Residential Fuel Cells - Natural Gas

ClearEdge Fuel Cell

ClearEdge Fuel Cell

We've covered the common types of alternative energy for your home - Solar PV, Solar Thermal, Small Wind, even Biomass - but until now we haven't even had a category for the residential fuel cell, much less a natural gas fuel cell.  The main reason for this is that up until now, there haven't been any options for residential customers who want to use a fuel cell to power their home!  Reinforcing that point is that a Google search for "natural gas fuel cells" turns up this very informative paper from the Department on Energy titled "Natural Gas Fuel Cells: Technology for improving energy efficiency while reducing environmental emissions"...the catch: it was written in 1995!

Thanks to several new companies arriving on the market this technology is getting a 21st century makeover.

The excellent blog Earth2Tech, which focuses on clean energy and smart grid technology companies, recently had two great entries on companies targeting residential Fuel Cells: Bloom Energy and ClearEdge Power.

The fuel cells you are used to hearing about in cars use pure hydrogen as the primary fuel, but both of these companies are using natural gas to power their fuel cell.  Why natural gas?  Because many consumers already have natural gas coming into their home (to cook with, heat their water, heat their air).  Natural gas is primarily made up of Methane, whose molecule is CH4 (1 Carbon atom and 4 Hydrogen atoms).  It is the best choice to use in residential fuel cells because it is usually easier to strip out the one carbon atom and be left with the hydrogen, than it is to find a hydrogen filling station (although that may be changing).   The fuel cell stack (see picture at top of article for a schematic of ClearEdge's fuel cell) runs off the pure hydrogen after the natural gas that comes into the unit is reformed (the carbon atom stripped away).

Bloom Energy

This company has massive funding from Kleiner Perkins Caufield & Byers  (which invests in several Green Tech ventures and Al Gore works with them) and has been generating a lot of buzz. This NY Times article on green capitalism has a great synopsis of how a Bloom Energy residential unit is performing in a trial at the University of Tennessee :

Over the past two and a half years, engineers at the University of Tennessee in Chattanooga have been testing a five-kilowatt Bloom box, which looks like a squat refrigerator and produces about as much electricity as a typical home requires. And at this point there seems little doubt that the idea K. R. Sridhar pitched to Kleiner in 2001 has become a high-functioning machine. “We installed one of his first units here to assess its durability and performance, to see if it matched the claims,” Henry McDonald, a professor at Tennessee who is overseeing the Bloom box, says. McDonald ran the box nonstop on natural gas for 6,000 hours, and its performance beat expectations. In everyday terms, the box was twice as efficient as a boiler burning natural gas, and its carbon emissions were 60 percent lower.

Until Bloom Energy comes out with more news about what they are doing (or actually reveals anything) then it's tough to speculate much more.

ClearEdge Power

Unlike Bloom Energy, ClearEdge actually has a picture of their product!  They have a nice, concise description of how their fuel cell works:

The Fuel Processor converts natural gas into ultra-clean hydrogen through a catalytic process, as opposed to burning the natural gas, which dramatically reduces pollutants. The hydrogen is processed through a Fuel Cell Stack, creating direct current (DC) power and heat. The Power Conditioning Unit converts the DC electricity into alternating current (AC), which then ties directly to the main electrical panel, providing steady continuous power for your electricity needs. The heat produced by the fuel cell is moved to the building through a heat exchanger supplying a continuous source of heating for hot water or space heating.

So this unit will create electricity AND heat for your home, making it that much more efficient.

In their FAQ section under the "How much does the CleanEdge5 cost" they say:

The list price for the ClearEdge5 is actually less expensive than equivalent residential solar PV systems, based on production. A major advantage over solar, the ClearEdge5 generates eleven times more energy than the same size solar installation. For the same capital investment, the ClearEdge5 gives you 90 MWh of annual combined electricity and heat, compared to approximately 8MWh generated by a 5kW solar system. Operating costs for the CE5 are as low as 6.0¢ per kWh based on $1.20 per therm for natural gas, assuming full electrical and heat utilization.

