GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Fuel Cells versus Micro combined heat and power

MICHAEL CHANDLER | Posted in Green Products and Materials on

Occasionally I get questions about fuel cells (as an alternative to solar PV particularly.)
I recently looked at a comparison between the Honda Freewatt CHP and the ClearEdge Fuel cell. Either way they are still primarily natural gas powered generators.

The Clearedge 5 fuel cell looks like it costs $50,000 and generates 35-40% eff electric with 55% heat from Natural Gas, producing 5KW / hour electric and 20 Kbtu/hr in heat I’m not clear if the heat output is hydronic or hot air. Hard to store hot air.

The Honda FreeWatt Micro CHP looks like it costs around $22,000 and seems to be primarily a 95% eff 12 kBTUh heater that secondarily produces 1.2 KWh electricity. The hydronic system can serve for both Domestic hot water and space heating.

So two FreeWatts would kick out 24 kBTUh heat and 2.4 kWh electricity for $44,000 at 95% eff
and one Clearedge would do 20 kBTUh heat and 5 kWh electric for $50,000 at similar efficiency.

So it looks like the fuel cell does have a better electricity-to-heat ratio. Off hand it seems that a 10 kBTUh / 2.5 kWh fuel cell would be a better match for the projects I see.

Does this seem right to folks who have experience with these systems?
Do any utilities offer net metering for fuel cells or micro CHP?
Just trying to get a handle on the options and capacities here.

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. WilliamLi | | #1

    BC Hydro (Canada, province of British Columbia) offers net metering for "clean energy" sources including cogeneration and fuel cells. ( Unlike in Ontario and some other jurisdictions, the current net metering rate for extra power is only at 8.16 cents per kWh (vs. Step 1 rate of 6.27 cents per kWh for the first 675 kWh/mth & Step 2 rate of 8.78 cents per kWh after that), as opposed to some much higher feed-in-tariff.
    Natural gas in this region (Terasen Gas -- Vancouver BC) works out to around 3.9 cents per kWh ($10.84/GJ) before value-added tax (HST), including delivery charges and carbon tax per GJ consumed, and not including basic per-day hookup charge. Not much of a spread.
    Using some numbers cadged from my house (92 GJ/yr, pre-envelope improvements, but after the 95% AFUE combi-boiler went in), the ClearEdge would be running about 12 hours a day on average, so generating about 60 kWh per day. Consumption here is about 15 kWh/day on average, which puts the simple payback out to around 73 years assuming rates stay the same (which they won't; electricity rates have already been proposed as going up a bit over 7% over the next few years) vs. no replacement. If you spot $15k installed for a high efficiency boiler system, simple payback comes down to about 51 years.
    The main problem I can see with the cogeneration economics is that if i invest (or build new) with lower heat requirements, the generated electricity also goes down, thus lengthening my payback period unless I do something arguably perverse like running the fuel cell or cogenerator 24/7 and shunting the gobs of extra heat...somewhere (heat my neighbour's house, maybe? ;> )... so I can sell electricity to the utility to pay for my equipment, taking the simple payback down to a mere 34 years (24 years including a boiler replacement).
    Michael, I'm curious how you're pitching these systems, and under what circumstances? What sort of spread in the utility rates (gas & electricity) do you have for your clients?

  2. GBA Editor
    Martin Holladay | | #2

    I agree with William Li: the payback periods are way too long to make any sense.

    I repeat my old mantra: take the $40,000 you would have invested in fancy equipment and use it to build a better envelope.

    I have looked into the FreeWatt. If you spend $22,000 on the FreeWatt, you get a 1.2-kW generator along with your heating plant. But you also have to maintain an internal combustion engine: spark plugs, oil changes, and trips to the mechanic. (It's a big piece of equipment in your basement, so you can't put it in your pickup truck.)

    I have a Honda gas-powered generator with all of the same problems (change the spark plug, change the oil, and occasionally take the generator to the mechanic). But my generator produces 5 kW and it only cost me $1,900.


