12 Small Windmills Put To the Test In Holland

[Mike]

No, it's 100W of panels per sq metre. 1/ 0.1 =10 - as long as you are just looking at panel area and not land area occupied.

Take a Kyocera 200W panel and you approach around 140W per sq metre. (At standard test conditions of 1000W/ sq m, 200W output from an array measuring 1425mm x 990mm

Who do you mean by people? Wh per day is a reasonable unit to use for non continuous power sources. kWh per annum is a reasonable unit for overall system output for comparison purposes.

Using the methods I outlined in my posting enables Met Office or NOAA insolation data to be rapidly inserted into the formulae and overall output per day or per annum to be evaluated. Bogging yourself down with kWh and kW when you have discontinuous supply, local battery storage and discontinuous use can lead to endless confusion, of course you need to know the loads,and the storage capacity but the power available is probably the most important figure to any off grid user.

[Rick... (The other Rick)]

Look up "Sabatier Reaction" No idea of the efficiencies or the power needed. However NASA is developing a system to use on Mars

Rick... (The other Rick)

Science and sound engineering will always prevail in the end "for nature cannot be fooled" [Feynman]

[nightjar]

Hubbert's Peak Oil theory is a myth, as the assumption that the recoverable oil reserves are fixed is an essential part of the model. That was a reasonable assumption in 1956 when oil prices had, in real terms, been declining for decades. However, it breaks down once oil prices rise significantly. It then becomes economic to extract oil from sources that would previously have been rated as irrecoverable reserves, so the level of recoverable reserves are not fixed and the model has failed to work on several occasions since the early 1970s.

A good example of this was last year, when oil prices went above $100 a barrel. At that point, it became economic to extract oil from oil shale and tar sands, which, between them, contain twice as much oil as the declared reserves of all the conventional oil fields in the world combined, so recoverable reserves suddenly increased enormously. I say declared reserves, because nobody really knows how much oil those fields contain. Officially, the estimate is 1.2 trillion barrels, but that is the P90 figure - a volume of production that it is 90% probable each well will reach or exceed. That is a very conservative figure and, if you are looking at one well, it is a prudent figure on which to base the economics of running that well. On a global scale, actual production is much closer to the P50 figure, which would give us up to three times as much conventional oil in reserve.

So, do I believe in Hubbert's Peak Oil Theory? - No. Do I believe we will eventually run out of fossil oil sources ?- Yes. Do I think that will happen soon? - No. Do I think we will have developed alternatives before the problem becomes critical? - Probably. Technologies like algal oil contain the promise of us being able to do so, but it is a question of whether the necessary investment will be available to make them viable.

Colin Bignell

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember The Natural Philosopher saying something like:

[Mike]

I understand where you are coming from, but Wh per day are a very convenient uint to use.

45Wh per day per 10W panel / 24 = 1.875 Wh x 10 panels per sq metre = 18.75 W per sq metre.

[dennis]

Batteries aren't need for solar, just some way to store the energy. It is quite possible to store it in say a lump of metal but you need a lot of it. There are probably better storage mediums like molten salt. Water is no good as you just can't get it hot enough without pressurising it to dangerous levels. It also doesn't work well in small micro generators as you really need a few hundred degrees to be useful. This requires heliostats and concentrating mirrors and some good weather.

[The Natural Philosopher]

Given enough energy, we can in principle get rid of the CO2, but of course we will never have the energy with renewables.

Unlike humans, who are always fooled all the time.

[The Natural Philosopher]

Sadly, 1Kw per sq meter is only approached in a califirnia desert, at midday, not in the UK.,

I am not looking at how clever the technology is, but how much land area is needed to get an average power out.

Not when you are trying to ascertain how much land area you need to devote to capturing sunlight or wind, to give a steady generation of power.

No, the power delivered, is what counts. And the cost in terms of environmental impact, and sheer money.

[The Natural Philosopher]

An artificial lake the size of loch ness and 1000ft high would keep the lights on for almost three days.

No need for batteries..;-)

[Andy Champ]

I did lots of maths. Apparently not enough arithmetic...

[John Stumbles]

Actually if you've just driven 400 miles - or even half that - an enforced break of, say, half an hour at the motorway services or whatever while the vehicle is recharged is probably not a show-stopper.

[The Natural Philosopher]

Well the temptation is to start with just 100 miles in the tank, and then be pissed off when you have to stop for 15 miinutes to get another

100 miles in the tank..

Its fine if you have a garage and floating charger in it, but not so good for street parkers.

[Owain]

Alternatively we could have in-journey recharging. Some mechanism of overhead electric wires and a collector on the roof of the vehicle picking up the current. Metering could be handled on the vehicle, along with mileage and congestion charging.

The same overhead wires could be used by electrically-powered buses.

Owain

[Mike]

But the 1000W per sq metre standard test conditions is the only way you can realistically compare and size panels, it's bugger all to do with California or anywhere else at midday.

The 4.5/3.7/0.9 and more importantly the 2.25 average x panel ratings are proven UK figures at dozens of locations across the UK.

Which is precisely what you can get using the figures already provided. The figures assume the panels are inclined at installation latitude, so in a level field you have to account for shading caused by an adjacent panel.

See previous posting, you had a real world cost of provision, and typical output of solar power in the UK fed to you on a plate, REAL WORLD here in the UK data, not some mythical PR blurb form someone wanting sell panels or from someone with a political agenda.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "nightjar" saying something like:

A very interesting figure appeared last year relating to the Canadian tar sands - at max production they'd supply last year's world demand for a mere six years. Not a lot of fallback reserve there. Oil shale is a pig's ear - it takes so much energy to extract usable oil from shale it's fallen on its face every time it's been tried, save for the early days when it was an alternative to whale oil. It will be the absolutely last resort for dino oil.

[nightjar]

I presume you find it interesting because that figure is so completely at variance with the conventional view, which is that Canada and Venezuela each have tar sands deposits that equal the entire world proven reserves of conventional oil. If conventional oil were to be likely to run out within six years, we really would be in trouble.

Except last year, when oil prices went above $100 a barrel However, one oil company is claiming that it is developing a technique that would make it economic at a world price of $20 a barrel.

None of the unconventional oil sources are likely to be exploited until absolutely necessary. However, the point I was making was that these sources and more expensive methods of extracting additional oil from conventional sources made nonsense of the assumption that recoverable reserves are fixed, which is an essential part of the Peak Oil theory.

Colin Bignell

[Jules]

Hmm - wireless inductive charging. You'd just have to drive very close to the inductive charging loops in the barriers at the side of the road ;-)

[Dave Liquorice]

Unlike fuel that is burnt and destroyed when used the lithium stays in the battery and thus can be recovered and reused in a new battery. Still need an energy source to do that though...

[John Stumbles]

On Fri, 24 Apr 2009 14:36:06 +0100, "nightjar" None of the unconventional oil sources are likely to be exploited until

I hope - and if I thought it would do any good would pray - that you're right. If oil suddenly runs out the world economy is likely to collapse catastrophically. A steady increase in fossil fuel prices making the use of alternative sources more competitive, thus promoting their further development making them yet more competitive etc, seems to be what we need vis-a-vis [global warming deniers: look away now!] climate change.

[Dave Liquorice]

It hasn't collapsed, if it had we wouldn't be communicating over the internet, we would be all out fighting for the last two grains if rice on the floor of Tesco.