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Messages - BenB

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1
Arctic sea ice / Re: The 2020 melting season
« on: July 16, 2020, 01:37:36 PM »
I haven't had any time for sea ice this year, but wow, this season is exceptional. I thought it was worth reminding ourselves where the ice is this year vs. 2012 (first image). Basically, 2020 is slightly ahead north of the Barents and Kara seas, ahead in Chukchi, and far ahead in ESS and Laptev. In the areas that matter, 2012 is only far ahead in Beaufort. Having said that, an extent comparison exaggerates the difference a bit, as there is greater compaction in 2020.

Then, looking at current melt conditions, I looked back at Worldview for the second half of July in 2012, 2016 and 2019. All were dominated by cloudy weather, although 2012 did clear up a few times. 2020 is forecast to stay relatively clear.

Looking at the most recent day in 2012 and 2020 (2nd and 3rd image), the difference is striking. 2012 has slightly more rubble north of Beaufort, and obviously much less ice in Beaufort, but apart from that 2020 looks worse in every way. There is definitely more melt ponding/surface wetness in 2020. Cloud cover speaks for itself.

Qs: Is insolation in the second half of July strong enough to do so much damage to the relatively thick ice in the CAB that some of it will melt out by the end of the season?
Will continued clockwise rotation of the ice push the weak-looking ice in the ESS into the warm Laptev waters? If so, it won't be long of this world. Will some of the Beaufort ice also be pushed into warmer waters?
Will the Atlantic ice edge continue to push north, or will it stagnate just north of Svalbard/Franz Josef?
Is this the big year, or is it just setting us up for next year?

2
Arctic sea ice / Re: The 2019 melting season
« on: August 28, 2019, 10:55:56 AM »
I think the rebound on the Pacific side is matched by a reduction in concentration further into the pack on that side, which is consistent with the low over Beaufort and what you can see on Modis - ice being pushed south into Chukchi/Beaufort from the central pack, leaving gaps behind further north. The low stays around for a couple of days more, although it's not very deep, so the general pattern should continue. Most of the ice that gets pushed into Chukchi/Beaufort melts fairly quickly, so I don't think the advances will last long. The question is how significant the reduction in concentration deeper into the pack will become.

3
Policy and solutions / Re: Renewable Energy
« on: August 27, 2019, 10:06:15 PM »
Gerontocrat, I know about the unit conversion page, but ultimately that's generally information you can work out for yourself anyway. The bit that's missing is their own methodology for calculating the primary energy in each energy source, which is individual to each source and hence not covered by the unit converter. You can find some of that information on other pages, but they don't go out of their way to make it easily accessible.

4
Policy and solutions / Re: Renewable Energy
« on: August 27, 2019, 04:14:19 PM »
You're welcome Terry. It would make life easier if all of the main providers of statistical information used the same methodology, but I suppose that – like with sea ice – the various methods all have their merits, and different agencies/companies prefer different ones.

I think that the IEA could be clearer with how they do their calculations, as you have to dig around quite a bit to find the information, and it's not all in one place. Even now, I haven't been able to find their explanation of how they calculate the primary energy for coal, but I've tried to infer it as best I can from their comments and the figures for electricity generation vs. primary energy.

5
Policy and solutions / Re: Renewable Energy
« on: August 27, 2019, 12:12:48 PM »
Yes, Oren, but a couple of points to bear in mind:

  • I believe most of the renewables in the IEA figures are biomass - basically people burning wood for food and heating in poorer countries. So if you treble the contribution from "modern" renewables, the total amount of renewables doesn't increase as much as you might expect, but the change over the past decade say is much more pronounced.

  • It's the IEA, not EIA. This may seem pedantic, but confusingly the EIA is the Energy Information Administration, which is responsible for energy statistics in the US. The IEA is the International Energy Agency, which is a kind of think tank on energy matters for the OECD countries.

6
Policy and solutions / Re: Renewable Energy
« on: August 26, 2019, 08:54:25 PM »
Incidentally, the IEA used to assume a conversion efficiency of, I think, 36% for renewables, so that their numbers would be more directly comparable to those of fossil fuels and nuclear power. However, they decided that the conversion figure had no basis in any real conversion loses, and it created spurious losses in their overall energy balance. On the other hand, it means you can't use primary energy figures to accurately assess the contribution of renewables.

