... The usual rule of thumb is that a wind farm could sustain production rates of 2 to 4 watts per square metre. Over a square kilometre, that is 2-4 megawatts. ...

Interesting numbers when you realize what they actually are...

From my own understanding, those numbers are for a 'global average' assuming a height of 100m and whatever wind turbine you imagine, and at maximum density slowing the wind down across the entire planet.

Compare that to solar radiation which is about 1kW per square meter perpendicular to the sun's rays.

Yet also compare that to individual wind turbines that can be over one mega watt for the one turbine.


So, simply, you don't put the wind turbines too close together.

(Just as you don't put fossil fuel power stations too close together... Too much concentrated pollution!)


As always, it is a case of making things work.

What is the cost of pollution?

All on our only planet,
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

[Very odd, this post didn't appear. Reposted.]

Research on wind farms says that the current estimates of up to 4W/m^2 are unobtainable on large farms. Due to the localised climate changes caused by each turbine the output could be as low as 1W/m^2.

Is Large Scale Wind Power Handicapping Itself?

Thank you for a beautiful example of headline grabbing FUD... (Your URL has been truncated to give a direct link.)


Looks like good research for the worst case extreme case that no right minded engineer would ever put up let alone get funding for. So... All an interesting case of what would be achieved if a wind farm was designed to be as bad as possible.

Ofcourse in the real world, wind farms are engineered to be as good as possible to achieve the highest returns.


So let's read the article eh?

Because each turbine carries a “wind shadow” beyond it, wind farm entrepreneurs have to compromise: they need to space their turbines as far apart as possible, given that it makes sense to erect as many turbines as possible on the limited land available.

That is, output is going to depend on calculations involving both capacity and density. The usual rule of thumb is that a wind farm could sustain production rates of 2 to 4 watts per square metre. Over a square kilometre, that is 2-4 megawatts.

Adams and Keith calculate that, in wind farms bigger than 100 square kilometres, generating capacity is more likely to be limited to one watt per square metre, because of the local drag on winds. In effect, harvesting the resource also reduces the resource.

There are other problems. Wind farms change the natural wind shear and produce turbulence; they also – consistent with the logic of thermodynamics – affect local temperatures. ...

So... The article is banging on about worse case conditions for maximum density for a hypothetical over-populated wind farm spanning a continuous 100 square kilometres or more. OK, so that looks to be pretty much the worse hypothetical case possible.

Talk about negatively cooking the numbers! I'm sure noone imagines anyone would be so dumb as to try building anything like that with too many turbines too densely packed! I'm also very sure that wind farm designers are fully capable of maximising their return for wind turbine spacing vs number of turbines for a given surface area.


The last comment about "they also – consistent with the logic of thermodynamics – affect local temperatures" pretty much discredits the article as FUD-mongering. Any temperature increase is so slight as to be negligible, as was always originally reported. Of greater interest is that the local weather may well be altered, in a similar orographic fashion as land features influence the local weather. There are far far greater effects from building buildings. No surprises there then.



In contrast, note: Fact check: Harvard study misses real-world facts about wind power

... Regardless of who is correct, the inescapable fact is that America's developable wind energy resources are many times greater than our country's energy needs. ...


Even assuming the unrealistic worst for wind turbines "slowing down the wind", all that means is that current practice is right in that you don't see vast areas uniformly planted with thousands of turbines. Instead, engineers have done their sums to make them work well.

Note that new wind turbines produce power more cheaply then "new coal fired plant". Shame we have to wait for the old plants to burn out.


All on our only planet,
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

We got to do something about the oil .I herd 100vt of power fall on the earth as light and we use only 19vt world wide . Build more solor power stations plenty of desarts

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Wind terbine's need a lot of mantance solar , once it is built there is little or no mantanace and most of the cost is the building of it for 100yrs i'm surprised more cash is not pored in to it first 20yrs ya get ya money back after that all profit ????? for 80yrs ??????

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We got to do something about the oil .I herd 100vt of power fall on the earth as light and we use only 19vt world wide . Build more solor power stations plenty of desarts

Especially in Australia.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

Wind terbine's need a lot of mantance solar , once it is built there is little or no mantanace and most of the cost is the building of it for 100yrs i'm surprised more cash is not pored in to it first 20yrs ya get ya money back after that all profit ????? for 80yrs ??????

If you believe solar is low maintenance then you are in for quite a shock.
There is also the problem of how to keep solar panels cool in the desert.

