Energy efficiency and embodied energy split from "gas&q

Little John · Post by **Little John** » 02 Jun 2018, 15:41

I would add that the total energy embodied in the production of a wind turbine, as described by V, is even worse than he has very helpfully shown so far. That is to say, all of these other industries on which the turbine erection (and maintenance) relies are part of a broader societal infrastructure which requires energy over and above the specific, tasks outlined to build and maintain themselves to be able to do those tasks in the first place. Although exceedingly difficult to quantify, that broader infrastructural energy cost needs to be added in somehow. Furthermore, notwithstanding the proximal energy equation, those broader infrastructural factors are arguably, distally, the weakest link of all in wind turbine (and other renewable) technologies. Not to mention many other technologies we already take for granted.

Post by **kenneal - lagger** » 02 Jun 2018, 16:09

Charles Hall in his book Energy and the Wealth of Nations estimates that an EROEI of 5 is required from an energy source to enable society to profit from that source and as is the amount of energy required to support the extraction of one unit of that energy.

Wind turbine EROEI exceeds this but the closer we get to five the smaller the number of activities not directly related to food growing and housing ourselves we can indulge in. That includes overheads such as the NHS, the arts and music, manufacturing and even office work.

Post by **adam2** » 02 Jun 2018, 17:00

Hopefully the EROEI of wind turbines will improve due firstly to the benefits of mass production, and secondly when existing machines need replacement the concrete foundations, the grid connections and access roads are still there.
A replacement should therefore be cheaper in terms of both money and embodied energy than the original.

Oil and other fossil fuels by contrast will almost always have a steadily worsening EROEI, each barrel of relatively easy oil that is extracted means that the average effort to extract the next barrel is greater.

emordnilap · Post by **emordnilap** » 02 Jun 2018, 17:14

I read an |(admittedly simplistic) statement from Dale Vince once, where he stated his turbines paid for themselves in around 6 months.

That's not quite the same as 'embedded energy costs' but.

Post by **kenneal - lagger** » 02 Jun 2018, 17:26

If they're replacing like with like the turbine tower should be reusable as well. There has been a tendency, though, to replace with a larger turbine so even the foundation might need enlarging in that case.

Shouldn't be a problem with pv though.

Post by **clv101** » 02 Jun 2018, 21:24

Little John wrote:I would add that the total energy embodied in the production of a wind turbine, as described by V, is even worse than he has very helpfully shown so far. That is to say, all of these other industries on which the turbine erection (and maintenance) relies are part of a broader societal infrastructure which requires energy over and above the specific, tasks outlined to build and maintain themselves to be able to do those tasks in the first place.

Two points, firstly 'all of these other industries on which the turbine erection (and maintenance) relies' apply similarly to building a coal, gas or nuclear power plant. Nothing unique about the build and maintenance of wind. If you want to widen the system boundaries, do it for everything, not just wind.

Secondly and more importably, the embodied energy in wind is actually less than the global average for electricity generation infrastructure, less than coal, less than gas that's arrived by LNG.

It is simply incorrect to berate wind with a low-EROEI argument.

PS_RalphW · Post by **PS_RalphW** » 02 Jun 2018, 22:20

The AWEL web site has documents giving detailed financial breakdown of the installation and maintenance costs for their wind turbines. The biggest single cost is buying the turbines and concrete towers themselves (about 60%), installation costs (access road, concrete base, grid connection etc) was another 20%. The rest was mostly finance, insurance, maintenance etc.

Financial payback will be several years, CO2 payback relative to fossil fuel consumption saved will be much shorter, but hard to be precise.

Little John · Post by **Little John** » 02 Jun 2018, 23:52

clv101 wrote:
Little John wrote:I would add that the total energy embodied in the production of a wind turbine, as described by V, is even worse than he has very helpfully shown so far. That is to say, all of these other industries on which the turbine erection (and maintenance) relies are part of a broader societal infrastructure which requires energy over and above the specific, tasks outlined to build and maintain themselves to be able to do those tasks in the first place.
Two points, firstly 'all of these other industries on which the turbine erection (and maintenance) relies' apply similarly to building a coal, gas or nuclear power plant. Nothing unique about the build and maintenance of wind. If you want to widen the system boundaries, do it for everything, not just wind.

Secondly and more importably, the embodied energy in wind is actually less than the global average for electricity generation infrastructure, less than coal, less than gas that's arrived by LNG.

It is simply incorrect to berate wind with a low-EROEI argument.

I did not narrow the system boundaries. I am merely pointing out those same boundaries apply to technologies like wind turbines.

Also I am not "berating" the EROEI of wind. Just pointing out that the underlying EROEI is potentially underestimated, as seems to be so often the case with such technologies. We could also get into a speed of flow argument here. But, notwithstanding that, what I am basically doing is calling into question **all** technologies that rely on an industrial civilisation's infrastructure.

