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crissdee
1337761.  Fri Nov 29, 2019 3:31 pm Reply with quote

suze wrote:
I've never actually noticed a parking ticket machine with a solar panel on top, but then i) I don't use public pay car parks all that much, and ii) when I do, I have not hitherto gone looking for solar panels. The solar panel would only need to be about six inches square, so if it's on the lid of the machine you wouldn't notice it unless you were actually looking.


In my last job, I spent almost as much time looking at parking ticket machines as I did looking at the machines I was paid to fix.* A substantial number of them seemed to be solar powered (or at least assisted) and it seemd that the whole upper surface, or near to it, was a solar panel, Some of them, from memory, were in the order of 12"/300mm square.

*My mate came round to help me get ahead on my expenses one day. As we sat on the floor, trying to sort out the various business receipts, he said to me;

"Do you just drive around looking for places to park or something?"

At least half of my receipts were in the form of parking tickets.

 
dr.bob
1337980.  Mon Dec 02, 2019 7:35 am Reply with quote

PDR wrote:
PV cost estimates vary as you look around - for a 5MW array the range seems to run from around £280/kW to around [url=solarguide.co.uk/how-much-does-it-cost-to-install-solar-panels#/]£1,500/kW[/url], giving ballpark costs of £1.4m to £7.5m for the array.


I'm assuming that £280/kW figure is a typo. However your figures belie a lack of knowledge of the subject. Taking your figures from a website based on residential installations and assuming the same figures will apply for a large-scale commercial installation is dumb.

30 seconds of googling took me to this website which clearly shows that for a 50kW solar PV installation, the price is £750/kW. Is that the right figure to use? Personally I don't know, since we're talking here not only about an installation potentially 100 times larger, but also an installation for a local council with significant spending power and the desire to install more in the future. All those factors suggest to me that they would be able to drive the price down even lower.

PDR wrote:
but where the 5MW PV array produces under 180kWh/day averaged over a year


Where on earth does that 180kWh/day figure come from? A 5MW solar panel installation running at an efficiency of about 20% for around 5 hours a day would output 5,000kWh/day. If you're going to quote figures, at least try and get them right to within an order of magnitude.

PDR wrote:
Against that it would probably have to be located a bit offshore to get more consitant and stronger winds


And have you factored in the transmission losses incurred through siting your wind turbine offshore? Or any other real world effects that are important here? No, of course not. You've just taken a few random figures from the internet and then assumed you know what you're talking about. As usual.

That might give you a warm fuzzy feeling inside, but it's really hampering the rest of us who want to have a measured conversation about renewables.

PDR wrote:
You said the purpose of the solar array and battery system wasn't to be the primary source of energy for recharging (which we demonstrated it couldn't do)


WE haven't done any such thing. What has happened so far is that YOU have thrown around a bunch of bogus figures to try and convince the hard of thinking that you know what you're talking about. So let's look at some sensible numbers.

As mentioned above, the solar panel array could conceivably generate around 5,000kWh/day. To be honest, I'm not comfortable with that figure since it assumes the entire roof is covered in solar panels which seems logistically tricky, so why don't we use a more realistic figure of 2,000m^s array producing 2,000kWh/day. Admittedly the 5 hours of sunshine per day is using figures for summertime, so they're a best case scenario, but let's see what it's capable of.

2,000kWh is enough to run a 22kW charger for nearly 4 days! Or it can run nearly 4 22kW chargers at full pelt all day long.

Ah but, I hear you say, Dundee council has installed 20 chargers. What good is only running 4 of them? The answer to that is childishly simple. The idea that these chargers are going to be running full pelt all day long is absurd. The press release clearly stated these were to be used to trickle charge cars over a period of several hours. A Nissan Leaf only has a 30kWh battery. Plug it in to a 22kW charger and it'll be done in less than 2 hours if the charger was at full pelt. Are you seriously imagining that people will be constantly switching these chargers to different cars to try and drain the solar panels as fast as they can?

I've asked in the past, and I've asked just recently, please, for the love of god, will you stop posting lies and misinformation on this thread. It could be a really interesting forum for discussing the challenges people will face with EVs and renewable power in the future, but not while you're poisoning the discussion with your complete nonsense.

