Renewables and backup power

[guydewdney]

A question that has been bothering me - can we have a reasoned / calm explanation for this:-

we need something like 40,000MW power to stop the lights going out in the UK (source - national grid last 24 hours peak was 32,000MW http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Demand/demand24.htm )

so - lets say, for the purposes of this intellectual discussion - that 100% is made by renewable energy, wind, hydro (dams) hydro (wave), solar, biomass, geothermal etc.

Some of these are less than day to day reliable - ie clouds, still air, no rain. Some are 'reliable' eg (geothermal).

The anti brigade spout that we need to cover the capacity of the 'unreliable' RE with non RE or continuous - eg nuke, coal gas etc. So even if we are producing 100% by RE, we still have to have  a backup of the total capacity, but in coal nuke etc - which has to run at tickover (in order to be able to fire up when the wind drops / a cloud comes) which is very inefficient. They say the coal stations run at 10% (IIRC) power, but produce almost nothing, as all that power is used in running the plant itself, but they have to do this, so that they can flick a switch when the wind drops....


Any reasoned / calm comments?

[camillitech]

What we need are some big 'START O MATIC' power stations Guy, it's not 'rocket science, Lister were doing it in the 1930s, If we can put a man on the moon and a cruise missile down Saddam Husein's trousers then surely we can design a large start on demand power station or two. Or am I missing something 

Cheers, Paul

[cj]

If we have smart metering, we can then have dynamic load shedding, so non urgent or non essential loads can be removed for minutes or hours, so the picture should not be quite that bad.

Street lighting could be turned off to protect essential supplies in freak conditions as well.

[guydewdney]

But if the street lights are turned off in London, women will be raped and childen abducted, just cos the wind drops in scarborough? (you can just hear the newspaper headlines)

[billt]

I was under the impression that the grid already had this capability in order to cope with variable demand. Very fast response from pumped storage, with low capacity, fairly fast response from gas fired plants. Load shedding also features.

Some large consumers pay less for their power in exchange for the possibility of losing it at short notice.

Street lights used to be switched off late at night years ago. It's coming back into fashion again!

[Countrypaul]

Surely with wind power we know roughly how much wind there will be a day or two (or even more) in advance and in which areas of the country. Similarly, with solar we know roughly how much cloud cover there is likely to be in any given area a day or two in advance. The others biomass, hydro etc. are even more forecastable. Combining the forecasting with better load balancing could releve a lot of the backup generation required.

I was under the impression that, I think it was Hartlepool Nuclear Power station, had a couple of gas turbines that could be turned on to generate 90MW and that these ran from standstil to full power in something like 60 seconds. If gas power can be turned on so quickly (and presumably off jsut as quickly) then why look at coal and nuclear for backup purposes, using the coal and nuclear for base load until such time as it isn't required would make more sense?

Paul

[GavinA]

Any reasoned / calm comments?

1 - providing we spread our generation across all renewable sources, and over a wide geographic area there will never be a time when there is absolutely no input from variable renewables in total.

2 - If we invest in additional HVDC interconnectors between us and surrounding countries which also have high levels of renewables, then point 1 is increased further

3 - We have 3GW, soon to be 3.5GW, of pumped storage to assist with smoothing out short term fluctuations should we choose to use it in this way instead of mainly storing french nuclear excess overnight for use in our morning peak.

4 - We could well have around ~ 10GW of biomass, on top of around 1.5-2GW of hydro.

5 - Demand reduction, greater dynamic demand controls to better balance short term fluctuations etc will help.

6 - Anyone arguing for 100% renewables in anything other than the very long term is unlikely to be doing so from a realistic position IMO. For the forseeable future whatever else we do, we're at least going to have significant capacity of gas generation, which I suspect will increasingly end up being used as peaking stations / back up for periods of low renewable generation as our renewable capacity increases (if we're actually going to achieve long term targets).

 I suspect that aiming for something like 70-80% of electricity generation from renewable sources may well be an achievable aim within the next 50 years or so, but to achieve this would require significantly more total peak renewables generation capacity than our total existing generation stock, with renewables generating 100% or over much of the time (with the additional amounts going into pumped storage or other storage means, or simply being peak lopped if not required as they're already doing in Germany with PV), and gas picking up the shortfall when renewables generation drops below demand.

Providing that this was matched with similar carbon reductions across the board, we should then easily be able to meet the 80% carbon reduction targets while still using a level of gas, oil and to a lesser extent coal (which when co-fired with biomass generally improves the thermal efficiency of biomass generation, and could be needed as a back up fuel source for biomass generators if there were temporary supply shortages).

[cj]

They are being dimmed in places, a sign in Chippenham I saw today said 'street lighting reduced after 24.00 Hrs.'

