So clearly there is a need to store electrical power, but batteries are very expensive and inefficient. So there’s Pumped-storage electricity but even that seems like a relatively expensive solution.
Why is it not more common simply to slow down hydro power generation when the power isn’t needed? Niagara Falls has huge reservoirs on both the US and Canadian sides which are filled up at night and run down during the day. Why can these not be made bigger and used to buffer the supply during times of high wind- and solar-power generation?
I recognize that there will be problems with the grid and problems with contracts with the peak-supply generation contracts, but where can I find a discussion of this?
Well, sure. But there must be some wiggle room: spring run-off will be a maximum for the capacity downstream; and there’s droughts and periods of heavy rainfall.
I’m willing to believe that in some situations there will be very little room to maneuver; but at Niagara Falls, for instance, the nighttime flow is half the daytime flow.
So my inquiry isn’t just some off-the-wall craziness - it’s a known technique. And I’m wondering why it isn’t used more, to avoid these episodes of negative pricing. There must be some economic answer, but I don’t know where to find the information.
The problem is that solar only works when the sun shines, and wind when it blows. The has to be sufficient oil/gas/coal/nuclear backup to give us the power we need when it’s dark and windless. This is raising the cost of energy, not reducing it.
If the geography allows, hydraulic storage is possible, but that is not for most of us in the UK or in the USA. I imagine that a lot of people are working hard on a solution.
Most of the current problems that end up with underutilized wind power is due to transmission infrastructure shortfalls. There are utilities who want to buy it, but there are bottlenecks in getting it from A to B.
A complete upgrade to our current flaky and inadequate long distance power grid would have a host of benefits and would pay for itself easily. But inertia on such a big and complex project involving many entities is a problem.
This would even out a large part of the “wind doesn’t always blow” issue. It does blow in a lot of areas most of the time.
Solar for the foreseeable future is a local supplement source. Major infrastructure issues don’t affect it. (But penury US tariffs on Chinese solar panels do.)
First it is true that solar is there when the weather is hot and there is peak demand and that is a good thing. However the last I read there still are problems with getting all the small lot solar power to be in tune with the cycles and harmonics of the overall power grid. I have not yet read that this problem is solved.
As for Niagara that is a heavily populated area. So who are the ones that will have their homes and businesses condemned and move to create the impound area for the water you wish to store?
As for the power dams out west the problem is there is not enough water. The designers, federal government and states back in the 1930’s made the mistake of thinking that things will always stay the same as they were and not taking into account climatic changes with extensive dry cycles as we have now. To be fair I am not even sure that science was even more than a theory at the time.
Invent a way to store massive amounts of power bub, and you not have to worry about the next mortgage payment. But it is a difficult problem.
I wouldn’t assume it’s necessarily an economic answer, there could also be an inertia answer; changing how something is done isn’t going to happen just because someone thinks it would be a good idea. That’s true whether it’s actually a good idea or not.
I’d also imagine you’d want to tie into weather forecasting. Release more water overnight when it’s going to be especially sunny, if you’ve got a lot of solar electricity that’s going to cause the chasm, and not as much water when it’s going to be overcast. That’s going to require setting up some software to support it, and determining how best to adjust flow.
I wouldn’t worry about Niagara in this case, since it’s a tourist destination. You wouldn’t drop the water flow in response to high solar power supply, for example, since people are there to watch the water fall.
I work for a company that operates a number of hydro power plants, as well as a pumped storage station. I can assure you that the hydro units are run to maximise economic utility, exactly as you suggest, and exactly as you would expect. This approach provides the maximum benefit to the market as well as to the plant owner.
If there is enough water behind the dam to run for four hours on a particular day, the plant will run during the four hours corresponding to peak demand and peak price. The same if there is enough water to run for 16 hours - it won’t run during the 8 hours of lowest demand. Of course, if there is enough water to run for 24 hours, the plant will run for 24 hours because there’s more water coming down the river and it has to go somewhere, so it may as well go through the turbines.
Of course things are never quite that simple; the running is closely constrained by present and forecast water levels upstream and downstream, and with the benefit of hindsight a unit may have run differently on a particular day, but in broad terms it is correct.
Disclaimer: any opinions expressed here are my own and not those of my employer.
What about using flywheels for energy storage? I’ve heard this talked about in the past. Is it still considered a viable idea?
For what it’s worth, Wiki mentions grid storage in it’s article on flywheel energy storage.
This company claims to supply flywheel energy storage systems. http://beaconpower.com/
It appears that it’s currently used more for balancing moment to moment demand as opposed to longer term storage, but could it be used for longer term storage? Could large flywheels on magnetic bearings store excess power from a solar farm and then release it overnight? How efficient are properly designed flywheels?
Well, sure. I’m certainly not very happy about the situation here in Ontario, where electricity bills have skyrocketed due to solar power. But all that money’s been spent and ripping out all the installations won’t get it back; I’m trying to understand the economics of negative wholesale power.
