# David Bidstrup: The simple things are always the best.

I read a letter a gentleman wrote to “The Australian” where he calculated how many solar panels would be required to replace a 2,000 MW coal fired power station. He used 500W solar panels and concluded that the replacement number was 4 million. I thought I would see what the answer really is.

Rated capacity does not give any indication of the total energy produced over time. The critical parameter is the capacity factor, (CF) which indicates the percentage of time that the generator produces energy.  A typical coal power plant has a CF of around 0.9 which means it will generate energy for 90% of the time. Solar has a CF of between 0.17 and 0.2 depending on whether the panels are fixed or have a tracking system that allows them to change angle as the sun angle changes over the seasons.

I am going to use 435W solar panels in this analysis as they are the highest rated panels I have found to be available. They have a service life of 25 years. Each panel will produce 0.76 MWh per year at a CF of 0.2.

The table below shows the comparisons. A 2,000 MW coal station with a CF of 0.9 will produce 15,768,000 MWh annually so the number of panels required to “replace” it is 20,689,655.  If CF was ignored and there was just a “straight MW” replacement the number of panels would be 4,597,701 so it is always important to know whether someone is talking about power in MW or energy in MWh when they make statements about renewable energy projects.

It is not as straightforward as it seems, there are some factors here that make it look better than it really is.

First; the output is averaged over a year. Solar systems degrade to around 40% of maximum output in the depths of winter so relying on an average is dangerous. There will be over production in the summer months and under production in winter. The chart below comes from one of my posts that did not make the cut, titled “Why solar power is not worth a cracker”, and shows the month by month comparison between a conventional 1 MW generator that can run all the time and a 1 MW solar system. It shows that the rated MW is not a basis for comparing generating options.

Second, and probably most obvious, is that we have day and night every 24 hours so the solar system will provide energy for about half of the year and some other system needs to cope with the nights.

Third, when the daily variations are considered things get even worse. The chart below shows a “typical” January for a 1 MW system, with the x axis showing the day of the month and the y axis showing MWh produced each day.

Output varies from a high of 6.44 to a low of 2.23 and these changes can be sudden. There is a view that solar “works” when the sun shines however the output can fluctuate widely with cloud cover and this is one of the reasons why domestic “rooftop” solar causes so much grief when it is connected to the grid. Things might be going OK then some clouds cause the output to plummet.

The next chart shows the output for a bad July day, again for a 1 MW system.

The output varies from a high of 4.39 to a low of 0.45.

For some strange reason those who have control over the decisions made about “energy policy” seem to have absolutely no idea what they are talking about, extremely piss poor decisions are made and the consequences are dire.

In simpler times large coal fired power stations churned out reliable electricity year round and were built to last a long time. Renewables last about half the life of a coal fired station, are unreliable and cost us the earth. All this because some charlatans would have us believe that carbon dioxide has a “special property” that no other gas has, namely the ability to “trap heat” and then radiate it back towards us in defiance of the laws of thermodynamics.

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### 30 Responses to David Bidstrup: The simple things are always the best.

1. Craig

DENIERRRRRR!!!!

sorry, couldn’t help myself. That’s basically the crap the warmies come back with.

2. Anthony

All this because some charlatans would have us believe that carbon dioxide has a “special property” that no other gas has, namely the ability to “trap heat” and then radiate it back towards us in defiance of the laws of thermodynamics.

It is pretty clear that in laboratory settings that CO2 absorbs and radiates various infrared wavelengths. In the real atmosphere it probably radiates in all directions, back into space, back to the surface etc. I don’t think we have much cause to believe CO2 radiates those wavelengths massively differently than in the lab. In a planet lacking oceans or cloud cover, modelling the heat accumulation of heat trapped via CO2 is (probably?) a bit more straightforward. I think reasonable people can reasonably disagree how for example, cloud cover scatters radiated wavelengths from CO2 and to what extent this does (or doesn’t) cause temperature increases.

3. Enlightenment will eventually follow from these Dark Ages and future generations will look back and wonder what caused this madness to afflict humanity.

4. Yes indeed bemused.
In exactly the same way that we look back on the life of James Charles Stuart; (19 June 1566 – 27 March 1625) and ponder how on Earth people could have been so gullible as to blame all of their hard luck on witches, werewolves, vampires, and other demons. All without the slightest shred of evidence.
C’est le meme chose!

