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« Solar heat illustrated - Josh 322 | Main | The Iris Hypothesis from the archives »
Tuesday
Apr212015

Solar heat

A fire at Hove Town Hall was caused by solar panels on its roof, it emerged today.

"The source of the fire is believed to be an electrical fault with a solar panel on the roof. An investigation is under way."

The council said all its solar panels were checked annually, with those at the town hall checked two weeks ago.

ESF&RS said solar panels were no more dangerous than any other electrical product.

Although according to this website, this is not actually true

Research commissioned by the DCLG and carried out by BRE on fire safety and solar electric/photovoltaic systems, identifies the major obstacle facing firefighters: “In contrast to the power used by conventional mains electrical equipment, the power that PV systems generate is DC (direct current) and parts of the system cannot be switched off. DC installations have a continuous current, making them more hazardous (volt for volt) than normal AC (alternating current) electrical installations.”  

The issue is that a household’s AC supply can easily be shut off by firefighters, however, the DC current supplied by the solar panels will also be generating as long as the sun is out.

The whole article is pretty interesting, pointing out for example that if a fire breaks out in your solar panels, it is not going to get picked up by your smoke detectors.

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Reader Comments (54)

While the smoke would not be picked up by smoke detectors, seems trivial to add some sort of fire detection device in the panels...

Apr 21, 2015 at 12:32 PM | Unregistered Commenterrms

While the smoke would not be picked up by smoke detectors, seems trivial to add some sort of fire detection device in the panels...

rms


I don't think it's trivial. DC is nasty! Panels on roof, wind blowing, where do you put the smoke detector? You could maybe fit a voltage surge detector but with the sun going in and out all day ? But none of that cures the problem of high current/voltage DC that cannot be switch off except by covering the panels with gunge.

Apr 21, 2015 at 12:37 PM | Unregistered CommenterStephen Richards

Domestic pv systems have a cut off switch. The issue for fighting fires in a non-domestic setting is finding someone who knows where the cut-off switch is located.

Apr 21, 2015 at 12:38 PM | Unregistered CommenterBloke down the pub

http://bit.ly/1bf8ihi
Dietz and Watson warehouse fire in USA

Apr 21, 2015 at 12:39 PM | Unregistered CommenterTmitsss

I presume that Hove town hall is in Caroline Lucas' constituency?

Apr 21, 2015 at 12:41 PM | Unregistered CommenterBloke down the pub

A "renewable fire"

It has happened before, and will happen again.

I am sure that tax payers helped pay for the original installation, and insurers will pay for the damage. The consumers of this electricity can simply switch back to the grid.

The manufacturers/installers can't be held responsible for an inherent concept fault, approved by the Government's agents, so the only losers are tax payers and insurers, and they don't count, because they "only" paid for it.

Apr 21, 2015 at 12:49 PM | Unregistered CommenterGolf Charlie

"The council said all its solar panels were checked annually, with those at the town hall checked two weeks ago."
Was the cost of this included in the cost-benefit analysis? The cost of an annual check of solar arrays on the roofs of (presumably often quite tall) council buildings must be considerable. I bet the cost per MWh is at least an order of magnitude higher then checking, say, gas boilers.

Apr 21, 2015 at 12:59 PM | Unregistered CommenterAlex

Have the Greens heard of the way in which Archimedes exploited solar power at the siege of Syracuse?

Apr 21, 2015 at 1:03 PM | Unregistered CommenterRoy

@ Alex at 12:59 PM

"I bet the cost per (solar) MWh is at least an order of magnitude higher than checking, say, gas boilers."

Especially as the gas boiler can be checked at any time of the day or night.

Presumably, each & every solar panel can only be checked in operational conditions, when the sun is shining. And that depends upon reliable day-ahead forecasting.

Apr 21, 2015 at 1:08 PM | Unregistered CommenterJoe Public

I wouldn't over-egg this greatly. After all, the proof of the pudding is in the eating. Have there been many more fires than expected in areas where PV has been used for many years - Germany, for instance?

Though I must admit, If you want to close down a PV installation, you can't just shut it like you can a warehouse. Someone has to actually get rid of the generating capability, otherwise it will remain dangerous...