And as solar power is daytime only, what you going to use at night or how are you going to store energy?

Solar has improved a lot in resent yrs storeage of energy's there are a few ways liquid salt , batteries and very some Capasitor Battery's . Oil ? 20 max before we realy start to feel it on food and things .Nucular 50-100yrs not much uranium on the planet .

So pay your bills or no uranium (seeing as we biggest ore reserves ) lol

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There's something afoot with the present flurry of articles:


Firms 'own unburnable fossil fuels'

Some 60% to 80% of fossil fuel reserves owned by listed firms could be classed as unburnable if politicians stick to CO2 emission limits, a report warns.

The research by the London School of Economics and NGO Carbon Tracker says firms spend billions of pounds of shareholders' money on exploration.

It says 200 listed firms spent £440bn in 2012 chasing more coal, oil and gas. ...

... To stick to the current agreed global limit on emissions - which is sure to be breached - the firms would probably be able to emit no more than about 125-275 billion tonnes of CO2 - about a quarter of their assets. ...


Fossil fuels and vested interests: a society in denial

The report released by Lord Stern and thinktank Carbon Tracker paints a picture of society in denial. It shows we're pumping almost $700bn (£458bn) of hard-earned savings and pensions annually into finding new reserves of fossil fuels, even though it's clear that almost all of those reserves will have to be written off to provide a decent chance of keeping the planet safe.

The ever-inflating "carbon bubble" is only part of the bigger picture, because most of the world's fuel – around three-quarters in total and almost all the oil and gas – is owned not by listed companies but by governments. And we don't need only to stop expanding the world's fossil fuel reserves; we also need to get used to the idea that we can't burn most of what we already have.

That is a much trickier problem, because with Carbon Tracker's detailed analysis and growing awareness of the carbon bubble, investors will surely soon start waking up to the madness...


Europe's climate chief vows to fight on to save emissions trading scheme

Connie Hedegaard's attempts to introduce longer-term reforms will face fierce opposition from a powerful business lobby...


Indeed, "madness" all round. Is this all leading up to a very large high pressure 'bubble' that is going to explosively burst?...

Can technology and politics save the day and our planet? The tech is progressing. Unfortunately, can they work before the problems overwhelm us?


All on our only planet,
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

There's something afoot with the present flurry of articles:

Quite. Perhaps a lot of people are starting to call BS on "scientists" who go practice outside their area of expertise.

---

http://www.youtube.com/watch?v=pvhYqeGp_Do

Two, four, six, eight.

I have lost the bit to confrontate.

When in Rome, do like the Romans.
Doing the Vatican Rag.

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"Freedom is just Chaos, with better lighting." Alan Dean Foster

......Build more solor power stations plenty of desarts

Glenn, you are forgetting the environmental impact of covering deserts with solar panels. Covering the deserts with solar panels would destroy a very delicate environment. The earthworks to construct the farms, the infrastructure (control and output cabling) and the access roads necessary for maintenance (cleaning the dust off the panels for a start) would increase the damage ten fold.

Most of Australia's deserts are not endless sand dunes like the Sahara, they are covered with Spinifex and low shrubs and have an active ecology, and the ones that are mostly sand dunes, like the Simpson, are unsuitable for just that reason, commercial solar panels need a firm base to keep them aligned and the drifting sands would cover them within 20 years.

As Gary and I have said many times, most of the people promoting wind and solar have no idea of the engineering problems involved with their large scale implementation. The problem is that because wind and solar are the only alternative energy sources that get any publicity (despite the fact they only have an average output of around 35% of their rated output), the more practical sources such as geothermal get starved of development funding. And, God forbid anyone dares to mention nuclear power, that's totally unPC.

T.A.

Well nuclear mmmmmmm solar in our case bro we only have 23 million people so not that much needs to be covered you would know about hot rocks , all i'm saying is we gotta do something that is sustainable . Oil wont last long at all even if you don't believe in climate change

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can anyone here even state the basic premise of the physics of global warming???

i'm not look "the earth is getting hotter dude"!!!

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Chris I thought the gulf stream was changing because the salinity of the water colums are changing due to the melting of the poles .?
What have you heard ?

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can anyone here even state the basic premise of the physics of global warming???...

1:
Our sun radiates light/heat energy at approximately 5000 K (5273 deg C).

2:
At that temperature wavelength (Sun), CO2 (carbon dioxide) is 'transparent' and so a large proportion of that energy reaches the earth's surface to heat the ground/water.

