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Author Topic: Aberthaw Power Station and Decarbonisation  (Read 3743 times)
mjones
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« Reply #15 on: October 17, 2020, 02:43:30 pm »

Some of the more unusual  methods  being proposed to store surplus renewable  energy should help in that respect,  for example as liquified air that would drive a turbine and heavy weights pulled up and down mine shafts  by motor/generators.  However other methods like hydrogen electrolysis and large  flow batteries will have the problem you describe.
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stuving
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« Reply #16 on: October 17, 2020, 04:01:51 pm »


Perhaps renewable sources need the same as UPS systems used to have; large motor/alternator sets running continuously.

There's a small energy (and cost) penalty but that's just part of the joy of sustainability.
It might even make re-newables more useful/marketable as a consistent energy supply.

OTC


Other solutions are being found including flywheels in Scotland

Flywheels cant store enough energy to compensate for calm weather and limited power availability.
They are however very helpful by adding inertia and thereby promoting stability, I expect more schemes similar to the one in the above link.

You don't need to - this contract was one of five signed by NG-ESO in January. They are paying for a service (presently called synchronous compensation), ?328M over six years. It is up to the contractors to find the capital cost. Together they provide 12.5 GWs of inertia - the grid had 300 not long ago, now has 100-200 depending on the connected plant mix (which is seasonal) and will soon be below 100 some of the time. So this is only a part of the solution.

In addition to that Statkraft one, there is another new one in Wales and three using existing things as flywheels. On is a turbine at Cruachan, operated by Drax. Uniper are using two old power station turbines at Killingholme, and building two new SCs at Grain. Triton are providing this service at Indian Queens (near St Dennis)  - of which they say this:
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Indian Queens Power Station is an OCGT (Open Cycle Gas Turbine) power station located in Cornwall. The station has an output capacity of 140 MW providing voltage support to the UK electricity market as part of an ancillary services contract with National Grid.

The turbine drives an air cooled generator through an SSS (Synchro Self Shifting) clutch which allows the plant to operate as a synchronous compensator when required. The power plant operates at peak times when power demand is high.   

Synchronous compensators (a big flywheeel and a synchronous motor) are not at all new, but big ones have become rare. Most of the work has gone into "static" systems, based on BESS*. The trick is similar to regeneration in a train - make the DC/AC converter work in both directions, and add software. I found a research project (SP's Phoenix) description from 2017 in which a plan to repurpose a closed power station was rejected as "of extremely high risk", in favour of building a new one. That is now an experimental hybrid (70M flywheel + 70 MW static), to look at the different effects of the two and how to link them.

Virtual inertia was included in the "Enhanced Frequency Control Capability" project for NG-ESO, which is reporting this year. But it's a slippery term - real inertia feeds power in or out immediately and proportionally as the phase angle (or RoCoF - rate of change of frequency) departs from its stable point. That reduces the RoCoF, but the methods EFCC ended up with don't - they intervene after a second or so (and non-linearly) to yank the system frequency back into line. I suspect that for those with power systems attached to the grid that can be an important difference.

*BESS - battery energy storage systems, or what were called batteries
« Last Edit: November 05, 2020, 07:11:15 pm by stuving » Logged
stuving
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« Reply #17 on: November 05, 2020, 07:10:38 pm »

On Tuesday night National Grid issued an "electricity margin notice" for yesterday evening - an urgent request for extra generation to be made ready, if need be using (big) firelighters. That's down to the lack of wind, as we are currently under an anticyclone. And, as is quite common, this stretches across France and Germany, so we can't import much. In the event, the supply situation improved and the EMN was withdrawn during yesterday.

But it might be back, as this thing is forecast to hang about all week - again they often do - so if anyone says "bring on the batteries" they'll need to get some very big ones indeed. For this case the planning shortfall was 750 MW so that might not be unfeasible; say 50 GWhr. But I think the reduced use of offices has reducing demand, just temporarily. Once we start reducing thermal power further this large-area shortage of wind would call for much bigger reserves.
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stuving
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« Reply #18 on: November 05, 2020, 10:19:01 pm »

It now appears that another EMN was issued for today, though for a smaller shortfall (466 MW). In part this is down of loss of several  thermal stations:
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Tight generation margins in the UK reflected a drop in temperatures, low forecast wind generation and a relative lack of flexible supply, Glenn Rickson of S&P Global Platts Analytics said Nov. 4.

Outages at Langage and Drax 4 compounded the long-term unavailability of three gas-fired power stations owned by Calon Energy, after the company was put into administration in August.