5. Chris M

Oh, so does that mean we need 10 million batteries to go with the 5 million solar panels?

6. sabena

The intrinsic unreliability of solar and wind power means back up has to run continuously.The result is that you are at least(if the cost of solar/wind is the same as coal(and it is more expensive)),paying twice for the same thing.

7. 20 million panels – what would that be in surface area required?

I recall reading a book years ago where someone did the calculations for the UK based on wind (well you wouldn’t bloody well use solar there). To power the current demand, the land area of Wales would need to be covered in wind turbines and I think the cost was about 5 times GDP and then there was the recurring costs of repair and replacement. Yet these idiots continue to spruik fraud energy. So where do all the panels go? Who pays? At what cost to the environment (neodymium mining and production)?
I’ve never heard anyone ever ask The Holocausters these questions…ever.

8. Roger

For some strange reason those who have control over the decisions made about “energy policy” seem to have absolutely no idea what they are talking about…

Lily D’Ambrosio called…she wants to know what these laws of thermodynamics are.

9. Trevor Brighton

Guest author has had a big rant, but didn’t really leave us with a conclusion.

The reality is that private money from large scale developers to households – when building these projects – already factor in capacity factors (Liddell is about 60%, solar is more like 25% these days).

That is, the levelised cost of electricity for renewables is still better than coal notwithstanding lower capacity factors.

Renewables are both cheaper and lower carbon emitting than thermal coal, and with firming, are just as reliable.

The silliest thing is to turn this issue into a right-wing = pro-coal, left-wing = pro-renewables.

We should simply be for the most efficient solution, and that is rapidly becoming renewables. Indeed, lots of private money is flowing into renewables, nothing into coal. Feel free to invest in coal, mine you – otherwise perhaps put up or shut up !

10. manalive

In simpler times large coal fired power stations churned out reliable electricity year round and were built to last a long time. Renewables last about half the life of a coal fired station, are unreliable and cost us the earth …

So far so good.

… All this because some charlatans would have us believe that carbon dioxide has a “special property” that no other gas has, namely the ability to “trap heat” and then radiate it back towards us in defiance of the laws of thermodynamics …

Absolutely false.
“… A greenhouse gas is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect.The primary greenhouse gases in Earth’s atmosphere are water vapour, carbon dioxide, methane, nitrous oxide and ozone. Without greenhouse gases, the average temperature of Earth’s surface would be about −18 °C rather than the present average of 15 °C …”.
Greenhouse gases don’t transfer heat from the cooler atmosphere to a warmer surface but impede the radiation of infrared energy back through the atmosphere into space causing the rate of surface cooling to slow until a new equilibrium at a higher temperature is reached, similar to building insulation or clothing.
Add to greenhouse gas concentration and the equilibrium point increases, doubling the concentration of CO2 causes about +1C in theory, ceteris paribus.
The difference is that a building or human body is generating heat from within while the Earth surface is heated by incident solar ultraviolet radiation — greenhouse gases react only to long wave infrared re-radiation.
The ‘greenhouse effect violates the 2nd Law of Thermodynamics’ canard is used by alarmists to make climate realists/sceptics look like idiots.

11. John Constantine

The mass hysteria posing as saving the planet has been carefully focus group tested and marketed.

The most hysterical of hysterics simply know in their hearts what their heartfelt truth is, and nobody will make their hearts shut up ever again.

12. Cannibal

Where can I get a reasonably economical diesel gen set. 12 kw should do…

13. BoyfromTottenham

David, so what was your final figure for the number of solar cells to equal the 2GW coal-fired power station? Your graphs showed that the 20 million cell figure has to be discounted further to allow for PV summer vs winter performance, but no final calculation. I guess at about 30 million.

14. Fat Tony

manalive
#2868811, posted on November 21, 2018 at 3:16 pm

what percentage of this “greenhouse effect” is caused by water vapour and what % by man-made CO2?

15. v_maet
#2868826, posted on November 21, 2018 at 3:49 pm

Thanks. So if my very rough sums are correct we would need 1/20th of the land mass of Australia covered in solar panels to supply the nations requirements. Remove the incompatible places and that’s about 1/5th (and we haven’t even considered batteries yet.)

