Electricity Dispatch | capacity credit | firm rating

Another copied PatLogan post

PatLogan Viridis

07 September 2014 8:31pm

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Wind most certainly isn't the back-up.

Anyone who's ever worked around grid management will tell you that the suitability of a generating technology as a back-up source is a function of it's ability to be "dispatched" (i.e. called on) on demand.

Not least because if a back up can't be called on reliably when needed, you need a back-up for the back-up.

The measure of dispatchability is "capacity credit" or "firm rating" (the latter is the UK term). It basically says that if I've got "n" megawatts of that technology, what proportion of it am I 90% likely to be able to rely on if needed.

For conventional technologies (CCGT, hydro, nuclear, coal) it's basically the lifetime availability of the plant, so around the 90-95% mark.

For variable renewables, it's never higher than the capacity factor. Onshore wind's capacity factor tends to be about 27% in the UK. Firm rating (depending on the site) is typically 8-14%. Solar's capacity factor in Germany is about 9%, suggesting a firm rating of 5-6%

If I've got 10,000MW of solar, it means I can rely on it to provide 50-60MW operating as a back-up.

Here's a thought. If I came to you and sold you car insurance that had a 6% of paying off whem you needed it, would you buy it?

WilliamAshbless: This doesn't make sense. The UK has ~ 10.5GWe of wind 'capacity'. Wind has been delivering an average of about 5% of rated capacity for an entire week now. Sometimes ,last week, it's dropped well below even 5% [e.g. it was 4% earlier this morning]

PatLogan: It's a probability based number, William - the basic definition (although it tends to get more complicated in applications) is what proportion of rated (i.e. nameplate) power am I 90% likely to get if the plant is called on in any given half-hourly period.

So yes, there will be periods when available capacity is below that, just as there'll be others when it's higher. 90% of the time, I'd be able to get that amount or higher.

Possible new UK nuclear builds (by PatLogan) ~ 17.7GWe

Another PatLogan repost from the Guardian CiF

Pat:

PatLogan commented on Pessimism won’t do. We need an energy revolution.

02 Sep 2014 10:26pm

0

at the moment, we've got three consortia (and probably a fourth) each putting up several hundred millions to buy the rights to develop one or more of the UK licensed sites.

• EdF:CGNPC:CNNPC:Areva for Sizewell and Hinkley Point ( in the ratio 51:20:20:9. Each site is 2x1600MW EPR
• Hitachi (100%) for Wylfa and Oldbury. Each site is 2x 1300MW ABWR
• Toshiba (60%) and GdF-Suez (40%) for Moorside The site is 3x1100MW AP1000
• and it's looking increasingly likely that a CNNPC:CGNPC consortium is buying Bradwell to build at least 2x1400MW CAP1400

you were saying?

Me:

Summary:

Actual demand for electricity in 2012 was 35.8GW on average, and 57.49GW at its peak. Planned new nuclear reactor builds will generate 15.525GW_e, with a possible addition of 3GW_e more (at Bradwell). By 2024 all other nuclear plants apart from Sizewell B should've closed. Add Sizewell B at 1198 MW. Apply a 90% capacity factor, the UK could expect 17.008 GWe of nuclear electricity by the late 2020s.

Consortium	Site	Locale	Type	#	Capacity (MWe gross)		Start
EDF Energyn	Hinkley Point C	Somerset	EPR	2	1650	3300	2015
EDF Energyn	Sizewell C	Suffolk	EPR	2	1650	3300	2017
Horizon	Wylfa Newydd	Wales	ABWR	2	1380	2760	2019
NuGeneration	Moorside	Cumbria	AP1000	3	1135	3405	2020
CNNPC	Bradwell	Essex	Hualong-1	2	1150	2300	2022
Horizon	Oldbury B	Glos	ABWR	2	1380	2760	2025
Total				13		17825

Current nuclear power gross capacity is up to 9190 MW_e, with 490 MW_e (Wylfa) due to close before the end of 2015.

Another copied PatLogan post : Does Geothermal make sense in the UK?

PatLogan commented on Nuclear reactors in northern England to be shut down due to faults.