Currently there is some wind in western Britain and southern France, but that's likely to edge away and by Sunday there's a serious shortage of isobars anywhere in Germany.
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onthecushions
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« Reply #19 on: November 05, 2020, 11:14:05 pm »

So the stability of the grid depends on generating companies of marginal solvency and is further put at risk by premature decarbonisation.

OTC
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stuving
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« Reply #20 on: November 05, 2020, 11:31:07 pm »

So the stability of the grid depends on generating companies of marginal solvency and is further put at risk by premature decarbonisation.

OTC

Ah, but there was a plan to cope with that, wasn't there? A new generation of nuclear plants, starting with Hinkley Point C. Of course by the time that got approved it wouldn't be on stream until 2023, and by the time building started it had slipped to ... well, I'm not going to guess a real date.
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TonyK
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« Reply #21 on: November 05, 2020, 11:34:00 pm »

So the stability of the grid depends on generating companies of marginal solvency and is further put at risk by premature decarbonisation.

OTC

That looks about the long and short of it, OTC. Power generation used to be a publicly owned utility with an unenviable record of inefficiency and pollution. Then it moved to private generators who produced electricity and made a profit. Now the companies make a profit with electricity as a by-product. This isn't confined to the big six or the dirty industries - the poster boy for wind power lives in a castle and owns a football team. Each looks after their own bit, leaving National Grid to try to make it all work, sometimes using nearly everything in the country that will create a volt or two, and hoping it doesn't get too much colder.

Meanwhile, the government is considering bringing forward the date when fossil fuelled cars can't be built, and stopping the installation of gas boilers in new-build homes. What could possibly go wrong?

I see we're burning coal again, for 2.5% of our leccy as I write.
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broadgage
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« Reply #22 on: November 06, 2020, 04:04:22 am »

Our significant wind and solar generating capacity have reduced the amount of coal and natural gas used for power generation, thereby reducing carbon emmisions and reducing the need for natural gas imports.
This later point is important becuase the UK is now very reliant on natural gas imports, AND we now have less gas storage capacity than a few years ago.
Any event that significantly reduced gas imports for more than a week or two would have most serious consequences.

However as recent events have shown, we dont have adequate plans for cold but calm weather.
Battery storage helps, but is not yet sufficient.
Pumped storage helps but is not sufficient and oportunities for expansion are limited.
Natural gas burning is the main alternative at present. Burning natural gas intermittantly in calm weather is better than for base load generation. (reduced carbon emmisions, reduced foreign exchange used, our limited storage will last longer)
The existing nuclear power station at Hinkly point is unlikely to be available for this winter.
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
broadgage
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« Reply #23 on: November 06, 2020, 04:16:05 am »

At present, wind power is meeting about 4% of our electricity demand, better than not having that 4% but a small contribution.
CCGT (combined cycle gas turbine) plant is meeting about 40% of demand.
Yesterday, some power was from OCGT (open cycle gas turbine) an expensive way of generating electricity. The main merits of OCGT plant are low capital cost, quick to build, and quick starting.
Some OCGT plant starts automatically in case of a sudden drop in grid frequency. Some can burn light distilate oil in an emergency, but natural gas is the usuall fuel.
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
TonyK
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« Reply #24 on: November 06, 2020, 10:34:59 am »

Wind was providing over 40% of our electricity, or 10% of our energy needs depending on how you look at it, some days last week. Now, it's under 4% of electricity. The output line on the graph for nuclear is flat, at about a quarter of our electricity at the moment, the proportion being dependant on need. Solar is wonderful in summer, cutting my own bill to pennies per day, but doesn't work too well when the daylight period is under 8 hours long and frequently dull, with demand at its peak.

Are batteries the answer, as some proclaim loudly? All the batteries in the known universe wouldn't power this country for a day, but they could possibly help manage the load. As any builder will tell you, it's usually the battery that dies before the power tool, so they may not be the end of the matter. In any case, a lot of batteries are going to be needed for the millions of new electric vehicles. Also, if you are looking to batteries to store excess renewable power, there isn't any.