Even taking that into account, the contribution of renewables to overall useful energy is still quite small, but not as small as the tpes number implies. For example, hydro generates, globally, significantly more than nuclear, but on a primary energy basis it looks like less.

I believe BP still makes an adjustment to renewables to make them more comparable.

7
I'm not yet (that) old, but I agree with Gero that in general people on ASIF create GIFs that are too fast. You end up having to watch them lots of times, and still don't get as clear an understanding of what's going on as you would if they were slower. Also support having the last frame slow/long, so that if the GIF is looping, it's clear what the final state is, and when the GIF starts/ends.

8
Arctic sea ice / Re: The 2019 melting season
« on: August 15, 2019, 10:18:23 AM »
All hinges now on bottom melt, and to a certain degree, on how much heat is pulled from depth by wind.

2019 has a lot of ocean heat "in the bank". With the winds that are forecast over the coming week, it will withdraw some of the heat from its savings account, and use it to melt the ice.

This will involve both northerlies pushing ice into warm waters (Beaufort, Fram), southerlies pushing warm water and warmish, humid air into the ice, and a bit of both at different times (Kara, Barents, Laptev, ESS). How much damage can that do at this late stage? Significant amounts of damage to volume, but how it will affect area and extent is harder to judge, and depends where the ice stops when the music (melt) stops.

9
Arctic sea ice / Re: 2019 vs 2012
« on: August 12, 2019, 09:41:34 AM »
SST update for 11 August 2012 vs 2019. The next few days will see warm, humid air and warm waters push north into the Laptev sector of the CAB. Meanwhile, northerlies will transport/export ice into the Chukchi, on one side of the Arctic, and into the Barents/Greenland seas on the other. I would expect area declines to pick up, but extent may hold up better initially. We could also see more areas of open water near the Pole as the ice is pushed apart.

10
Arctic sea ice / Re: The 2019 melting season
« on: August 01, 2019, 05:35:06 PM »
A couple of points in relation to CAB area/extent:

1. How far 2019 is behind depends on the numbers you're using. The Wipneus graphs show CAB area and extent near record low (see below). I do think we're a bit behind 2012, but not necessarily as far as the NSIDC figures suggest.

2. Normally the CAB starts melting from the Atlantic side, which is where we're behind this year. On the other hand, we're far ahead on the Pacific side. This means that the CAB will relatively soon be attacked from all sides, whereas normally it would take longer for open water to reach it on the Pacific side.

Edit: Part of the difference in the numbers is due to the difference in how the seas are defined, but that only emphasises that you can draw demarcation lines between the surrounding seas and CAB in different places in order to reach the conclusion you want to reach. I think the overall amount of ice is most relevant at this stage.

11
Arctic sea ice / Re: 2019 vs 2012
« on: July 30, 2019, 09:50:45 AM »
There's a lot of talk about average melt between now and the rest of the season. That's useful for keeping the discussion grounded in reality, but you also have to look at the current conditions:

SSTs - very important to bottom melt in the run-in of the season
volume/thickness - important for obvious reasons
current ice surface conditions/albedo - makes a huge difference to how much insolation is absorbed into the system
dispersion
the weather forecast for the coming week

I would say all of these factors suggest above average melt between now and the minimum. Not necessarily equal to 2012, but almost certainly higher than usual.

For SSTs, last year Neven handily posted a comparison of conditions on 28 July for 4 recent years. I've added 2019. 2012 and 2016 both lost significantly more extent than normal between 28 July and minimum. 2017 and 2018 lost less. Which is 2019 most similar to?


12
Arctic sea ice / Re: The 2019 melting season
« on: July 29, 2019, 12:15:57 PM »
I'm attaching today's view of the area north of the Laptev bite (visible in the top left of the image), reaching as far north as 86N. The forecasts have this area being anomalously warm for the foreseeable future, even as the highs and lows move around the Arctic basin. As well as the many smallish polynyas, there is evidence of surface melting everywhere, and the ice looks in pretty bad shape. I think we'll lose quite a bit of it over the coming couple of weeks.

In fact, the next two weeks will be extremely interesting, because they will help to answer how much of an impact the GAC really had. Was the rapid melting mainly due to preconditioning, or would the ice have survived in the absence of the GAC? This time, with similarly preconditioned ice and warm SSTs, there will be more high pressure systems, clearer skies and warm anomalies.

