Grid Integration of Large-Scale Renewables

Capt'n Midnight

easychair wrote: »

Conventional power stations, such as oil and gas and peat and nuclear are reliable precisely because they are not intermittent. Which is why they are still needed.

'cos they all have 100% capacity and never have unplanned downtime :rolleyes:

easychair

Capt'n Midnight wrote: »

'cos they all have 100% capacity and never have unplanned downtime :rolleyes:

Thats just being silly.

In Ireland, every business, home, school and so on reply on a more or less continuous supply of electricity, provided by a network of conventionally powered electricity stations.

Try getting all your electricity from wind, and you'll know what it means to have an unreliable source of supply.

djpbarry

easychair wrote: »

He actually said "Yes it is" correcting my use of the word "reliable" implying that the wind is reliable, which by any definition of the word ( I chose the OED) it is not.

[MOD] Enough of the pointless semantics please. If you want to argue the intended definitions of words as they appear in a dictionary, please do so elsewhere. [/MOD]

easychair wrote: »

If you are not able to understand that being intermittent means that it is unreliable, that's also fine.

[MOD] For the last time, intermittency and reliability are not one and the same. End of. I do not believe for a second that you are incapable of grasping this very simple concept. [/MOD]

As someone who looked into this... the main reasons why there is no chance of this happening in Ireland at the moment is: -

1. Eirgrid's algorithm for running the electricity market would not support it. Once built Eirgrid would (under current rules) be given control of the pumped storage plant and operate it. It would only be used for peaking and the main payment would be a paltry capacity payment.
There is no way that you would get bank funding for something that expensive to be handed over to another body for operation!

2. The transmission network would not be able to handle the voltage. Maybe when moneypoint closes that part of the network could be used but that hv connection might not even handle it and you'd still have to connect to there.

3. The financials are far from proven. It would cost approx €1 billion to build one and again you'd need a lot of bank debt which would only be provided with risk mitigation - e.g. guarantees of payments by state to cover the debt repayment part etc.

That's before the planning, environmental, other feasibility issue etc. etc.

Pumped storage is only currently used for peaking (providing energy during peak capacity), not for storing up renewable energy.

this one in South Africa is being built at the mo...

http://www.power-technology.com/projects/ingula-scheme/

easychair

glasso wrote: »

As someone who looked into this... the main reasons why there is no chance of this happening in Ireland at the moment is: -

1. Eirgrid's algorithm for running the electricity market would not support it. Once built Eirgrid would (under current rules) be given control of the pumped storage plant and operate it. It would only be used for peaking and the main payment would be a paltry capacity payment.
There is no way that you would get bank funding for something that expensive to be handed over to another body for operation!

2. The transmission network would not be able to handle the voltage. Maybe when moneypoint closes that part of the network could be used but that hv connection might not even handle it and you'd still have to connect to there.

3. The financials are far from proven. It would cost approx €1 billion to build one and again you'd need a lot of bank debt which would only be provided with risk mitigation - e.g. guarantees of payments by state to cover the debt repayment part etc.

That's before the planning, environmental, other feasibility issue etc. etc.

Pumped storage is only currently used for peaking (providing energy during peak capacity), not for storing up renewable energy.

this one in South Africa is being built at the mo...

http://www.power-technology.com/projects/ingula-scheme/

Many of the threads on this type of thing are theoritical, with some not understanding that practicalities are equally important. Many schemes such as the one this thread is about might be great ideas, but the business plan would never pass muster. What is curious is that often when the common sense practicalities are pointed out, some refuse to countenance that good ideas are not enough.

djpbarry

glasso wrote: »

Eirgrid's algorithm for running the electricity market would not support it.

That's hardly an insurmountable obstacle.

glasso wrote: »

The transmission network would not be able to handle the voltage.

Why not?

glasso wrote: »

The financials are far from proven. It would cost approx €1 billion to build one...

What are you basing that figure on?

pljudge321

djpbarry wrote: »

What are you basing that figure on?

Thats probably an underestimate if you look at the cost of large pumped hydro schemes in other countries that aren't even the scale of this pipe dream.

djpbarry

pljudge321 wrote: »

Thats probably an underestimate if you look at the cost of large pumped hydro schemes in other countries that aren't even the scale of this pipe dream.

I'm slightly confused now - are we still talking about the relatively small project referred to in the OP?

pljudge321

djpbarry wrote: »

I'm slightly confused now - are we still talking about the relatively small project referred to in the OP?

My bad, I was referring to spirit of ireland, fourth year has my head rather frazzled of late.

djpbarry

djpbarry wrote: »

That's hardly an insurmountable obstacle.
Why not?
What are you basing that figure on?