3:
The earth's surface of ground/water radiates heat energy at about 287 K (14 deg C).

4:
At that temperature wavelength (Earth), CO2 (carbon dioxide) is 'opaque' and so a proportion of that energy is absorbed to heat our atmosphere.

5:
Simplistically: To maintain a steady temperature on Earth, heat energy received from the sun must equal the heat energy re-radiated back out to space.

6:
We RELY on a certain level of CO2 to capture a proportion of re-radiated Earth surface heat to keep us comfortably warm. Otherwise, we would suffer something like the cold of Mars.

7:
Varying the concentration of CO2 in our atmosphere is one mechanism to directly change the proportion of re-radiated heat that is lost to space and so controls the temperature maintained.


That CO2 absorbs Earthly heat radiation has been known for about two centuries now. Iain Stewart gives a nicely visual demonstration:

Iain Stewart demonstrates infrared radiation absorption by CO2



And our continued Industrial Revolution continues to pollute our atmosphere with vast tonnes of CO2 that is directly, measurably, rapidly increasing the concentration of CO2 in our atmosphere. There has been an ever more widespread awareness of the changes wrought by that for our planet since WWII...

Hope that is a brief enough summary.


All on our only one planet,
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

Just one small part of many parts to a possible (non-genocide non-apocalyptic) solution:



'Most energy-efficient' LED light revealed by Philips

... the prototype tube lighting LED is twice as efficient as those currently used in offices and industry around the world but offers the same amount of light.

Being able to halve the amount of energy used could bring huge cost and energy savings.

Lighting accounts for more than 19% of global electricity consumption.

The prototype tube lighting produces 200 lumens per watt (200lm/W) compared with 100lm/W for equivalent strip lighting and 15lm/W for traditional light bulbs. ...

... In the US, for example, such lighting consumes around 200 terawatts hours (TWh) of electricity annually. Swapping to the energy-efficient lamps could save $12bn (£7.8bn) and stop 60 million metric tonnes of carbon dioxide from being released into the atmosphere, according to Philips. ...


Let there be light! ;-)

All on our only planet,
Martin

---

See new freedom: Mageia Linux
Take a look for yourself: Linux Format
The Future is what We all make IT (GPLv3)

How the burning of fossil fuels was linked to a warming world in 1938

THE ARTIFICIAL PRODUCTION OF CARBON DIOXIDE AND ITS INFLUENCE ON TEMPERATURE (pdf)

Re LED lights. Have you seen the price of them? the May Which? report has an article on them. The Best Buys range from £23-30 each, for a domestic lightbulb. Granted 2 of them are dimmable ones. Ordinary standard CFL bulbs Best Buys are £2-4 each. I don't see many people changing very soon!

Think you need to go and do a search for them. They can be got much cheaper I got a GE 4W candle shaped one from Tesco last week for £6.99 IIRC, it's brighter than the 9W CFL it replaced and claims it will last 15,000 hrs.

Try
http://www.amazon.co.uk/s/ref=a9_sc_1?rh=i%3Aaps%2Ck%3Aled+light+bulbs&keywords=led+light+bulbs&ie=UTF8&qid=1366707334
http://www.homebase.co.uk/webapp/wcs/stores/servlet/Search?storeId=10151&langId=110&q=PHILIPS&pp=20&c_1=1|category_root|Lighting|16849318&int_cmp=dropdown
http://www.diy.com/nav/decor/lighting/lightbulbs/led_bulbs
http://www.scan.co.uk/shop/computer-hardware/all/miscellaneous/lighting-led-for-pcs

A 4W candle is equivalent to an old 15W one, where would you use that?

It's in the desk light here by the computer. Plugged into the UPS so stays on if we have power failure. We get quite a lot of blips in the winter as it is O/H cable also get swans flying into them up the hill. The swans cannot decide where to live, the river or the reservoir.

Hi WK. You have just given me a thought! It just never crossed my mind to put a small wattage desklight into a UPS. My APC Smart UPS hooked up to the PC is only a 1000W one, so it wouldn't last too long in a power cut, maybe 20 minutes. But it might give me a chance to find the candles and torches before it does go.

Hmmmm.....

You can also get small battery powered LED lamps operated with a PIR that stay on for about 30 sec, I have put four in strategic places so that now most of the time we don't have to put on the stairs or passage way lights. Saves a fortune as some people, not to be named, think that lights should go on when it gets dark and switched off when the sun comes up.