13 Aug 2014 9:50pm

2

No, I stated that 75% of ELECTRICITY comes from conventional hydro - which it does, and leaves geothermal generation as a minority contributor to a small overall total volume of generation. After al, your original question was about

drilling down deep enough to hit hot rock in order to power the steam turbines in a power station

You do understand the difference between total energy use and electricity usage, don't you?

So, let me explain the difference between the sorts of conditions that you need for generating power from geothermal, as opposed to just getting hot water.

Power station steam needs to be hot and dry - and chemically pure. If you have droplets of water in it the blades of the turbine get eroded, and if you've chemicals like sulphur in there, you'll get etching and corrosion. That latter means it's generally a very good idea not to take water/steam direct from the heat source, but to pass it through heat exchanger - which means a loss of temperature of some tens of degrees.

The minimum temperature you'll realistically get way with at the turbine inlet is maybe 200C (otherwise you get those droplets) - and ideally 250C+

Even in Iceland the number of sites with that sort of conditions is limited. But Iceland's geologically very unusual - sitting on the North Atlantic Ridge, with all it's volcanic activity

In the UK, the general temperature lapse rate is about 25C/Km. That is, to get 250C temperatures, you need maybe a 10Km bore. That's deep - a lot more than is routine in oil and gas exploration - but not infeasible.

More than that, you need to transfer a lot of heat from the rocks to whatever's the working fluid. That means you need much more surface area than you get from just the bore walls.

So, when this was tried at Cambourne School of Mines, they came up with a system where you drilled two bores some metres apart (one for the fluid to go down, one for it to come up). They then needed to "frack" between the two - the idea being the fractures give a path for the fluid to flow through and pick up heat on the way. When Cambourne did it, they used explosives - you can't use water at pressure as in fracking for gas, as the rocks are too hot.

They found a number of problems; first the cost of drilling. Second, the crack systems run in all directions from the bottom of the bore, and a lot of the fluid gets lost. Third, the amount of energy to pump the fluid through the crack system is high. Fourth, the crack system tends to close up, through a mixture of plasticity in the hot rock, and chemicals leached from the rock tend to deposit in restrictions in the cracks and blocking the flow.

End result, it's a phenomenally expensive way of getting small amounts of power. At current costs, it'd be north of even tidal/wave which gets CfD support of £305/MWh.

As to "Are you a woman ?"

One of the brightest people on my BSc course was a female. She finished up as technology director for one of the world's biggest bulk chemical manufacturers.

I suspect she's got the edge on you for clarity of thought and brains....

PatLogan - Comparing Solar vs Nuclear (EPR) costs

PatLogan commented on UK energy dependence – five hidden costs expose truth about fracking.

18 Aug 2014 3:00pm

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Perhaps you should note that the original Feed-in Tariff of 42p/KwH has be halved.

It has. and strangely enough, I the wake of that the rate of new installations has collapsed.

The strike price for the new nuclear plant at Hinkley Point is over 3-times that.

You'r a factor of ten out. £92.5/MWh is for 1000 KWh, not 100. So the price is 9.2p/KWh. So, the solar cost is about 3 1/3 x the Hinkley price. Of course, the solar price omits the costs of either sles torage or back-up generation. Solar requires 100% back-up; nuclear about 10-15%

They take the form of tax breaks

In fact, even larger tax allowances apply to renewables. Investment in renewables schemes attracts "Enterprise Investment Allowances" for individual investors at 30%. From the corporate perspective, all capital expenditure in renewables generation falls under "Enhanced Capital Allowances" - a far more generous regime that applies to any other form of generation, or for investments in oil and gas. In fact it allows capital investment to be charged against tax at up to 100% in the first year.

relief from liability for cosequent environmental and health issues

Similarly, intermittent renewables are exempt from penalties under the "Balancing and Settlement" code - i.e. from the costs they impose on the rest of the system.

PatLogan: Guesstimate for gas-fired CCS project

Another post copied from Guardian CiF comments by PatLogan

PatLogan commented on UK energy dependence – five hidden costs expose truth about fracking.

19 Aug 2014 6:42pm

3

Hard to say exactly; there aren't any gas-fired CCS projects I'm aware of. But we can do some "rule of thumb" guesstimates.

Probably the best approach is to look at an IGCC (a coal gasification based generation technology) CCS plant. Probably the furthest advanced example is the Kemper County plant in the US.