13
Arctic sea ice / Re: The 2019 melting season
« on: July 10, 2019, 10:40:02 AM »
It's not just the Pacific where there's a lot of melting going on. On the border between the Kara and Barents seas, the ice edge has gone from being a solid, compact line on 5 July to having lots of swirls of melting ice on 9 July. A wide band of the ice is also significantly darkened.

14
Arctic sea ice / Re: 2019 vs 2012
« on: July 09, 2019, 09:43:18 AM »
And another comparison. This time the latest data from this year is compared with 3 weeks forward in time in 2012 (July 7 vs July 28). It looks like there's a lot of ice that needs to melt, but I think 2019 will be ahead on the 28th, at least in the areas that matter to the final extent. This year, a huge swathe of ice south of 75N between the New Siberian Islands and the eastern edge of Chukchi is vulnerable. Not all of it will melt out, but a lot will. Sea by sea:

Kara/Barents: 2019 is far behind, but these areas are melting rapidly. 2012 will stay ahead at 28 July, but not by very much.
Laptev: The areas by the Lena delta and between the Laptev bite and Severnaya Zemlya will again melt out completely. The Laptev bite will extend further into the CAB. 2019 a bit ahead, if you include the Laptev sector of the CAB.
ESS: The area south-east of the New Siberian Islands will melt out fully, as will most of the eastward extension of the Laptev bite. In addition, there will be significant melt along the Siberian coast. 2019 well ahead.
Chukchi: 2019 is already ahead and will extend its lead. 2019 far ahead.
Beaufort: there's some thicker ice here, so I think the two years will be similar.
CAA: 2012 had earlier momentum, so I think it will be significantly ahead.
Baffin: not really relevant to the final extent, but I think 2019 will also melt out fully by 28 July. Equal.
Hudson: again not relevant, but 2019 may not melt out fully by 28 July. 2012 possibly a bit ahead.

Even if I'm right and 2019 is ahead on 28 July, 2012 has the GAC to come, so for me the final outcome is still very uncertain. 2019 could end up significantly ahead or behind 2012. The latest forecasts suggest cooler weather is coming...

15
Arctic sea ice / Re: 2019 vs 2012
« on: July 09, 2019, 08:54:56 AM »
To add a bit of context to the Piomas comparisons from 30 June, here is a comparison of the ice edge at 30 June and 7 July (latest available) this year. Apart from the retreat in the Chukchi, what is striking is how much has been lost from the areas where the big positive anomalies were in the Barents and edge of the Kara:

16
Serks, yes, I think so too. Technically called "sediment plumes", according to NASA, because it's the sediment in the meltwater (picked up at the base of glaciers as they grind the bedrock) that causes the colours:

https://earthobservatory.nasa.gov/images/84464/sediment-plumes-around-greenland

17
Interesting questions Rox. A couple of general points (based on my understanding, and I'm happy to be contradicted) before trying to answer some of your specific questions. Sea ice, particularly first-year ice, contains pockets of salty brine. This initially remains liquid when the sea ice freezes, as it has a lower melting point, and some of it then drains out, leaving air pockets. Some remains as trapped pockets of brine, which melt at a lower temperature than the surrounding ice. This, as well as other factors, mean that there are weaker and stronger points within the ice, including potential routes for the water to escape from the surface to the sea. When melt water refreezing blocks these cracks/passages, it doesn't necessarily block them at the base of the floe. If surface melt has started before the ice is all at 0C, the water will refreeze at some point on its way through the floe.

The water in melt ponds can reach temperatures above zero.

Fresh water coming into contact with subzero salt water won't necessarily freeze on contact. It may manage to mix sufficiently before losing enough energy to its surroundings to change state.

Now to your questions:

1. Yes, probably in general, but only at the column where the water drains. The whole floe won't be the same temperature. It is also possible that "warm"  (1 degree?) melt water is able to escape before refreezing through a larger crack produced by dynamic processes.
2. Usually, but not always, I think. From observation, sometimes you see melt ponds drain in areas where it is unlikely that the water has reached 0. The buoy temperature profiles could help with this.
3. Not sure, but I don't think so. See 2 and the point about losing energy to change state.
4. Yes, it must be thick and strong enough, but I think the depth implied by this varies a lot. Sometimes floes melt out very quickly after melt ponds drain, sometimes slowly.
5. Floes are massive, and they are constantly losing and gaining heat in different places, and heat is being transferred through them. The temperature won't be uniform when the pond drains. Either way, the energy needed for the change of state is much greater than the energy needed to raise the temperature a degree or two, so I don't think this has a huge impact on the subsequent rate of melt.