 
PDR
1337987.  Mon Dec 02, 2019 9:13 am Reply with quote

dr.bob wrote:

I'm assuming that £280/kW figure is a typo. However your figures belie a lack of knowledge of the subject. Taking your figures from a website based on residential installations and assuming the same figures will apply for a large-scale commercial installation is dumb.


I'll let the vocally challenged seek your apology for using a disability as an insult, but it doesn't surprise me, frankly.

I used numbers based on domestic installations because the installation in question has more in common with domestic roof-top installations (a series of small canopy arrays, mounted on top of a building with a structure that has to pick up in the existing building rather than a large ground-level array with simple concrete footings). I got a range of prices developed from the data on the websites I referenced - I picked the upper and lower bounds. You've picked a number which lies between the two, but which derives from installations of a very different character to the the one in question. So we aren't really disagreeing, where are merely choosing different baseline comparitors for our estimates for what we each see as good reasons.

There are a number of problems even with these estimates - I picked 5,000sqm as an array size because it was a generous over-estimate of the largest physical area which could be fitted onto the roof of that building in an attempt to pick a best possible case for the potential power capacity of such an array. When you look at the actual sketches and photos it's clear that the actual array is likely to be nowhere near that big - looking at the canopies they (at a guess) take up less than half of that area. This will do two things - it would reduce the capital cost number, but also reduces the numbers for energy available from the array. If we're going to refine numbers I suugest this is probably the elementthat needs correcting first.

Quote:

PDR wrote:
but where the 5MW PV array produces under 180kWh/day averaged over a year


Where on earth does that 180kWh/day figure come from? A 5MW solar panel installation running at an efficiency of about 20% for around 5 hours a day would output 5,000kWh/day. If you're going to quote figures, at least try and get them right to within an order of magnitude.


Yes, you're right - I have no idea where that number came from. My eye must have slipped or something. Deepest apols. In my post 1337399 I came up with a rather less empirical number of 5,200kWh/day, but Suze pointed out that I had used the wrong Dundee(!) so I applied a lattitude correction. In fact now that I look at it I see where that error jumped in, so I've corrected it. The number for available energy from a 5,000m^2 array on a Dundee rooftop comes out to around 4,000kWh/day.

Quote:
And have you factored in the transmission losses incurred through siting your wind turbine offshore? Or any other real world effects that are important here? No, of course not.


Not really, for a number of reasons. Firstly (as I mentioned) the wind turbine doesn't suffer the large drop off in power output over most of the day due to angle of incidence issues, and these more than offset those transmission losses. Secondly the losses themselves are minimised by transforming the generated voltage to around 30kV, reducing the currents and therebuy the losses. Thirdly the losses would almost certainly be less than those in the National Grid network which provides the bulk of the energy to the carpark anyway (due to their respective distances), because (as we have shown) the solar arrany only generates a fraction of the power needed for more than a handful of cars, so these losses apply to both solutions and are thus not a discriminator beytween them. And fourthly the wind turbine option is "scalable" - if you need more you add more or bigger turbines, whereas the PV option is limited to the size of array that can be fitted to that garage roof.

Quote:
WE haven't done any such thing. What has happened so far is that YOU have thrown around a bunch of bogus figures to try and convince the hard of thinking that you know what you're talking about. So let's look at some sensible numbers.


I produced a set of figures which (other than the error in the final one, which doesn't relate to this aspect anyway because it was only part of a cost comparitor) seem similar to your own. As I have said, I erred on the generous side to avoid being accused of unfairly underestimating the capability, but ho hum.

But you came on here and said that Dundee were doing a system intended to be able to charge 20 cars initially, and then to expand the ports as demand grew. So lets look at that.

Quote:

Admittedly the 5 hours of sunshine per day is using figures for summertime, so they're a best case scenario, but let's see what it's capable of.