An IGCC plant is basically made of three components: a coal gasification unit (which makes the coal into CH4), a gas reformer (which converts the CH4 into separate streams of H2 and CO2) and a CCGT gas turbine optimised to burn hydrogen. The H2 from the reformer goes to the turbine, the CO2 to sequestration.

Were you to use gas, obviously the gasification stage would be redundant. The reforming stage would still be required.

Kemper's costing about $5.5Bn for a 580MW plant which can capture about 65% of the carbon content of the coal. In the US a CCGT unit without CCS would typically come in at about $800-1Bn/GW.

So, crudely scaling Kemper to 1GW gives us $9.5Bn/GW, of which something like $1.2bn will be for the adapted CCGT.

That gives us $8.3Bn for the "balance of plant". If we crudely assume that's split half and half between the reformer and the gasifier, and that as this is "FOAK" (First Of A Kind) plant that costs double what a series build unit would cost. we get about $2.1Bn for a series built reformer capable of supplying a 1GW unit.

That has the whole system coming in at about $3.1Bn - 3 to 3 1/2 times the cost of a standard CCGT. for a comparison, that's not dissimilar to the cost of an AP1000 PWR unit.

The system also absorbs some of the output of the plant - we'll assume about 20% for a gas fired CCS CCGT. That equates to a 25% increase in fuel usage.

The underlying cost of power from a CCGT is usually about 80% fuel and 20% fixed (operations, capital and finance). In the UK gas can currently produce at breakeven at about £60/MWh.

So, gas cost is about £48/MWh at the moment, and other costs about £12.

On the basis of the above, you'd expect gas costs per MWh of output to rise to about £60/MWh, and other costs to rise to about £42/MWh - giving a total of £102/MWh.

Which is somewhat more than the Hinkley C strike price, or that for new onshore wind. But it's predicated on a few key assumptions/omissions

1 - that the technology can be matured to a stage where series build cost reductions can be reached.

2 - that gas prices stay where they are.

3 - that there's no carbon cost - I'd expect a system like the above to outperform Kemper in terms of carbon capture, but not to approach 100% - I'd guess in the 80-90% range, giving CO2 output of 45-90g/KWh. It'd be a small contribution, though.

4 - I've not the faintest idea of the costs of the sequestration system - compression, piping and disposal in geological formations. I'd be staggered if it came in under £5/MWh, surprised at £10, though.

So, not easy to develop, and certainly not cheap!

Comparing wind and nuclear raw material costs (repost of Guardian CiF PatLogan post)

PatLogan commented on Tree loses out in battle between Aldi and Ecology.

29 Aug 2014 10:32am

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There are some really interesting comparisons around materials usage between wind and nuclear.

http://bravenewclimate.com/2009/10/18/tcase4/

A typical 2.5MW land-based turbine uses about 390 tonnes of steel and 1100 tonnes of concrete (that's ignoring access roads) It's got a 20-25 year operational life, and (in the UK) will average about a 27% capacity factor.

Output over life is

(2.5*25*0.27) = 16.875 MW-years.

So that's 23.1 tonnes of steel per MW-year and 65.2 tonnes of concrete per MW-year.

A 1620MW EPR (the most resource intensive of the UK new-build designs) . That's got a 60 year design life, at a capacity factor of 90%.

That's

(1620*60*0.9) = 87,480 MW-years

It uses 205,000 cubic metres of concrete (at about 2.4 tonnes/cubic metre 492,000 tonnes- ) and 71,000 tonnes of steel.

That's 5.6 tonnes of concrete per MW-year, and 0.81 tonnes of steel per MW-year

In other words, the wind option uses about 13 times as much concrete, and 28 times as much steel per unit of output over life.