That's an average figure of similar developments of similar spec built around the world. Obviously there will be large considerations for the individual project in terms of the earth-moving, civil engineering etc. but in terms of this discussion it's not a bad figure to use. Of course, this is in relation to developments of about 1000mw, with constuction cost of c. €1m euro / Mw. Not sure what scale OP was talking about.

changing the eirgrid algorithm would actually be a significant thing to do - all the existing peaking players would have to be compensated - there would be significant ramifications.

the transmission network in Ireland is not great - moneypoint has output of 915mw so the hv connection there might be able to handle the large output but other parts of the country do not have this large hv infrastructure. this sort of connection is expensive and planning for building it would be also difficult to get.

pljudge321

glasso wrote: »

That's an average figure of similar developments of similar spec built around the world. Obviously there will be large considerations for the individual project in terms of the earth-moving, civil engineering etc. but in terms of this discussion it's not a bad figure to use. Of course, this is in relation to developments of about 1000mw, with constuction cost of c. €1m euro / Mw. Not sure what scale OP was talking about.

changing the eirgrid algorithm would actually be a significant thing to do - all the existing peaking players would have to be compensated - there would be significant ramifications.

the transmission network in Ireland is not great - moneypoint has output of 915mw so the hv connection there might be able to handle the large output but other parts of the country do not have this large hv infrastructure. this sort of connection is expensive and planning for building it would be also difficult to get.

http://www.eirgrid.com/media/Grid%2025.pdf

We are about to spend €3.5 billion upgrading the network, most of that is going on new 220 kV and 400 kV lines.

And yes planning permission is a bitch, it takes somewhere in the region of 8 years to build a 400 kV line.

pljudge321

pljudge321 wrote: »

http://www.eirgrid.com/media/Grid%2025.pdf

We are about to spend €3.5 billion upgrading the network, most of that is going on new 220 kV and 400 kV lines.

And yes planning permission is a bitch, it takes somewhere in the region of 8 years to build a 400 kV line.

yes but that investment is not taking into account any requirement for pumped storage facilities and / or where they could be.

323

glasso wrote: »

yes but that investment is not taking into account any requirement for pumped storage facilities and / or where they could be.

It is Ireland, "Sure we'll worry about that when the time comes". At first glance, looks to me like this €3.5 Billion will be spent to give a 20th century grid rather than what may really be needed for the 21st.

pljudge321

323 wrote: »

It is Ireland, "Sure we'll worry about that when the time comes". At first glance, looks to me like this €3.5 Billion will be spent to give a 20th century grid rather than what may really be needed for the 21st.

What does that even mean? We currently are achieving up to 50% wind penetration and are aiming on safely and reliably achieving 70% once the upgrades are complete, levels that are unheard of in any other system in the world.

easychair

pljudge321 wrote: »

What does that even mean? We currently are achieving up to 50% wind penetration and are aiming on safely and reliably achieving 70% once the upgrades are complete, levels that are unheard of in any other system in the world.

I have read this a few times, and have no idea what "wind penetration" means. Even if Ireland achieves 100% wind penetration, it's still of little use when the wind isn't blowing.

pljudge321

easychair wrote: »

I have read this a few times, and have no idea what "wind penetration" means. Even if Ireland achieves 100% wind penetration, it's still of little use when the wind isn't blowing.

Wind penetration is the percentage of system load that is being satisfied by wind generation. Here's the chart for today where we averaged around 32%. If it reaches around 50% EirGrid will actively curtail the output of the wind farms to keep the system from becoming unstable.



No-one (who has any idea what they are talking about anyway) is proposing trying to satisfy 100% of demand with wind generation.

easychair

I am in Ireland at the moment and, having driven from Mullingar to Dublin, know that today is a very windy day.

I love wind power and love the idea of getting "something for nothing"

However, wind power as it is currently used, is not as useful as it might at first glance appear.

The first thing is that the wind doesn't always blow and, as we say last winter, on some of the very coldest days when demand for electricity was at its peak in ireland, your graph would have shown that there was almost no contribution from wind.

The next problem is what to do when the wind suddenly drops (which happens). If the ESB shuts off an oil powered station to save oil while it's windy, how long do you guess it takes to restart it again and have it up producing power? How much for a Peat Powered Station? How much for a Gas powered station? How do they do that without having power cuts all the time when the wind suddenly drops if they are depending on wind power to produce electricity? Or even sometimes when the wind drops if they are depending on wind power to produce electricity?

Wind power is a wonderful thing, but it's not that useful to us as we currently use it, as our current technology doesn't allow us to store the power and use it in a predictable way, which is the only real way we can use wind power as a substitute to save large quantities of other sources of power, mainly oil, gas and peat.

pljudge321

easychair wrote: »

I am in Ireland at the moment and, having driven from Mullingar to Dublin, know that today is a very windy day.

