Intermittency of Wind Power Generation

SirPeter

So much of greenery is, in any case, dogma. For example, I don't know anyone who would rely on , say, wind power for their household electricity, for obvious reasons. So that means we have to have installed capacity to back up the wind generators. Otherwise you'd have a very unreliable supply of electricity.

That doesn't mean, as some fondly imagine, that there is a little man with a switch somewhere in Ireland with his finger poised so that when the wind dies down he presses the switch and, hey presto, no one notices the smooth transition from wind power to other forms of power.

It means we have to run the two side by side, so the real benefit from wind power is , actually, quite negligible. But the dogma has it that wind power is "good" and anyone who questions it "bad".

One often overlooked benefit from this political and economic fiasco is that it looks as if all the green party will be without any seats on the far side of the general election. Their time in office, both propping up the most venal FF government ireland has ever had, and for their "green terror" imposing taxes on anything which moves and on many things which don't, all in the name of "greenery", has been a disgrace, and should not be forgotten.

positron

SirPeter wrote: »

That doesn't mean, as some fondly imagine, that there is a little man with a switch somewhere in Ireland with his finger poised so that when the wind dies down he presses the switch and, hey presto, no one notices the smooth transition from wind power to other forms of power.

It means we have to run the two side by side, so the real benefit from wind power is , actually, quite negligible. But the dogma has it that wind power is "good" and anyone who questions it "bad".

Out of context on this thread, but I completely disagree! While it's true that you would need a backup system, today's technology is developed enough to have the backup system providing to the grid on-need basis, which would mean all of the wind power produced will get used, while the backup system only produces enough and saves on conventional fuel / nuclear fuel or whatever.

Wind, along withe rest of the renewable energy ideas that's now gaining momentum (solar, wave etc) are most definitely good, and if they don't look attractive to you today, that's only because we are drunk on the cheap fossil fuel, which we will run out of sooner or later, and that's probably when wind becomes good to some of us. (Can I also add, every time you move, breath, walk or whatever, you are actively busy filling the coffers of middle eastern countries who still don't have democracy, and who still don't care about basic human rights? We are very conveniently overlooking these factors too! )

Anyway, I suppose that's all for many other threads, so suppse we should go back to the topic at hand for now.

SirPeter

positron wrote: »

Out of context on this thread, but I completely disagree! While it's true that you would need a backup system, today's technology is developed enough to have the backup system providing to the grid on-need basis, which would mean all of the wind power produced will get used, while the backup system only produces enough and saves on conventional fuel / nuclear fuel or whatever.

It seems you think there is a little man with a switch and his finger poised!

Electricity in conventional systems is made by boiling water to produce steam, and the steam is then used to drive turbines which produce electricity.

How long do you think it might take for a power station, for example Poolbeg, or even the most up to date power station in Cork, to turn on the oil fired or gas fired burners, and get them to heat up the vast quantity of water to enough steam needed to turn the turbines and produce a continuous supply of electricity into the grid?

And once you have thought about that, at what point does the man with the switch decide to do that in relation to the wind dropping? Half an hour before it drops? At the same time it drops? 20 minutes after it drops?

positron

I am not professing to be an expert this this area, but I think you are probably slightly exaggerating the issue as if the wind and coal power are the only two things supporting the grid and has to cover each other's back at any given time.

While intermittent nature of wind (and other) source, it's not the end of that. There are various ways to cope with it. More here:
http://en.wikipedia.org/wiki/Intermittent_Power_Sources

Can I just remind everyone (mostly myself) and this is seriously out of topic for the thread, and probably should be discussed in a different thread?

SirPeter

positron wrote: »

...today's technology is developed enough to have the backup system providing to the grid on-need basis, which would mean all of the wind power produced will get used, while the backup system only produces enough and saves on conventional fuel / nuclear fuel or whatever.

positron wrote: »

I am not professing to be an expert this this area, but...

Really, you can’t make a post and then say no one should reply to it as you think it’s off topic!

