* Fuel cells have a 150-year history and the science is well understood. Solid Oxide Fuel Cell technology, Bloom’s focus, is also not a new concept.
* The solid oxide fuel cell firm is focusing on a new business model by engaging customers in a power purchase agreement (PPA). With this approach, Bloom might keep the fuel cell themselves (or own it in a joint venture with a utility) and sell the power. PPAs have been effective financing tools for solar, wind and some biomass/manure firms. PPAs also eliminate any fears about maintenance and upkeep.
* Bloom customers include eBay, Google, Lockheed, Wal-Mart, Staples and the CIA. Backlog and sales are in the $2 billion range.
Conservative assumptions based on the video: (All amounts in US $).
– $800,000 for a Bloom Box that generates power for 100 American Households
– American household energy usage is 10,000 kWh per year (10,600 in 2001)
– Bloom Box hence generates 1 million kwh per year at an investment cost of $800,000
– Production costs US for electricity from natural gas for residential use is $ 0.10 per kwh (http://www.eia.doe.gov/cneaf/electricity/epm/table5_3.html)
– costs for 1000 cubic foot of natural gas for residential use is 12 dollars (http://tonto.eia.doe.gov/dnav/ng/ng_pri_sum_dcu_nus_m.htm)
– 1 cubic foot of natural gas has an energy content of 1,034 BTU
– 1 kWh is equivalent to 3413 BTU spent in an hour
– Bloom Box can turn natural gas into electricity at an 80% conversion efficiency
– Costs per year for 1 million kWh from natural gas from centralized power sources is $100,000.
– 1000 cubic foot of natural gas gives 1,034,000 BTU which can be converted at 80% efficiency, hence 827,200 BTU of power which is equivalent to 242 kWh, costing $12 for the fuel. So 12/242 = $ 0.05 per kWh incorporating fuel costs only. Which amounts to a total fuel cost of $50,000 for 1 million kWh.
At an investment cost of $800,000 dollars it would take approximately 15 years (800,000 / 50,000) to pay back investments, excluding the costs of connecting to the grid.
Bloom eventually hopes to make home units that cost around $3,000. That would be a lot less than the ones currently sold by Panasonic in Japan or ClearEdge Power in California. ClearEdge sells its 5 kilowatt system for $56,000. Ceres Power in England comes out with fuel cells for residences next year that in part are made from diesel engine components to cut costs.
The project’s road map calls for a price tag of around $9000 by 2010 or 2011; Matsushita says it hopes to get its selling price to energy companies down to approximately $5500 by 2015.
Japan’s regional energy suppliers have installed just 3700 units for field testing in the METI program. By 2010 METI expects from 20,000 to 100,000 systems to be installed
Kyocera may have a better chance of reducing costs in a solid-oxide fuel cell it’s been developing, also with METI support, because that system does not use platinum.
Panasonic, Ceres Power and ClearEdge Power have developed fuel cells that can do this and Panasonic and ClearEdge already sell such fuel cells. They aren’t as large as Bloom’s fuel cells and may produce more heat and less electricity than Bloom’s, but they roughly do the same thing. (Ceres will produce a cell that produces 50 percent electricity and 50 percent heat–a fairly impressive ratio, particularly because electricity has a higher value.) And all of these fuel cells can provide energy in a more efficient manner than the grid, so even if they emit carbon dioxide–and the ones from Panasonic, ClearEdge and Ceres do–you get a lot more power for the amount of greenhouse gases generated than you ordinarily would
The present invention is generally directed to Solid Oxide Fuel Cells (SOFC’s), and more specifically to reversible SOFC’s referred to as Solid Oxide Regenerative Fuel Cells (SORFC’s).
The overall potential efficiency of the SORFC is restrained by a charging voltage for very high efficiency which is below the thermal neutral voltage. This means that heat must be added to the SORFC operating in the charge or electrolysis mode in order to keep it at operational temperature to operate at these voltage levels.
There is an abundance of extra heat generated during the SORFC discharge or fuel cell mode. One method of obtaining a high SORFC round trip efficiency is to store the extra heat produced in the discharge mode and use that heat to maintain the system temperature during the charge mode. This requires an appropriate high heat capacity material to accomplish adequate heat storage. Such a heat storage system is appropriate for a very high efficiency SORFC based on a water cycle. In such a cycle, water is electrolyzed during the charge or electrolysis mode with the product hydrogen stored and the product oxygen discharged to ambient. During the discharge or fuel cell mode of the SORFC based on the water cycle, the hydrogen and oxygen from air are reacted to produce power and water. However, the heat storage material increases system mass and complexity, which may be disadvantageous for certain applications.
A method of operating a terrestrial solid oxide regenerative fuel cell system comprising: operating the solid oxide regenerative fuel cell system in a fuel cell mode to generate power; and operating the solid oxide regenerative fuel cell system in an electrolysis mode to generate oxygen and a hydrocarbon fuel; wherein: the step of operating the solid oxide regenerative fuel cell system in the electrolysis mode comprises providing power, carbon dioxide and water vapor to the solid oxide regenerative fuel cell and generating the oxygen and the hydrocarbon fuel; the step of operating the solid oxide regenerative fuel cell system in the fuel cell mode comprises providing oxidizer and the hydrocarbon fuel to the solid oxide regenerative fuel cell and releasing carbon dioxide and water vapor from the solid oxide regenerative fuel cell; the hydrocarbon fuel comprises methane; and the step of generating the oxygen and the hydrocarbon fuel comprises: providing hydrogen and carbon monoxide emitted from the solid oxide regenerative fuel cell into a Sabatier reactor; and converting the hydrogen and carbon monoxide to methane and water vapor in the Sabatier reactor.
Many advantages accrue from the SORFC system’s electrolyzation of not only water but carbon dioxide as well in an electrolysis mode. These advantages include generating a hydrocarbon fuel in addition to oxygen, converting hydrogen and carbon monoxide byproducts into useful storable hydrocarbon fuel and excess heat which sustains the electrolysis reaction in the SORFC, consumption of accumulated carbon dioxide, and enhancing the overall efficiency of the process. For example, the hydrocarbon fuel may be a methane fuel, a mixture of methane and other fuels or hydrocarbon fuels other than methane. Preferably, the stored volumes of all the accumulated fluids (e.g. oxygen, carbon dioxide, and methane) are minimized by liquefaction using a primary electrical energy source (i.e., a source other than the SORFC) or by using the power generated by the SORFC. Carbon dioxide may also be liquefied using the heat for vaporizing of the oxygen and methane. Alternatively, if desired, the reactants, such as fuel, oxygen and carbon dioxide may be stored in gas rather than liquid form.