In Ontario we’ve got all kinds of extra geography lying around. If geography means we can’t fix this problem of negative prices, I’d like to know why.
… but I’m not sure how seriously to take this proposal, particularly since there wasn’t even a cost/benefit allusion, let alone analysis, in the article. Additionally, it was written before negative pricing became a major issue.
Well, perhaps, but I would really like to see some numbers; some kind of engineering plan; even if it’s only an undergraduate engineering essay.
I’m sure that would help the efficiency of the process, but I’m not sure how much.
Thank heavens! Now all I have to do is try to understand the economics that mean it doesn’t happen more!
OK, this makes eminent sense. So my question is - and without asking for proprietary information of course, but you’re probably more aware of the location of public information than I am - has the change in the pattern of supply due to solar materially changed the economics of these ‘part-time’ hydro generators? Is the answer to the problem the creation of a relatively large number of dams and reservoirs on smaller rivers, that will provide power on demand?
And if so, is there a reason why it isn’t happening now? For instance, I can conceive of a situation where a new hydro plant of this nature would be competitive with a NEW natural gas plant, but not competitive with an EXTANT natural gas plant. Is this a reasonable hypothesis?
And this suggests to me that you could address the problem by increasing the size of the reservoir (or building it from scratch, which would be more expensive, of course). Possibly you’d also have to install a new turbine as well.
Is that reasonable? Are there any public proposals out there?
That is currently in use in downtown Chicago with the two Northwind facilities. This building near the Sears tower and this one at Adams and State store excess energy generated at night as ice, melting it during the day. They distribute 33 degree water to buildings via pipes run through the famous Chicago grid of tunnels. This allows buildings to be built without sacrificing floors to air conditioning.
I did an animation for them when they introduced the program back in the 90s, but I don’t know how successful it has been since then.
How about hydrogen generation as a storage method? When you have excess energy production, use the extra power to electrolyze water into hydrogen and oxygen. Store the gases and then when energy needs rise above the normal production rate, burn the stored hydrogen and oxygen back into water for additional energy.
IIRC (and I look forward to being shown wrong), electrolytic production of hydrogen from water is only about 12% efficient. Then you have difficult storage issues and further inefficiencies when you try to produce electricity again.
But the idea is a good one. Conversion of excess electrical energy to storable chemical energy is IMO the way to go. Imagine being able to produce methane or ethanol from some readily available waste product (sawdust, garbage, atmospheric CO2) using grid electricity whenever supply exceeds requirements. Even if the process is a bit inefficient it would kill a few birds with one stone — regulating electricity usage to match supply cycles, waste processing and producing a usable chemical fuel. (Obviously a pipe dream at this point awaiting a brilliant chemical engineer to come up with a feasible process as well as someone with a bunch of capital.) The benchmark to beat is the efficiency of pumping water uphill for later hydroelectric production. I am not sure what that number is, but if I was to guess I would say 25-30%.
Check the Energy Storage Association site for more tech info. Numerous technologies for both immediate response / grid stabilization and longer term demand variations are in various stages of development.
Another solution is smart metering. Some forms of consumption are time-flexible, and so can be scheduled to run whenever the power is cheapest. The power company could vary their rates minute-by-minute, lowering prices whenever the windmills or solar panels are producing and raising them when they’re not, and communicate that information to consumer devices over the Internet. The device would then be programmed to use power when it’s cheap and to idle when it’s expensive.
This will probably become significant once electric cars start becoming more mainstream. If your car needs 8 hours to charge, and you can leave it plugged in for 16 hours overnight, you can program it to draw power only when it’s below the median price for that time span. Effectively, you’re using customer-owned batteries to do the load-balancing, but you’re doing it in a situation where the customer has already decided that the cost and inefficiencies of batteries are worth it anyway.
In the meanwhile, this could be used for recharging of other devices, and to an extent for most household heating and cooling. It’s OK for temperatures to fluctuate within some range, which means you can usually tolerate waiting a little while before turning on your AC or heater until the price is right.
It’s difficult to take the linked article seriously with obvious howlers like:
This is absurd on its face. The worst-case scenario (the wind and solar generators fail to produce any power) is equivalent to never building the wind and solar generators in the first place. They can fail to avert the need for new gas plants, but not cause such a need.
I’d wonder if the author got his credentials as an expert on energy policy out of a cereal box, but it turns out that he doesn’t even claim to have any particular expertise about the subject:
Instead of trying to store the energy, another option would be to find high energy usage manufacturing that is also open to shifting when they use their power. What if we could find a company that was ok with being told “Ok, Tuesday afternoon is forecast for a lot of sunshine. We (the power company) will give you a break on your cost if you do your heavy usage between 11AM and 3PM on Tuesday”. In other words, match peak usage to peak production, instead of the other way around.