So I see a town up here is putting in a huge fuel cell for standby power. I’m familiar with fuel cells used in special situations like spacecraft and some aircraft, and my understanding is that they are useful in those situations, but have limitations up against more conventional sources of electricity.
This installation is, of course, being heavily subsidized (55%) by government credits, which to me confirms it’s in the class of speculative technology that’s not really self-supporting or self-funding and can only exist with these subsidies.
Since fuel cells burn a hydrocarbon or hydrogen and produce vastly more expensive power than generators, what is their advantage, and do they have any better future than wind, solar, etc.? Or are they another “we gotta throw money at something” boondoggle?
A fuel cell simply stores energy, unless there’s something huge here I’m missing. What kind of fuel cell it is, is based on how it stores fuel. It does not generate anything whatsoever. Why your local municipality or county helped pay for it, I can’t say, but I would guess they’re trying to ensure a temporary backup supply in case the main power source went down.
This has nothing to do with alternative energy, unless I’m really clueless.
Smiling Bandit is correct. In relationship to alternative energy consider that solar and wind energy are intermittent (when the sun is shining and the wind is blowing). So fuel cells would be a possible mechanism of energy storage to use in conjunction with them or for powering vehicles.
Fuel cells produce electricity directly from a fuel and oxygen; in spacecraft it’s usually pure H2 and O2, but I believe ground-based ones can use hydrocarbon fuels (and air) to the same end. It’s a specialized technology and I am questioning its value as a grid-power source.
Carbon tends to poison fuel cells, so alcohol is an attractive fuel because it doesn’t contain carbon.
Fuel cells that burn hydrocarbons tend to be part of a system that cracks the carbon off, and possibly uses the carbon to fuel the cracking part of the system. The hydrogen is then burned in a fuel cell. In most cases though, the carbon is just wasted.
Fuel cells are very efficient because they are not subject to Carnot cycle* limitations on the efficiency of heat engines as any internal or external combustion turbine or reciprocating system is. This is possible because they do not depend on the heat of combustion for power, but rather use the chemical energy to directly pump electrons.
*The Carnot cycle is a theoretically maximally efficient heat engine. It defines what the maximum possible efficiency of an engine is depending on the combustion temperature and exhaust temperature, and efficiency is always less than 100% unless the exhaust is at absolute zero. Real engines must always fall short of this.
um, sorry, but fuel cells need hydrogen. it ain’t the fuel cell’s fault that the cheapest way to get hydrogen is from hydrocarbon molecules.
and yes, hydrogen as a fuel is equivalent to a battery. with current tech it’s an energy storage medium just like a battery. I don’t think that’ll change since I doubt there are untapped reserves of elemental hydrogen on this planet.
There are different kinds of fuel cells; it’s the correct term for anything which stores, well, fuel. This is the energy source inside the fuel cell - whether that’s in the form of hydrogen or what is irrelevant.
There are indeed different kinds of fuel cells. The kind that stores fuel is a racing fuel cell, which is basically a battle-hardened fuel tank.
If the one described in the OP is receiving government subsidies, then it’s probably the type of fuel cell that oxidizes fuel and produces electrical power. This does not store fuel; you feed it fuel.
Alcohols, by definition, contain carbon. As the Wikipedia page on fuel cell suggests, methanol and methane are attractive fuels because they don’t contain much carbon (compared to the amount of hydrogren atoms). That means they waste less energy when they dump the carbon.
Yes, I know what a racing fuel cell is; I have one. I mean, my summer car has one. I didn’t think my original post was particularly unclear, but there you go.
Anyway, now that we’ve clarified the topic, does anyone care to address the original question: does a fuel cell have any advantages for grid power production (over, say, wind/solar for production power or a highly clean generator for backup power)?
To address this question the fuel cell has good potential for off-grid applications since the types of fuel used in the fuel cell can be trucked in with containers. So for places where stringing power lines is cost prohibitive (think small island or mountain cabin) the fuel cell can be a viable alternative.
In places where sound level abatement is desired (think quiet island or mountain cabin) they really outdo any conventional generator.
Of course alcohols have carbon. Must fully engage brain before posting. They have a higher hydrogen/carbon ratio than petroleum based hydrocarbons.
Fuel cells are a great way to supply power to spacecraft if they are using hydrogen/oxygen fuel anyway. They also supply water as a byproduct, which is otherwise heavy to lift into space…might as well lift the H and O separately and get some energy along with the drinking water.
That will depend on which alcohol and which hydrocarbon are being considered. Methane is a petroleum-based hydrocarbon, and has a 4:1 ratio; there are alcohols for which the H:C ratio gets close to 1.
In fact, even if you’re comparing methanol to methane, they have the same 4:1 ratio. Methanol’s advantage over methane lies in the storage requirements: no pressure vessel required (just a racing fuel cell ), and much more energy per unit-volume than methane.
