Tidal Lagoon - Energy from the Ocean, UK Gov is putting money in it

[SeanB]

The one large energy source available mostly to the UK is nuclear power from France, fed through an undersea cable and a DC interconnect. That helps with sudden grid demand as the French timing typically is different from the UK, and the French reactors provide a lot of power to most of Western Europe via assorted links.The Danish ones both pass power through and add the wind power as a small extra to it, but most power in the mainland will be French nuclear as base load.

[coppice]

Martin Lorton mentioned something recently about large solar farm destabilising the grid as well due to sudden fluctuations of output which cannot be picked up fast enough by other generation means.
The only way we are going to get the amount and reliability of supply is going to be from thorium reactors.

The article tggzzz referenced raises the point strongly that early solar installations were poorly designed for grid stability, and that upgrades will take some time. Most people currently talking about stability refer to current problems. I haven't seen a good analysis of what is inherently hard to fix, especially if the higher levels of the grid were adapted to the changing generation patterns.

The paper from California, which mojochan referenced, talks about the need to avoid distributed generation pushing energy into the higher levels of the grid. For stability, they assume energy generated in a distributed way, and pumped into a sub-station's catchment area, will be used within that catchment area. The snag is, current equipment does not enforce this. In fact, it appears a lot of current equipment might pump up the local voltage to a dangerous level, as they don't limit this properly. I've seen reference to that in several places, including the California paper. The grid was never designed to have energy pushed upstream through the major transformers. It isn't designed to stabilise itself under those circumstances. Whether is could be adapted to do so is another matter.

One of the nice things about solar PV is it only outputs what you draw. As a system it  can go from full output to zero to full as fast as the control loop of the inverter can react. With effective regulation of the design of inverters approved for grid connection, it seems a lot of stabilisation could be provided by this. The reason it requires regulation is that doing the right thing is not in the interests of the owners of the inverters. They want to push out every scrap of energy they can muster, and get it metered, regardless of what the grid needs at any instant. Only rules strictly enforced could help there. In this sense solar PV has the potential to provide the opposite effect from the one Martin Lorton described.

In Europe it seems solar PV inverters will trip if the grid frequency appears to vary by more than 1%. In a continent with a super stable grid that probably seemed like a very sensible protection a few years ago. Now, as there is more reliance on solar output, it means a short term hiccup in the grid could turn into a full scale outage, as things trip on a huge scale. The Spectrum article raises this as one of the key concerns in Mainland Europe about what might happen in the eclipse. Its being addressed, but upgrades take time.

[dannyf]

-early solar installations were poorly designed for grid stability, and that upgrades will take some time-

Under voltage dropout. It is a fairly recent thing and depending on the panels used the upgrade could be north of 20k USD.

Good luck to the early adopters and tax payers who subsidized such systems.

[coppice]

-early solar installations were poorly designed for grid stability, and that upgrades will take some time-

Under voltage dropout. It is a fairly recent thing and depending on the panels used the upgrade could be north of 20k USD.

Good luck to the early adopters and tax payers who subsidized such systems.

Under voltage dropout is not one of the more serious limitations of early systems for grid stability. It wastes potential capacity, but it just drops the system off the grid is a relatively benign way.

[Galenbo]

...you are a neo-con liberal.

Sorry, we don't use that terms here, difficult for me to know how it is interpreted exactly. The circumstances are also different because we don't live in a two-party system here.

I discribe myself as a libertarian most of the time.
What we know as liberal is very different from this.

[tggzzz]

This shows that today there will be almost zero wind power generation anywhere in the UK. It will be very little better tomorrow.

[G7PSK]

Not much solar either due to heavy cloud and rain along with virtually no wind today. It seems rather stupid to rely on French nuclear power via the cross channel link, you never know when we could have slight disagreements with them as we did in the 19th century But seriously it is daft to rely on a cable that could get cut through natural or man made events.   

[coppice]

If there's not much wind, there won't be much wave power either, but the tide will still go in and out. 

[Mechanical Menace]

This shows that today there will be almost zero wind power generation anywhere in the UK. It will be very little better tomorrow.