Overall, I think you're underestimating the dynamic nature of the process and the variation in conditions within avsing floe.

18
Adding lighter water to the glass doesn't change the water column that the ice is resting on. It's still going to be floating on the same dense layer if the new water doesn't mix.

In theory, you can add lighter water water all the way up to the 6" line which will not impact the relationship between the ice and the dense water underneath it.

If I understand what you're saying correctly, I think you're misunderstanding how hydrostatic pressure works. The water column doesn't need to be directly above you for it to affect the water pressure at a point below the surface.

I'll give two different kinds of (brief) explanation:
  • Imagine a diver swims down to 10 metres below sea level. He then swims horizontally into a cave where there is only 1 metre of water above him. The water pressure will be the same in the cave as it was outside it.
  • In your glass of water, the water pressure directly below the water you've added will increase, because there will be a higher water column above it. Water pressure acts in all directions. The pressure under the water you've added can't remain higher than in the water next to it under the ice cube, because it would displace that water, as it would be pushing "harder" than the other water would be pushing back. So, in fact it reaches a new equilibrium where the pressure is the same everywhere at the same depth.

Is that what you meant? And does that help?

19
Policy and solutions / Re: Nuclear Power
« on: June 27, 2019, 06:49:20 PM »
This interview is from 2015, so things will have moved on quite a bit from then:

https://energypost.eu/interview-steve-holliday-ceo-national-grid-idea-large-power-stations-baseload-power-outdated/

What is the future of baseload generation in such a system? “That’s asking the wrong question”, says Holliday. “The idea of baseload power is already outdated. I think you should look at this the other way around. From a consumer’s point of view, baseload is what I am producing myself. The solar on my rooftop, my heat pump – that’s the baseload. Those are the electrons that are free at the margin. The point is: this is an industry that was based on meeting demand. An extraordinary amount of capital was tied up for an unusual set of circumstances: to ensure supply at any moment. This is now turned on its head. The future will be much more driven by availability of supply: by demand side response and management which will enable the market to balance price of supply and of demand. It’s how we balance these things that will determine the future shape of our business.”

20
Arctic sea ice / Re: The 2019 melting season
« on: June 27, 2019, 09:04:51 AM »
I found a paper called:

Sediment transport by sea ice in the Chukchi and Beaufort Seas: Increasing importance due to changing ice conditions?

Quote: Sediment-laden sea ice is widespread over the shallow, wide Siberian Arctic shelves, with off-shelf export from theLaptev and East Siberian Seas contributing substantially to the Arctic Ocean’s sediment budget.

Also (my  bold): Sediment loads averaged at 128 t km–2, with sediment occurring in layers of roughly 0.5 m thickness, mostly in the lower ice layers.

https://pdfs.semanticscholar.org/40de/e8b9d38feb5d9cfc74ad898d904892a87ac7.pdf

So, I would guess that it's sediment. I would guess that the darkness is at least partly an indicator of thickness, as when the ice melts, most of the sediment remains, as others have suggested. Also, if the sediment is mainly in the lower ice layers, it would only become more visible as surface melt progresses.

I don't have time to read the full article at the moment, but it would be interesting if someone did have time to look at it properly.

21
Arctic sea ice / Re: The 2019 melting season
« on: June 25, 2019, 05:23:36 PM »
Each year, many posters (particularly new members) say this year is the big one. Depending on the year, we hear "the ice is badly fragmented", "extent is record low", "area is record low", etc. A lot of the fragmentation we are seeing this year is nothing new, and can be found going back a long way.

However: this has been one of the warmest years on record for spring/early summer, perhaps the warmest. Direct heat transfer between the air and ice only does a limited amount of damage, but the warmth gets surface melt started, keeps melt ponds open, and provides some heat. Either way, warm years like 2007 are associated with strong melt.