The last is a very good point. However, the instance that sparked this question has no special conditions at all; it’s a project to provide grid power to an area of a town up here where we’ve had frequent multi-day blackouts in recent years. Without knowing the whole picture, it seems like a large, clean generator (natural gas or propane fueled) would be a wholly adequate solution, based on cheaper and better-vetted technology.
The fuel cell solution (which is a ten-foot cube, to give you an idea of scale) is only within financial reach with a 55% subsidy and, in my view, brings nothing to the game except a chance to play with different tech. I don’t know what the standby life and maintenance of a fuel cell is, but I suspect it is more costly and specialized than that for an equivalent generator.
I’ll narrow the question down. You have to provide 250kw of standby power to, say, a couple of shopping malls. Over a ten-year operational period, what does a fuel cell system bring to the game that a modern, NG/propane-fueled generator does not?
Comparing fuel cells to wind turbines is a bit apples-to-oranges, since then you’re looking at something that uses fuel to something that doesn’t. But if you compare, say, a methane-powered fuel cell with a conventional methane-burning steam turbine power plant (both of which have the goal of converting chemical energy to electrical energy), the fuel cell can, in principle, be significantly more efficient. I don’t think they’re practical yet for something large-scale like a power plant, but that’s a reasonable reason for giving them government subsidies to develop the technology further.
Saying fuel cells are batteries or that they aren’t is kind of missing the point. A fuel cell is really a generator, like a gasoline-powered generator you can buy at Home Depot. Put fuel in, and get electricity out.
Now, the fuel is elemental hydrogen, and you can get that fuel a couple of ways. As pointed out, there are no hydrogen mines (on this planet, anyway), so you need to create it.
One way is to use electricity to hydrolyze water. Using this method, the whole system is indeed essentially a battery : electricity in, and (a little less) electricity out at a later time and place. Note that if you get the original electricity from a windmill or something, it’s sustainable, carbon-neutral, etc. Even if you get the original electricity from a fossil-fuel power plant, since large plants are more efficient and less polluting (on average) than an individual gas/diesel generator, it’s quite likely the fuel-cell system could be better overall.
But the other way to get hydrogen is to strip it off of hydrocarbons, either from fossil fuel or from plant-based ethanol or something. In this case, the fuel cell is working exactly like a diesel generator; the greenhouse impact of course depends on whether you’re burning fossil fuels or a plant-based source. Additionally, with a fuel cell there’s no other air pollution (smog-forming emissions and diesel particulates) which you get from an internal-combustion engine.
Finally, one non-environmental advantage of fuel cells, compared to internal-combustion powered generators, is that there are many fewer moving parts. This is a big advantage for back-up generators, which need to sit for a long time without too much chance of things seizing up, and is I think often the key factor for facilities that choose fuel cells as emergency power.
Hydrogen is not a fuel, except in the most narrow technical sense. Any energy storage or distribution system relying on highly compressed hydrogen is best viewed as if hydrogen is a carrier or conduit, because the amount of energy needed to extract and compress hydrogen often exceeds the fuel value of the H2 itself. Hydrogen is a way to store energy where it’s cheap and transport it to where it’s needed. Regarding it as a fuel in and of itself leads to faulty conclusions about its usefulness.
Back to the topic, though: while generators might have more moving parts, those parts have 100+ years of engineering refinement behind them. While the components of a fuel cell might be static, I question whether the technology has reached the point where a giant cell installation has better maintenance and durability costs and needs than a highly refined static-operation engine. Or whether fuel cells are anywhere on a path to a 10-year life cycle with little maintenance, as generators are.
Other than the pump, does a fuel cell have any moving parts?
If you have a power source that is capable of producing a constant supply of power, like a nuclear power plant, “wasting” some of that capacity during periods when nobody wants it to make hydrogen to power a fuel cell makes sense. For instance, Commonwealth Edison built a system called “Northwind” in downtown Chicago that makes ice all night long during the summer. The melting ice supplies chilled water to nearby buildings. This helps even out the demand on their nuke plants during the day.
Also, a fuel cell should be able to supply additional power quickly, as opposed to bringing an additional reactor on-line. ComEd uses jet engines as generators as part of several of their nuclear stations. It’s not efficient, and jet fuel is expensive, but it comes up to speed very quickly.
Sure, a ‘hydrogen economy’ is a kind of silly idea, and not a good way to think about things.
But we’re talking fuel cells, and you don’t need a tank of compressed hydrogen to run a fuel cell – you can run one from a tank of (liquid or gas) hydrocarbons and a device to strip off the hydrogen from the hydrocarbon fuel. I don’t think such devices are yet efficient enough to make the whole thing more efficient than an internal-combustion engine, but it accomplishes exactly the same thing as an internal combustion engine. So it’s more useful to think of such a system as an engine that burns hydrocarbons, than some kind of battery.
), and much more energy per unit-volume than methane.