Business for Britain

Business for Britain, produced a report called Energy policy and the EU - How a better deal could bring down the cost of energy and save jobs. Since 2003 the cost of UK retail electricity has more than doubled: from 4p/kWh in 2004 to 10p/kWh today [page 14]. BfB blame much of the price rise on EU regulation. Gas prices have seen similar price rises. A further 33% increase is projected by 2030. These price rises will cripple UK industry, especially energy intensive industry such as steel, chemicals, ceramics, glass and aluminium. We will not be able to compete with India, China or the USA which have the lowest world-wide electricity prices. EU regulation is the main reason for the price rises. By regulation BfB mean EU mandated carbon taxes and such. Page 21 has a cost breakdown where they factor the contribution from 12 regulatory sources. Some of these regulations may have reduced costs but most have increased costs dramatically. 2 regulations leading to highest cost increases are:

• EU Renewable Energy Directive
• EU Climate and Energy package

The immediate effect of these regulations has been a forced phase out older cheap coal-burning electricity plants and price increases as energy companies raised prices to cover future investment. Wind-farms and domestic solar panels are subsidized and energy markets deformed to ensure that wind suppliers benefit even when they generate no electricity. Coal and gas generated electricity has also risen in price because such generators must be kept on standby (burning fuel) just in case they're needed; because wind is intermittent. Money from price increases has been invested in unworkable alternative zero-carbon energy sources. The money Britain has invested in solar and wind generation has been a total waste.

There's no doubt in my mind that BfB have a point. We never needed to increase prices as far as we've done. A small carbon tax could've generated a few billion sterling per year and the funds invested in R&D for Gen IV reactor designs such as the IFR and molten salt reactors. The overriding weakness of the BfB document is in offering no alternative pathway for a European energy future. The phrase "global-warming" is only mentioned once in their report - when referencing another document. They conclude that energy prices must come down (by deregulation) but don't have a policy to tackle global warming and ocean acidification.

I have no problem with a carbon taxes provided they are not too high and the money is invested in R&D for low cost zero-carbon energy. Let's consider the technologies we could be investing R&D in:

• fuel-cells
• energy storage
• synthetic fuels
• CCS
• biomass
• biofuels
• onshore wind
• offshore wind
• solar CSP
• solar PV
• tidal
• wave
• geothermal
• hydroelectric
• Gen IV fission breeders
• Gen IV fission converters
• Gen III+ fission reactors
• Fusion
• Electrical transmission

There are a lot of potential R&D pathways. We should realistically concentrate on those which can lead to real benefits:

• fuel-cells
• synthetic fuels
• Gen IV fission breeders
• Gen IV fission converters
• Electrical transmission

Here's my rationale:

• fuel-cells: have be shown to work for many liquid fuels and give much greater efficiencies than the internal combustion engine
• synthetic fuels: If we want to decarbonise, we must move away from petrol and diesel driven vehicles. Ammonia has been used in the past as a vehicle fuel and it could be in future, especially in a fuel cell.
• Gen IV fission: Only Gen IV nuclear reactors with closed fuel cycles have the scope to reduce electricity costs by any worthwhile amount and satisfy the public's need for safety. Transatomic Power calculate a price of 6¢/kWh; about what we were paying 10 years ago before these recent EU-mandated price increases. [see: slide 11]. It's been argued that nuclear power is risky. I argue that the risks are exaggerated by 3 or 4 orders of magnitude by anti-nukes. For example the LNT theory upon which our regulators and governments base their rules are fraudulent - literally. [see: Ed Calabrese - Researching Dose Response: blog | 1½ hour podcast (ignore the 30 second jingle). Also see my previous post on LNT: Linear no-threshold, LNT, evidence, contra-evidence and links]
• Electrical transmission: This is probably an ongoing area for R&D. Transmission line power losses are huge.

I have good reasons for rejecting R&D in all the other technologies

• Renewables: These energy sources don't pay for the effort that goes into them. EROI studies by recognised researchers find an EROI = 20 is suitable. [see: Jessica Lambert, Charles Hall, et al, 2013], with a minimum EROI = 12. Renewables generally have low values: EROIs below 10 when energy storage is included [see: Catch 22 of energy storage]. If we decarbonize with renewables in preference to Gen IV nuclear power we will deindustrialize and severely lower future economic growth and wealth. Nuclear power has much higher EROI (up to 79), see: Energy intensities, EROIs, and energy payback times of electricity generating power plants. Weißacha, Ruprechta, et al
• Gen III+ fission: There are a number of problems with all LWRs and PWRs. A pressurized reactor can never be intrinsically safe and the open fuel cycle is wasteful
• Fusion: Will it ever work? Bogdan Maglich explains errors in fusion theory. Fusion researchers live in a bubble universe where they need never talk to their critics, nor consider defects in their theories. I never met anyone who expects fusion power to work within the next half century.