Now, at peak insolation, we have lots of melt ponding and low albedo across much of the Arctic. Also very warm water. That gives momentum. That momentum is confirmed by PIOMAS. In recent years, Neven has repeatedly warned people about getting carried away because in spite of the area/extent numbers, there hasn't been much momentum at the key time. This year, I think there is. Having said that, there are some areas that have been protected, so maybe I'm wrong. The Arctic has a way of proving all of us wrong most of the time.

22
Arctic sea ice / Re: The 2019 melting season
« on: June 21, 2019, 09:41:09 AM »
Edit: One thing I've been wondering(and its a bit OT so I'm happy to be directed to another thread) is at what water temperature does sea ice begin to struggle to form  a freezing fresh boundary layer as it melts at the bottom? Ice in Boiling water, or water hot enough for active convection is surely not going to behave that way until substantially cooling the body of water. But what about water that's over 4C, where water is densest. Cooling 4C water to 2C makes it more buoyant, cooling 6C water to 4C has the opposite effect. Does this have any significant effect in diluting and mixing the boundary layer, and exposing the ice to more heat?

I'm not sure how relevant the 4C is, because although the sea ice is fresher than the seawater, it is still salty, and salt water is densest at its freezing point, not at 4C. However, being fresher, the melting sea ice is less dense than the saltier seawater, so in the absence of dynamic processes, it will not sink, preventing mixing.

To what extent it will form a boundary layer is more a question of fluid dynamics, and depends on viscosity and other factors. I'm not qualified to comment on that.

23
Arctic sea ice / Re: The 2019 melting season
« on: June 20, 2019, 12:16:59 PM »
I found a paper that I thought is relevant to the discussion here:

Increases in the Pacific inflow to the Arctic from 1990 to 2015, and insights into seasonal trends and driving mechanisms from year-round Bering Strait mooring data

http://psc.apl.washington.edu/HLD/Bstrait/BStraitSeasonalInterannualChange2017/Woodgate2017BeringStraitChanges_28ththJune2017_TextTablesFigureswithfc.pdf

I haven't had time to read the whole thing, but it suggests that the average annual heat flux through the Bering Strait has increased as follows:

1991-2015: 7.2 ± 4.5 1018J/yr (after correction: 5.9± 4.6)
1998-2015: 8.7 ± 5.7 1018J/yr (after correction: 6.9 ± 5.9)
2000-2015: 9.7 ± 6.5 1018J/yr (after correction: 7.8 ±6.80)

It also cites Serreze et al, which I believe has been mentioned on here various times before:

Moreover,  a  recent  study  of  in  situ,  satellite  and  modeling  results  [Serreze  et  al., 2016] conclude the oceanic heat flux through the strait (in April-June) may explain 68% of the variance in the timing of sea-ice retreat in the Chukchi Sea, with model correlations suggesting the Bering Strait heat  flux  is  a  more  efficient  predictor  than  the  atmospheric  forcing  terms  of  wind,  surface  airtemperature,  or  radiation.

Bearing in mind the unprecedented (I believe) heat not just in the Chukchi Sea but also in the Bering Sea, this could be particularly significant this year.

24
Arctic sea ice / Re: The 2019 melting season
« on: June 15, 2019, 08:21:29 AM »
The Chukchi is looking particularly bad, and this is one of the main reasons:



Those anomalies are equivalent to up to 5C, which can cause a lot of damage.

25
Arctic sea ice / Re: The 2019 melting season
« on: June 10, 2019, 12:12:07 PM »
As well as the ESS/Laptev, melt ponding has really picked up in Hudson Bay over the past day or so:



Not too relevant to what happens in the CAB at the end of the melt season, but should start contributing even more to the daily melt figures.

26
Arctic sea ice / Re: The 2019 melting season
« on: June 08, 2019, 04:38:40 PM »
This page provides quite a lot of good information about snow melt processes, including sublimation:

http://portal.chmi.cz/files/portal/docs/poboc/CB/snowmelt/print.htm

With respect to the process I was describing, it has this to say (my bold):

When vapor pressure decreases with height in the atmosphere, moisture from the snow will be diffused to the atmosphere above. In this situation, moisture sublimates from the snow, latent heat is lost from the snow, and the snow stays cold, even if the air temperatures are rather warm.

When vapor pressure increases with height in the atmosphere, moisture from the atmosphere above will be deposited to the snow's surface. In this situation, latent heat is gained by the snow, and the snow surface will warm. This warming may start the melting process within the snowpack. To achieve melting in this manner requires winds strong enough to induce turbulent transfer, so that warmth and higher humidity from above continually come into contact with the snow surface.