..and again - it's wrong. It just looks at sunshine hours (not really relevant to solar power). It ignores the detail that the amount of energy that falls on the panel changes as the sun (metaphorically) moves across the sky from horizon to zenith and on to the horizon again. So for most of the day the panels are not collecting anything like the 1kW/m^2 maximum rating. You choose to guess this averages to 5 hours a day. It's such a shame you choose to guess when it's not needed, because more authoritative information is available. If you care to read back to post 1337399 and post 1337419 you will find a sourced number for what this correctin comes out to, averaged over a year in a specific location.

Quote:
2,000kWh is enough to run a 22kW charger for nearly 4 days! Or it can run nearly 4 22kW chargers at full pelt all day long.


But of course it can't, because they only generate your 2,000kW number at noon. "All day" includes time periods that are definitely not "at noon". But lets ignore that. You came on here and evangelised about a facility that would charge 20 cars at a time, and allow others to charge overnight, based on solar energy. You now say that it's perfectly reasonable that this system is only actually expected to charge four cars at a time - presumably the other 50,000-odd Dundee car owners (in 2016 Dundee had the UK's highest car ownership rate) can just go whistle? And the vaunted ability to expand to meet further demand? It's just hogwash.

The only "news" here is that Dundee has decided to install 20 charging points. That in itself is a good thing and should be encouraged as long as we have the ability to generate the electrical energy needed to supply
them. The solar power aspect of this just doesn't stack up, I'm afraid.

Everything I've looked at in this has suggested it's primarily a supply-side problem, so we should be focussing our efforts into setting up PRACTICABLE electricity generation capacity. Tidal barages and wind farms look to be under-exploited options IMHO.

Quote:

I've asked in the past, and I've asked just recently, please, for the love of god, will you stop posting lies and misinformation on this thread. It could be a really interesting forum for discussing the challenges people will face with EVs and renewable power in the future, but not while you're poisoning the discussion with your complete nonsense.


And as I've asked you in the past - perhaps you could read what was said and focus less on the insults, put-downs and general rudeness it might be possible to hold such a discussion.

PDR


Last edited by PDR on Mon Dec 02, 2019 12:45 pm; edited 1 time in total

 
barbados
1338008.  Mon Dec 02, 2019 12:14 pm Reply with quote

I'm reminded of a totally inappropriate meme relating to arguning on the internet, and likening it to winning the 100mtrs at the para-olympics,
More appropriately, post 1325756 has an image that highlights a similar thing - although I suspect it will go over some heads (as it appears to have previously)

 
Jenny
1338026.  Mon Dec 02, 2019 2:02 pm Reply with quote

Excellent point barbados, to the extent that I will repeat it:

I have a few suggestions to make here, since we have now degenerated into bickering.

Firstly - please don't make assertions without backing them up with sources: however well-known you think the material is, consider that it may be less well-known to people outside your field of experience.

Secondly - please don't nitpick over inessential details. Unless it is vital to the sequence of events, skim over it. Nitpicking is boring at best and mostly tedious. Let's all avoid being tedious.

Thirdly - please don't take disagreement personally, and as Oliver Cromwell once wrote in a letter to the general assembly of the Church of Scotland (3 August 1650), "I beseech you, in the bowels of Christ, think it possible you may be mistaken."

Fourthly - consider that the person with whom you are arguing has areas of knowledge within their own areas of expertise about which you know nothing, and therefore it is possible that they are approaching the topic from an angle that includes things you didn't know you needed to consider - Donald Rumsfeld's unknown unknowns.



Fifthly - if you find yourself getting hot under the collar, step away from the keyboard and refrain from commenting, however wrong the other person is in your opinion. Use the time constructively by having a nice dinner with your family, watching something fun on TV, going for a walk, having a pint, playing a game, but don't become this person:

 
dr.bob
1338069.  Tue Dec 03, 2019 6:35 am Reply with quote

PDR wrote:
dr.bob wrote:

I'm assuming that £280/kW figure is a typo. However your figures belie a lack of knowledge of the subject. Taking your figures from a website based on residential installations and assuming the same figures will apply for a large-scale commercial installation is dumb.


I'll let the vocally challenged seek your apology for using a disability as an insult, but it doesn't surprise me, frankly.