The problem is the same as it has always been - politics. The last example I can remember of a government riding completely roughshod over public opinion with unseemly haste was the construction of the South Wales gas pipeline in 2007. In the Cotswolds, the digging started while the protest meetings were still being organised, and the grass had grown again before the point where we would normally have started the first public inquiry. Generally, though, a major issue that will involve something unpopular is normally booted down the road for someone else to sort out. I think we are at the end of that now, with closure of coal power stations being popular, we just don't have a proper replacement in place as yet. Fusion will be with us in 10 years, as it has been since I was a kid. Hinkley C will be on stream just in time for some other nuclear plants to close, and the protest industry has moved on to HS2 for the time being. I am hoping that the so-called biomass plants will be the next target. Rotting down food waste, sewage and farmyard slurry for fuel is fine by me, solving two problems in one. Importing millions of tonnes of wood pellets from forests in the Americas and growing vast acres of maize just to generate subsidies energy is not.
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ellendune
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« Reply #25 on: November 06, 2020, 10:45:15 am »

I think we are at the end of that now, with closure of coal power stations being popular, we just don't have a proper replacement in place as yet. Fusion will be with us in 10 years, as it has been since I was a kid. Hinkley C will be on stream just in time for some other nuclear plants to close, and the protest industry has moved on to HS2 for the time being.

I was always told 40 years so if it is 10 that is progress. 

Rotting down food waste, sewage and farmyard slurry for fuel is fine by me, solving two problems in one. Importing millions of tonnes of wood pellets from forests in the Americas and growing vast acres of maize just to generate subsidies energy is not.

Agreed
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Red Squirrel
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« Reply #26 on: November 06, 2020, 11:25:03 am »

So the stability of the grid depends on generating companies of marginal solvency and is further put at risk by premature decarbonisation.

OTC

Decarbonisation can't really be described as 'premature', can it? The transition should have been better-planned, and it should have started earlier, but it is overdue rather than premature. If only some of the eye-watering subsidies given to fossil energy companies had been directed into grid storage ten years ago we would be in a much better place today.

...the poster boy for wind power lives in a castle and owns a football team.

Boy done good! We don't have a problem with that, do we?

Are batteries the answer, as some proclaim loudly? All the batteries in the known universe wouldn't power this country for a day, but they could possibly help manage the load. As any builder will tell you, it's usually the battery that dies before the power tool, so they may not be the end of the matter. In any case, a lot of batteries are going to be needed for the millions of new electric vehicles.

It does seem a bit eccentric to use lithium-ion batteries for this. These are good for highly energy-dense lightweight installations, such as light vehicles or phones. Using them for grid storage is like harnessing a racehorse to a brewer's dray. Heavier less energy-dense solutions ought to do the job and, land cost aside, should be cheaper and more reliable.

Also, if you are looking to batteries to store excess renewable power, there isn't any.

Apart from massive amounts overnight on windy nights?
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broadgage
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« Reply #27 on: November 06, 2020, 04:41:55 pm »

There is not AT PRESENT any regular surplus of renewably generated electricity even in windy weather. Inspection of the gridwatch site will show that overnight and in windy weather, that natural gas is still being burnt for electricity generation.
However with increasing numbers of wind turbines, the day will come when there WILL BE a surplus at night in windy weather.
With more solar power being installed, a daytime surplus in mild weather and bright sun is a future possibility at weekends when demand is less.

It is therefore well to plan for FUTURE surpluses and how to either use the surplus in some productive way, or to store it.
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
Red Squirrel
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« Reply #28 on: November 06, 2020, 05:37:17 pm »

Beg pardon to broadgage and TonyK; you are of course quite right. There may be regular wind surpluses one day, but not yet awhile. Unless they are emitted by me.
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onthecushions
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« Reply #29 on: November 06, 2020, 05:55:44 pm »

So the stability of the grid depends on generating companies of marginal solvency and is further put at risk by premature decarbonisation.

OTC

Decarbonisation can't really be described as 'premature', can it? The transition should have been better-planned, and it should have started earlier, but it is overdue rather than premature. If only some of the eye-watering subsidies given to fossil energy companies had been directed into grid storage ten years ago we would be in a much better place today.



It is premature without adequate, timely replacement. No one, Greens included, is prepared to sit in unheated darkness at this time of the year. The Carbon cycle is the basis of life and combustion is the basis of advanced human societies until better energy sources are acquired.

Your point about subsidies is well made; the post war "subsidy" to the coal and rail industries by opting for large generating stations, like Drax, away from settlements, fed by MGR coal trains, meant that smaller ex-municipal power stations (like Earley at Reading, etc) that could have supplied their rejected, waste heat for district heating and cooling, doubling their thermal efficiency and reducing gas demand, were closed. Equally, little has been done (IMHO) to address heating demand seriously until recently. I've seen a German house with 300mm/12" of insulation that had no need of extra space heating even in a continental winter of -20C. It was also not flammable!

OTC
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