NSS

Cement is 3 times more polluting than aviation fuel

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1 hour ago, scottishjohn said:

re bar made from grp  is available --just expensive 

 

Never heard of it. Is there a downside other than cost?

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Are they similar to GRP wall ties as these are expensive?

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5 minutes ago, Mr Punter said:

 

Never heard of it. Is there a downside other than cost?

mainly used where passage of radio waves are important --like radar bunker

no downside other than cost

I suppose the may use them in areas where they have problem with corrosion as well

Edited by scottishjohn

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7 hours ago, PeterW said:

Its a myth....Methane Research

 

Digging into the paper referenced above just a little more deeply shows;

  • The publisher's explicit aim is to ' ... 

     share with you all the possibilities that consistently contradict (emphasis added) the theory of man-made global warming (AGW).... '    https://climatechangedispatch.com/about-us/amp/  (accessed Dec 2018)

  • Does not name the author of at least some articles published

  • Does not name the editor(s) of the site

  • Solicits financial help from readers

  • Appears not to maintain their website professionally (many internal links are broken) 

The internet is an excellent medium for sharing ignorance.

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One of the points that this discussion begs a question on is longevity of residential builds. How many of the homes we're building (people on this forum, not the mass builders) today 'need' to stand for more than 50 years or so? 

 

Surely, in 2068, a home built today will likely be as out of date in terms of its relation to a home built in 50 years time as one built in the 1800's is to your average passive house of today. 

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16 minutes ago, NSS said:

How many of the homes we're building (people on this forum, not the mass builders) today 'need' to stand for more than 50 years or so? 

 

 

Yes, good point. I think that I heard a figure of 80-years mentioned as the expected longevity of a house built today. I think it was from this podcast:

 

https://www.houseplanninghelp.com/hph233-how-to-choose-a-construction-system-for-a-house-build-with-mike-hardwick/

 

 

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Re energy payback of PV, a good place to start though it's clear some people have been very confused by the first paper linked: https://www.carboncommentary.com/blog/2016/12/8/musqo7036dslptm1b8efduj6i3e7ms

 

Linked, indirectly, from there though only the abstract is public: https://onlinelibrary.wiley.com/doi/abs/10.1002/pip.2548

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@Ed Davies calculations above for PV panels made sense. Wholesale electricity costs do not vary that much globally. Generally electricity is made using globally available and priced generating equipment. The cost of fuel may vary, but again fossil fuels often have a global pricing structure. The retail price of electricity in China is around 8c per kWh compared to 13c in the US and 22c in the UK. Retail prices can be affected by distribution costs, government subsidies and taxes. 

 

https://www.statista.com/statistics/263492/electricity-prices-in-selected-countries/

 

This paper from the US Department of Energy references various studies that seem to suggest a 2-3 year payback for a PV system in terms of energy.

 

https://www.nrel.gov/docs/fy04osti/35489.pdf

 

As to wind turbines, Berkshire Hathaway opened Pacificorp, recently announced that due to improved efficiency of equipment they plan to "repower" their existing wind turbines, that I believe had been in use for less than 12 years as the efficiency of new equipment was so much higher that the investment would pay for itself.

 

I would like to hope that people making billions of dollars of investment know a little bit about the expected return on the investment which would be considerably affected by the life expectancy and repair costs.

 

http://www.pacificorp.com/es/energy-vision-2020.html

 

You hear this kind of anti progress or renewables chat all the time, such as that electric cars use more energy in their production than they save, they don't. Or that the batteries only last a few miles, there are Teslas already with hundreds of thousands of miles on the clock. As with most cars something else will give out long before the motor/battery combination. There are places where EVs are barely cleaner than ICE cars depending on the local generating mix, but the good thing is that in general generating is getting less carbon intensive all the time.

 

https://cleantechnica.com/2018/02/19/electric-car-well-to-wheel-emissions-myth/

 

Cement does produce a lot of CO2, but again you would have to look at this relative to its lifespan and the emissions of alternatives to see whether or not it is an environmentally friendly material.

 

In general I think human ingenuity fixes these issues as it has in the past. I don't see us running out of resources.

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2 hours ago, NSS said:

One of the points that this discussion begs a question on is longevity of residential builds. How many of the homes we're building (people on this forum, not the mass builders) today 'need' to stand for more than 50 years or so? 

 

Surely, in 2068, a home built today will likely be as out of date in terms of its relation to a home built in 50 years time as one built in the 1800's is to your average passive house of today. 

Now living in a reasonably well insulated and airtight house that does not take much energy to keep it comfortable, I hark back to what I used to accept as "normal"

 

Thinking in  particular of the 1930's house I grew up in as a child, and then a bit later, a different 1930's house that I bought myself.  Both were cold, draughty and damp, and both took a lot of heat input and even then, they were not always comfortable.