<sarcasm>
Of course, I forgot there was only one definition of the word "dumb".
</sarcasm>

Thank you for bringing the level of this discussion down to the level of a primary school playground and for confirming my suspicion that you have absolutely no interest in having a sensible, mature discussion about a potentially interesting subject.

PDR wrote:
I picked 5,000sqm as an array size because it was a generous over-estimate
<snip>
When you look at the actual sketches and photos it's clear that the actual array is likely to be nowhere near that big
<snip>
If we're going to refine numbers I suugest this is probably the elementthat needs correcting first.


Which is exactly what I did in the post immediately above your when I said "To be honest, I'm not comfortable with that figure since it assumes the entire roof is covered in solar panels which seems logistically tricky, so why don't we use a more realistic figure of 2,000m^s array". Maybe you didn't bother to read that bit.

PDR wrote:
Secondly the losses themselves are minimised by transforming the generated voltage to around 30kV, reducing the currents and therebuy the losses.


Of course the losses are minimised. The National Grid wouldn't be doing a very good job if it decided to run a sub-optimal power losses, would it? The fact remains that transmission losses still occur.

PDR wrote:
Thirdly the losses would almost certainly be less than those in the National Grid network which provides the bulk of the energy to the carpark anyway


Are you suggesting that the wind turbines are not routed through the national grid but rather plugged straight into the car park? That's a very strange idea, but it's the only way I can see where the transmission losses of the national grid would be irrelevant.

Though I'm not interested in vanishing down a rabbit hole of discussing wind turbine options. I merely wanted to point out that your conclusions are based on naive calculations based on an incomplete set of data and so they should be approached with extreme caution.

PDR wrote:
because (as we have shown) the solar arrany only generates a fraction of the power needed for more than a handful of cars


"We" have not shown that at all. This is a simple, flat out lie. I have supplied plenty of information to cast doubt on your erroneous conclusions, but you simply choose to ignore it and repeat your tedious falsehoods. This seems to me to be simple trolling.

PDR wrote:
But you came on here and said that Dundee were doing a system intended to be able to charge 20 cars initially, and then to expand the ports as demand grew. So lets look at that.

Quote:

Admittedly the 5 hours of sunshine per day is using figures for summertime, so they're a best case scenario, but let's see what it's capable of.


..and again - it's wrong. It just looks at sunshine hours (not really relevant to solar power). It ignores the detail that the amount of energy that falls on the panel changes as the sun (metaphorically) moves across the sky from horizon to zenith and on to the horizon again. So for most of the day the panels are not collecting anything like the 1kW/m^2 maximum rating.


This is a very good point, so thank you for raising it. You are quite right that I forgot to account for this effect. In an attempt to quantify this effect, I found this explanation of how to correctly calculate the variation using spherical trigonometry. It shows that the total energy collected over the course of one day is calculated by integrating the peak power generation multiplied by the sine of the angle of incidence of the Sun multiplied by the length of the day divided by pi (since the Sun travels across pi radians over the course of the day). This results in the equation:

E = P x Td / pi

PDR wrote:
You choose to guess this averages to 5 hours a day.


I didn't guess, so please don't rewrite the narrative to categorise my actions in a negative way. This is simple trolling. I took the figures from the link suze supplied for climate data in Dundee. However, this is where I made my second mistake. I took the average monthly sunshine hours as my basis. This is clearly wrong.

Any solar installation has to cope with the peaks and troughs of unreliable sunlight. In particular, it has to cope with the maximum power output of the system on a clear summer's day. If it can't handle this load, then energy will be wasted.

Checking the data on timeanddate.com, I find that on May 15th 2019 and June 25 2018, Dundee experienced unbroken sunshine from morning 'till night. Timeanddate.com also tells me that on May 15th 2019 Dundee enjoyed more than 16 hours of sunlight, while on June 25 2018 daylight lasted for 17.5 hours.

If we plug those numbers into the equation above, we can see that, for a solar panel that will generate 1kW at peak sunlight, the total energy created over a long sunny day in Dundee will equal about 5.5kW.

