Hydrogen Electrolysis Efficiency Breakthrough

[Sxotty]

The turbines would need a water source, hydrogen storage, and a more complex power generation scheme that includes the fuel cell.

As wind is a minority producer and not as controllable, it's not going to be common that a wind farm can produce more power than the grid will want. Even if that were the case, the electrolysis of water and then passing through a fuel cell would have efficiency issues.

Actually for all the reasons you list (not controllable) that is exactly why it makes sense. Further if you think about interconnectino costs to the grid it makes sense.

Think about it if you make a windfarm you don't size the lines to carry the maximum the wind farm can produce. Instead you size it so it can transmit the max power that is made 90% of the time. This saves money, but you lose out on the peak. Anyway the other points are accurate though.

 

[3dilettante]

There's hardly ever a time that the wind farm can't sell all the power it produces, (edit) because it's such a small share of the total.

If attached to power grid, the turbines would have to hold back output to put into the fuel cells, even though the system can already ignore them in most cases.

It is possible in one case that such a scheme would work, where the turbines power a massive aggregate number of fuel cells whose capacity to be used in times of peak/emergency power demand.
However, that contradicts the idea of speccing the power connection at below peak. If anything, such a scheme might require an overengineered connection.

There's money to be made competing with the few rapid response generation plants for those critical periods, such as a plant failure or system-wide drain (a desperate system has to pay through the nose for the power required to keep the grid stable).
However, that would have the adverse effect of raising the average cost of wind power, and it involves a fair amount of gambling that the vast store of hydrogen won't leak too much between such emergencies. It's virtually guaranteed that any long-term storage will leak a good deal, and such a scheme does increase the maintenance and overhead over standard plant-them-and-leave-em turbines.


edit:
On second thought, storage might make sense for keeping the power output more stable for a given period of time, though this doesn't do much for when the wind farm is in dead air for an extended period.
From a grid management perspective, it might make sense, but the wind farm might not see a benefit unless wind is a far more dominant player than it is right now.

 

[Sxotty]

Yeah your view of the power grid is not really fully fleshed out. No offense though please.


Wind farms can sell all the produce b/c the law forces other generators to ramp up and down to make up for the inconsistency. And that is not terribly efficient b/c no generators they use to make it up operate at their peak efficiency unless they are in steady state. There are thus increases in pollution and costs associated with balancing the grid to the power that wind produces. Luckily the inertia of the blades themselves at least smooth it a little bit on the shortest time frame.

 

[3dilettante]

I can accept the usefullness of reducing variability for wind generated power.

I was not aware that wind power producers are able to sell otherwise unwanted bids on the grid due to statute.

There is a limited way of stabilizing power output beyond what the blade inertia provides, but it does involve having a wind farm that is overspecced for the power bid.

If there are too many turbines producing too much, then x% can be disengaged and reengaged as needed.

The wind's variation is such that enough surplus turbines can capture variation for the duration of a time slice, though this method is weak in the case that the wind dies quickly.

 

[Sxotty]

Honestly that doesn't really work either. The capacity factor of a wind farm is probably <40%. And the power output is highly correlated over a geographic area. So either you have massive amounts of wind farms all over with new transmission lines to carry the power or you have some form of energy storage nearby. Like I said compressed air is the current front runner.

You can use natural gas turbines (like they do now) to balance the power output.


Your idea's problem is it would waste the majority of the power wind farms generate. Then there would be no point in having them. It all depends on how much you have though. Your "small" percentage thing is somewhat true, but where they are their percentage is much higher so the impact on the grid can be very large. In west texas for example you have a whole lot of wind power and it isn't a small factor at all in the grid.


Anyway it is an interesting issue. Until we can store electricity somehow renewables besides hydro will face problems.

Solar Thermal obviously can be better in that respect if it has a large buffer of heat, but if it isn't sunny you are still in trouble eventually. (CSP plants do not necessarily have a large thermal storage unit, if not then their power fluctuates pretty quickly as well.)

Heck even the grid itself could really use electrical storage to even out the load swings.

http://currentenergy.lbl.gov/pjm/index.php That will show you what I mean.

 

[Gubbi]

Another big motivation for wind energy producers to look into energy storage is economic.