I love wind power and love the idea of getting "something for nothing"

However, wind power as it is currently used, is not as useful as it might at first glance appear.

The first thing is that the wind doesn't always blow and, as we say last winter, on some of the very coldest days when demand for electricity was at its peak in ireland, your graph would have shown that there was almost no contribution from wind.

The next problem is what to do when the wind suddenly drops (which happens). If the ESB shuts off an oil powered station to save oil while it's windy, how long do you guess it takes to restart it again and have it up producing power? How much for a Peat Powered Station? How much for a Gas powered station? How do they do that without having power cuts all the time when the wind suddenly drops if they are depending on wind power to produce electricity? Or even sometimes when the wind drops if they are depending on wind power to produce electricity?

Wind power is a wonderful thing, but it's not that useful to us as we currently use it, as our current technology doesn't allow us to store the power and use it in a predictable way, which is the only real way we can use wind power as a substitute to save large quantities of other sources of power, mainly oil, gas and peat.

Says the power systems engineer :rolleyes:

Capt'n Midnight

just a reminder about the the interconnectors


http://www.soni.ltd.uk/upload/All%20Island%20Generation%20Capacity%20Statement%202011-2020.pdf

450MW (+50MW) Moyle Interconnector Scotland to NI
100MW Louth-Tandragee 275kV Transmission Tie Line (In the past up to 396MW have passed North-South)

Mostly completed
500MW East-West Interconnector to Wales.

Future
100MW-1500MW North-South High Capacity Transmission Tie Line

When these projects are complete this Island will be able to import/export up to 1000MW

pljudge321

Capt'n Midnight wrote: »

just a reminder about the the interconnectors


http://www.soni.ltd.uk/upload/All%20Island%20Generation%20Capacity%20Statement%202011-2020.pdf

450MW (+50MW) Moyle Interconnector Scotland to NI
100MW Louth-Tandragee 275kV Transmission Tie Line (In the past up to 396MW have passed North-South)

Mostly completed
500MW East-West Interconnector to Wales.

Future
100MW-1500MW North-South High Capacity Transmission Tie Line

When these projects are complete this Island will be able to import/export up to 1000MW

There's murmurs about one to France as well. That'd be a fair few years away if it happens at all.

Oldtree

Might as well get on with it and build a nuclear power station then

easychair

pljudge321 wrote: »

Says the power systems engineer :rolleyes:

Only power system engineers are allowed to ask questions?

Those points are important as many people misguidedly seem to think that for every Mgw produced in wind power, we save one Mgw's worth of oil, or gas, or peat etc.

pljudge321

easychair wrote: »

Only power system engineers are allowed to ask questions?

Those points are important as many people misguidedly seem to think that for every Mgw produced in wind power, we save one Mgw's worth of oil, or gas, or peat etc.

Because you obviously have little to no idea about what your are talking about.

Also energy in power systems are measured in MWh, not Mgw which is meaningless.

djpbarry

easychair wrote: »

The first thing is that the wind doesn't always blow and, as we say last winter, on some of the very coldest days when demand for electricity was at its peak in ireland, your graph would have shown that there was almost no contribution from wind.

[MOD]Why must this be put forward on every single thread discussing wind power? It's like saying gas-fired power stations don't generate electricity in the absence of gas. Apart from it being a case of stating the blindingly obvious, I'm interpreting it as soap-boxing from this point forward.[/MOD]

Chloe Pink

pljudge321 wrote: »

Wind penetration is the percentage of system load that is being satisfied by wind generation.

Is wind penetration the percentage of system load that is being satisfied by wind generation or is it the installed wind capacity as a percentage of the system installed capacity?

pljudge321 wrote: »

Here's the chart for today where we averaged around 32%.

What were the CO2 savings as a result of the wind on this day?

pljudge321

Chloe Pink wrote: »

Is wind penetration the percentage of system load that is being satisfied by wind generation or is it the installed wind capacity as a percentage of the system installed capacity?
What were the CO2 savings as a result of the wind on this day?

I've seen it referred to as both, I prefer the first as it gives any indication of how much of the load is being satisfied by wind while the second is highly dependant on the total level level of installed capacity on the system.

Our CO2 intensity at the moment is 421 gCO2/kWh with 1.5 GW of wind generation and a total load of 4 GW. If there's a calm day soon we should be able to get a valid comparison.

easychair

pljudge321 wrote: »

I've seen it referred to as both, I prefer the first as it gives any indication of how much of the load is being satisfied by wind while the second is highly dependant on the total level level of installed capacity on the system.

Our CO2 intensity at the moment is 421 gCO2/kWh with 1.5 GW of wind generation and a total load of 4 GW. If there's a calm day soon we should be able to get a valid comparison.

