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Topic Title: Offshore wind - laying the foundations - Tavner
Topic Summary: Offshore wind costs
Created On: 18 November 2012 07:52 PM
Status: Read Only
Related E&T article: Offshore wind - laying the foundations
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 18 November 2012 07:52 PM
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BryanLeyland

Posts: 45
Joined: 09 November 2001

Onshore wind is expensive and unreliable and, on many occasions, the wind does not blow when the load is high.

Offshore wind is even more expensive and, as the article points out, the operation and maintenance costs are very high.

Enthusiasts for renewable energy seem to forget that the object of the exercise is to reduce carbon dioxide (a perfectly harmless gas whose main effect is to make plants grow better). As Dieter Helm pointed out, the most efficient way of reducing carbon dioxide levels is to change from coal fired to gas-fired generation. The next best way is to adopt nuclear power. Yet the same people who promote expensive and unreliable renewable energy also oppose drilling for shale gas and nuclear power.

I would expect that the IET that is (or was) an Institution founded on technology rather than politics, should be in the forefront of pointing out these simple truths.

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BryanLeyland
 20 November 2012 10:24 AM
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aroscoe

Posts: 91
Joined: 18 October 2002


But you also have to consider two points:

1) Its not all about "climate change". Its also about energy security and sustainability. Just going for gas and nuclear doesn't address those issues.

2) Even if you adopt the primary target of "CO2 reduction", its been shown by numerous studies and tools that to achieve these proposed targets, you need to adopt all the proposed technology shifts together. (Renewables, gas, sequestration, nuclear, EVs, insulation, demand-side management, domestic heating fuel switching etc). Simply changing power stations to gas and nuclear doesn't do enough across the whole energy spectrum which includes all the (presently) non-electric energy uses like domestic heating, transport etc.


-------------------------
Dr. Andrew Roscoe

http://personal.strath.ac.uk/andrew.j.roscoe
 20 November 2012 10:00 PM
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BryanLeyland

Posts: 45
Joined: 09 November 2001

I do not know anything about the studies you have mentioned. But the fact is that the world has huge energy reserves in uranium, thorium, shale gas and methane hydrates. More than enough to provide us with abundant, cheap energy beyond the foreseeable future.

Wind and solar do not provide energy security because, much of the time, they are not producing anything. They are not particularly sustainable because the life of wind turbines onshore might be 20 years or so and the life of offshore wind turbines is unknown. Given their very high cost and their likely very high maintenance cost, the chances are that many of them will be abandoned as the companies that own them go broke. Nuclear power stations have to provide a fund for decommissioning. Offshore wind farms do not.

But, the most important thing is that the world has not warmed in the last 16 years and that this proves that carbon dioxide does not cause dangerous global warming. People who study sunspot cycles are predicting that the world is about to enter - or has entered - a cooling cycle. History tells us that warming is good and cooling is bad. History is more valuable than computer models that have produced a long series of failed predictions.

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BryanLeyland
 21 November 2012 01:59 PM
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jarathoon

Posts: 1043
Joined: 05 September 2004

Originally posted by: BryanLeyland

But, the most important thing is that the world has not warmed in the last 16 years and that this proves that carbon dioxide does not cause dangerous global warming. People who study sunspot cycles are predicting that the world is about to enter - or has entered - a cooling cycle. History tells us that warming is good and cooling is bad. History is more valuable than computer models that have produced a long series of failed predictions.


The climate is extremely complicated, I am not sure anyone has proved their case.

On short timescales heat flows and temperature changes may not correlate in simple ways. Some simple examples highlight why we should be wary of rushing to premature conclusions on this topic.

1. If I apply a bunsen burner to a glass of water filled with ice cubes the temperature of the glass will not rise until all the ice is melted. How much net ice being melted needs to be factored into your calculations. Latent heat of melting/freezing

2. The thermal capacity of the atmosphere is low compared to water. Therefore the same amount of heat will raise the temperature of air more than the temperature of water. How much excess heat in the atmosphere will ultimately be being mixed into the deep ocean? I am not sure anyone knows this; any significant mixing will reduce the rate of atmospheric temperature increase for a given heat input.

3. The problem of vertical convection and the lack of experimental data on this.

4. The problem of water evaporation from the oceans and land into the atmosphere, and recondensation in the atmosphere. What are the heat flows here, and how much of this gets radiated away in the high atmosphere.