 

There is no way I could contemplate going back to living in one of those, unless I had a sudden unexpected input of capital to either upgrade them or just pay the huge heating bills.

 

But those, and Victorian and earlier must make up a huge percentage of the UK housing stock that simply waste vast quantities of heating fuel.

 

You would think in the current era of recognising the need to reduce fuel usage, particularly fossil fuels, that these old poor houses would be in less demand.  We even have an EPC system that (for all it's faults) will at least give you an idea of the running costs and you might think would make the older poorer houses less attractive.  You might also think it would encourage all mass builders to produce good houses, all striving for an EPC rating of A.  But neither of these seems true.  People might only buy an  A++ rated fridge, or an eficcient car, yet the largest purchase they make it seems "character" and "period" win over practicality.  About the only place the EPC has had any effect is buy to let, where the very worst EPC ratings now cannot be let.

 

I am sure this will change in time.  Perhaps it is time to charge more council tax for properties with a poor EPC?

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6 minutes ago, ProDave said:

Now living in a reasonably well insulated and airtight house that does not take much energy to keep it comfortable, I hark back to what I used to accept as "normal"

 

Thinking in  particular of the 1930's house I grew up in as a child, and then a bit later, a different 1930's house that I bought myself.  Both were cold, draughty and damp, and both took a lot of heat input and even then, they were not always comfortable.

 

There is no way I could contemplate going back to living in one of those, unless I had a sudden unexpected input of capital to either upgrade them or just pay the huge heating bills.

 

But those, and Victorian and earlier must make up a huge percentage of the UK housing stock that simply waste vast quantities of heating fuel.

 

You would think in the current era of recognising the need to reduce fuel usage, particularly fossil fuels, that these old poor houses would be in less demand.  We even have an EPC system that (for all it's faults) will at least give you an idea of the running costs and you might think would make the older poorer houses less attractive.  You might also think it would encourage all mass builders to produce good houses, all striving for an EPC rating of A.  But neither of these seems true.  People might only buy an  A++ rated fridge, or an eficcient car, yet the largest purchase they make it seems "character" and "period" win over practicality.  About the only place the EPC has had any effect is buy to let, where the very worst EPC ratings now cannot be let.

 

I am sure this will change in time.  Perhaps it is time to charge more council tax for properties with a poor EPC?

Completely agree with that last sentence, but the problem is that inefficient old housing stock is (largely) lived in by those with the least chance of improving them (I'm not talking about the Victorian mansions and 'chocolate box' cottages). Perhaps a way forward would be to allow certain energy efficiency improvements to be made by owners with a quid pro quo reduction in council tax payments (whatever is spent on, for example, improving insulation is deducted from your CT bill for that year).

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You only need to (perish the thought) watch Homes Under the Hammer to see street after street of old, poor,  small, Victorian terrace houses in poor repair.  Perhaps it is tome for another "slum" clearance program? 

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1 minute ago, ProDave said:

You only need to (perish the thought) watch Homes Under the Hammer to see street after street of old, poor,  small, Victorian terrace houses in poor repair.  Perhaps it is tome for another "slum" clearance program? 

Well, according to Lewis Hamilton, that's Stevenage for the bulldozers then 😉

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18 hours ago, AliG said:

Wholesale electricity costs do not vary that much globally. Generally electricity is made using globally available and priced generating equipment. The cost of fuel may vary, but again fossil fuels often have a global pricing structure. The retail price of electricity in China is around 8c per kWh compared to 13c in the US and 22c in the UK. Retail prices can be affected by distribution costs, government subsidies and taxes. 

 

https://www.statista.com/statistics/263492/electricity-prices-in-selected-countries/

 

I'm not entirely convinced by this statement that wholesale electricity prices do not vary that much globally. Here is the graph of retail prices from your link:

 

20181222-retail-enectricity-prices-2018.thumb.jpg.1dc0050392dc62d5d999d91e3e90270c.jpg

 

Here is a graph from the EU of wholesale prices in Europe in Spring 2018, which shows a variation of more than 100% relative to the lower price.

(Source: https://ec.europa.eu/energy/sites/ener/files/documents/quarterly_report_on_european_electricity_markets_q1_2018.pdf)

 

20181222-wholesale-enectricity-prices-2018-q1.thumb.jpg.6ee06b7ccc150ca44b8de6169248e78c.jpg

 

And here is the "bandwidth" (max/min) graph for the EU countries from the same source.

 

20181222-wholesale-enectricity-prices-2018-q1-bandwidth.jpg.5acabe3dee758c9d9b92218347a0f6f4.jpg

 

That wholesale price data is a lot of things, but consistent is not one of them. 😀 It could be the variation in quotes for an identical building job !

