T-Pain Is On A Boat: [Electric Boats] The Hydrogen Fuel Option

Thursday, July 16, 2009

[Electric Boats] The Hydrogen Fuel Option

Hi all,

since there was some discussion of the hydrogen fuel cell option offered by
Ian Souter up in this neck of the woods, I thought I'd price out a few
items.

Mostly the system works like any other electrical system, so I'm going to
rattle these numbers off assuming you want enough hydrogen capacity to run
full-time off H2 in a boat similar to mine. First, we'll assume you're
running something like the Mars 8kW electric engine. This means you'll want
the 5kW stack, as a 2kW stack is unable to provide sufficient power to
maintain cruising speed indefinitely*. Assuming a fairly optimistic
efficiency of 50%, a 1kW fuel cell consumes about 60g of H2/hr. That means a
5kW stack will consume 300g/hr. Obviously running at lower speeds is going
to increase run time in the usual ways.

Now the painful part. The 5kW fuel cell stack will set you back $15,000.
Plus installation and taxes. Okay. The real problem (in my opinion) is the
cost of the hydrogen.

According to my research, the price of hydrogen in a cylinder is "fairly
stable at $100/kg". This means actually running your boat at 5kW will set
you back $30/hr.

A few notes for those who have managed to catch their breath. First, the
cost for a smaller fuel cell is proportionally smaller. If you can manage
with 2kW, you're looking at more like $6k for the fuel cell stack and more
like $10/hr to run at WOT. Fuel cells are (nearly) silent, and produce no
emissions (locally) except water vapor. The waste heat could and probably
should be used to supplement hot water or other heating needs, and on a boat
could probably be run through some kind of heat exchanger rather than
dissipated by fan as it is in most stock models. I've checked these numbers
with Ian, and he agreed with most of them but wanted confirmation from his
partner on the cost of hydrogen and I have not heard back yet. Perhaps they
know of some way to find cheap H2.

At any rate, the cost is plainly prohibitive. The real problem is not (just)
the capital cost, but that the ongoing cost of purchasing hydrogen fuel
vastly exceeds that of gasoline. Further, as H2 production comes from
industrial chemical processes the warm and fuzzy green feeling you get from
running alternative fuel is really only warm and fuzzy if you live (like I
do) somewhere with clean power generation.

Hope this helps people decide whether hydrogen is right for them.

-pvh

*: until the hydrogen runs out, anyway.

--
Peter van Hardenberg
Victoria, BC, Canada
"Everything was beautiful, and nothing hurt." -- Kurt Vonnegut

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