windows, the stereo/infotainment system, the heating and all the other bits of a car that need power outside the powertrain itself. This includes all vehicles: BEV, PHEV, FCEV, and ICEV.


I think that it is much better to use the available money to build out Battery Electric transit buses first. There are about twice as energy efficient and probably cost less than 2/3 the cost of a fuel cell bus and will cost less to maintain and run. That way you get the maximum benefit for the money spent. Once all feasible Battery Electric routes are covered, then maybe the few remaining routes could use Fuel Cell buses but by this time the batteries may have improved sufficiently, so that it is a non issue.

Having said this, I am not against looking at all possible options and it may pay off to use Skeleton Technologies Ultracaps with batteries.

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