5. The problem of the radiative effects of clouds. The subject of my unwritten up PhD.

6. The problem of developing regional climate change models that will be of more use to political decision making than a single global temperature average output. Even if global temperatures rise in future years the temperature in the UK northern european region may decline on average.

etc etc

How will climate change affect us in future? What are the consequences for society if our climate predictions prove wrong?

There are other climate change effects that could happen: What would be the effect of a seriously big volcanic eruption in Iceland? Have we enough food to go around if there are two or three very severely cold years in the northern europe following an eruption?

It is because we are uncertain about what will happen next, that (systems) engineers should be involved in helping policians to make decisions.

Remember, changes in the spatial distribution of precipitation produce hardship for societies on much shorter timescales than changes in the spatial distribution of ambient temperatures. It is important that we develop and improve climate models; even just being able to predict rainfall distibutions a few months in advance would be a massive boon. Climate scientists could flag up to politicians if there is a higher than normal chance of widespread crop failures, and help save lives.

If you are interested in these topics, you will need to use your knowledge of engineering principles to think through issues to a much deeper level than the general media can supply.

James Arathoon

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James Arathoon
 21 November 2012 02:23 PM
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drhirst

Posts: 46
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The world has warmed.
But there is considerable variability year to year. So some years are warmer than others, and some are cooler.
If you take a particularly warm time from a few years ago, and compare it with a particularly cool time today (as the Mail did), you can get two temperature figures that are the same. All you need to do is choose your measurements carefully. That is not a sensible way to detect a trend in the presence of noise.
Some of the evidence is published here:
http://www.guardian.co.uk/envi...warming-stopped-wrong
Also one of the sources is quoted here:
http://judithcurry.com/2012/10...use-discussion-thread/ and complains that the article distorted what she said.
Regards
David Hirst

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David Hirst
 23 November 2012 09:04 PM
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cookers

Posts: 205
Joined: 10 February 2012

Building high cost off shore wind farms in the extreme environment of the ocean to take advantage of a low density intermittent energy source is the "consensus" policy our government is deploying on our behalf.

This is happening, some see it as an "exercise in futility" others see it as "sustainable".

Just seems a bit daft to me!
 26 November 2012 12:55 PM
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markjackson

Posts: 1
Joined: 18 January 2003

On the other hand :

If British Engineering Companies, can do it, and do it well, then we can export our engineering expertise to the rest of the world.

Mark Jackson
http://uk.linkedin.com/in/logicalimprovementprojects
 27 November 2012 09:33 AM
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ArthurHall

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Unfortunatly most of the technology is imported from Denmark, Germany etc
A lot of the parts are also assembled abroad.
 27 November 2012 07:37 PM
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cookers

Posts: 205
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Originally posted by: markjackson

On the other hand :



If British Engineering Companies, can do it, and do it well, then we can export our engineering expertise to the rest of the world.


Mark you are correct, the rest of the world will learn from our success or failure.
 28 November 2012 01:47 PM
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geoffbenn

Posts: 247
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Originally posted by: drhirst

The world has warmed.

But there is considerable variability year to year. So some years are warmer than others, and some are cooler.

If you take a particularly warm time from a few years ago, and compare it with a particularly cool time today (as the Mail did), you can get two temperature figures that are the same. All you need to do is choose your measurements carefully. That is not a sensible way to detect a trend in the presence of noise.

Some of the evidence is published here:

http://www.guardian.co.uk/envi...g-stopped-wrong

Also one of the sources is quoted here:

http://judithcurry.com/2012/10...use-discussion-thread/ and complains that the article distorted what she said.

Regards

David Hirst
Thankyou David neat summary of stuff I've been trying to make clear to Bryan over Here

James and Andrew seem to understand the climate issue too

-------------------------
Geoff Benn BSc(Hons) CEng MIET
George Washington: Truth will ultimately prevail where there is pains taken to bring it to light.
skepticalscience.com: getting skeptical about global warming skepticism
sourcewatch.org: exposing public opinion manipulation
 20 December 2012 06:55 PM
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dowlere

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Joined: 25 April 2003

I am a retired electrical engineer but I am fairly new to joining this kind of discussion. I therefore apologise in advance if my topic is unsuitable for this theme.