Apr 21, 2015 at 1:12 PM | Unregistered CommenterDodgy Geezer

The lesson learnt should be that Firefighters be issued with umbrellas to shade panels to combat similar self-propagating fires. /sarc

Apr 21, 2015 at 1:18 PM | Unregistered CommenterJoe Public

The website contains a good example of useless advice provided by experts:

...
- Avoid application of firefighting water directly on to the PV array
- Consider covering the PV panels to reduce the generation of DC power
- Seek specialist advice where necessary...

All very sensible. Now consider an actual incident. You arrive with the apparatus at a house fire. The flames are coming through the roof. How do you do 1) and 2) above? Perhaps you need to consider 3)? Not a lot of use in an emergency....

Apr 21, 2015 at 1:19 PM | Unregistered CommenterDodgy Geezer

Dodgy Geezer - there is always Option 4....

Wait till night time....

Apr 21, 2015 at 1:25 PM | Unregistered Commentersherlock1

why not tell the greenies that from now on, all fires involving solar panels will be extinguished with Frakking fluid minus some sand.
They will have those panels down PDQ

Apr 21, 2015 at 1:34 PM | Unregistered CommenterEternalOptimist

Wonder what the risk is ? I expect it increases your insurance *.
last week I read about another one but dismissed risk,thinking whatever you'd spent your money on their might be a fire

- Kent 30 March 2012 Fire warning after Britain's first solar panel blaze
- Worksop June 2014 House fire was caused by new ‘solar panels’ say residents
- DailyMail 31 August 2014 - Third roof blaze damaged two classrooms at Sutton Bonington Primary School in Nottinghamshire,
- Jonova May 2014 At least 70 houses with rooftop solar panel arrays have had solar driven burnouts.
- Sep 26th, 2013 " a 300,000-square-foot refrigeration facility stocked full of a business’ deli meats and cheeses burn to the ground. The reason? There was no safety mechanism for shutting off the building’s 7,000 rooftop solar panels. "
New Solar Panel Sensor Addresses Fire Risk Dec 19th, 2013

"bushcrush 9:03 PM on 12/06/2014 I work for a solar panel company and it is not possible for solar panels to cause a fire. Solar panels generate electricity through chemical reactions, there is nothing on them that can catch fire." sure ?
* Zurich Insurance : Solar Panel Risk White Paper May 2014

US Anti Solar fire video sums it up
- Are fires caused by solar panels ZERO CO2 fires ?

Apr 21, 2015 at 1:37 PM | Registered Commenterstewgreen

@ Alex at 12:59 PM

I also wonder if the regular weekly surface cleaning in included in the cost-benefit analysis. What, they don't clean them every week? Maybe that is why they are so useless.

Friends that have a very large array (they are too far from power lines for an economical connection) have to clean them every two days or the see a falloff of output of up to 50% and that is just from the dust in the air - it is clean every day when there is work in the vineyards going on.

I suspect the panels in Hove are only there to get the subsidies because I hate to think what the bird droppings do to the output. Bird droppings can also cause local overheating of panel elements which, if left unchecked can result in a fire in the panel.

Apr 21, 2015 at 1:56 PM | Unregistered Commenterivan

Wonder what that 'checking' involved..? Are we going to be told..? Or was it more a case of:

'Yep - they're still there...'

Apr 21, 2015 at 2:01 PM | Unregistered Commentersherlock1

Knowing Hove as I do (20mph speed limits - totally ignored) - the local gull population must wreak havoc with the efficiency of those panels...

Apr 21, 2015 at 2:04 PM | Unregistered Commentersherlock1

Stephen Richards, Dodgy Geezer
Spraying with foam as used by Fire Services in aircraft fires? I guess not water based foams though, as chlorine may be a result?

Apr 21, 2015 at 2:20 PM | Unregistered CommenterSandyS

Golf Charlie:

A "renewable fire"
Not to mention, 'sustainable'!

Apr 21, 2015 at 2:29 PM | Unregistered CommenterHarry Passfield

"Domestic pv systems have a cut off switch"

"If you want to close down a PV installation, you can't just shut it like you can a warehouse. Someone has to actually get rid of the generating capability, otherwise it will remain dangerous..."