You make a claim, then when I pose questions about it you say you aren’t an expert in this area. That’s fair enough, but the practical problems which I pose need answers, and you have made a claim which needs exploring.

Especially as a lot of people think you can fire up a conventional powered electricity plant in seconds, or even less (which is obviously a fallacy), and don’t think through the lack of logic in that position.

positron

Fair enough I suppose. May be it's worth taking it to a separate thread then? I have created this one.

positron

SirPeter,

Here's another interesting read about dependability of wind energy. (I haven't read it thru - will do soon)

Link to Google Cache of a Renewable UK page

PS: And the earlier link that didn't get copied: http://en.wikipedia.org/wiki/Intermittent_Power_Sources

djpbarry

This thread is derived from a discussion that began in this thread.

djpbarry

SirPeter wrote: »

It seems you think there is a little man with a switch and his finger poised!

Wind generation can be forecast up to one day in advance with over 90% accuracy. Same day forecasts are ∼94-95% accurate.

http://www.eirgrid.com/operations/systemperformancedata/windgeneration/

mgmt

djpbarry wrote: »

Wind generation can be forecast up to one day in advance with over 90% accuracy. Same day forecasts are ∼94-95% accurate.

http://www.eirgrid.com/operations/systemperformancedata/windgeneration/

Tell me you're joking???:eek:

You cannot rely on wind power. Full stop.

Do you want to live in a world full of brownouts and blackouts?

djpbarry

mgmt wrote: »

You cannot rely on wind power. Full stop.

And yet, as shown in the link above, Eirgrid's wind generation forecasts match actual wind generation reasonably well.

SeanW

And yet, as shown in the link above, Eirgrid's wind generation forecasts match actual wind generation reasonably well.

They show that what happened bore only a marginal resemblance to what they thought, at one point their own forecast was 300MW too high! I don't call that reliable.

djpbarry

SeanW wrote: »

They show that what happened bore only a marginal resemblance to what they thought, at one point their own forecast was 300MW too high!

At one point? What about the average performance over time? A cursory glance back over a few days’ data suggests the forecasts are at least 75% accurate on average. Now that's far from perfect, but I would hardly call it a "marginal resemblance". Furthermore, I'm guessing these forecasts are made reasonably far in advance - at this time, there are forecasts available right up to 18:00 on 13/10.

zod

if only we had a way to store the wind energy.

..maybe using pumped storage

.. maybe using our fairly unique coastal valleys..

oh yeah now I remember

PaulGogartyTD

zod wrote: »

if only we had a way to store the wind energy.

..maybe using pumped storage

.. maybe using our fairly unique coastal valleys..

oh yeah now I remember

Storage is the key. It is possible. And not just pumped storage and coastal values, but also conversion to hydrogen, which would fuel cars. It may seem expensive now, but as oil and gas peak it could make Ireland super-efficient in the medium term, but only if we ramp up while we can afford to.

quentingargan

Another hidden, but very low cost alternative to storage is demand side management. By incentivising people and businessess to use electricity at times when the wholesale price is low, you can ensure that a higher percentage of our energy can come from renewables.

There are many processess that use a lot of power which can run at times when electricity is plentiful and cheap. Dairy farmers for example can run their coolers at night only to reduce their costs. The wholesale price of electricity varies from 2.5c to 25c depending on the time of day, so there is a potential incentive there. Already large industries are able to avail of wholesale pricing and time their processess accordingly. Hopefully smart metering will allow consumers and small businesses to do likewise:)

Heroditas

PaulGogartyTD wrote: »

Storage is the key. It is possible. And not just pumped storage and coastal values, but also conversion to hydrogen, which would fuel cars. It may seem expensive now, but as oil and gas peak it could make Ireland super-efficient in the medium term, but only if we ramp up while we can afford to.

Pumped storage has been dismissed due to the ridiculously high costs associated with it.
There's a reason only Turlough Hill exists in Ireland and it's because it was the only suitable cost-efficient site.