    To be clear. Im not pitching or promoting these systems. Just trying to get better information to help clients who have heard great things about them put them on the proper context. So maybe the right answer is that you really need a huge heating demand like an Olympic pool to make this work. They seem not to realize how much gas they consume and how much of the output is heat.
    Yesterday I had a client tell me they were thinking of upgrading their roof to Energy Star listed shingles for $5,000 it was pretty easy to show that they would be better off putting that money into increased attic insulation. Some questions I have more of a challenge with, specifically the ground source heat pump and fuel cell questions as the equipment is so complex and the sales forces so avid that it is more difficult to show that the claims and assumptions don't hold water.

  4. David Meiland | | #4

    First of all, this is not a "fuel cell", is it? It's a generator that harvests most of the waste heat of the combustion process for use in the building. That's a great idea, but you would have to run the genny and use the power (or charge batteries with it) whenever you want heat (or somehow store the heat?). I can see limited applications for this, maybe residential in very cold climates where heating happens 12 months of the year, and definitely in large buildings where a LOT of energy is used for both heat and electricity.

    Overall, great concept. Distributed electrical generation using NG wastes a ridiculous amount of energy. An astronaut with an infrared camera would be blinded looking at the plumes of heat rising from our power plants. Burning the fuel locally and using that heat in the building makes a lot more sense, and avoids heating all those long transmission lines.

    Roughly a year ago I read a short piece in the Economist magazine about research into generating electricity directly from waste heat. Sell me one of those, I'll wrap it around my propane stove flue.

  5. user-757117 | | #5

    Roughly a year ago I read a short piece in the Economist magazine about research into generating electricity directly from waste heat. Sell me one of those, I'll wrap it around my propane stove flue.

    I wouldn't hold my breath for that one. Turning one form of energy into another drives down the EROEI. Better to think of a way to use the waste heat as heat - challenging as that may be at the scale of a thermoelectric power plant.

  6. Riversong | | #6

    Forget fuel cells and CHP. Zero Point energy is the way to go. Tesla was about to demonstrate this in 1900 when his financier, JP Morgan, withdrew funding and bankrupted him. Tesla died a pauper in NYC and the FBI seized his records.

    Telsa was the greatest inventor who ever lived and is considered the father of the 20th century. Among his contributions were:

    Tesla Coil
    Tesla Bladeless Turbine and Pump
    Alternating Current (AC), Polyphase current and high voltage rectification
    Radio (11 years before Marconi – Supreme Court awarded him the patent posthumously)
    Brushless Synchronous and AC Induction Motors
    Wireless Power Transmission
    Wireless Telegraphy
    Cellular Technology
    Telephone Repeater
    Flourescent Lights
    Hydroelectric Generators
    Vacuum Tubes
    Arc light systems
    Neon lights
    Directed Energy (particle beam) Weapons (seized and classified by J. Edgar Hoover)
    Disinfectant Treatment of Water with Ozone
    Robotics and the "AND" logic gate
    Wireless Remote Control (Tesla demonstrated a wireless controlled boat 1898)
    VTOL aircraft
    Concepts for electric vehicles
    Dynamic theory of gravity
    A Unified Field Theory – completing Einstein's work (though never published before death)

    The most reputable organization working on zero-point or over-unity devices is the Orion Project, led by Dr. Steven M. Greer, who has briefed the White House and Congress on these issues.

    Orion Project
    Briefing Paper

  7. Roy Harmon | | #7

    That is some really interesting stuff Robert, what are the odds of getting the people percieved to be at the top to persue these technologies today?

    Michael, Do these units actually contain fuel cells of some sort?

  8. user-757117 | | #9

    Occasionally I get questions about fuel cells (as an alternative to solar PV particularly.)