27
Policy and solutions / Re: Coal
« on: June 08, 2019, 02:19:26 PM »
Check out the Nature Climate Change paper that I referenced, much more thorough (and peer reviewed of course) and concludes that only the Balkans and part of the Mediterranean could provide the balancing required.

I have now. So, if the Balkans and Mediterranean provide the necessary balancing, that's what we use. Without having checked, I imagine their grids are linked to e.g. the UK's. Certainly Spain and Portugal are/will be (new HVDC interconnectors are being built/planned between France and Spain, which will massively increase capacity). But France is linked to Germany, is linked to Austria and Hungary (I guess), is linked to Romania and Slovenia (probably), etc. If they aren't, they can be.

Even then, output isn't uniform. However, as they state in the paper, solar is negatively correlated with wind, so using both is better than using either individually. And then you have hydro, which is totally despachable, demand management, batteries, etc. Solar in Morocco/Algeria with interconnectors, perhaps. Trying to solve the problem with one technology alone will never work. As the paper itself says: Further studies are required for designing an optimally balanced electricity system, considering also other generation types, storage, transmission, demand, and costs.

28
Arctic sea ice / Re: The 2019 melting season
« on: June 08, 2019, 12:54:09 PM »
A couple of points about the lack of melt ponding and dry vs humid air.

Although the ice is quite fragmented in places, the individual ice floes are still mainly hundreds of metres or even tens of kilometres across. More than big enough for melt ponds, and more than big enough for the melt ponds to be big enough to be visible on one of the products available to us. 

The latent heat of vaporisation of water is roughly 7 times higher than the latent heat of fusion (melting). This means that 1 g of water condensing releases enough energy to the surroundings to melt 7 g of ice (assuming the ice temperature was close to freezing point). When warm humid air enters the Arctic, it cools, and some of the water vapour condenses, releasing energy. This can start surface melting and melt ponding. In past years we've frequently seen this happen in practice - a warm, cloudy weather system moves through part of the CAB, and when it leaves and you can see the area on Modis again, there is lots of surface melt/melt ponding. Obviously if the weather front brings rain as well, this will also contribute to melting. This effect has also sometimes been visible on the buoys.

29
Policy and solutions / Re: Coal
« on: June 07, 2019, 12:05:05 PM »
Perhaps you're right. I take the view that there are lots of people reading who don't contribute, and if no answer is given, they assume that it's because we don't have any answers.

Anyway: let's all get back to topic (coal).  ;)

30
Policy and solutions / Re: Coal
« on: June 05, 2019, 01:06:12 PM »
Totally agree, b_lum, I'm not arguing with you, I'm just challenging rboyd's assertion that if renewable generation doesn't reduce the number of (potentially) operational gas-fired power stations, it somehow doesn't count or isn't doing any good.

31
Policy and solutions / Re: Coal
« on: June 04, 2019, 05:30:34 PM »
SH, not great news, but not awful either:

From the link: Global coal demand in the next five years is set to be stable, with declines in United States and Europe offset by growth in India and other Asian countries ­– though China, the main player in the global coal market, will see a gradual decline in demand. In terms of the total energy mix, coal’s contribution will decline from 27% to 25%, mainly due to growth of renewables and natural gas.

A few years ago, the mainstream forecasts all argued that coal demand would continue to expand extremely rapidly for the foreseeable future. I suspect that the forecasts continue to overestimate rather than underestimate demand for coal in 5 years' time.

32
Policy and solutions / Re: Coal
« on: June 04, 2019, 04:03:55 PM »
Just to add to what b_lumenkraft says, the aim is to reduce CO2 emissions, and the emission of other pollutants. Reducing the amount of natural gas and coal burned does exactly that. And adding renewables leads to a reduction in gas and coal-fired generation – that's what the figures show. They also clearly show that overall, coal is not being replaced by gas, it is being replaced by renewables.

If the end state involves having some gas-fired power stations in reserve that are needed very occasionally, that's no great tragedy. Emissions follow power generation, not the number of power stations. For the moment, we don't need to worry about the end state - plenty more renewables can be added to replace even more of the coal- and gas-fired generation. Let's try to get to 80% clean power (renewables+nuclear) - by then the technology will undoubtedly make it easier to replace the remaining 20% than it is today.