 

Comments on further post.


F

Edited by Ferdinand

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eg Compare Germany vs UK vs Poland. The difference in wholesale vs retail prices for Germany is huge. Fine - Germany is an outlier, but there are at least half a dozen or ten other not dissimilar outliers just within the EU.

 

Retail 2018: 0.33 vs 0.22 vs 0.16 Euro per kWh.

Wholesale: 0.0356 vs 0.0596 vs 0.0442 Euro per kWh.

Ratio Retail/Wholesale: 9 vs 3.7 vs 3.6.

 

Obvs there are issues of definition, and extraordinary political shenanigans from time to time or constantly (eg in Spain where retail prices do not seemed to have shifted much since about 2010 whilst retail inflation is about 12-14% and there is a corresponding massive subsidy iirc, never mind all the Solar Tax buggering about), and we do not know where France will end up after their current "Reform"-"Burn-Down-Paris"-"Cancel-Reform" cycle (perhaps exactly where they started).

 

Suspect that the real thing highlighted here is that EU stats are not really "wholesale", but "wholesale after political messing about", and that Germany is subsidising energy for industry - whilst the UK refused to do so for large intensive users and we now have no aluminium industry left. There is also probably the hangover of Frau Merkel's (I  think it was Mutti) anti-nuclear spasm after the accident in Japan, but that impact seems to be less than I thought, and perhaps also a residual headache from the subsidies for the now-gone solar manufacturing sector in Germany.


Comments most welcome, as I think is probably about elucidation not basic disagreement.

 

F

Edited by Ferdinand

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20 hours ago, recoveringacademic said:

 

Digging into the paper referenced above just a little more deeply shows;

  • The publisher's explicit aim is to ' ... 

     share with you all the possibilities that consistently contradict (emphasis added) the theory of man-made global warming (AGW).... '    https://climatechangedispatch.com/about-us/amp/  (accessed Dec 2018)

  • Does not name the author of at least some articles published

  • Does not name the editor(s) of the site

  • Solicits financial help from readers

  • Appears not to maintain their website professionally (many internal links are broken) 

The internet is an excellent medium for sharing ignorance.

and properganda  to suit the view of some

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looking at one of the graphs its shows china as second cheapest --.I suspect thats not the real figure --but no proof 

If this is linked to what  was saying costings for making pv panels   its pretty simple 

raw materials are a world price .

labour and home produced power,pollution  stds  and associated cost  and taxation are the things a country can control and therefore the  production cost and export price .

china are only now starting to do something about pollution ,due to problems it is causing them --they not doing it to save the world 

we have very expensive labour +taxation in comparison to other countries ,that why we cannot compete with china etc 

 

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Prices do vary clearly. My line about not varying that much needs clarification.

 

They don’t vary so much that you could profitably make a panel in China using more energy than the panel would then produce in other countries The difference in energy prices would have to be orders of magnitude. As many of the inputs into making a PV panel are globally priced that just isn’t possible.

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The CO₂ emissions embodied in cement was one of the things which put me off a passive slab-type build. By contrast my house has used one mixer load (7.<something> m³) for the founds. There may be a few paving slabs later for the drawbridge, etc, and maybe a few pre-cast bits to sit the container on if I decide to keep it.

 

For a passive slab, though, could you use CLT [¹] as a substitute? I'm thinking maybe two layers, with joins offset, with UFH groves and maybe internal wall, etc, slots CNCed out. Layers glued and screwed. Obviously the thermal characteristics would be a bit different (heat less immediately accessible) but it seems generally plausible to me.

 

[¹] Cross-laminated timber: big kids' plywood.

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2 hours ago, AliG said:

Prices do vary clearly. My line about not varying that much needs clarification.

 

They don’t vary so much that you could profitably make a panel in China using more energy than the panel would then produce in other countries The difference in energy prices would have to be orders of magnitude. As many of the inputs into making a PV panel are globally priced that just isn’t possible.

 

Let's say you can get energy at 2p/kwh in China.

Let's say that this is the only cost involved in a panel. So the people all work for free, in a factory that was built for free. The copper, silicon, aluminium, and glass are all free. The units are shipped around the world for free. Nobody at any stage extracts any profit or takes any overheads.

This same panel is sold at cost for 60p/w which is not far from the current wholesale rate.

 

The panel would have to operate at rated output for 30,000 hours to claw back its production cost.

At an average of 8 hours a day, this is just over ten years. Most panels are capable of lasting longer than that.

 

So can we put this whole thing to bed, please? Even with the scales stacked completely against them, PV panels are still quite clearly energy positive over their lifespan.

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