Updated March 2016
Fuel cells for caravans are non-polluting and ultra-quiet. Available since 2010 their close to A$10,000 (plus high fuel cost) still excludes general RV use.
Fuel cells are unusual in being part generator/part battery that use hydrogen and oxygen to generate electricity. Theoretically any fossil fuel will do. Large scale fuel cells for space, military and industrial use have existed since the 1950s. Many companies produce them – but typically at huge cost. The major longer term market is for providing affordable small-scale power in third world countries. This, as with fuel cells for caravans, necessitates a running cost of less than A$1.0 per generated kilowatt hour. Plus a unit cost of less than A$1000/kW.
Fuel cells for caravans – EFOY
Now, the only currently available fuel cells made for caravans and boat use, the EFOY unit, uses methanol. It initially converts the fuel into hydrogen. Those used for caravans were initially priced at around A$3500 but, around, 2012, escalated close to $10,000. Those currently marketed in Australia produce 130 amp hour (1600 watt hours/day) and 180 amp hour (220 watt hours/day). They are about the size of a jerry can, and weigh 7-8 kg. As with all fuel cells they can be run 24 hours a day if necessary.
The EFOY units require pre-packaged ethanol canisters that have limited distribution. Consumption is about 0.9 litres per 1.0 kW/h of methanol (that is supplied in purpose-made 5.0 and 10 litre canisters). Locally available (claimed to be high quality) methanol is available in 20 litre drums at a fraction of the price, but as ultra high quality fuel is stated to be essential, warranty is invalidated unless the EFOY supplied fuel is used. There are also even more costly industrial (and also military specification) versions of the EFOY unit.
The EFOY methanol-powered fuel cell. Pic: Webasto.
Fuel cells for caravans – Truma VeGA (now defunct)
The seemingly promising Truma VeGA LP gas unit was originally announced for delivery in 2007. This became 2008, 2009, 2010, and then ‘early 2011’. Orders finally began to be accepted (in Europe) for installation in new vehicles in 2013. Its claimed maximum daily output was about 6000 Wh/day. It generated about 23 kWh from a 9 kg LPG cylinder, so running costs were comparable with a petrol generator. The unit itself however cost over A$12,000. By 2015 this proved to be not viable.
Truma subsidised the product for a time, but was unable to attract significant sales. Finally, massive costs increases in key components caused Truma to cease production of the VeGA fuel cell – and to cease all further work in the fuel cell area.
Installation mostly consists of providing a suitably ventilated space. The exhaust is claimed to be virtually pollution free. It is mainly pure water vapour.
The EFOY units need a battery to cope with any load in excess of their maximum output. Long term battery storage however is not required (because the energy is stored far more efficiently in the fuel these units run from). Because of their ability to deliver high current, starter batteries are fine. If space and weight is at a premium, the smaller and lighter lithium-ion batteries should work well.
Fuel cells for caravans – an economic alternative?
A fuel cell’s ability to provide silent, non-polluting electricity is a major bonus, but their operating cost is very high. Unless money is not an issue, they are probably best seen as a back-up for solar during times of low input. Not as the prime source of electrical energy.
Often-made comparisons with petrol generators are flawed because such generators are only fuel efficient whilst under 50%-80% load. That works fine if that amount of energy can be used for battery charging. If used, as many are, for powering a small TV and a few LEDs at night, they use a hugely disproportionate amount of fuel. A small (50-150 watt) fuel cell’s consumption, however, is more or less proportional to the load at any time.
Whilst the Truma Vega outcome is a hugely costly failure, fuel cell technology has the potential to turn the world’s energy economy from petroleum based to hydrogen based. This requires massive changes but the benefits are equally huge – not least because hydrogen can be produced from renewable as well as other resources and also readily stored.
This is not simply conjecture. A research report (McCormick 2003) noted General Motors had looked at the feasibility of a US-wide infrastructure that would place a hydrogen pump within 3 km of 70% of the US population, plus every 40 km on most interstate roads at a then cost of US$10-15 billion. Since then, a major hydrogen pipe-line has been built in the Gulf states of the USA.
Right now, in the small boat and RV area, a fuel cell is best seen as a useful back-up for solar, and is ideal for that purpose as the units are in effect sophisticated battery chargers that can also run in parallel with solar input. On a larger scale, a 31 kWh/day natural gas powered unit is commercially available – cost is about $35,000.
How fuel cells work
How a typical fuel cell works. Pic: courtesy of Michegan Molecular Institute, USA.
As with individual cells in a conventional battery, fuel cell technology typically combines many cells – each producing a small amount of power. Each individual cells contain a positive electrode (the cathode) and a negative electrode (the anode) separated by a solid or liquid electrolyte. Hydrogen is fed to the anode and oxygen (from the air) is fed to the cathode. The hydrogen is split into positively charged protons, and negatively charged electrons via a platinum catalyst. The protons are able to flow to the cathode via an external circuit, thus producing usable electrical energy. The re-united protons and electrons combine with oxygen at the cathode.
Whilst the Truma Vega content is now invalid, more about the use of fuel cells in cabins, camper trailers, caravans and motor homes is included in my book (now in its third edition) Solar That Really Works! (for cabins and RVs). All that you need to know about RV electrics generally is in my (2013) Caravan & Motorhome Electrics. These books are bought globally – even auto electricians use them as working guides. My other books are the all-new Caravan & Motorhome Book, the Camper Trailer Book, and Solar Success (for home and property systems).
I seriously advise buying these books as their cost will be repaid multiple times by getting the system right first time. They are unusual in that the author (Bio) has both an engineering and a writing/publishing background of over 50 years. The books are both technically competent and written in plain English. The few technical terms used are likewise explained.