And the Greentards have a hissy fit when a few hundred metres of earth is dug up to get da evil coal. Further, 1/5th of the “always was, always will be Aboriginal land” – is that correct Greentards?
By their own rules it cannot be done, bwahahahahahaha!

16. Rohan

All this because some charlatans would have us believe that carbon dioxide has a “special property” that no other gas has, namely the ability to “trap heat” and then radiate it back towards us in defiance of the laws of thermodynamics.

Then

manalive
#2868811, posted on November 21, 2018 at 3:16 pm

Absolutely false.
“… A greenhouse gas is a gas that absorbs and emits radiant energy within the thermal infrared range. Greenhouse gases cause the greenhouse effect.The primary greenhouse gases in Earth’s atmosphere are water vapour, carbon dioxide, methane, nitrous oxide and ozone.

A rebuke straight from the wiki I see. David is in fact correct. 2nd law of thermodynamics states a cold mass will not give up it’s energy to a warm mass. The reason why this is important is that the atmosphere has what’s known as the adiabatic lapse rate. Every gain in altitude realises a drop in temperature of 4-9 deg c/km. At 10,000m its typically -35-45C when you look at the outside conditions flying off on business or holidays.

So what you are saying is that a few ppmv CO2 caused by humans (4% of 405 ppmv or 0.0016% of the atmosphere) at -40C/10km altitude or whatever is going to heat the planet uncontrollably at the surface when the surface is an average of 18C. Cold mass heating a warm mass. That’s a direct violation of the 2nd law of thermodynamics.

You could prove this point with a very simple experiment. Next winter, freeze a 1000lt IBC filled with water down to -40C and stick it in your living room as the sole source of heating. You’ll be nice and snug from the radiative forcing if the theory holds true. I bet you a weeks salary that it wont.

And water vapour is a greenhouse gas. So the experiment above is relevant. It’s the most abundant greenhouse gas in the atmosphere. It’s 22 1/2 times the concentration of CO2 and according to the Koyoto Protocol, is 7.6 times stronger a GHG than CO2. Why isn’t something being done about that? I mean that’s like a gazillion degrees right there. Something doesn’t add up. It never has.

Because it’s a scam.

17. cohenite

Yeah, energy density is another way of comparing real energy – fossils, nuclear, hydro to a certain extent – but only to a certain extent because capacity factor as correctly defined in this article ignores another further measure which is reliability point; RP is the probability of the installed or maximum capacity of the installation occurring at any one time. Fossils and nuclear are pretty much 100%: wind and solar are about 5%.

18. cohenite

Another way is land area. Allowing for a capacity factor of 20% and for 100MW of both wind and solar requiring 10 square kilometres, to replace Eraring power station, Australia’s best at 2800 MW, would require 1400 square kilometres covered with either wind turbines or solar panels.

19. Dr Faustus

David: Like the piece, although it seems to me that you have rather let the solar farm off the hook in your replacement calculation.

For a proper like-for-like comparison, the solar array + backup storage must be capable of sending out 2,000 MW 90% of the time, not 90% of 2,000MW all of the time.

Using your numbers, I think the total solar panel requirement is actually around 22,900,000 units. But, in the spirit of renewable energy, phffft, what’s an extra 2,200,000 panels in the greater scheme of things…

(Obviously, we both assume no additional panels to supply the power loss in and out of whatever storage ‘solution’ is used to supply 2,000 MW for the 19.2 hours when the solar array is black)

20. manalive

Fat Tony:
Google tells me ‘water vapour and clouds account for 66 to 85 percent of the greenhouse effect, compared to a range of 9 to 26 percent for CO2’.
Rohan:

David is in fact correct. 2nd law of thermodynamics states a cold mass will not give up it’s energy to a warm mass …

That doesn’t contradict what I wrote viz. the 2nd Law of Thermodynamics is irrelevant to the greenhouse effect.

So what you are saying is that a few ppmv CO2 caused by humans (4% of 405 ppmv or 0.0016% of the atmosphere) at -40C/10km altitude or whatever is going to heat the planet uncontrollably at the surface when the surface is an average of 18C ..