I notice that the flow of water from my kitchen tap is smooth up to a certain flow-rate and then becomes turbulent if I try to increase it further. I recall from my college days in the 1950s that fluids and gases flow in layers ( I think it was called laminar flow). Could turbulence initiate or intensify storms and account for the increasing severity of the weather in recent years? I searched the NASA website for references to turbulence and found a comment stating that most climatologists believe that typhoons are initiated by turbulence. This led to the question: do wind turbines create turbulent air flow over smooth coasts which once had laminar flow? Are there hundreds of thousands of such places world-wide which might do this? If this idea has any substance then blaming carbon dioxide and increasing wind generation even further would a disaster.






 20 December 2012 11:35 PM
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jarathoon

Posts: 1043
Joined: 05 September 2004

dowlere,

You are talking about subject matter that is conceptually difficult. How do we best extract and communicate qualitiative information from complex and very approximate mathematical models of the atmosphere?

The central point of your question is perhaps: can we make comparible meteorological measurements at the earths surface over long time series whilst at the same time making changes to that surface and how air moves accross it. The answer to that specific question is, I don't know.

There is also astronomical changes that affect how we might compare meteorological measurements over a long period of time, hundreds to thousands of years. The size effect of these over 10's of years including precessional changes to the earths direction of spin relative to the plane of the orbit appears small.

I cannot answer your point exactly, but one way I would start to think about the problem qualitatively is by considering three cases:

1. Still air
2. Laminar Flow
3. Turbluent Flow

The fact that wind turbines cause turbulence is to some extent irrelevant as trees and buildings etc cause turbulence as well. Also the solar heated ground surface creates convection driven turbulence during the day.

However if we add a lot of wind turbines, the total amount of turbulence in the atmosphere may change, especially at night, so your question has value, but may be unanswerable in any straight forward way.

Cases in turn:
1. Still air (Inversion conditions, Hot air above cold air - no convection)
Still air can will occur if you are in a sheltered position with no solar driven convection, or if there is no horizonal air movement and no vertical convection.
2. Laminar Flow
This happens if there is low velocity horizonal air movement and no vertical convection. Perhaps more typical of air moving above the surface boundary layer (where air doesn't inteact with the rough surface of the earth).
3. Turbulent flow
All other cases of surface air flow. Generally wind turbines will convert lower frequency horizonal wind flows into a mixture of horizonal and vertical turbulent flows, as will buildings and trees.

Generally turbulent flow will bring down cooler air higher up in the atmosphere to lower down in the atmosphere, and reduce horizontal wind speeds at the earths surface to some extent. Whether using frequency domain analysis we can distinguish between turbulence created by wind turbines, and wind turbulence arising from other causes I am not sure.

Even if there is some small difference in the size distribution of the eddies (between say buildings and wind turbines) in the initial forcing, this may not last for long. Greater than a certain length scale down wind we may not be able to tell the difference any more.

You might conclude qualitatively that reducing the horizonal component of the wind increases the surface temperature, but increasing the vertical component reduces the surface temperature. Which effect wins out at what length scale from the turbine I have no idea. (Is this even a generally valid way of thinking about it?)

Local city microclimates are partially created by reduced horizonal wind flows in the lowest levels of the atmosphere. Is it possible to fully understand all this in some qualitative hand waving way, both night and day, that is applicable everywhere? No probably not, because of the differences in day night solar radiative forcings, if nothing else.

Separating the effect of carbon dioxide from other effects in some hand waving qualitative way that would convince anyone is very more difficult than what I have attempted above.

You ask, can turbulence intensify storms? The bufferfly effect myth is a little over done, in the sense that turbulence gradually dissipates away. If it didn't the atmosphere would gradually get more and more turbulent over time. But that does not really answer your question.

Does what we build on the earths surface effect the local microclimate? - Undoubtedly.

Does what we build on the earths surface effect the global climate?
- I don't know.

We may be having more of an effect by changing the biological balance of plant species on the earths surface, that we do with changing the non-orgainic built environment. I am not sure anyone really knows the definitive answer to this question.

Given our collective ignorance, it seems to come down to a simple choice: Is it worth taking the risk or should we divert a slightly larger percentage of our total economic wealth (perhaps as a sort of insurance policy) to recycle more of what we use, to bring the design of our human ecosystem, more into line with other stable and long lived natural ecosystems we observe all around us.

James Arathoon

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James Arathoon
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