FuelCell Energy (FCE) is developing high-temperature fuel cells that can work with natural gas and coal plants to improve efficiency and cleaner energy. The Connecticut-based firm has developed a new type of fuel cell that uses molten carbonate electrolytes. This electrochemical cell can capture CO2 from a power plant’s flue gas while generating additional electricity from natural gas, coal, or other fuels. The company has more than 100 US fuel-cell patents, big-name partners, and a soaring stock price. What it doesn’t have yet are profits or a marquee project that shows its technology pays off at commercial scale.
A fuel cell is a device that generates electricity through an electrochemical reaction, not combustion. There are some who claim that producing heat from hydrogen without combustion is unique or magical.
Real energy solutions have measured metrics to determine if they are economic to replace the entire coal burner or to add the fuel cell along side the coal plant. Molten carbonate fuel cells are clearly defined in terms of science, engineering, economics and scalability. There are pretenders that are not defined and are not performing transparent engineering design and cost studies and are not working towards clarifying actual potential benefits.
Molten carbonate fuel cells (MCFCs) were developed for natural gas, biogas (produced as a result of anaerobic digestion or biomass gasification), and coal-based power plants for electrical utility, industrial, and military applications. MCFCs are high-temperature fuel cells that use an electrolyte composed of a molten carbonate salt mixture suspended in a porous, chemically inert ceramic matrix of beta-alumina solid electrolyte (BASE). Since they operate at extremely high temperatures of 650 °C (roughly 1,200 °F) and above, non-precious[dubious – discuss] metals can be used as catalysts at the anode and cathode, reducing costs.
Improved efficiency is another reason MCFCs offer significant cost reductions over phosphoric acid fuel cells (PAFCs). Molten carbonate fuel cells can reach efficiencies approaching 60%, considerably higher than the 37–42% efficiencies of a phosphoric acid fuel cell plant. When the waste heat is captured and used, overall fuel efficiencies can be as high as 85%
The threat of rapid depletion of fossil fuel reserves and the discharge of pollutants due to the depletion of these resources has had catastrophic consequences for the ecosystem. Using efficient energy systems, waste heat recovery from these systems, and decreased carbon dioxide emission cycles is one approach to averting this looming threat in this context. It is proposed in this paper to utilize the electricity generated by the bottoming absorption power cycle to create hydrogen for use in a molten carbonate fuel cell-based energy system. The system is called near-zero carbon since the efficient waste heat utilization allows maximum hydrogen and minimum hydrocarbon fuel use. The concept of the near-zero carbon cycle is being explored from the viewpoints of technology, economics, and the environment. It is necessary to do multi-criteria optimization to establish the optimum operating point of the system under consideration to reduce costs and CO2 emissions while simultaneously increasing efficiency. A parametric analysis is performed to discover the important design parameters that impact the system’s performance under consideration. Included among the factors under investigation are the fuel utilization factor, current density, stack temperature (Tstack), and the steam to carbon ratio (rsc). Upon investigation, it was discovered that the suggested system had an energy and exergy efficiency of around 66.21% and 59.5%, respectively. According to the findings of the exergy analysis, the MCFC and afterburner ranked highest in terms of exergy destruction (93.12 MW and 22.4 MW, respectively). The tri-objective optimization findings also reveal that the most optimal solution point has an exergy efficiency of 59.5%, a total cost rate of 11.7 ($/gigajoule), and CO2 emission of 0.58 ton/MWh.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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The too short durability is a big and probably unresolvable problem for MCFC.
“There are some who claim that producing heat from hydrogen without combustion is unique or magical.”
Yeah, and there are some who claim that the pyramids were impossible to build without the help of aliens in UFOs. But I wouldn’t see the need to bring up the lunatics when discussing what is supposed to be a serious proposal.
So this makes it easier to extract CO2 by increasing concentration to 70% of produced gases, vs 10% in coal flue gases. Decent, though we’d still need to do something permanent with that CO2.
We’ve got around 100 years technically accessible (known and projected natural gas supply in the US – enough to make the capital investment worthwhile even at current NG use levels.
Since this would be added onto coal plants, it’d have about the biggest potential CO2 reduction per unit installed, without forcing us to leave coal in the ground or decommission coal plants. If proven out in practice, it’d probably be enough better to justify mandating them on coal plants, similar to the way pollution control systems were mandated, without being overly burdensome financially.
And if we can then reduce use of natural gas for electricity generation (e.g. by idling NG power plants when there’s plenty of wind and solar, ramping up only when those fall short), we’d probably be able to stretch the NG supply to match the years of coal supply – around 400-500 more years – or keep centuries of coal as an emergency supply in case of future civilizational collapse.