33
Policy and solutions / Re: Coal
« on: June 03, 2019, 12:19:55 PM »
In 2009, GB used produced 147,137 GWh from natural gas, and 99,049 GWh from coal.
In 2018, the figures were 115,278 GWh and 15,379 GWh respectively. So, while being used to replace coal, natural gas use has fallen...
In fact, that 116,000 GWh reduction in coal and natural gas-fired generation has been replaced by:

~49,000 GWh increase in solar, unmetered (embedded) wind and energy savings.
~36,000 GWh increase in metered wind.
~17,00 GWh increase in biomass.
~9,500 GWh increase in imports from France
~6,500 GWh increase in imports from Netherlands.

See: https://www.ref.org.uk/fuel/index.php?tab=year&valdate=2019-06-02&share=N&pd=M


34
Greenland and Arctic Circle / Re: What's new in Greenland?
« on: May 14, 2019, 10:14:55 AM »
Poof!

12 May:


13 May:


Uummannaq Fjord system. Clearly the consistently warm weather in the west of Greenland is taking its toll on the fast ice.

35
Arctic sea ice / Re: The 2019 melting season
« on: May 01, 2019, 10:43:42 AM »
This image is based on yesterday's Modis image with bands 7-2-1 overlayed with the daytime ice surface temperature using a compressed palette. Yellow has been calibrated to around 273 K (with orange-red being warmer), so the idea is to an alternative indication of where surface melt is likely:

36
Greenland and Arctic Circle / Re: Greenland 2019 Melt Season
« on: April 29, 2019, 11:58:06 AM »
The (relatively) warm weather in Greenland is reflected in a further spike in the melt extent:


37
Policy and solutions / Re: Batteries: Today's Energy Solution
« on: August 30, 2018, 09:06:52 PM »
What do we do, on a still winters night, -10 outside, when we have no fossil fuel and no Nuclear?  Wind is useless, solar is worse, it is off.

I'm willing to be enlightened, but the whole point is we have to get off fossil fuels and we have to do it as fast as we possibly can.

I suggested what the solution might involve, just a few posts ago. You didn't engage with that. But to remind you: 9 GW of interconnectors + battery storage + demand response + hydro/pumped storage + biomass + natural gas when necessary. We don't need to eliminate natural gas - if we're just using it for extreme cases (which is what you are citing). Using natural gas for backup has a negligible impact on overall emissions.

38
Policy and solutions / Re: Renewable Energy
« on: August 30, 2018, 08:59:48 PM »
Neil, you seem more interested in soundbites and making a political point than in objective facts and figures, but I'll keep providing them, in case you and others are interested:

"If you were contributing on WebCameron prior to 2010, you would have seen the posted UK report that says the average onshore UK wind production is just 19% of the NamePlate power with an absolute maximum of 30% of NamePlate power."

Onshore UK capacity factor (load factor) according to DUKES 2018 (the official UK energy publication): 28.0%. Obviously this varies from year to year, but it's always higher than 19%.

Source: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/736153/Ch6.pdf

"Wind is predominantly onshore as Germany doesn't have the coastline."

April 2018. Germany approves offshore wind farms with 1.6 GW nameplate capacity. Price: 4.66 euro cents/kWh. https://www.reuters.com/article/us-germany-power-offshorewind/germany-approves-offshore-wind-parks-able-to-generate-1610-mw-idUSKBN1HY25I (For reference – Hinkley: 9.25 pence/kWh. The prices are comparable because the price is paid per unit of electricity actually produced.) Germany already has several GW of offshore wind. Yes, there's still much more onshore, but offshore is ramping up quickly.

Finally, here is Lazard's 2017 estimate of the unsubsidised LCOE for different technologies:

Wind: 30-60 $/MWh
Utility solar PV: 43-48 $/MWh
Nuclear: 112-183 $/MWh

Source: https://www.lazard.com/perspective/levelized-cost-of-energy-2017/

Yes, by all means keep using misleading figures about how much money Germany spent developing renewables in the past, when costs were higher. But we're not building in the past, we're building in the present and future. And LCOE is what tells us what is the cheapest electricity source to build now.