As it turns out, using the average sunlight values of 5 hours per day coincidentally gave me a good estimate for the peak output of the array on a sunny midsummer's day, so I stand by those figures.

PDR wrote:
Quote:
2,000kWh is enough to run a 22kW charger for nearly 4 days! Or it can run nearly 4 22kW chargers at full pelt all day long.


But of course it can't, because they only generate your 2,000kW number at noon. "All day" includes time periods that are definitely not "at noon".


I have now corrected that, and my figures stand.

PDR wrote:
You came on here and evangelised about a facility that would charge 20 cars at a time, and allow others to charge overnight, based on solar energy.


This is a lie.

I did not "evangelise" about anything. I merely reproduced a report on the BBC. Was the BBC evangelising too? After all, I reproduced their words.

I thought it was an interesting article about an attempt to solve a particular problem about EV charging, to wit how do people with no off-street parking charge their cars? Instead you've decided to try and prove that you know better than Dundee council based on your reading of a couple of websites and make the whole discussion about how useless the solar panels are (even though I've provided plenty of information to suggest you've almost certainly got your assumptions wrong).

PDR wrote:
You now say that it's perfectly reasonable that this system is only actually expected to charge four cars at a time


This is an even bigger lie.

At no point have I said the system is only actually expected to charge four cars at a time, nor have I said that this would be reasonable. I've already covered why the solar panels would power 20 chargers, not 4, in my previous post. Indeed, I described the explanation of this as "childishly simple." It's a shame you chose not to bother reading that part of my thread in your desire to simply indulge in pointless trolling.

Just to summarise, a solar panel array producing 2,000kWh over the course of a long sunny midsummer's day will produce enough energy to charge 66 Nissan Leafs (Leaves?). Since there are only 20 charging points and they're expected to be used by one car during the day and one car during the night, this is clearly producing an excess of energy that needs to be stored in a battery.

Even this is a wholly unrealistic example since it assumes that the Nissan Leafs are completely empty when they arrive at the charging station. This is very unlikely to be the case. If the Leafs arrived on average half full, then we immediately have enough energy to charge over 100 of them. Your constant insistence that you've "proved" that the solar panels are not producing sufficient energy is simply wrong.

PDR wrote:
presumably the other 50,000-odd Dundee car owners (in 2016 Dundee had the UK's highest car ownership rate) can just go whistle?


So what's your point here? Are you saying any charging system that doesn't cater for 50,000 people is useless? Are you saying that Dundee Council should install enough charging points for every car driver long before they're made the switch to EVs? This strikes me as a pointless and silly thing to say, probably just more trolling.

PDR wrote:
The only "news" here is that Dundee has decided to install 20 charging points. That in itself is a good thing and should be encouraged


What about those other 50,000-odd Dundee car owners? Should they just go whistle?

You're kind of all over the place here. It's almost as if you don't have any coherent argument and are just indulging in pointless trolling.

PDR wrote:
The solar power aspect of this just doesn't stack up, I'm afraid.


It does, you're just ignoring any figures that contradict your worldview thus rendering sensible discussion impossible.

PDR wrote:
Tidal barages and wind farms look to be under-exploited options IMHO.


In the first 6 months of this year Scotland generated almost twice the entire country’s domestic power requirements from wind turbines. Describing it as "under-exploited" once again belies your ignorance of the subject.

PDR wrote:
And as I've asked you in the past - perhaps you could read what was said and focus less on the insults, put-downs and general rudeness it might be possible to hold such a discussion.


I've pointed out where you have either not read what I've posted or chosen to simply ignore it. As far as I can see that makes you either a colossal hypocrite or a massive troll. Either way, the inability to hold a sensible discussion is as a direct result of your behaviour.

 
barbados
1338079.  Tue Dec 03, 2019 8:16 am Reply with quote

Absolutely unbelievable.
This topic is really quite interesting, and the efforts that are taking place in Dundee are even more interesting.
What spoils it is, despite repeated requests it is falling into an ad-hom playground

 
Alexander Howard
1338095.  Tue Dec 03, 2019 11:01 am Reply with quote

Village nuclear - that's the answer. I said it before and I'm boring you with it again. A back-of-a-van-sized nuclear reactor in every town and sizable village, and in every bus station with e-busses and attached car charging station. It could be small enough hoist the core out when it needs refuelling, if it ever needs refuelling, and for mucking-out.

