** The Climate Change Thread **

[roubaixtuesday]

I've read lots on this topic and also recently attended a talk by Mike Berners-Lee who does seem to have his head screwed on.

The most telling statistic I've gleaned is that if we use renewables to power everything and ditch both fossil fuels and nuclear altogether, we will need to reduce our overall energy consumption to about 10% of what it is now. Renewables simply cannot produce more than this even with acres of solar panels and wind farms and tidal schemes etc. etc.

This will take time and most importantly, unpopular legislation. So with a world run by self serving, careerist politicians I see little hope.

Which is sad because well insulated zero carbon houses can be built (but will seriously erode property developers profits). We could cycle and walk almost everywhere - if towns were redesigned to eliminate the need for cars. We could stop buying throw away goods but again we would only really do this in meaningful numbers if they were legislated against.

Somewhat depressing.

A source for this 10% figure would be nice. I don't think it's correct.

The "purist" vision for a zero Carbon Britain is from the rather excellent Centre for Alternative Technology (you may not agree with them, but they do a proper analysis and don't pretend magical solutions exist) on a practical way to go 100% renewables reckon a 60% reduction in overall energy demand is required:

It's well worth a read, both summary and full report. https://www.cat.org.uk/info-resources/z ... he-future/

Personally, I'd keep nuclear.

[roubaixtuesday]

Renewables are wonderful. We lag behind on the hydro front though with a mere Gigawatt of installed capacity.
http://www.gridwatch.templar.co.uk

Renewables may be wonderful, but there is very little potential for further hydro in the UK. We simply don't have enough land at high enough altitude.

We could perhaps invest heavily to import more from Norway through further interconnectors.

I fear for once I disagree with you.
There is in Scotland a great deal of potential. And high rainfall!
But a willingness to sacrifice wilderness is an issue and a serious one.
To replace our dependence upon fossil energy will require sacrifice and compromise.

This is not correct, and requires quantification rather than warm words.

The Centre for Alternative technology (referenced above), a very strongly pro-renewables group, gives:

- current hydro 5TWhr
- Total UK potential 8TWhr
- Current energy demand ~1800TWhr

It's just not very significant.

[PDQ Mobile]

Renewables may be wonderful, but there is very little potential for further hydro in the UK. We simply don't have enough land at high enough altitude.

We could perhaps invest heavily to import more from Norway through further interconnectors.

I fear for once I disagree with you.
There is in Scotland a great deal of potential. And high rainfall!
But a willingness to sacrifice wilderness is an issue and a serious one.
To replace our dependence upon fossil energy will require sacrifice and compromise.

This is not correct, and requires quantification rather than warm words.

The Centre for Alternative technology (referenced above), a very strongly pro-renewables group, gives:

- current hydro 5TWhr
- Total UK potential 8TWhr
- Current energy demand ~1800TWhr

It's just not very significant.

Gridwatch gives installed capacity of pure hydro as 1GW.
http://www.gridwatch.templarm.co.uk
There is a good deal of pumped storage (2.5GW) but that is (or was) mostly nuclear.

The one Gigawatt figire always stuck me as extraorinarily low for a country with such high rainfall.
There is no doubt in my mind that reliable leccy from micro hydro could be increased from the many old mill sites around the country.
Damming upland valleys is a contentious issue for sure and transmission losses would be high to the centers of population.
Some progress has been made in N Wales with micro hyro though.
On top of older schemes like Dolgarrog, Maentwrog and Nantgwynant, new capacity has been installed Cwm Tragalen under Snowdon and at Coed y Brenin and Cwm Croesor and more.
These schemes, basically diverted rivers at natural falls or very small dams, have attracted some criticism, but are for the most part very unobtrusive.

It's about tough choices really.
If we only used leccy as a mechanical power source, trains, power tools, heat pumps etc, there would be ample supply.
Once pure heat is generated demand soars.

All IMHO.

[Psamathe]

I've read lots on this topic and also recently attended a talk by Mike Berners-Lee who does seem to have his head screwed on.

The most telling statistic I've gleaned is that if we use renewables to power everything and ditch both fossil fuels and nuclear altogether, we will need to reduce our overall energy consumption to about 10% of what it is now. Renewables simply cannot produce more than this even with acres of solar panels and wind farms and tidal schemes etc. etc.

This will take time and most importantly, unpopular legislation. So with a world run by self serving, careerist politicians I see little hope.

Which is sad because well insulated zero carbon houses can be built (but will seriously erode property developers profits). We could cycle and walk almost everywhere - if towns were redesigned to eliminate the need for cars. We could stop buying throw away goods but again we would only really do this in meaningful numbers if they were legislated against.