I still don't understand why "this is intermittent" equates to "we shouldn't bother at all" if I'm honest. Surely it's a good excuse to diversify as much as possible? I mean I'll admit that without some new grid storage developments renewables are not perfect but 1) it would probably make people more willing to consider it and 2) would be useful even if for some miraculous reason we don't have to at least reduce fossil fuel burning plants.

[coppice]

This shows that today there will be almost zero wind power generation anywhere in the UK. It will be very little better tomorrow.

I still don't understand why "this is intermittent" equates to "we shouldn't bother at all" if I'm honest. Surely it's a good excuse to diversify as much as possible? I mean I'll admit that without some new grid storage developments renewables are not perfect but 1) it would probably make people more willing to consider it and 2) would be useful even if for some miraculous reason we don't have to at least reduce fossil fuel burning plants.

Intermittent isn't the really big issue with wind. Unpredictability is. Try looking up estimates for how much oil and coal has been saved through the use of wind. The numbers are all over the place, due to biases, but even the most optimistic aren't very inspiring. Wind is so unpredictable that you need a large amount of backup up and running, ready to pick up the slack at short notice. Tidal power is also intermittent, but its highly predictable. At least you know in advance pretty much what you need to do to fill in the gaps. That puts it way ahead of wind as a quality energy source.

[Mechanical Menace]

Wind is so unpredictable that you need a large amount of backup up and running, ready to pick up the slack at short notice.

If only we couldn't flood more of Wales and Scotland

[tggzzz]

This shows that today there will be almost zero wind power generation anywhere in the UK. It will be very little better tomorrow.

I still don't understand why "this is intermittent" equates to "we shouldn't bother at all" if I'm honest.

Who says that? I don't.

Surely it's a good excuse to diversify as much as possible? I mean I'll admit that without some new grid storage developments renewables are not perfect but 1) it would probably make people more willing to consider it and 2) would be useful even if for some miraculous reason we don't have to at least reduce fossil fuel burning plants.

And there's the problem that some people (not you) are "reluctant" to acknowledge: having xGW of intermittent sources doesn't mean that we can get rid of xGW of conventional sources.

Diversification is good. Downplaying/denying/ignoring disadvantages isn't - and that's what I object to. It is a limited, albeit important point.

[tom66]

This shows that today there will be almost zero wind power generation anywhere in the UK. It will be very little better tomorrow.

And yet... http://www.gridwatch.templar.co.uk/

660MW of wind power, or 1.5% of current UK demand, does not a renewable grid make. That's under 10% of total capacity.

To even meet the current 8GW maximum generation right now, we'd need 12x as much wind turbines... and the whole grid would need 90x as many...

[tom66]

Clearly we have different definitions of "almost zero".

For power generation purposes sub 1GW may as well be zero. Granted, it's some power - but it's really nothing much compared to nuclear despite having an 8GW installed capacity (nearly 2/3rds of the installed nuclear capacity.) A grid simply wouldn't work on purely intermittent renewables unless you had either a large amount of grid storage, or a significant overhead (for example, 10x as many turbines as typically needed.)

[Zucca]

Thanks for all the posts, very interesting! For my side it was just a FYI only, I didn´t expect these many reactions.

BTW, here it looks like there IS wind in UK:
http://www.dailyrecord.co.uk/news/weird-news/watch-hilarious-video-showing-man-5342404

[dannyf]

Intermittent isn't the really big issue with wind. Unpredictability is.

A grid is unique in that at any given time, it is perfectly balanced: supply = demand all the time.

So even if you know for sure that 100MW of power is coming on line at 10am, it is still a huge headache for the grid operator on consuming that additional power.

That's why the base load operators insist on charging solar or wind generators to pull them into the grid. Intermittent power generation has negative value to a grid.

The only reason we are paying them now is driven by policy and not economics.

[tom66]

It's not entirely impossible, I suppose, to power a country with wind 99% of the time.

We'd just need something like 600GW installed capacity, and turn off 90% of turbines in the heaviest wind. Short term, general area trends in wind can be predicted - so it would be possible to see when there would be insufficient wind and that's when you'd have to switch to fossil fuel or other sources, or Dinorwig/etc could fill in for shortfalls whilst the slower plants catch up.

Obviously extremely costly - not just from a £/MW basis but also maintenance costs of such a large network. And those costs aren't likely to fall significantly any time soon.