Local people would not object either, if no one told them what is going on.

 
crissdee
1338105.  Tue Dec 03, 2019 1:01 pm Reply with quote

Alexander Howard wrote:
A back-of-a-van-sized nuclear reactor in every town and sizable village, and in every bus station with e-busses and attached car charging station.


The seeds of twenty thousand "dirty bombs". The bad guys wouldn't even have to get their own radioactive waste, just plant enough weedkiller bombs and lay waste to the nation.


Alexander Howard wrote:
Local people would not object either, if no one told them what is going on.


Well, quite.......

 
barbados
1338109.  Tue Dec 03, 2019 2:15 pm Reply with quote

dr.bob wrote:
Checking the data on timeanddate.com, I find that on May 15th 2019 and June 25 2018, Dundee experienced unbroken sunshine from morning 'till night.

From your links, June 25th was one of two days that experienced unbroken sunnshine, the same with May 15th, in fact using the method to calculate the "unbroken sunshine" in June 2018, there were as many days of unbroken rainfall - although I think you'll agree that three intervals a day is a little light on data.
I could hunt out more precise figures, one of my hobbies involves taking a keen interest in cloud cover but to be honest with you I'm not too inclined to hunt it down. The one thing I think most will agree with is the data you are basing your figures on may be flawed.
dr.bob wrote:
In the first 6 months of this year Scotland generated almost twice the entire country’s domestic power requirements from wind turbines. Describing it as "under-exploited" once again belies your ignorance of the subject.

Again your link seems to contradict what you are suggesting.
it suggests that jobs are shrinking in the sector, when they should be on the increase, It also points out that policy changes have resulted in the near death of the industry with a 94% drop in planning applications - if you feel that the source is adequately exploited, I'm not sure that you are really aproaching the debate from a position of strength.
As I see it, the problem with renewable is there is a problem with meeting demand - should I wish to boil the kettle now (or charge my car for that matter)I would struggle at 7pm unless there is a reliable way to store the energy in such a way that it can be available on demand across the national grid in the way that it is now. Perhaps we need to find a way to distribute the energy efficiently before we try to get everyone switching to a renewable energy source that is not freely availble

 
dr.bob
1338133.  Wed Dec 04, 2019 9:01 am Reply with quote

barbados wrote:
I think you'll agree that three intervals a day is a little light on data.
I could hunt out more precise figures, one of my hobbies involves taking a keen interest in cloud cover but to be honest with you I'm not too inclined to hunt it down. The one thing I think most will agree with is the data you are basing your figures on may be flawed.


I think you're looking at the wrong part of the website.

At the top of the page, under the title "Weather in Dundee — Graph", there is a brief overview of the data with only three symbols describing the weather data for that day. This seems to be what you're referring to.

However, if you scroll further down, you'll see a section labelled "Dundee Weather History for <date>". Here you can select the date you're interested in and see weather data for each 30 minutes of the day. I would suggest that this is sufficient data to base my figures on.

barbados wrote:
Again your link seems to contradict what you are suggesting.
it suggests that jobs are shrinking in the sector, when they should be on the increase


Not quite. It suggests that domestic jobs are shrinking. It's a shame that these wind turbines are being built abroad rather than in the UK, but that doesn't mean there's a fundamental problem with the industry as a whole.

barbados wrote:
It also points out that policy changes have resulted in the near death of the industry with a 94% drop in planning applications


This is factually incorrect. Policy changes have affected onshore wind farms, but not offshore ones. It's true that planning applications for new onshore wind farms have dropped by 94% but to portray this as "the near death of the industry" is absurd. All the existing wind turbines are still busy generating energy and new offshore wind farms are being built.

barbados wrote:
As I see it, the problem with renewable is there is a problem with meeting demand - should I wish to boil the kettle now (or charge my car for that matter)I would struggle at 7pm unless there is a reliable way to store the energy in such a way that it can be available on demand across the national grid in the way that it is now.