From a firefighting point of view it doesn't really matter if there is a cut off switch or not. These only isolate the supply from the panels to the inverter(s). The largely overlooked danger is that these panels are wired up in long series strings, which can produce upwards of 500 volts DC. In fact, a quick search shows some inverters accepting over 600 volts - and that's under loaded conditions. The potential open circuit voltage on a sunny day doesn't bear thinking about... An Australian company manufactures remote isolator modules which allow the strings to be broken down into much smaller segments, and this is done on the roof. Only with this arrangement can hose reels be safely used in the event of a fire.

A friend rents space in a sub-divided factory unit, and the adjacent premises has a substantial (60kw) roof mounted array. A small fire broke out in the adjacent unit a year ago, unfortunately the fire brigade were seriously hampered in their work. It was a bright, sunny day, and they wanted to smash some roof panels to let the smoke escape, but couldn't risk going up to do so. Only as darkness fell was it safe to finish their job. It was thought that the relevant wiring had been disconnected, but due to the damage this proved not to be the case - the following morning, as the sun rose, sparks began emanating from the charred remains of the inverters...

Apr 21, 2015 at 2:32 PM | Unregistered CommenterDave Ward

@SandyS

Stephen Richards, Dodgy Geezer
Spraying with foam as used by Fire Services in aircraft fires? I guess not water based foams though, as chlorine may be a result?

Not sure why you would want to do that. Foams ARE water-based (imagine trying to carry vast quantities of non-water liquid around with you!) and they are used on inflammable liquid fires. Aircraft and Car fires may involve petrol or kerosene, and spraying water on that would simply float the fire somewhere else.

I think Sherlock1 had the best idea above. Wait until night time. Then either the fire will have gone out, or you will be able to see it clearly...

Apr 21, 2015 at 2:33 PM | Unregistered CommenterDodgy Geezer

According to Le Monde (2010) one in three PV systems fail to comply with safety standards resulting in a risk of electric shock or fire.

According to the Dutch Food and Goods Authority up to 650,000 Scheuten ‘Multisol’ PV modules have a design flaw in a junction box resulting in a fire risk.

Apr 21, 2015 at 2:34 PM | Unregistered CommenterTerryS

I wonder what the insurance companies’ take on this is? Once they start to load premiums (or refuse to pay up) roof-mounted panels will be dead in the water...

Apr 21, 2015 at 2:43 PM | Registered Commenterjamesp

Hang on a mo, Dodgy, if you wait until night so that you can see the fire clearly won't the panels start trying to generate power from the light of the fire? [grin]

Apr 21, 2015 at 3:06 PM | Unregistered CommenterHarry Passfield

Hi,

An additional hazard are all the PV panel installations that feed through an elcheapo chinese inverter that has no output short circuit disconnect facilty.

In the old days all the elecc travelled from the sub station TO the consumer. If the linesman opened the breakers at the sub, then the local area was safe to work on. In todays world, having PV panels feeding into the local street supply means turning off at the sub does not protect the electricity linesman.

The problem is that to protect themselves, the linesmen apply a short circuit across the phase to neutral, on the section where they are working, which ensures their safety.

This causes all the PV installations on the street or local area to detect the S/c and shut off the inverter. That is of course those inverters that are capable of recognising the S/C.

All the other sub standard inverters will attempt to feed the S/C, and will either pop their O/P stage or even worse keep running and cook themselves.

Which brings me to the point of the thread....... A substantial fire risk!

cheers

GG

Apr 21, 2015 at 3:15 PM | Unregistered Commentergrumpy granddad

You'd think this kind of thing would have been addressed before the subsidy tap was turned on.

With a tiny bit of forethought you could perhaps put a mains powered fail safe switch on every panel. If the incoming mains supply is switched off the panels and inverter continue to produce power but if you go a step further and switch the inverter off the panels will be isolated. Knowing nowt about solar installations, is this a possible solution?

Dodgy Geezer said:

Not sure why you would want to do that. Foams ARE water-based (imagine trying to carry vast quantities of non-water liquid around with you!) and they are used on inflammable liquid fires.

The foam might reduce solar panel output in much the same way as bird muck.

Apr 21, 2015 at 3:17 PM | Unregistered CommenterGareth

Telephone switching offices are powered from huge glass battery banks. They can fill an entire basement floor of a large building. The produce the standard telephone battery voltage of -48V DC. Battery and ground are carried throughout the building on copper bus bars that are bigger in cross section than a 2x4. In case of mains failure, backup is provided through redundant gas turbine engines which are essentially jet engines stationed in the building basement. Massive amounts of current are carried around the building on exposed copper bus bars which are the thickness of a man's arm. The safety considerations must be similar to solar installations.