    Interesting conversation.
    Another way to consider these questions might be to determine if the alternative [to a form of renewable energy like PV] should also be a form of renewable energy.
    If so, micro CHP or fuel cells are not options.
    (I only mention this because there are many people out there who won't necesarily know what technologies offer renewable energy - some people think hydrogen fuel cells are a form of renewable energy for example.)

    Edited to include (bracketed portion).

  9. Riversong | | #10


  10. wjrobinson | | #11

    To me it looks like a Triangle tube modcon has the same efficiency as the FreeWatt at way less money and far more useful controllable output.

    The FreeWatt is (as usual for marketing)... exactly the opposite. For my two above examples to be equal I have to add both the energy of the heat generated and the electric generated of the "not" FreeWatt together to equal the Triangle Tube output of heat energy alone.

  11. MICHAEL CHANDLER | | #12

    A proton exchange membrane fuel cell is sort of like a battery that you can add chemicals to to maintain the continual production of electricity (and heat).

    The chemicals you add can be hydrogen or methane, (natural gas) and water or chlorine. The purity of the feed stock is very important as there are precious elements in the Anodes and Cathodes etc. The feed rate is very inflexible the membrane has to stay wet to stay flexible. Some of them operate at such high temperatures that collecting the electricity is an issue due to wire connections melting and corroding.

    They are sold by secretive companies with goofy You-Tube pitches that make them look like perpetual motion machine meets sorcerers stone alchemy. There is potential there but the hype is pretty thick and tax credits are involved and I have a few clients who are intrigued with the potential which is why I posted the question here.

    There is really interesting stuff happening in the green tech world all the time. Check out some of the stuff happening in Asia at new stuff that wouldn't immediately be thought possible is happening in battery design these days and I'm not knocking fuel cells out of the running yet, just like to see more electricity and less heat.

    I also think we need distributed micro-generation rather than smart grid technology. Every concrete plant should be generating electricity and feeding it into the grid. I wonder if it would be possible to use heat pump technology on concentrate waste heat streams to the point that we could use it for making electricity.

    The future could be brighter than we think, if we keep thinking.

  12. Riversong | | #13

    Well, if all the teeming millions who live near the coast would employ hydro-thermal heat pumps to use ocean temperatures to heat their homes, then we could reverse sea temperature rise, restore the corals and bring back the cod.

    Or not.

  13. WilliamLi | | #14

    In its defence, fuel cell technology is somewhat more real than any of the "overunity" (ROFL) systems which defy the laws of physics. One company which has got fairly decent technology but really horrifically bad commercialization is the local company Ballard Power, which lists among its applications residential cogeneration ( They recently produced their one millionth membrane electrode assembly (

    The bigger problem with the market overall has been transitioning over from hydrogen as a fuel to other, more readily-available fuels such as natural gas. All PEMs work by passing hydrogen through. Natural gas devices such as the ClearEdge one have a fuel reformer in front of the fuel cell itself to break out hydrogen from the natural gas. See ( for some more reading about how this process works.

    What Ballard and others in the market realized is that fuel cells are a no-go for the car industry -- too much hydrogen infrastructure to be built up -- so they've all been scrambling to reposition themselves for the stationary generation market away from trying to just do hydrogen automobiles. In the meantime, these things just cost $$$$$, and having to use natural gas rather than hydrogen pulls down efficiency and increases pollution due to the fuel reformer step.

    The attraction of fuel cell technology vs. big grid distribution, though, is that piping natural gas one does not lose as much energy as stuffing electricity down big metallic power lines over long distances. It's all a bit situational, of course, depending on where in the world you are.

  14. user-659915 | | #15

    Zero Point Energy: if it weren't for a government conspiracy we'd have free, unlimited electricity for all.

  15. 2tePuaao2B | | #16

    Thanks for this post Michael.

  16. user-757117 | | #17

    What Ballard and others in the market realized is that fuel cells are a no-go for the car industry

    That's interesting William.
    I grew up in the Lower Mainland and remember all the hype from Ballard - they've been trying to crack that nut since the 90s.
    Hopefully this is a sign that the nonsensical idea of a "hydrogen economy" is finally going away.