This problem will be solved by a combination of small scale distributed generation (like the solar panels on the Dundee car park for example) combined with battery storage to smooth out the peaky nature of renewable sources.

barbados wrote:
Perhaps we need to find a way to distribute the energy efficiently before we try to get everyone switching to a renewable energy source that is not freely availble


This will occur if people are encouraged to install their own small scale power generation as they switch. The more people with their own solar panels and/or wind turbines, the more reliable the power supply will be.

 
barbados
1338135.  Wed Dec 04, 2019 9:59 am Reply with quote

Just a quick response between classes,
dr.bob wrote:
This is factually incorrect. Policy changes have affected onshore wind farms, but not offshore ones. It's true that planning applications for new onshore wind farms have dropped by 94% but to portray this as "the near death of the industry" is absurd.

That comment was taken from your source - are you suggesting that your source was being absurd? if so then does it not suggest that you don't trust the integrity of that source and we should ignore it?


Last edited by barbados on Wed Dec 04, 2019 2:55 pm; edited 1 time in total

 
barbados
1338140.  Wed Dec 04, 2019 12:14 pm Reply with quote

Firstly, apologies for the split response - however to address the nub of your post more fully.
dr.bob wrote:
At the top of the page, under the title "Weather in Dundee — Graph", there is a brief overview of the data with only three symbols describing the weather data for that day. This seems to be what you're referring to.

However, if you scroll further down, you'll see a section labelled "Dundee Weather History for <date>". Here you can select the date you're interested in and see weather data for each 30 minutes of the day. I would suggest that this is sufficient data to base my figures on.

I have taken another look at the page for May 15th, and it does indeed say that there was unbroken sunshine through that day, however it also says on May18th there was pretty much unbroaken rainfall, so my point does stand - what you need to look at (which isn't available on that page) is the average hours of sufficient sunshine to provide a power source to maintain a charge on a vehicle parked at the charging point. There is probably a formula to calculate that - but it isn't as simple as "how sunny" you also need to consider what accompanies that sunshine. I'm no expert but I would consider that any haze that would accompany the sunshine would also affect the quality of charge. In a similar way you would also need to consider outer atmospheric pollution that, again, would affect the quality of the charge - simply put, it is a bit disingenuous to suggest that because it appears sunny, charging will be optimised, in a similar way that climate and weather are not exactly the same thing.
Quote:
Not quite. It suggests that domestic jobs are shrinking. It's a shame that these wind turbines are being built abroad rather than in the UK, but that doesn't mean there's a fundamental problem with the industry as a whole

Correct, however the fact that part of the wind turbine sector is being scaled back would suggest to me that that particualr power source is not being fully exploited - some might suggest it is even being under exploited (taking into consideration the bits of the article linked to that you don't appear keen to acknowledge).
Quote:
This problem will be solved by a combination of small scale distributed generation (like the solar panels on the Dundee car park for example) combined with battery storage to smooth out the peaky nature of renewable sources.

Yes it likely would be resolved by that - however, it isn't at the moment is it? so at the moment, it is still a problem. In the future I don't doubt there will be a way to do this, but until that time arrives we will need to continue to use fossil fuels to power us, be it in a car or at home. As has been pointed out previously (I'm pretty sure) - at the moment I can travel from Lands End to John O Groats in a little under 15 hours in my 2.0 Kia Sportage - that includes time for refueling stops. How long will it take in a Nissan Leaf? and more importantly how much of that journey would be wasted in refueling?. It is another issue that needs to be addressed before we transform everywhere to be like Dundee.

 
dr.bob
1338168.  Thu Dec 05, 2019 3:43 am Reply with quote

barbados wrote:

dr.bob wrote:
This is factually incorrect. Policy changes have affected onshore wind farms, but not offshore ones. It's true that planning applications for new onshore wind farms have dropped by 94% but to portray this as "the near death of the industry" is absurd.

That comment was taken from your source


This is wholly untrue. Please re-read my source more carefully. At no point does it describe the policy changes or the reduction in planning applications as "the near death of the industry".

barbados wrote:
are you suggesting that your source was being absurd?