But I must point out two key points:

  1. It is a little unfair to compare a system (the fuel cell)  that - while efficient - still relies on fossil fuel as it's source of power to a system that (solar) only relies on sunshine.  I guess it is fair if CleanEdge is only assuming that solar buyers are only buying a solar system for the long-term financial payback over the utility grid, but this usually isn't the case.  While financial aspects usually make or break a decision to go solar PV, for the most part people install solar because the energy is completely renewable and only reliant on a free source of power - the sun.  But I understand that if buyers only want to buy a system that will save them money over the very long term, then yes, CleanEdge has an advantage over solar.
  2. Potential buyers, make sure you are aware that while the annual energy output of this fuel cell is more than a 5 kW solar system, a solar system has negligible operating costs!  With the fuel cell, you still have to pay for the system AND the natural gas it uses.  With a solar/wind system, you just pay for the system, and the fuel is free!

With that said, I am still a fan of the residential natural gas fuel cell.  If you have access to natural gas and you do need electricity and heat in your home (just about everyone), then I think this is a great technology. Improving the picture for residential fuel cells is that there is a Federal Tax incentive for them.  From the ClearEdge Rebates and Incentives page:

A federal fuel cell tax credit, an extension of the Investment Tax Credit (ITC), adds additional savings. A tax credit is different from a tax deduction, which subtracts money from gross income before tax liability is calculated. The ITC actually entitles the taxpayer to subtract the amount of the credit—dollar-for-dollar—from total federal tax liability.

For Home Owners, the fuel cell extension of the ITC will credit 30% of the cost of the unit, up to $1,000 per kW. When a ClearEdge5 is installed at a home, it qualifies for a $5000 total credit.

I would love to see some long-term payback studies! I still have some technical questions about these devices and I'd like to see a line diagram showing how one of these units connects to the home's electrical panel and how the heat is transferred to the hot water heater/furnace, but I'm sure more information will become available as they gain in popularity.  It is important to point out that these units are meant to supplement grid power, not replace it.

I look forward to seeing more from this section of alternative energy (though I can't call it renewable energy since it relies on fossil fuel, but it is energy).  I'm a fan of all technologies that make us more efficient in our daily lives and result in us using less coal to power our national grid.

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Ah! But what if your gas comes from a bio-digester in the back yard?
ckmapawatt's picture
That would be great! But could you produce enough gas to make a difference?
Everyone is speaking of NG as costly, "why" it can be made at your home thus giving you your gas for your generator in which will power your home, heat your water, and power your A/C unit. The question is will the government start taxing us on this power created like they do in Europe? And the laws set in place by the government about gas creation on personal property will they be lifted?
ckmapawatt's picture
Tod, are you talking about biogas made from stuff like human waste?
people look for the use of hidrogen not only for energy production but for production of METHANOL that saves tons of CO2 from the atmosphere
Will buy on if it works and is a reasonable investment! Respond
Paul, I've got one on order for August 2011 installation in my pool house equipment vault, but I haven't seen one in action. How noisy is it? Is your's outdoors or indoors? Has it been reliable? Thanks, Jerry
Just to reinforce what Chris, making some assumptions (below) I might guesstimate that a 5 KW solar array might produce between 60,000 and 90,000 kwhrs. annually. Assumptions: * that the 5 KW rating reflects what can be produced during peak sunlight hours at that site (probably a bad assumpmtion) * that, on clear days, you can get about 6 hours of that peak production * that in your area you get about 300 clear days (out of 365) in a year Using those numbers, 5 KW x 6 hours per day = 30 kwhrs per day, x 300 clear days per year = 90,000 kwhrs per year. Assuming some inefficiency, I reduce the guesstimate to 60,000 kwhrs per year. This also assumes you can do something with the electricity during those 6 hours of peak production per day--either charge it into batteries, or feed it back to the local electric grid (utility).
to rhkramer Your math is incorrect. 30 x 300 = 9,000; NOT 90,000. Author's assumptions are good then.
I am interested in methane fuel cells because we have 420,000 worthless stripper wells with sufficient methane to make electricty.


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