I do know that in the design of telephone equipment that fire safety is rigidly enforced. Sourced components must not be able to sustain a flame. Obviously if the telephone switch is on fire no one can call the emergency number. Are solar installations subject to the same fire safety standards. Are their components in them that can sustain a flame?

Apr 21, 2015 at 3:36 PM | Unregistered CommenterTAG

Telephone switching offices are powered from huge glass battery banks. They can fill an entire basement floor of a large building. The produce the standard telephone battery voltage of -48V DC. Battery and ground are carried throughout the building on copper bus bars that are bigger in cross section than a 2x4. In case of mains failure, backup is provided through redundant gas turbine engines which are essentially jet engines stationed in the building basement. Massive amounts of current are carried around the building on exposed copper bus bars which are the thickness of a man's arm. The safety considerations must be similar to solar installations.


I do know that in the design of telephone equipment that fire safety is rigidly enforced. Sourced components must not be able to sustain a flame. Obviously if the telephone switch is on fire no one can call the emergency number. Are solar installations subject to the same fire safety standards. Are their components in them that can sustain a flame?

Apr 21, 2015 at 3:36 PM | Unregistered CommenterTAG

They'll need a full structural inspection of the roof structure, at some stage, & it will be interesting if the FB want one done before they get onto the roof once the fire is out! Or do they just let it burn itself out?

Apr 21, 2015 at 3:42 PM | Unregistered CommenterAlan the Brit

On the other hand a gas explosion will take out the entire house with zero warning....
http://www.bbc.co.uk/news/uk-england-hampshire-30092439
http://www.bbc.co.uk/news/uk-england-essex-26046430
http://www.express.co.uk/news/uk/568741/Gas-explosion-rips-house-leaving-utter-destruction

... if the carbon monoxide doesn't get you first.

Apr 21, 2015 at 3:46 PM | Unregistered CommenterJamesG

Curiously, nothing on the BBC News website about this, although it was on the tv at lunchtime! Is that telling?

Apr 21, 2015 at 3:48 PM | Unregistered CommenterAlan the Brit

Following the Precautionary Principle, and the Grauniads "Keep it in the Ground" campaign, would it not be cheaper and safer to bury solar panels in the ground?

Apr 21, 2015 at 4:12 PM | Unregistered CommenterGolf Charlie

Dodgy Geezer
I was thinking that by covering the fire and panels with foam you kill two birds with one stone. The fire goeas out and sunlight is cut off so no more power is produced. I understand that there are in fact non-water based foams available to fire fighters, but I could be wrong.

Apr 21, 2015 at 4:14 PM | Unregistered CommenterSandyS

What about wind turbines? Is their output DC as well? I know there is a major problem with fighting fires involving the larger turbines. Most of the largest onshore turbines are in relatively remote areas, and most rural Fire and Rescue Services do not have access to platform or skylift tenders such as Brontos. So if a big one catches fire, all they can do is watch it burn.

Apr 21, 2015 at 4:15 PM | Registered CommenterSalopian

For those asking what happens in Germany: They let them burn until the PV has been destroyed.
e,g, http://www.welt.de/finanzen/immobilien/article8856358/Feuerwehr-laesst-Haeuser-mit-Solardach-abbrennen.html

And a collection; in German: http://www.konrad-fischer-info.de/pvbrand.htm
They're getting about one fire per day.

The problem is that the loft space is often occupied and any fire in that part of the house cannot be extinguished until the electric shock hazard is eliminated. Regardless of what initiated the fire. And that is what increases the insured risk.

Apr 21, 2015 at 4:19 PM | Unregistered CommenterBernd Felsche


Curiously, nothing on the BBC News website about this

Curiously, this was the first line of the Bish's post.

Apr 21, 2015 at 4:54 PM | Registered Commentersteve ta

@ grumpy granddad & Gareth - as I understand it all grid connected solar inverters must have a mains fail shut off capability. This to avoid exactly the situations you describe, and particularly, to prevent any part of the local network from being "live" when engineers are working on it. As to whether they all DO, is another matter....