Countless studies have been carried out, the latest by Poyry working on behalf of the CER to look at Demand Side Management and storage has been analysed and found to be not cost effective.

I can see us still using natural gas for a sizeable percentage of our energy needs for many more years until there is another quantum leap forward in renewable technology. Time will tell.

positron

Like PaulG mentioned earlier, when the price of oil goes up after peak oil (whenv ever that is, let's not go there, but I am sure we can agree that will happen someday), a lot of the renewable energy methods now considered expensive, will look a lot less expensive.

With respect to wind and other 'unpredictable' renewable sources feeding to the grid, while coal powered reactors may (I don't know, SirPeter says they do) need a prolonged process of bringing up the output, I know new generation nulcear reactors are well capable of producing more to match the load.

http://www.eoearth.org/article/Advanced_nuclear_power_reactors

IMHO, moving away from conventional fuel sources (especially oil and gas from middle east) is of huge significant, not just for economic reasons, but also for ethical reasons. I think a long term renewable solution can be reached in future, but we will need a short to mid term nuclear solution to support us until then.

Again, IMHO, with the right balance of conventional, nuclear and renewable sources feeding the grid, it should be able to (without needing little people, magic hands etc) sustain a very reliable and robust grid, and a grid that also makes us some dosh by selling the excess production to the EU.

SirPeter

djpbarry wrote: »

What about the average performance over time? A cursory glance back over a few days’ data suggests the forecasts are at least 75% accurate on average.

I'm sure "average performance over time" will be a great comfort to all of us, and the corporate "all of us", who find that for 25% of the time they get it wrong, and we find we have no electricity. Hospitals, for example, would be delighted, no doubt, to find their theater lighting not working mid way through an operation because the wind stops blowing. Without installed capacity ready to cut in at a moments notice, wind power is of little value.

While we are all keen to see alternative forms of power generation found and used, wind power for most uses is simply too unreliable to be of much use until we find a means of storing it.

djpbarry

SirPeter wrote: »

I'm sure "average performance over time" will be a great comfort to all of us, and the corporate "all of us", who find that for 25% of the time they get it wrong, and we find we have no electricity. Hospitals, for example, would be delighted, no doubt, to find their theater lighting not working mid way through an operation because the wind stops blowing.

Have a look at this data on the Eirgrid site and show me a point at which wind generation suddenly drops to zero.

Heroditas

Around 30MW being generated this afternoon from an installed capacity of about 1800MW.

Dear oh dear.

SirPeter

djpbarry wrote: »

Have a look at this data on the Eirgrid site and show me a point at which wind generation suddenly drops to zero.

Excuse me? You may not realise it, but your instruction to "show me a point" comes over as a little bossy and confrontational. That may not, in fact, have been your intention, but that’s how it comes over to me.

Are you not able to look for yourself rather than barking instructions at me to do it for you?

Heroditas wrote: »

Around 30MW being generated this afternoon from an installed capacity of about 1800MW.

Dear oh dear.

The great thing about our current system is that, even though the power is reduced to less than 2% of the capacity in the example you give, not one customer of any of the power companies will have their supply reduced or cut off, as the conventional power stations have been running alongside the alternative supply and the power is not interrupted for even a microsecond.

Wind power is wonderful, but not as a reliable means of supply. There are still those who don’t understand how power generation works, and who believe that while the wind blows one or two or even more of our conventional power stations close down, and all or some of the workers all go home.

When they are told that the conventional power stations continue producing electricity as normal, and that it simply isn’t possible to shut them off without having interruptions to supply when the wind drops, as it takes time to fire the conventional station up, they simply put their fingers in their ears and go “na na na na na na” and don’t want to hear how the world works in reality.

Wind power is wonderful, but not as a reliable means of supply to the national grid.

Heroditas

Or else, instead of putting their fingers in their ears, they say "well what would you do then?"

djpbarry

SirPeter wrote: »

Excuse me?

I said, have a look at this data on the Eirgrid site and show me a point at which wind generation suddenly drops to zero. It might, y’know, add some weight to your argument.