Somewhat depressing.

A source for this 10% figure would be nice. I don't think it's correct.

The "purist" vision for a zero Carbon Britain is from the rather excellent Centre for Alternative Technology (you may not agree with them, but they do a proper analysis and don't pretend magical solutions exist) on a practical way to go 100% renewables reckon a 60% reduction in overall energy demand is required:

Capture.JPG

It's well worth a read, both summary and full report. https://www.cat.org.uk/info-resources/z ... he-future/

Personally, I'd keep nuclear.

I think we waste a lot of energy and could reduce consumption a fair bit without impacting our lifestyle. Without needing people to wear full body Puffa indoors, heating can be reduced, the truth about woodburners, insulation can be improved, do we really need to floodlight (some of) our churches in dark evenings?, home delivery scheduling, transport, etc. So much of our energy consumption seems designed without energy consumption considerations, etc.

We have figures for food waste that people don't seem to question and whilst establishing energy waste is not quite as black and white (food is ether eaten or thrown away) it would be interesting to see figures on how much energy we waste and could save without impacting our lifestyle (e.g. not leaving lights on outdoors all night, switch to LEDs rather than incandescent, switch to home delivery maybe every other shop, etc., etc).

Ian

[roubaixtuesday]

I fear for once I disagree with you.
There is in Scotland a great deal of potential. And high rainfall!
But a willingness to sacrifice wilderness is an issue and a serious one.
To replace our dependence upon fossil energy will require sacrifice and compromise.

This is not correct, and requires quantification rather than warm words.

The Centre for Alternative technology (referenced above), a very strongly pro-renewables group, gives:

- current hydro 5TWhr
- Total UK potential 8TWhr
- Current energy demand ~1800TWhr

It's just not very significant.

Gridwatch gives installed capacity of pure hydro as 1GW.
http://www.gridwatch.templarm.co.uk
There is a good deal of pumped storage (2.5GW) but that is (or was) mostly nuclear.

The one Gigawatt figire always stuck me as extraorinarily low for a country with such high rainfall.
There is no doubt in my mind that reliable leccy from micro hydro could be increased from the many old mill sites around the country.
Damming upland valleys is a contentious issue for sure and transmission losses would be high to the centers of population.
Some progress has been made in N Wales with micro hyro though.
On top of older schemes like Dolgarrog, Maentwrog and Nantgwynant, new capacity has been installed Cwm Tragalen under Snowdon and at Coed y Brenin and Cwm Croesor and more.
These schemes, basically diverted rivers at natural falls or very small dams, have attracted some criticism, but are for the most part very unobtrusive.

It's about tough choices really.
If we only used leccy as a mechanical power source, trains, power tools, heat pumps etc, there would be ample supply.
Once pure heat is generated demand soars.

All IMHO.

I appreciate your laudable sentiments, but the cold, hard figures clearly show otherwise.

Total energy demand 1800TWhr
Total hydro potential 8TWhr

That's about 0.5%

It's not significant.

Tidal and wind are the big potential in UK renewables. Physics can't be overruled by sentiment, unfortunately.

[Mike Sales]

I appreciate your laudable sentiments, but the cold, hard figures clearly show otherwise.

Total energy demand 1800TWhr
Total hydro potential 8TWhr

Doesn't the estimate of potential depend on how you value the cost of an installation against its economic returns?
A tiny turbine on an old mill leat might or might not be thought worthwhile depending on how you value its output.

[roubaixtuesday]

I appreciate your laudable sentiments, but the cold, hard figures clearly show otherwise.

Total energy demand 1800TWhr
Total hydro potential 8TWhr

Doesn't the estimate of potential depend on how you value the cost of an installation against its economic returns?
A tiny turbine on an old mill leat might or might not be thought worthwhile depending on how you value its output.

Individual hydro installations may well be excellent both economically and environmentally.

But their totality can never make a significant contribution to UK energy demand. There is simply insufficient volume of rainfall at substantial altitude.

[Mike Sales]

I appreciate your laudable sentiments, but the cold, hard figures clearly show otherwise.

Total energy demand 1800TWhr
Total hydro potential 8TWhr

Doesn't the estimate of potential depend on how you value the cost of an installation against its economic returns?
A tiny turbine on an old mill leat might or might not be thought worthwhile depending on how you value its output.

Individual hydro installations may well be excellent both economically and environmentally.

But their totality can never make a significant contribution to UK energy demand. There is simply insufficient volume of rainfall at substantial altitude.