This also means that homes with solar installations lose power when the mains fails, even if the sun is shining, no doubt contrary to what many (most?) of those householders think! There are ways to keep your panels supplying power during mains outages, but this requires additional equipment and wiring.

Apr 21, 2015 at 5:14 PM | Unregistered CommenterDave Ward

Bernd Felsche,

I don't know about the situation in Germany. But I'm sure in the UK, the rate of subsidy is rigged to cover not only the costs of installation and underproduction, but also any resulting increased insurance costs.

Apr 21, 2015 at 7:51 PM | Registered CommenterSalopian

@ Bloke Down The Pub

No. Her constituency is further east along the seafront. About 2 miles from Hove Town Hall.

Apr 21, 2015 at 9:01 PM | Unregistered CommenterRB

Can't stand Caroline Lucas or her politics but it ironic how such a hottie can get the Brighton Gay vote.then the solar panels on her roof corode short out and catch the roof on fire and burn her house down.So is there a British EU Standard kite mark for PV if it is to be made compulsory.

Apr 21, 2015 at 9:32 PM | Unregistered CommenterJamspid

Because of their relatively recent invention, the average age of solar panel installations must be less than any other domestic electrical appliance. Plus, parts of them are expected to perform day in, day out in a harsh environment, with greater temperature extremes than most other appliances.

I therefore predict that as average age increases, we will be seeing a lot more fires caused by solar panel installations.

Apr 21, 2015 at 9:39 PM | Unregistered CommenterMax Roberts

Dave Ward (5.14)

Yes, this was the shock my sister got when there was a power cut during the day she still had no power despite generating a surplus prior to the outage. I thought it was to do with the metering, but after reading the comments on this thread it looks more like a safety feature.

Here in Canada there have been many warnings by the fire departments that they cannot put out fires on houses with rooftop PV panels until the panels have been discharged. It is not a trivial problem by any means.

Apr 21, 2015 at 10:18 PM | Unregistered CommenterRob

By Coincidence Planning Engineeer has a post on the extra costs of solar panel customers to the power companies.
"Customers with their own generation are receiving a different service from the utility than traditional customers and traditional cost structures will not work for them. "
"Extra costs are incurred to provide backup service to residential solar customers from the grid.
Utilities can’t collect transmission expenses from them that are spread out across hourly energy costs."

Apr 22, 2015 at 5:21 AM | Registered Commenterstewgreen

Oh no! Green technology, all heat and not much light and is it all that it was cranked up to be? What did you expect?

The boon.....doggles of Green energy and the law of unintended consequences kicks in..........again. Green energy is dangerous and one step 'forwards', mains - a life time to regret it.

All that luverly reliable Chinese technology, I wonder if any sort of guarantee is given on PV solar panel installation and if there is, is it worth the paper it is written on - I would guess at, not bloody likely.

Apr 22, 2015 at 7:27 AM | Unregistered CommenterAthelstan.

And another one, from 2 years ago... the panels might not have been the cause, but still made it difficult.

Apr 22, 2015 at 8:35 AM | Unregistered CommenterHyperthermania

"And another one, from 2 years ago... the panels might not have been the cause, but still made it difficult."

Did the link fail?

'Hyperthermania' btw is a great moniker - luv it.

Apr 22, 2015 at 8:46 AM | Unregistered CommenterAthelstan.

Yup, link failed, but meant to go here: http://www.bbc.co.uk/news/uk-england-devon-22439099

Apr 22, 2015 at 8:52 AM | Unregistered CommenterHyperthermania

The Bishop gets a H/T on Breitbart, who mention in their report that passers-by were complaining of particularly acrid smoke from the Hove Town Hall burning solar panels. Aren't these panels made with some fairly noxious materials?

Greens not only go by air, they also make toxic emissions? :)

Apr 22, 2015 at 9:07 AM | Unregistered CommenterMessenger

Add to all this that DC installations at a given voltage are much more fire-prone than AC at the same voltage. Electrical fires are usually caused by arcing. In an AC installation arcing is mostly self-damping since voltage goes through zero 50 times per secod (60 in the US). In an DC installation arcing simply goes on until something melts.

Apr 22, 2015 at 9:51 AM | Unregistered Commentertty

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