BritDownUnder · Post by **BritDownUnder** » 03 Jun 2018, 00:17

BZE in Australia are doing a study on "Reinventing Concrete". If the Grauniad is to be believed then one kilo of cement will release one kilo of CO2 when it is produced in the kiln from raw materials.

Let's say the concrete foundations of a wind turbine are 1000 tonnes of concrete (concrete has other stuff in it like sand and maybe steel as well as cement but lets not split hairs) so it has cost 1000 tonnes of CO2.

A 1MW wind turbine 'may' produce about 1000MWh of electricity per year. Apparently one MWh of coal generated power 'liberates' about one tonne of CO2 in its production. So I am going hazard a guess that a wind turbine will pay back the concrete CO2 'debt' in about a year if it replaces coal power.

vtsnowedin · Post by **vtsnowedin** » 03 Jun 2018, 00:21

Little John wrote:
I did not narrow the system boundaries. I am merely pointing out those same boundaries apply to technologies like wind turbines.

Also I am not "berating" the EROEI of wind. Just pointing out that the underlying EROEI is [b]potentially underestimated, [/b]as seems to be so often the case with such technologies. We could also get into a speed of flow argument here. But, notwithstanding that, what I am basically doing is calling into question **all** technologies that rely on an industrial civilisation's infrastructure.

Yes the energy and other returns from our infrastructure are quite high and under appreciated. If it was not the case we would be hunting our dinner on the plains of the Serengeti with stone tipped spears while being hunted ourselves by the lions and leopards.
Imagine the value of your home if there was no road between it and the nearest town, or power and phone lines (or cell towers) serving it. Imagine no rail or interstate highway system bring goods to and from that nearest town? Could you stay there and prosper or would you have to move?

BritDownUnder · Post by **BritDownUnder** » 03 Jun 2018, 00:28

vtsnowedin wrote: Yes the energy and other returns from our infrastructure are quite high and under appreciated. If it was not the case we would be hunting our dinner on the plains of the Serengeti with stone tipped spears while being hunted ourselves by the lions and leopards.
Imagine the value of your home if there was no road between it and the nearest town, or power and phone lines (or cell towers) serving it. Imagine no rail or interstate highway system bring goods to and from that nearest town? Could you stay there and prosper or would you have to move?

You are quite right. Imagine the CO2 released by producing the concrete for just one metre (or a yard if you prefer) of six lane highway.

I have often thought that roads could be built in sunnier climes by melting rock using an enormous curved mirror and forming the molten rock into a pavement as a replacement for at least some concrete. We can get into discussions on how such a road may be surfaced and levelled but the take away point is that the embedded CO2 in a lot of things is mindblowing.

woodburner · Post by **woodburner** » 03 Jun 2018, 08:36

BritDownUnder wrote: I have often thought that roads could be built in sunnier climes by melting rock using an enormous curved mirror and forming the molten rock into a pavement as a replacement for at least some concrete. We can get into discussions on how such a road may be surfaced and levelled but the take away point is that the embedded CO2 in a lot of things is mindblowing.

Theyâ€™re doing that in Hawaii now, but just tapping into the molten rock pool below. The control system needs a few tweaks though, as the levelling function lacks fine control.

(Edited to correct origin of quote and deleted subsequent post now irrelevant- Ken)

vtsnowedin · Post by **vtsnowedin** » 03 Jun 2018, 16:01

Thanks Ken.

BritDownUnder wrote:

I have often thought that roads could be built in sunnier climes by melting rock using an enormous curved mirror and forming the molten rock into a pavement as a replacement for at least some concrete. We can get into discussions on how such a road may be surfaced and levelled but the take away point is that the embedded CO2 in a lot of things is mindblowing.

An enormous mirror would take a lot of energy to build transport and manipulate and you having no control on the base rock you were melting so would have quality problems in the finished product.
An air drill in a quarry and explosives produce rock when crushed that is of uniform quality that can be mixed with cement or asphalt and placed in uniform layers where desired. All this efficiently both from an energy and human labor standpoint.
How to build good roads and bridges was worked out in Roman times, even concrete being used in their construction. Sense then we have added in blast furnace produced steel, Diesel engines and equipment using hydraulic pumps and pistons taking full advantage of their abilities.
Roads are expensive to build but their durability and utility make them a bargain on a trip by trip or a tons/mile basis. So" if it ain't broke don't fix it" when it comes to how to build them.

Post by **kenneal - lagger** » 03 Jun 2018, 16:18

Rail is more efficient for long distance travel and requires less infrastructure than a road carrying the same volume of traffic.

vtsnowedin · Post by **vtsnowedin** » 03 Jun 2018, 16:37

Yes of course. A railroad is just another type of road to the people in the construction industry. It has the disadvantage of not being able to deliver you or your goods right to your door in most cases so must have some streets and highways connected to it. But building it is just moving earth and rock just like a motor highway.