  17. user-659915 | | #18

    Sorry for the sarcasm in my last two posts, folks. From time to time I do get stuff like this in one way or another from clients or potential clients who have heard about some product or system that is being promoted as a free lunch in some form or another. CHP has been around for at least forty years to my knowledge and has been successful at utility scale where there is some consistent use for the spare heat, either as process heat for industry or for district heating in climates with a long and predictable heating season. Some, like the CHP plant at UNC Chapel Hill are even able to deploy spare heat in summer for refrigeration, if that sound complicated it is, just look up absorption chillers. The technology does not scale down well however: manufacturers have tried to achieve the same efficiencies at the single-home scale over a similar period with the unsatisfactory ROI results that William Li has already clearly shown. Fuel cells have followed a similar trajectory. Martin's supremely sensible response to such gadgetry is the one which I give my clients: you'll get far better ROI and EROEI by spending the money on enclosure improvements. They can choose to ignore this advice - this usually means they end up working with someone else - but that's the reality.

  18. wjrobinson | | #19

    Plug power is near me. An engineer from there said they were flooded with free money for years, and what was wanted was silly hard to invent. Fuel cells take a fuel energy and change it to electricity and heat. Not at all the same as solar or wind or wave or hydro. They are good for specialized niche energy applications. You may own a Duracell one for a week long cell phone battery slash hand warmer someday. Lol

  19. WilliamLi | | #20

    At this time, I'd tend to agree with AJ and James on the applicability of fuel cells. The major issues with fuel cells are the heat of operation, service life, capital cost of materials, fuel requirement, ...
    As AJ says, in niche situations, fuel cells are better. I'd say the more apt displacement comparison for a fuel cell would be against a propane, NG, or gas generator rather than actual green technologies like solar, wind, or hydro, as the nominal efficiency of what you get out is better for the fuel cell vs. a plain-Jane generator. But, the service life and 10x capital cost difference (vs. regular generators at small scale) is a real barrier. I worked with some of the physicists who ended up at Ballard, and shamefully own some way-below-water stock, but have to say that this technology is something of an ugly stepchild.
    fyi, here is another link on fuel cell technologies and efficiency:

  20. WilliamLi | | #21

    The "hydrogen economy" depends on not only infrastructure, but also, more importantly, a way of producing hydrogen which does not make hydrogen so much more expensive than other fuels. Other than vaguely sci-fi-ish schemes like big solar mirrors, direct hydrogen production currently burns too much energy vs. what you end up getting out at the other end of the pipeline.
    Likewise, the fuel reformer step which locally does this (convert NG, etc. to hydrogen) imposes a big efficiency penalty which forces the overall fuel cell into a bit of a niche, being only somewhat to moderately more efficient than simply burning the source fuel (NG), dependent on scale.
    Ballard principals have been quoted as directly stating the above.
    So yeah, hydrogen economy is pretty dead and was never alive.

  21. user-757117 | | #22

    Not sure what that GBA graphic is all about. Click on it to see the chart.

  22. user-757117 | | #23

    I couldn't agree more.
    I'm just waiting for people to stop talking about it. Remember the push for hydrogen filling stations before the 2010 winter games? A showcase of greenwashing... or at best of misguided pipe-dreams.
    Here's an interesting chart from the IEEE that compares the efficiency of hydrogen (after electrolysis) to straight electric in transportation:

  23. lionelAnonymous | | #24

    To burn oil is a crime considering all its uses,but since we do why do we do it so inefficently ,example firing a one gallon nozzel when a 0.40 will do the same job and has the potential to save a lot of # 2 fuel oil.I heat my 4 apartment 100 year old house one in the attic with a 0.4 .Located in Amherst N.S. Canada.The theory of burning oil is to burn the oil 24/7 and modulate it to match the heat loss.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |