June 26, 2019

Johan Erlandsson

Last week we launched our new co-operation with the German Aerospace Center (DLR), when presenting a fuel cell system demonstrator for the Armadillo:

We have also done another fuel cell demonstrator in the past, together with RI.SE:

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In this article, we would like to explain why we are interested in this technology.

Without electric assist on the Armadillo cargo bike, it would not be a competitive or attractive tool in last mile delivery or field services. Today we use detachable li-ion batteries for energy storage. They are convenient to use, just plug in overnight or swap battery if you need more energy fast. The energy losses in the whole system are acceptable. Energy losses occur from transferring electricity in grid, from charging the batteries and from using them, around 25 % of the electricity is lost this way. Electricity is cheap, the cost of batteries are manageable and safety concerns are also manageable. There is risk of fires, but so far, not many incidents have been reported from ebikes in general and we have not yet had any incident ourselves.

Instead of batteries for energy storage, we could use hydrogen high pressure tanks and fuel cells. The energy is then stored as hydrogen and the hydrogen is converted to electricity and water in the fuel cell. However, fuel cell systems like these are not commercially available for cargo bikes. The refuelling process is also not really developed, infrastructure needs to be invested in to make it easy to use hydrogen. There are also much bigger energy losses compared to batteries, around 80 % of initial electricity is lost if taken through electrolysis, transport and use, according to Transport and Environment:

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There are also some safety concerns around carrying hydrogen in high pressure tanks in vehicles. Probably manageable (we hear the tanks can take a shotgun blast), but safety certifications and standards for hydrogen tanks cargo bikes are not really there yet.

So, why are we interested to try out hydrogen and fuel cells as energy storage, as it seems more complex and has much bigger system energy losses?

Well, batteries also has some drawbacks. Batteries require a lot of energy when produced, causing substantial CO2 emissions as electricity mixes are nowhere near clean on any continent. Limited and environmentally problematic metals are required, like lithium and cobalt. And while it is true that the energy losses look far worse for the hydrogen/fuel cell system than the battery, the hydrogen has the advantage that it can be produced and stored when there is a surplus of electricity, e.g. when wind mills produce more electricity than is currently consumed. Of course, batteries could also be used as this type of energy storage, but then a lot of batteries are needed and as already pointed out, they are a bit problematic to produce. Also, hydrogen is sometimes a by-product from the industry and there are even ideas on how to produce hydrogen from plastic waste and algae. So, there is a possibility that hydrogen, or some other energy carrier, could be sustainably produced from other sources than grid electricity, and there is no or at least substantially less need for rare or problematic metals. For Velove, this is enough reason to help out to develop fuel cell systems. We do not know if this is the energy storage of the future, but it definitely is worth a shot. Climate crisis is here and we need to come up with all sorts of solutions to solve this huge challenge and batteries are not yet the perfect solution.

There are also a couple of potential functional advantages that could be interesting. We might be able to carry more energy, which would enable us to run auxiliary modules with high energy consumption on the cargo bike. There is also a chance fuel cells can work better than batteries in extremely cold temperatures.