I wasn't aware that such figures were available, and they will be most interesting to see. I wonder how it's calculated, and how other countries compare who have nuclear power which presumably has a positive effect on the amount of CO2/kWh.

pljudge321

Data and methodology are here: http://www.eirgrid.com/operations/systemperformancedata/co2intensity/

For comparison our CO2 intensity averaged in the region of 600 gCO2/kWh during the bad weather last December where there was relatively little wind. Its difficult to read data from this as Moneypoint, Great Island and some of the lower merit less efficient plants would have been running.

Figures for the UK have them averaging about the 350 gCO2/kWh. They are a much larger system though so economies and efficiencies of scale have to be factored in. It'd be possible to have far more units running at peak capacity at a higher efficiency in a system of that size while still meeting all of your reserve and operational constraints. I would be interested in knowing the figures for Denmark and Switzerland, but then again they aren't really separate systems, might be more useful to look at the EU average.

Chloe Pink

Capt'n Midnight wrote: »

'cos they all have 100% capacity and never have unplanned downtime :rolleyes:

I think the difference in the reliability of wind versus conventional generators is quite clearly put here by Eon UK:
http://www.publications.parliament.uk/pa/ld200708/ldselect/ldeconaf/195/8061708.htm

Conventional generators:
" 8. From the point of view of the system operator (National Grid) who must schedule sufficient capacity in order to meet winter peak demand with a very high degree of probability, an assessment must be made of how likely it is that the capacity available will in fact operate at the time required. For this purpose, planned outages and weekend maintenance can be ignored as they are highly predictable and scheduled for low demand periods.

9. Excluding these factors, the weekday availability (actual availability/maximum total availability) of thermal (ie burning coal, gas, oil or biomass) plant over the winter period is about 95% with breakdowns accounting for 5% of maximum total availability. Crucially, breakdowns are generally not correlated with each other. There are exceptions and these have to be taken into account (such as loss of gas supply at a number of stations, or type faults), but they are generally a small effect. So, if a unit at Station X is unavailable, there is no reason to suppose that another unit at a different station is going to be unavailable. This means that conventional units are very effective at backing each other up, especially when the portfolio contains a mixture of plant types and fuels."

Wind turbines:
" 10. To assess the extent to which investment in wind capacity will be able to replace thermal plant on the system while ensuring that peak demand can be met at the same level of reliability, we need to assess how much wind capacity on the system can be relied on to meet peak demand at a dependability of 95%. Our assessment of winter wind generation data in 2007[5] indicates that the system operator could rely on 8% of total UK wind capacity to meet winter peak demand at the same level of dependability as thermal plant. On this basis, if the UK required, say, 40,000MW of wind capacity to meet its renewable target by 2020, only 8% of this renewable capacity (3,600MW) could be relied on to meet winter peak demand. This would avoid the need to build 3,600MW of new thermal plant but the remaining 36,400MW of renewable capacity would need to be "backed-up" by thermal plant to meet winter peak electricity demand in 2020. This effect could be to some extent mitigated by more extensive electricity interconnections with continental Europe (which would enable "back-up" power to be imported), the longer term development of new electricity storage technologies at a significant scale (which would be able to store power from the grid and produce it when required), or more demand side management capability which would enable demand to be varied in relation to the level of wind generation."

Chloe Pink

Capt'n Midnight wrote: »

just a reminder about the the interconnectors...

... When these projects are complete this Island will be able to import/export up to 1000MW

And another reminder about the interconnectors:

http://www.ref.org.uk/attachments/article/228/pr%20110401.pdf

"In subsequent work for REF, published in July 2010, Mr Bach updated and extended his work in a book entitled, The Variability of Wind Power: Collected Papers 2009-2010. This work revealed the degree to which wind variability might be synchronized across Europe, with the implication for spot prices and the value of trans-continental interconnections. As Mr Bach wrote: “The combination of wind power in Denmark, Germany, and Ireland produces a statistical smoothing effect […] however, the effect is not strong, and even assuming market interconnections which are perfect in a physical and regulatory sense there would still be extreme peaks and troughs in wind output” (p. 47)."


"Pöyry’s study goes some way to addressing the questions raised by Oswald and Bach’s work, and reiterates many of the conclusions previously drawn by REF in its research work on intermittent renewables, namely that:

(i) A geographical spread of wind (and, Pöyry argue, solar) supported by a supergrid would not resolve the problems of intermittency because similar weather patterns can extend across much of the continent of Europe and the UK and Ireland."


Quote from the summary of the Pöyry report which can be down loaded from here: http://www.poyry.com/media/media_2.h...301471113.html

"This heavy reinforcement of interconnection doesn’t appear to offset the need for very much backup plant, however. This surprising observation comes from the fact that weather systems – in particular high pressure ‘cold and calm’ periods in winter – can extend for 1000 miles, so that periods of low wind generation are often correlated across Europe."