SirPeter wrote: »

Are you not able to look for yourself rather than barking instructions at me to do it for you?

You support your own points – that’s how this forum works.

SirPeter wrote: »

Wind power is wonderful, but not as a reliable means of supply. There are still those who don’t understand how power generation works, and who believe that while the wind blows one or two or even more of our conventional power stations close down, and all or some of the workers all go home.

Has anyone on this thread espoused that belief? Or is this just more of your own opinion?

SirPeter wrote: »

When they are told that the conventional power stations continue producing electricity as normal...

Define “as normal”.

SirPeter wrote: »

Wind power is wonderful, but not as a reliable means of supply to the national grid.

And yet, there it is, reliably supplying power to the national grid. Of course, I suppose that depends on one's definition of "reliable".

positron

djpbarry wrote: »

Of course, I suppose that depends on one's definition of "reliable".

Absolutely, and how 'reliable' are traditional power stations themselves? Hydro depend on rainfall, coal/oil ones depend on reserves, imports, world politics, currency fluctuations and what not.. I know this is far fetched, but there are issues with traditional power plants too - which is only going to get worse in future.

The Nipp

SirPeter wrote: »

Hospitals, for example, would be delighted, no doubt, to find their theater lighting not working mid way through an operation because the wind stops blowing.

hospitals or anyone who needs 100% reliable power will have some form of expensive UPS installed.

gas turbines, chp plants, hydro stations can be switched on at a moments notice. there is more to the national grid than wind turbines and always-on fossil fuel behemoths

lostinsuperfunk

not one customer of any of the power companies will have their supply reduced or cut off, as the conventional power stations have been running alongside the alternative supply

This isn't correct. The output of wind generators, like all other generators, can be subject to fluctuations. The system needs reserve generators to allow for this. There are different categories of reserve which are able to react at different rates. The fastest of these is "spinning reserve" -- these are the constantly-running generators you refer to, which have spare capacity to rapidly balance supply and demand. The system doesn't need to maintain spinning reserve to cover all the wind generators. There are other categories of reserve which act more slowly. This is standing reserve, it is not running all the time, but can start up within minutes if the wind falls off or if a large generator goes down.
The variability of wind can also be dealt with to some extent with wind forecasting which allows other generators to be scheduled for when there is low wind. So yes, some other generators do not operate when there are high winds, but this happens as part of a schedule, not in an ad hoc fashion. The forecast is updated every few hours, you only see the day-ahead forecast on Eirgrid's site as far as I know.

Capt'n Midnight

mgmt wrote: »

Tell me you're joking???:eek:

You cannot rely on wind power. Full stop.

Do you want to live in a world full of brownouts and blackouts?

Two of the main causes of brownouts are when there isn't enough capacity, the other is when you have the likes of Enron messing with the supply.

You are 100% correct in saying you cannot rely on wind power but only if you completely ignore the rest of the grid. Gas power stations can start up fairly quickly. If we invested in more pumped storage a la Turlough Hill we'd have full power in about a minute, if we pre-spin the turbines like they do in Wales you are talking about 10-15 seconds to achieve full load.

In markets with large industrial users you can offer discounts if they reduce their demand at peak time, this can be cheaper than building extra capacity or powering stations for short periods of time, also interconnectors are good for catching wind in other places.

I'm still trying to find a utility company that shows unsmoothened demand curves to show that it's worse than people imagine
http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Demand/Demand60.htm - 5 minutes
http://www.eirgrid.com/operations/systemperformancedata/systemdemand/ - 15 minutes


windpower by itself isn't the solution, the ideal solution is hydro but we've already got most of that, we've fossil fuel stations with differing characteristics , coal / peat / oil / gas - even with them one size doesn't fit all. we should be looking at tidal turbines and biomass too.