On what assumptions is the 8TWhr figure you quote based?
I have gathered that to make renewable supply meet demand will need contributions from many sources, some small but nevertheless worthwhile.

[PDQ Mobile]

I appreciate your laudable sentiments, but the cold, hard figures clearly show otherwise.

Total energy demand 1800TWhr
Total hydro potential 8TWhr

Doesn't the estimate of potential depend on how you value the cost of an installation against its economic returns?
A tiny turbine on an old mill leat might or might not be thought worthwhile depending on how you value its output.

Individual hydro installations may well be excellent both economically and environmentally.

But their totality can never make a significant contribution to UK energy demand. There is simply insufficient volume of rainfall at substantial altitude.

And yet one of the big plusses is reliability.
Clearly a drought will have influence but the vagaries are less than wind.

Hydro (and pumped storage) has such a rapid reponse to demand time that it represents perhaps the best solution to peak demand supplimenation.
In the end we will need a diversity of supply sources.
I still think a mere single Gigawatt of installed capacity is pitifully low.
Tidal offers potential especially perhaps under sea turbines but the cost and complexity are extremely high.

[roubaixtuesday]

Doesn't the estimate of potential depend on how you value the cost of an installation against its economic returns?
A tiny turbine on an old mill leat might or might not be thought worthwhile depending on how you value its output.

Individual hydro installations may well be excellent both economically and environmentally.

But their totality can never make a significant contribution to UK energy demand. There is simply insufficient volume of rainfall at substantial altitude.

On what assumptions is the 8TWhr figure you quote based?
I have gathered that to make renewable supply meet demand will need contributions from many sources, some small but nevertheless worthwhile.

It's referenced in the CAT report above. The excellent "Without Hot Air" book comes to similar conclusions and takes you through the logic if you're interested. It's available online.

Regardless of the specific numbers, you can very clearly see the proportion can never be [edit] significant. 0.5% is very small.

As I say, that doesn't mean individual projects aren't worthwhile in themselves.

[roubaixtuesday]

.
I still think a mere single Gigawatt of installed capacity is pitifully low.

Alas, your thoughts have no influence on the laws of physics!

[Mike Sales]

It's referenced in the CAT report above. The excellent "Without Hot Air" book comes to similar conclusions and takes you through the logic if you're interested. It's available online.

Regardless of the specific numbers, you can very clearly see the proportion can never be specific. 0.5% is very small.

As I say, that doesn't mean individual projects aren't worthwhile in themselves.

Ta.

[PDQ Mobile]

.
I still think a mere single Gigawatt of installed capacity is pitifully low.

Alas, your thoughts have no influence on the laws of physics!

True.

And yet France has over 12 Gigawatts of installed capacity.
Twelve times more.

And it's not all in the Alps but a deal of it is river sourced.

http://www.gridwatch.templar.co.uk/france/

[roubaixtuesday]

.
I still think a mere single Gigawatt of installed capacity is pitifully low.

Alas, your thoughts have no influence on the laws of physics!

True.

And yet France has over 12 Gigawatts of installed capacity.
Twelve times more.

And it's not all in the Alps but a deal of it is river sourced.

http://www.gridwatch.templar.co.uk/france/

The Thames is, I think, the largest flowrate river in the UK. It has a quoted rate of 65m3/s

The Rhone has a flowrate of 1700m3/s

Twenty six times more.

It's simple physics, which comes from the geography.

[PDQ Mobile]

Alas, your thoughts have no influence on the laws of physics!

True.

And yet France has over 12 Gigawatts of installed capacity.
Twelve times more.

And it's not all in the Alps but a deal of it is river sourced.

http://www.gridwatch.templar.co.uk/france/

The Thames is, I think, the largest flowrate river in the UK. It has a quoted rate of 65m3/s

The Rhone has a flowrate of 1700m3/s

Twenty six times more.

It's simple physics, which comes from the geography.

You must allow for precipitation variables though.
Clearly the Rhone and it's tribtaries are far more favourable but only sometimes.
In deep winter for example the flow will be far under the quoted figure.

It would appear the Tay has the greastest flow rate in the UK and is probably more favourable than the Thames in terms of "geography".

The Tay's quoted mean flow in 2008 is stated as " 208.5 CuM/Sec."
Which is not insignificant?

The other biggys are given as :- "The Tay is a convincing winner, compared with the Trent at 98 CuM/Sec the Severn at 69 CuM/Sec and the Thames at 83 CuM/Sec."

If we can't get a bit of leccy out of that lot I reckon we are not being sensible.