The western part of Denmark has 650MW installed capacity, yet has consumption that is around half that. This means that when you have gale force winds and produce at (or above) capacity you have to dump the excess electricity on the international market. Trouble is that the nearest energy exchange partner, Germany itself has a huge wind power production. That means that gross electricity prices tanks during these periods, to the tune of 0.01-0.02 €/kWH.

If the excess energy could be stored it could be sold during periods with higher gross price, increase income for wind power producers.

Cheers

 

[Sxotty]

Another big motivation for wind energy producers to look into energy storage is economic.

The western part of Denmark has 650MW installed capacity, yet has consumption that is around half that. This means that when you have gale force winds and produce at (or above) capacity you have to dump the excess electricity on the international market. Trouble is that the nearest energy exchange partner, Germany itself has a huge wind power production. That means that gross electricity prices tanks during these periods, to the tune of 0.01-0.02 €/kWH.

If the excess energy could be stored it could be sold during periods with higher gross price, increase income for wind power producers.

Cheers

It all depends how economical the storage is though. The have some short term storage now in CAS, and NaS, VRB etc..Those are pretty expensive.

By the way I don't know if you realize this (and maybe it isn't the case there), but the LMP actually goes negative sometimes. In other words they will pay you to take the electricity. So the price falls below 0.

 

[Gubbi]

It all depends how economical the storage is though. The have some short term storage now in CAS, and NaS, VRB etc..Those are pretty expensive.

Oh, sure. It has spurred research in hydrogen technology, becasue hydrogen is a high quality energy source on level with natural gas and oil (ie. portable and has high energy density). Using hydrogen to produce electricity again directly would be less economical since you only get around 30% energy out of what you put in.

By the way I don't know if you realize this (and maybe it isn't the case there), but the LMP actually goes negative sometimes. In other words they will pay you to take the electricity. So the price falls below 0.

Don't think that has ever been the case in Denmark though. If it comes to that point they would just set the rotor-wings into neutral and stop producing electricity all together.

Cheers

 

[hoho]

I've heard that one quite efficient way to store energy is to pump water higher and use hydroelectric plants to get the energy back from it.

 

[Sxotty]

I've heard that one quite efficient way to store energy is to pump water higher and use hydroelectric plants to get the energy back from it.

http://en.wikipedia.org/wiki/Raccoon_Mountain_Pumped-Storage_Plant
It has 78% efficiency and I believe that is one of the best there is. You cannot just build such a facility unless the geography supports it though. If it exists great, (though there are negative impacts as well of course).

Oh, sure. It has spurred research in hydrogen technology, becasue hydrogen is a high quality energy source on level with natural gas and oil (ie. portable and has high energy density). Using hydrogen to produce electricity again directly would be less economical since you only get around 30% energy out of what you put in.

That isn't quite accurate, well it depends on your system bounds I guess. If you use a fuel cell then your efficiency is much higher than that. The round trip currently can get to 50% with creation of hydrogen and back to electricity.

Don't think that has ever been the case in Denmark though. If it comes to that point they would just set the rotor-wings into neutral and stop producing electricity all together.
Cheers

I wrote it poorly and you misunderstood. It isn't the windmills that make the electricity so cheap. If you have nuclear reactors they don't ramp up and down really. Coal doesn't either much. So it is actually cheaper for the company to pay you to take electricity from them then to turn off a base load plant and then turn it back on later. Ramping them up and down is expensive.

 

[3dilettante]

I was googling separate data sources, so I am open to correction on my math.

The Danish wind industry site puts the cost to intall wind turbines at $1000 per kilowatt installed.
Various sources on Google that I lack the knowledge to fully evaluate put the cost per kilowatt for fuel cell power generation at $4000+.

One could buy at least 5 times the number of standard turbines than could be gotten with a wind turbine + fuel cell generator (cost of the electrolysis machine capable of multikilowatt load, I don't know).

If the utilization of the fuel cell wind farm is capped at 100% (and we know it isn't going to get that high), one would hope that the wind farm 5x its size can only produce profitable power <20% of the time.

Obviously there are space and infrastructure concerns for the standard farm, but also far higher maintenance for the fuel cells and electrolysis units.

 

[Sxotty]

I was googling separate data sources, so I am open to correction on my math.

The Danish wind industry site puts the cost to intall wind turbines at $1000 per kilowatt installed.
Various sources on Google that I lack the knowledge to fully evaluate put the cost per kilowatt for fuel cell power generation at $4000+.