But to recap, it's possible to build pumped storage systems with very fast responses, in theory we could use a big flywheel to keep the system running for even that little time too. The electricity supply voltage does fluctuate , it's built into the standard, and most ectronic devices use regulators so they should not be as badly affected as in the old days. ( Surge protection is a differenty story , be thankful that our electricity is fairly clean and spike free )

bartizan

Capt'n Midnight wrote: »

Gas power stations can start up fairly quickly. )

How quickly does it take for a gas power station to (i) realise that the wind has died down and (ii) boil water from scratch to steam point before the turbine begins to turn?

Capt'n Midnight wrote: »

if we pre-spin the turbines like they do in Wales you are talking about 10-15 seconds to achieve full load.

What happens for the 10-15 seconds you claim it might take?

Capt'n Midnight wrote: »

In markets with large industrial users you can offer discounts if they reduce their demand at peak time, this can be cheaper than building extra capacity or powering stations for short periods of time, also interconnectors are good for catching wind in other places.

I )

Surely the other places want to hang on to their own wind power rather than export the little bit of it they have? No where I know of has 100% of their power supplied with wind, so how do they meet their power needs if they are exporting their wind power to someone else?

Capt'n Midnight wrote: »

windpower by itself isn't the solution, the ideal solution is hydro but we've already got most of that, we've fossil fuel stations with differing characteristics , coal / peat / oil / gas - even with them one size doesn't fit all. we should be looking at tidal turbines and biomass too.

But to recap, it's possible to build pumped storage systems with very fast responses, in theory we could use a big flywheel to keep the system running for even that little time too. )

You are right that wind power is not the solution, and its unreliability is its achillees heel. The only effective way we have to store it is via pumped storage, but its worth remembering that pumped storage only works if the wind has been blowing when it is needed to pump the water. If the wind is not blowing when power is needed to pump the water back up the hill, then obviously we still need back up from other more reliable sources.

Capt'n Midnight

bartizan wrote: »

How quickly does it take for a gas power station to (i) realise that the wind has died down and (ii) boil water from scratch to steam point before the turbine begins to turn?

the gas station does not wait for the wind to die down
www.met.ie - we actually have weather forecasters, actually more important are the demand forecasters. Wind gradualy dying down in different parts of the country over a period of hours is less of a problem than the spike in demand when everyone plugs in the kettle after corrie (in the UK there was something like a 2,800 MW spike after England lost thier last penalty shoot out )

What happens for the 10-15 seconds you claim it might take?

I like they you cast aspersions on my 'claim' ,
The voltage drops and the frequency drops too. BUT because of steam pressure in some plants and flywheel action in multiple generators in most plants it's unlikely to drop out of band.

http://www.esb.ie/esbnetworks/en/business-customers/voltage_problems.jsp
ESB Networks delivers electricity in a voltage range of 207 Volts to 253 Volts. This is in accordance with European Standard EN50160.

Surely the other places want to hang on to their own wind power rather than export the little bit of it they have? No where I know of has 100% of their power supplied with wind, so how do they meet their power needs if they are exporting their wind power to someone else?

yeah other countries store thier wind power in a big bucket until they need it, 'cos other wise they'd generate revenue by exporting it :rolleyes:

In case you haven't grasped the concept, wind power is a use it while you can resource, sell the surplus to pay for the when you need to import over an interconnector

Interconnectors and National Grids mean wind power can be used in a different area to where it was produced.

If the wind is not blowing when power is needed to pump the water back up the hill, then obviously we still need back up from other more reliable sources.

In case you haven't grasped the concept, wind power is a use it while you can resource,

Also wind power is probably more reliable than other resources other than hydro. It's rare for a whole wind farm to fail, true you can't depend on a wind farm to produce X MW next week but given the weather patterns you can be resonably sure it will deliver Y MW in a few hours time. Here we have a few large power stations that would cause major problems if they suddenly went offline, in the North they were even more susceptible to stuff like a strike at one power station crippling them.

derealbadger

the key is connectivity if you were to have a world wide grid with all the different renewables wind solar wave etc and have substantial storage they could make up the majority of power needs the wind is always blowing somewhere and the sun is always shining somewhere lol on the sun bit somewhere just not here