Biggest wind farms in South Africa

itareanlnotani

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Did I get my math wrong, or have these only been generating the equivalent of about 5.2h per day at capacity?
535000/(365) = 1465MWh per day
That means they are equivalent to a coal station of ~61MW, assuming 100% up time - so call it 80MW?
Math does sound a bit off though, hours should be longer than that, unless they're quoting winter?

Haven't checked, but the main problem is that you're thinking about it wrong.

First some ground "rules" -

The solar PV farms are built to supply electricity at a certain price.
They supply electric at that price at those hours of operation.
Eskom only pays them for energy delivered.
When they don't deliver, they don't earn money for the supplier.

We need electricity at certain times of the day, at others not so much.
When they're supplying - roughly correlates to when we *really* need electricity.

In terms of supplying need - if we put a financial aspect to the electricity in terms of time of day usage/costs, daytime (pre-solar) would be the most expensive time, then early evening, so electricity generators would make the most money supplying for those times.

Costs map to needs. Higher needs means higher selling cost. Lower needs (i.e. late evening - early morning) is pretty worthless to most generators as their costs are still the same, but the income is low.

Solar has already changed that financial timing, as daytime is now the cheapest generation, and coal plants (in other countries) are now told to idle during their profitable time, and to run when its their least profitable time. Solar is just so cheap to implement now, that daytime pricing is turning cheaper than evening pricing in some places.

Alternately, you can think of it like daytime a coal plant is idling and can't sell electricity. At evening peak, they can sell maybe 3-4 hours of peak expensive electricity, then for another 10 hours 1/2 price power (overnight).

Previously they were selling for 10-12 hours of good profit, then another 10 hours of 1/2 price power.
The economics of coal now don't really work, as their costs are still the same per hour of operation.

If we make some fictitious costing - running costs are R0.4/kw for coal.
Previously they could sell 10-12 hrs at R1 /kW.h, and 10 hours at R0.5/kW.h
So, in a day they'd make R0.6 x 12hrs + R0.1 x 10hrs profit per kw / day after costs.
= R8.2 / day profit * capacity

They need to run for similar times now, but now only can sell for much lower pricing.
R0.6 x 3hrs + R0.1 x 10hrs profit a day after costs.
= R2.8 / day profit * capacity.

As you can see, coal is starting to make 300% less income than it used to. This covers running costs (i.e. coal), but doesn't cover capital depreciation, loans, maintenance costs, carbon taxes etc. Due to this, it now makes a lot less financial sense to run coal as you can't make a profit, which is why a lot of coal generation is now being replaced elsewhere, and more variable generation like wind is being added.

You can see this reflected in loans now - very few if any lending institutions will now lend for coal plants - the finances just don't make sense anymore.

You can tacitly see this here -

With regards to solar, it would be good if we could eke a few more hours out to cover the evening peak, and this is actually becoming more financially feasible -
The time can be extended fairly reasonably now with battery, which is making solar pv + battery start to become more competitive further into the evening. That however is basically the last nail in the coffin for coal.


Rather think of that equivalent coal station as an asset that sits there for 10hrs of the day pumping out at full blast, and the other 14hrs of the day idling.
Thats more like our usage.

(Well, it would be if we had sufficient generation, but thats another story).

Even with limited output hours, the economics of solar are so good, that it makes sense.
Tell me what other assets you have that make financial sense, and decent profits working for 30% of the time!

This does mean that alternate generation will come at different times, however the financials for a lot of these have changed significantly, so it makes more sense for Electricity suppliers to run 2-3 hours of natural gas at R4/kW.h than it does to run a coal station for 24hrs "just to have it running".
Eventually we'll have a basket of supply, which will predominantly be Solar, Wind, supplemented with some existing Coal, some existing Nuclear, and as storage comes down in price (which it is, rapidly), more storage.

Solar is so cheap now, that the economics of things are really out of whack. Wind is even cheaper.
Solar is reliable and predictable. Wind slightly less so, but the economics of both mean that its irrelevant.



The TLDR; for all this is the repetitive - we don't need 24 hour generation.
We need generation when our requirements are high. Solar maps relatively well to those needs.



-----
I've gone and written this up here, as part of my ongoing series to get off my rear and update my blog :) -

 
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hj2k_x

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facts are that endangered birds are being killed by wind turbines. im done arguing with you, have a nice life.
Good facts, those. I especially like the detail of your sources.

I'm off to clean up all the bird carcasses around all these wind turbines. I shan't be long.
 

Johnatan56

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not very smart i guess,

That Forbes article is nonsense, follow to the papers, e.g. Bat one is based on a tiny sample.


US fish and wildlife department stats was something like 300-500k birds died last year to wind farms, very little.
Comparative_bird_deaths_Source_National_Audubon_Society_djalbx.jpg
 

itareanlnotani

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Now we know what really happened to the dodo's.

(Yeah, I know you're being facetious, but the studies on that were quite interesting )

Mostly; We do - they were tasty, didn't move fast, and the ships brought predators with that ate their eggs (rats).
 

itareanlnotani

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not very smart i guess,

A 2009 study [https://ideas.repec.org/a/eee/enepol/v37y2009i6p2241-2248.html] using US and European data on bird deaths estimated the number of birds killed per unit of power generated by wind, fossil fuel and nuclear power systems.

It concluded:

wind farms and nuclear power stations are responsible each for between 0.3 and 0.4 fatalities per gigawatt-hour (GWh) of electricity while fossil-fuelled power stations are responsible for about 5.2 fatalities per GWh.
That’s nearly 15 times more. From this, the author estimated:

wind farms killed approximately seven thousand birds in the United States in 2006 but nuclear plants killed about 327,000 and fossil-fuelled power plants 14.5 million.
In other words, for every one bird killed by a wind turbine, nuclear and fossil fuel powered plants killed 2,118 birds.

A Spanish Study [http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2664.2011.02054.x/abstract] involved daily inspections of the ground around 20 wind farms with 252 turbines from 2005 to 2008. It found 596 dead birds.

The turbines in the sample had been working for different times during the study period (between 11 and 34 months), with the average annual number of fatalities per turbine being just 1.33. The authors noted this was one of the highest collision rates reported in the world research literature.

 

Datura

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JohnStarr

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There is a massive wind farm right near J-Bay/Humansdorp. It's awesome to see. And there are other smaller wind farms popping up along the coast all the way to Storms River.
 

Nerfherder

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Where? The Karoo? Not a lot of birds there. North Sea similarly so. Also, have you done some reading about whether that oft-touted alleged problem with wind power is accurate? Because it isn't.
and also by adjusting the blades its greatly reduced.

basically any excuse to stay on fossil fuels.
 

Nerfherder

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There is a list of power stations in South Africa at https://en.wikipedia.org/wiki/List_of_power_stations_in_South_Africa. To give some further context, the breakdown of the installed capacity per type of power station is:

Fossil Fuels

  • Coal fired: 40 036 MW
  • Gas turbine: 3 449 MW

Low carbon power and renewable energy

  • Hydroelectric: 3 573 MW
  • Nuclear: 1 860 MW
  • Wind power: 1 369.1 MW
  • Concentrated solar power: 400 MW
  • Solar PV power: 1 224 MW
With the planned future builds, both solar and wind power are set to become more important than nuclear in the near future. There is still some way to go before they can eclipse coal fired stations.
Is that including private ?
 
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