I hope something is wrong here. 1 kw wind is on average producing 0.3 kw, 1kw fuel cell=1kw. See the difference. That makes them downright affordable seeming (fuel cells) and I don't think they are.

Obviously there are space and infrastructure concerns for the standard farm, but also far higher maintenance for the fuel cells and electrolysis units.

I honestly don't know about that. A turbine has moving parts, moving parts break. I am not sure about th reliability of the electrolysis (which is what I said earlier, if 85% is reliable then it is amazing.)

 

[3dilettante]

I hope something is wrong here. 1 kw wind is on average producing 0.3 kw, 1kw fuel cell=1kw. See the difference. That makes them downright affordable seeming (fuel cells) and I don't think they are.

That seems plausible, my numbers were working with a 1:1 relationship between generating capacities, which is not necessary.
It would be doable to have a wind turbine capable of 1 KW peak feeding into a fuel cell capable of only a fraction of that.
The difference would be that the electrolysis and storage would have to be able to create and store more H2 than would be necessary for a fuel cell generator at that capacity.

Saying the fuel cell setup is generating may be a little incorrect, it's more that it's reconverting the power generated by the turbine.
If we go by the 50% efficiency figure, we might only expect the fuel cells to provide 1/2-1/4 the installed wind capacity. It would still double the cost each turbine, if it ran at 1/4 capacity.

The big unknown is how much the electrolysis and storage portion would cost.
I could assume it would cost in the same neighborhood as the other components, but I don't know. I doubt nanoparticles come cheap at this point in time.

The water infrastructure (possibly needs purified water to keep from poisoning the electrolysis chamber) and gas storage mechanism adds cost, but I can't quantify that amount either.

I honestly don't know about that. A turbine has moving parts, moving parts break. I am not sure about th reliability of the electrolysis (which is what I said earlier, if 85% is reliable then it is amazing.)

We'd have to compare the mechanical tolerance and wear rates of the turbine's moving parts to the tolerances and chemical degredation of the fuel cells, electrolysis hardware, and the gas containment method.

Any maintenance would be additive to the maintenance of the turbine coupled with them, as the fuel cell won't make the turbine any more reliable.

 

[Sxotty]

That seems plausible, my numbers were working with a 1:1 relationship between generating capacities, which is not necessary.
It would be doable to have a wind turbine capable of 1 KW peak feeding into a fuel cell capable of only a fraction of that.
The difference would be that the electrolysis and storage would have to be able to create and store more H2 than would be necessary for a fuel cell generator at that capacity.

Saying the fuel cell setup is generating may be a little incorrect, it's more that it's reconverting the power generated by the turbine.
If we go by the 50% efficiency figure, we might only expect the fuel cells to provide 1/2-1/4 the installed wind capacity. It would still double the cost each turbine, if it ran at 1/4 capacity.

The big unknown is how much the electrolysis and storage portion would cost.
I could assume it would cost in the same neighborhood as the other components, but I don't know. I doubt nanoparticles come cheap at this point in time.

The water infrastructure (possibly needs purified water to keep from poisoning the electrolysis chamber) and gas storage mechanism adds cost, but I can't quantify that amount either.


We'd have to compare the mechanical tolerance and wear rates of the turbine's moving parts to the tolerances and chemical degredation of the fuel cells, electrolysis hardware, and the gas containment method.

Any maintenance would be additive to the maintenance of the turbine coupled with them, as the fuel cell won't make the turbine any more reliable.

If you are talking about storage quantity there is some guy form the midwest who wrote some interesting stuff on CAS for wind turbines trying to find the optimal size. This is basically the same idea. Stored energy is tremendously valuable b/c you can sell it when the market clearing price is high.

Water should not be much of a problem as it is a closed cycle. Water-->H2+O2-->Water

 

[3dilettante]

I forgot the system could be closed, or mostly so. I was thinking of a fuel cell stacks that run with atmospheric oxygen.

I think we could expect a measurable amount of leakage over time, particularly with the hydrogen. There might be a small tank of purified water on standby to allow everything to remain at optimum between maintenance visits.

 

[soylent]

QuantumSphere has demonstrated production of hydrogen and oxygen in an alkaline electrolyzer with 85% percent efficiency under ambient conditions, making it a commercially viable replacement for fossil fuel-based production methods (e.g., steam methane reforming), according to the company.