Yes Guy that is what the newspaper will try to portray, politicians will say whatever will win them most votes next time around. We need truly independent assessment of what is reasonable, under what (freak) circumstances ie calm for weeks, France refuses to export to us, cloudy weather, political gas shortages, and no rain for 3 months, all at the same time.

Load shedding for some customers for lower rates has been operated for a while, with Smart Meters, that will come to all of us before too long - if there is a political agenda to do so.

We do need some serious proposals to reduce wasted consumption, remove VAT on LEDs paid for by a filament tax etc, an on a grander scale east - west hyper grid to maximise solar power through southern Europe, we can give hundreds of examples, if only they would listen.

[billi]

Taking the Graph out of guys link

and as far as i know 1000 MW is 1 GW




then the PV alone installed in Germany  would look quite helpful    during the day  here production  "data" of PV production

http://www.sma.de/en/news-information/pv-electricity-produced-in-germany.html

Sure that does not help during the night  , but for a  Generator idea that started only about 5 years  back to really  kick off over there , quite respectful i think

Billi

[martin]

I'm amazed that it's found necessary to keep so much streetlighting on - why on earth do we need it on motorways? I live in a rural area where the introduction of it would be strongly resisted, and am grateful for it being so. I suspect that a lot of it is that we've got into bad habits following WW2, when the ability to suddenly let the lights be seen was a very obvious reaction against the blackout years. It's certainly a dreadful waste of resources, and a somewhat sad indictment of most "town life" in that it would appear people are frightened that if they didn't have everywhere in a constant blaze of light that murder and mayhem would break out after twilight.........

[renewablejohn]

I see renewable gas being a big part of the solution as it can be stored relatively easily and used on demand in existing efficient gas turbine plants so no additional generating capacity required. What is required is the biomass gasification plants to turn biomass into usable gas rather than cofiring  in inefficient coal fired plants which should be consigned to the scrap heap. These distributed gasification plants need to be sited in areas with local access to fuel and sufficient population density to warrant district heating schemes.

[brackwell]

Cannot really believe we are discussing the same subject 2 weeks in a row.

Guy,  The anticipated peak this coming winter is 56Gw at 17.00hrs ( as always).  I trust you have read http://www.inference.phy.cam.ac.uk/withouthotair/  which attempts to answer this question and furthermore gives people of different energy persuasions the chance to choose their option.  I believe this is essential reading for people interested in this subject.

The problem is that people have difficulty understanding the scale of what we are discussing.  Leaving aside management of peak to trough the only renewable that can be relied on is geo thermal and partly rely on hydro and tidal. We would have to cover the whole country with these and transmission lines.   There is no point discussing hydro in Mw when the problem is in Gw.

Managing the Grid on a second by second basis is no mean feat.  Its alright people having fanciful ideas here but when one had the responsibilties of keeping the lights on !

Anyway people are coming at this from the wrong end. The National Grid is not charged with CO2 emissions or cost reduction it is charged with MAINTAINING SUPPLY.     Maintain supply with generation plant that cannot be relied on is impossible.

The real question is to what extent can we introduce renewables and the National Grid maintain supply. The answer to that probably depends on how much money are you prepared to throw at it.  Not much i am guessing from the way people kick off about energy prices. Anyway increasing energy prices will reduce demand.   And actually that is the way to bring in the change -just increase prices 10 fold and just sit back ,job done.

[brackwell]

"Our new target is to generate the equivalent of 100% of Scotland’s own electricity
demand from renewable resources by 2020.

By then we intend to be generating twice as much electricity as Scotland needs –
just over half of it from renewables, and just under half from other conventional
sources. We will be exporting as much electricity as we consume."

Did you notice that word "equivalent"  ie  Scotland will say they are 100% renewable electricity when the total renewable generation over the whole year equals the total consumed over the whole year. Not so sure that would be most peoples definition.   You PV guys can say you are 100% renewable if you total production over the year equals your total consumption-ye what

Ken

[dhaslam]

It all makes the decision against the Severn  barrage seem very wrong.   Although tidal power is intermittent it is very predictable and could be  used in conjunction with a smart metering system.   The other reliable natural source that doesn't seem to be in favour at present is  geothermal. 

[brackwell]

dhaslam,

I do agree with you on the Seven barrage/lagoon but having lived around the sea estuaries i would take some convincing that it would not just silt up.  If it was not for the large water flow in the Bristol Channel it would silt up. There must be other good places though.

It is strange about the geo thermal - perhaps it only works in places like Iceland,NZ,Hawaii where presumably the earths crust is thin or is it we just dont have the experience/expertise.

Ken