.
LOL, I’m being ‘verballed’ I didn’t say anything like that.

21. egg_

Without greenhouse gases, the average temperature of Earth’s surface would be about −18 °C rather than the present average of 15 °C …”.

By Qiancheng Ma — March 1998

Radioactive decay accounts for half of Earth’s heat (2011)
IIRC the Earth would be c. 0°C without sunlight.

22. egg_
23. Aynsley Kellow

David, you overlook the fact that PV panels degrade in their performance by a small but noticeable percentage annually. Your estimate of 25 years is a bit heroic – they are also subject to destruction by severe weather effects (Google solar panels in Puerto Rico after hurricane).
Then there is the energy lost in backing up renewables. Batteries and pumped storage hydro are only about 80% efficient.
But renewables are also currently parasitic on the reliable system. Trevor Brighton’s ‘levelled cost of energy’ is totally misleading and the source of much of our current problem. We have to think in system terms. As Leon Hirth shows in his ‘The Market Value of Variable Renewables: The Effect of Solar and Wind Power Variability on their Relative Price’ (a prepublication version available by Googling), the real cost of renewables escalates rapidly once their share of generation exceeds 40%, because they can no longer rely as much on the reliable system.
There is a very real danger in the ALP’s 50% renewables target.

24. Muddy

bemused
#2868780, posted on November 21, 2018 at 2:05 pm

Enlightenment will eventually follow from these Dark Ages and future generations will look back and wonder what caused this madness to afflict humanity.

The present period of history will be known simply as ‘The Void.’
It will be whispered about, and used to curse our enemies.
Jokes about Voiders will replace Irishmen and blondes in stand-up routines.

25. Bushkid

We should simply be for the most efficient solution, and that is rapidly becoming renewables. Indeed, lots of private money is flowing into renewables, nothing into coal. Feel free to invest in coal, mine you – otherwise perhaps put up or shut up !

That’s all very well, but the cost of coal-fired electricity generation has only been made so expensive (to the point of being uneconomical, e.g. the power station that closed in April last year in Vic) because fo warped and nonsensical government legislation and regulation (via subsidies, LRET, RET, NEM etc.)

So, the ones who need to put up or shut up are the so-called renewables advocates who are pushing for ever more unreliable, intermittent wind and solar, that HAS to have RELIABLE back-up baseload generation running in the background 24/7. In Australia, due to our lack of suitable terrain and rainfall hydro is very limited, and due to maniacal anti-nuclear policies we can’t have nuclear generation.

26. Chris M

…the fact that PV panels degrade in their performance by a small but noticeable percentage annually. Your estimate of 25 years is a bit heroic

Yes, and batteries even more so. Doing well if you get 10 – 12 years useful storage.

27. Rafe Champion

The simplest argument against the unreliable sources is to point out that two systems are going to cost more than one and we cant do without the old until the next generation of storage.
Plus as long as we have the old the spinning reserve of coal power means emissions persist.
Simplest way forward to phase in modern coal fired plants to give the desired emission reductions with full reliability and no additional system cluttering up the countryside.
No need to get into the climate science CO2 debate.

28. Herodotus

The entire climate scam and energy system disintegration proves that a large number of people can be fooled all of the time.
It can be done because of the cumulative haranguing by the dodgy proponents which is amplified by a compliant media until politicians (ignorant or knowing) buckle.
The current phase sees the Labor/green side doubling down on the madness after the Wentworth result while the Nero types in our formerly conservative parties continue their jellyback contortions – with violin accompaniment – and the nation burns in quite a different way to that threatened by the climate clubbers.

29. David,

the daily low output in winter is much worse than you have shown. Capacity factor is as low as 0.8% on some days in winter. Therefore, a 1 MW solar farm would produce 80 kW average power over 24 hours on that day. See. ‘Solar Power Realities – Supply demand characteristics, storage and capital costs‘ (Figure 7) http://www.solaripedia.com/files/393.pdf

30. Trevor Brighton says:
“That is, the levelised cost of electricity for renewables is still better than coal notwithstanding lower capacity factors.”

That is clearly nonsense. If it was true, renewables would not need the subsidies from the REC’s which are around \$80MWh. The renewables need to receive the spot price plus around \$80/MWh, which means they are about three times the cost of coal.