That's better than the current ~70% efficient electrolysers but it's hardly revolutionary.

If fossil fuels are used for generating the electricity it is not competetive with steam reforming of the same fuels.

If you generate electricity first and then generate hydrogen gas this is only about 60% * 85% efficient or 50%. Steam reforming and water gas shift reaction of both coal and natural gas easily beat this.

High temperature electrolysis is capable of taking both heat and electrical power to split water. For geothermal or nuclear that generate more thermal energy than they generate electricity this can be much more efficient than QuantumSphere's method. Unfortunately the technology is not cheap nor durable yet.

http://www.greencarcongress.com/2008/03/quantumsphere-n.html

This is truly amazing to me. At that kind of efficiency fuel cell back up for wind power suddenly makes a whole lot more sense, or using nuclear power to produce hydrogen instead of CTL.

Not useful at the present time. Hydrogen fuel cells are currently ~50% efficient and not very durable. The theoretical maximum efficiency of a hydrogen fuel cell is ~83%. The safe and efficient storage problem is not solved.

A good battery can manage close to 90% charge/discharge efficiency and a good inverter around 90% efficiency. Nuclear or geothermal with high temperature electrolysis, if it ever arives, may be able to compete quite favorably with batteries, but not regular electrolysis.

It may be more economical to turn barely useful, intermittent wind power into ammonia and derivatives(explosives, fertilizers) and sell them. There by saving natural gas instead of adding lots of intermittent power sources to the grid that need to be backed up with almost their entire nameplate capacity in hydroelectric or natural gas peaking plants.

 

[Fred]

"I've heard that one quite efficient way to store energy is to pump water higher and use hydroelectric plants to get the energy back from it."

Yes, and its quite the technological marvel and a beautiful solution to the 'energy storing' problem (which is probably one of the biggest issues with green alternatives atm). Its extremely efficient, but the tradeoff is many fold.

First, you sacrifice peak efficiency at the hydroelectric plant perse... Second, its exorbitantly expensive to build and way out of reach of most countries budgets. Third, geographical locations with the appropriate profile is difficult ot find.

 

[Frank]

I think the main problem with new energy breakthroughs is (as the interesting documentary posted said and Sxotty explained), that as soon as you report more energy coming out than going in everyone is going to dismiss it outright. You need to spend a very large personal fortune to even be able to produce and sell those devices, and just about all your media exposure is going to be negative.

While it can very well be that you add energy from an unknown source, like Zero-point energy. Or any other kind. As long as we don't try and research it, we don't know. And waiting for a scientific explanation up front is fruitless: you need to experiment to find out in the first place.

 

[3dilettante]

I think the main problem with new energy breakthroughs is (as the interesting documentary posted said and Sxotty explained), that as soon as you report more energy coming out than going in everyone is going to dismiss it outright. You need to spend a very large personal fortune to even be able to produce and sell those devices, and just about all your media exposure is going to be negative.

You've got it just about backwards.
There is no shortage of nimrods in the press that will take idiotic +100% efficiency claims and run with it.
There are also many nitwits willing to invest in said product.

If any such device were built and it wasn't a total fraud, a simple demonstration would be enough to catapult the inventor to nigh-infinite riches.

While it can very well be that you add energy from an unknown source, like Zero-point energy. Or any other kind. As long as we don't try and research it, we don't know. And waiting for a scientific explanation up front is fruitless: you need to experiment to find out in the first place.

How about a working demonstration?
That's really all it takes.
Plug the device back into itself and see if it keeps going or goes faster.

 

[nutball]

While it can very well be that you add energy from an unknown source, like Zero-point energy. Or any other kind. As long as we don't try and research it, we don't know. And waiting for a scientific explanation up front is fruitless: you need to experiment to find out in the first place.

Never mind the media, they're not the final arbiters. Extraordinary claims require extraordinary proof. Claiming >100% efficiency in any energy conversion device is about as an extraordinary a claim you can make within our current physics.

There have been many such claims, and each and every single one of them has turned out to be incorrect (usually due to an inability on the claimant to either to do simple arithmetic, or to draw the boundaries in the right place).

Each wrong claim raises the bar, it raises the standard of evidence required for similar such claims to be taken remotely seriously next time round.