No, because my source didn't refer to "the near death of the industry". That phrase is your own invention and to try and claim it came from my source is utterly wrong and misleading.

barbados wrote:
if so then does it not suggest that you don't trust the integrity of that source and we should ignore it?


It would suggest that if it had a shred of truth about it. Since it has absolitely no basis in fact, it suggests that I'm happy to trust my source and I recommend that you re-read it.

 
dr.bob
1338170.  Thu Dec 05, 2019 4:19 am Reply with quote

barbados wrote:
so my point does stand - what you need to look at (which isn't available on that page) is the average hours of sufficient sunshine to provide a power source to maintain a charge on a vehicle parked at the charging point.


No, you're wrong.

I've metioned several times that the fundamental problem with renewable sources is that their output is very peaky. As I clearly explained in my post above:

"Any solar installation has to cope with the peaks and troughs of unreliable sunlight. In particular, it has to cope with the maximum power output of the system on a clear summer's day. If it can't handle this load, then energy will be wasted."

That is why I focussed my example on the maximum output that would be generated on a sunny day.

barbados wrote:
There is probably a formula to calculate that - but it isn't as simple as "how sunny" you also need to consider what accompanies that sunshine. I'm no expert but I would consider that any haze that would accompany the sunshine would also affect the quality of charge. In a similar way you would also need to consider outer atmospheric pollution that, again, would affect the quality of the charge


This is a very good point, so I thank you for raising it.

All the discussions that have so far taken place about the power output of the solar panels in Dundee are based on incomplete information. PDR and I have disagreed about how effective this installation would be, but neither of us really knows how these solar panels would work in real life. As you say, there are countless real-world factors that you need to take into account which neither I nor PDR have sufficient knowledge of the subject to do.

Someone who would have full access to all the relevant information is whoever was in charge of planning the installation in Dundee. They would have requested full details from the solar panel installers and performed a complete due diligence before spending lots of public money on this project. Having received all that information, they decided it was a sensible thing to spend money on. This suggests to me that it's highly likely that the solar panel installation is a worthwhile thing to install.

To relate this back to my own figures, I've shown that in my not-real-world calculations, the solar panels should produce enough power to charge well over 100 half-empty Nissan leafs. This is based on the commonly quote maximum power output for solar panels in the UK of 1kW/m^2. If all the real world effects you mention were to reduce this output by 50% (which strikes me as a very conservative estimate), we would still have enough power to charge more than 60 half-empty leafs, which is more than the number of chargers can cope with. Given all this, even though these figures are not 100% reliable, I think that describing the contribution of the solar panels as insignificant is very misleading.

barbados wrote:
Correct, however the fact that part of the wind turbine sector is being scaled back would suggest to me that that particualr power source is not being fully exploited - some might suggest it is even being under exploited


Only the domestic production of turbines is being scaled back. The number of turbines generating power is not.

I genuinely don't understand how a country that produces 200% of their energy needs using wind power can be described as under explointing wind as a renewable resource.

barbados wrote:
(taking into consideration the bits of the article linked to that you don't appear keen to acknowledge).


I am very happy to scknowledge all parts of the article I linked to. Please don't try to rewrite the narrative to portray my actions in a negative light.

barbados wrote:
Yes it likely would be resolved by that - however, it isn't at the moment is it? so at the moment, it is still a problem.


Yes, the issue of storing power from renewable sources is still a problem. One that is being tackled, but it will take some time to fully deal with this issue.

barbados wrote:
It is another issue that needs to be addressed before we transform everywhere to be like Dundee.


I'm not sure what kind of renewable paradise you think Dundee currently is. All they've done is install a handful of charging points in a few different locations. As I've said several times on this thread, the changes in Dundee are simply a start, but at least they're moving in the right direction.

You're right to say that EVs are not currently in a position to replace fossil fuel-powered cars in all situations. However, in order to allow them to do so, development not only has to be done on EVs, but also on the infrastructure required to support the EVs. If we wait until all the problems have been solved before we start creating the infrastructure, then the problems will simply never be solved.

 

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