[coppice]

It's not entirely impossible, I suppose, to power a country with wind 99% of the time.

We'd just need something like 600GW installed capacity, and turn off 90% of turbines in the heaviest wind. Short term, general area trends in wind can be predicted - so it would be possible to see when there would be insufficient wind and that's when you'd have to switch to fossil fuel or other sources, or Dinorwig/etc could fill in for shortfalls whilst the slower plants catch up.

Obviously extremely costly - not just from a £/MW basis but also maintenance costs of such a large network. And those costs aren't likely to fall significantly any time soon.

There are also the energy costs. Such a vast amount of excess capacity would require vast amounts of energy for its construction. I wonder what the break even time purely on energy would be?

[tggzzz]

Clearly we have different definitions of "almost zero".

What is your definition?

Are you prepared to accept wind "outage" 1%, 5%, 10%, 50%, 90%, 99% of the time?

[tggzzz]

This shows that today there will be almost zero wind power generation anywhere in the UK. It will be very little better tomorrow.

And yet... http://www.gridwatch.templar.co.uk/

That's a very interesting resource; thanks; bookmarked.

From that we can see on the 17th we lost 95% of the peak wind power (~300 vs 5869) measured over the past year.
From that we can see on the 17th we lost 82% of the mean wind power (~300 vs 1705) measured over the past year.

Now, what conventional plant would you use to replace that when (not if) it occurs again?

[coppice]

This shows that today there will be almost zero wind power generation anywhere in the UK. It will be very little better tomorrow.

And yet... http://www.gridwatch.templar.co.uk/

That's a very interesting resource; thanks; bookmarked.

From that we can see on the 17th we lost 95% of the peak wind power (~300 vs 5869) measured over the past year.
From that we can see on the 17th we lost 82% of the mean wind power (~300 vs 1705) measured over the past year.

Now, what conventional plant would you use to replace that when (not if) it occurs again?

That site does seem to be an interesting source of data. Is there any way to monitor what solar PV is doing for the UK grid? From what I understand domestic UK installations are simply metered for billing purposes.

[tom66]

AFAIK there's no direct metering for the UK grid at the moment. But you can look at France which is geographically similar. Domestic installs only show up as a reduction in demand, but the larger industrial systems are metered on the far right of this page.
http://www.gridwatch.templar.co.uk/france/

It's beautiful to see near 100% of power coming from clean sources. (There seems to be an error in calculating total demand, but over 55GW is from nuclear and hydro.) Nuclear may not be renewable but it's a damn sight better than coal or gas.

[rolycat]

AFAIK there's no direct metering for the UK grid at the moment. But you can look at France which is geographically similar. Domestic installs only show up as a reduction in demand, but the larger industrial systems are metered on the far right of this page.
http://www.gridwatch.templar.co.uk/france/

It's beautiful to see near 100% of power coming from clean sources. (There seems to be an error in calculating total demand, but over 55GW is from nuclear and hydro.) Nuclear may not be renewable but it's a damn sight better than coal or gas.

Unfortunately for proponents of nuclear power, the Hollande government has committed to reduce France's nuclear generation to 50% by 2025.

[SeanB]

A simple way to look at the grid is to take the premise of the bus in Speed. You have a bus that will go bang if it goes under 55, and will go bang again if it goes above 65. You are on a long and straight imaginary road, with some hills and dales on it. the engine provides power to the bus till it runs out of fuel. This is the grid with power stations and such with coal, gas and nuclear supplies.

Now with intermittent sources you suddenly, and without warning, are going to have smaller vehicles either pushing the bus from the rear, or pramloads of cans suddenly pushed in front of it. you need to still have the bus do constant speed on the road.

Now, if you have a semi truck doing the push from the rear, or you hit a whole line of prams filled with concrete you will have the bus, along with Mz Bullock and Keanu Reeves, going up in a pyre of flame. That is what happens if there is too much load change beyond the ability of the grid control to compensate.

[SeanB]

Unfortunately for proponents of nuclear power, the Hollande government has committed to reduce France's nuclear generation to 50% by 2025.

Welcome Europe to rolling blackouts. A few weeks of this should be enough to have the citizens rather angry.