Not too windy today

[BlasterBates]

It's been on the news recently in Germany that their system is now unstable, it's basically a fight to keep the lights on; 200 times a year they face an emergency; this is the sort of thing that would happen a couple of times a year, 10 years ago. I doubt that they'll be able to add a great deal more wind capacity for the forseeable future, and one can see the same will happen in the UK. You get to a point when the variability in the supply simply causes too much instability.

[d000hg]

When I was a kid , we to run out of oil by the time I was 40.

I dont believe the doom-sayers any more, particularly the greens.

I do know two things, The Canadians have discovered and are exploiting their tar sands, which have more reserves that Saudis ever had or will have. The Canadians also have claims on oil reserves in the Arctic, which have more reserves that Saudis ever had or will have.
In addition we have shale gas and nuclear

I think the next generation will be ok, based on what we have now

particularly if they move to Canada

My problem is that the numbers are just too big to visualise. On the one hand, the amount of oil we use is a staggeringly big number - 10 million cubic metres (10^7 m^3) a day - so it seems impossible this can last that long. But then the volume of Earth is about a million million cubic kilometres (10^21 m^3).
So in 30 years we'd use approx 10^11 m^3, or 0.00000001% of the planet's volume.

Is that a lot or not?

[TimberWolf]

Current installed capacity is capable of feeding in 38% in winter & 20% in summer max at peak. This may be due to Feed-in to grid restrictions in some areas rather than lack of availibility (off-line).

We've capacity for 20%-38% wind, but currently only <1% of electricity generation is from wind? Something seems amiss here.

[EternalOptimist]

Got a source, preferably a chart spanning a decade or two?

The price the consumer pays for oil, gas and coal has certainly shot up inexorably

according to this report

wind runs at about 25% of capacity over the year
which gives 6500 MW * .25 = 1,625MW on average

average demand is about 40,000 MW

so wind, roughly averaged = 4% of demand


which is a lot higher than I thought it was

[EternalOptimist]

We've capacity for 20%-38% wind, but currently only <1% of electricity generation is from wind? Something seems amiss here.

he is talking about the % of capacity that was realised.

[TimberWolf]

It has, of course. And some say it will continue that way
others think that oil supply will increase in the next few years, and that the gas price is closely linked to the price of oil.

I suppose it becomes a matter of opinion

The future may a matter of opinion (although given that fossils are a finite source, perhaps not too distant a future), but historical data isn't. Got any historical data? Another game changer as far as the UK is concerned is that we rely more and on imported fossils, which would continue even if all our electricity was home generated. Doomed.

But the price of renewable seems to be dropping fast, with some people forecasting parity in price with fossils. A bit of opinion involved here, as with any forecasts, admittedly.

[TimberWolf]

My problem is that the numbers are just too big to visualise. On the one hand, the amount of oil we use is a staggeringly big number - 10 million cubic metres (10^7 m^3) a day - so it seems impossible this can last that long. But then the volume of Earth is about a million million cubic kilometres (10^21 m^3).
So in 30 years we'd use approx 10^11 m^3, or 0.00000001% of the planet's volume.

Is that a lot or not?

Those large volumes are easier to visualise if you turn the m^3 into a single cube. Take the cube root of 10^7 = 464m * 464m * 464m = a cube half a kilometre on its side. I often do this conversion for areas too, just for visualisation, not for future calculation purposes which would be a PITA.

[Diver]

We've capacity for 20%-38% wind, but currently only <1% of electricity generation is from wind? Something seems amiss here.

The national grid is currently limiting connection as the grid infrastructure need a complete overhaul.
The generation industry is currently looking a the supergrid option rather than a local (UK) one.

I do not know what the situation is with onshore wind farms as I only deal with offshore renewables and know little about the small turbines used on shore. I do know that they are significanly smaller and less efficient than those we are currently installing offshore. and the further we get from shore the more efficient we become.

The wind power density (the mean density of the wind’s kinetic energy, over the year) at the close to shore wind farm Kentish Flats is about 713 W per square metre of vertical plane, at 80 metres above sea level. The Vestas 3 MW turbines there have a net efficiency of approximately 30%, for that wind profile: i.e. 30% of the wind’s kinetic energy is converted to electricity; (so in this case the figure is efficiency, rather than capacity factor). The turbines have a swept diameter of 90 metres, and thus a swept area of 6360 m2 (45 m x 45 m x pi). So the power generated is:
713 W/m2 x 6360 m2 x 30% = 1.36 MWe per turbine.
The turbines are spaced in a 700 m x 700 m grid, so the turbine density is
1/(0.7×0.7) = 2.06 turbines per square km of seabed,
giving a density of harvested electricity of 2.8 MWe/km2, at 100% availability. A 90% availability gives around 2.5 MWe/km2.
And now to generalise to British waters, grouping the depths into shallow, medium and deep waters: 0-25 m, 25-50 m, and 50-700 m.
80 GW in shallow waters (0-25 m)
In the (territorial + EEZ) waters around Britain & Northern Ireland, there’s roughly 40 000 km2 of seabed shallower than 25 m, with a wind power density of 579 W/m2 (that’s per square metre in the vertical plane: the area that the turbine blades sweep through). So, for the depths of 0-25 m, scaling the Kentish Flats figure accordingly, the mean potential electricity density is:
2.5 MWe/km2 x 579/713 = 2 MWe/km2
40 000 km2 x 2 MWe/km2 = 80 GWe at 0-25m depths
270 GW in seas of depth 25-50m
For the 90 000 km2 of British waters in depths of 25-50 m, the wind power density is 868 W/m2(vertical). giving mean potential electricity of:
2.5 MWe/km2 x 868/713 = 3 MWe/km2
90 000 km2 x 3 MWe/km2 = 270 GWe at 25-50m depths
790GW in deeper waters 50-100m
And then there’s about 210 000 km2 at 50m-100m, with a wind power density of 1070 W/m2(vertical)
2.5 MWe/km2 x 1070/713 = 3.75 MWe/km2
210 000 km2 x 3.75 MWe/km2 = 790 GWe at 50-100m depths

London Array turbines for Phase One will have a capacity of 3.6MW each. They’ll be fitted with Siemens’ new 120m rotor. Each turbine will have a hub height of 87m above sea level. The turbines will each have three blades.
Dogger bank will be 50 miles off shore and be installed with ~6mw turbines in an area that has almost constant usable wind velocities.

[Diver]

he is talking about the % of capacity that was realised.

Correct, because grid will often not allow feed in if the local grid is at capacity. which is understandable at present as the small wind farms & small turbines in use on land are subject to so much variable output and poor forecasting of availibility that the grid is reliant on the more predictable power generation from existing power stations.

As wind farms move offshore, availibility and the ability to forecast will improve.

[EternalOptimist]

Correct, because grid will often not allow feed in if the local grid is at capacity. which is understandable at present as the small wind farms & small turbines in use on land are subject to so much variable output and poor forecasting of availibility that the grid is reliant on the more predictable power generation from existing power stations.

As wind farms move offshore, availibility and the ability to forecast will improve.

what he says ^

what he means > The wind can go from zero to max and back down again very quickly.

That means that the conventional generators must be able to be switched off and on very quickly, which they cannot. Therefore either the conventional generators must be left to idle
or the windmills must be left to idle


madness. economics of the madhouse