39
Policy and solutions / Re: Batteries: Today's Energy Solution
« on: August 30, 2018, 09:32:46 AM »
I'm not sure why people keep coming back to the idea that we have to back up all generation with batteries. This is clearly unaffordable (at the moment) and absurd. In practice we will use a combination of:

Interconnectors. The UK already has 4GW of international interconnectors, and another ~5GW under construction and in advanced planning. This will give 18GW of flexibility between maximum imports and maximum exports.
Demand response. Many large electricity users are happy to stop using electricity for hours or days on end if they are compensated for this through lower electricity bills. In the most recent capacity auction, demand response provided some of the capacity. This field is developing extremely fast, with lots of companies offering services to optimise companies' consumption of electricity and thereby minimise their energy bills. Consumers can also do this to a lesser extent, including by using EVs as batteries.
Large-scale batteries. They won't provide backup for 100% of electricity consumption, but they will play a part.
Natural gas. If all of the above are not enough, we burn natural gas for a few hours or days.
Spurious question 1: What's the point if we have to back it up with natural gas?
Answer: The aim is to avoid CO2 emissions, and if we avoid most of them for most of the year, using natural gas occasionally isn't a problem.
Spurious question 2: Won't that bankrupt us if we have to pay double, once for renewables and once for natural gas?
Answer: No. The main cost of natural gas is the fuel, so by avoiding using it most of the time, you avoid most of the cost. There are already capacity auctions to pay for having natural gas in reserve, and the cost is very low relative to the overall cost of the electric power system.

Yes things get tricky if we want to get to 80%+ renewables, but we're miles away from that at the moment. Let's get to 50% first... By the time we get there, technology will have moved on.

40
Policy and solutions / Re: Batteries: Today's Energy Solution
« on: August 21, 2018, 10:53:08 AM »

You only need to look at gridwatch in the UK to see the reality of that.  After a decade of "transition", we still have only 19% on renewables.  fully 68% is gas and nuclear.  Wind is 5% but  a few weeks ago it was 0%.  Solar is 5%.

Every time we go to stress points, we move back to coal.  Ferrybridge was a 2gw coal fired station.  The first transition was to 68mw biomas.  The second move will be 90mw biomas.

We have offshore wind growing like mad.  Wind farms growing all over the country, solar growth is about dead with the subsidies gone and new solar halving year on year.  With all of that, every time the wind stops blowing and the sun stops shining we dive back into coal.

UK electricity generation:

Coal in August: 0.6%. July: 0.7%. June: 0.9%.

The idea that we use coal to cover lulls in the wind in summer is simply not supported by the numbers. Actually we use much more coal in winter, when wind generation is much higher, because demand is also higher. In other words, coal is occasionally used to meet spikes in demand, and not primarily shortfalls in wind generation. Even so, coal is just ~5% year-to-date, down from a peak of ~43% in 2012. Wind, by comparison, is over 15%.

41
I would like my next car to be diesel or petrol, but until I can get one that has instant torque at all speeds, that produces no fumes, that is as silent as an EV and that I can fill up overnight in my garage, I'm not going to get one. Obviously petrol and diesel cars might one day catch up, but for the moment it's a bit unrealistic to consider them serious competitors to EVs.  ;)

42
Shared humanity, I think your numbers for EVs are out by a few orders of magnitude. 3 million is >0.2% of 1.14 billion, not 0.0000.......

43
Arctic sea ice / Re: The 2018 melting season
« on: May 15, 2018, 11:55:17 AM »
I'm well aware of the problems with GFS at those time scales, but 3.6 seemed pretty extreme for this time of year, even by its standards. Anyway, the point was more that the next week looks consistently warm, and even subtracting a 1.6 correction factor for 168 hours, you get a 2 degree anomaly. Speaking of which, the more reliable 3-day forecast is for a 2.2 anomaly:




44
Consequences / Re: Global Surface Air Temperatures
« on: May 14, 2018, 05:04:40 PM »
I'm not sure there's anything very controversial about the max/min temperature issue:

On average, daily minimum temperatures are rising faster than daily maximums, and winter temperatures are rising faster than summer ones, and this is reflected in record-breaking temperatures - we are breaking more "high minimum" temperature records than "high maximum" records. However, both maximums and minimums are rising, and we are setting more "high maximum" than "low maximum" records, again indicative of rising maximum temperatures. This is a slightly separate issue from the question of extreme weather events, and the extent to which they are becoming more common.

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