[Petrochemicals (OP)]

The average embodied carbon in those references for monocrystalline PV was 2,560 kg CO2e per kWp. The embodied carbon of all products vary notably, so that should be appreciated with any embodied carbon values.

From https://circularecology.com/solar-pv-embodied-carbon.html

Gas generation of electricity has a co2 output of 0.429kg of carbon per kwh. That means the solar panel has to generate well over 5000kwh of electricity before it is recouping the carbon invested in it. Is solar reducing co2 emmissions or is it a white elephant?

[SeanB]

Depends on what you use to generate the power. Coal is cheap, and common in China, where 90% plus of all solar panels are made, though hydropower is also a good part of the energy mix there, so the energy mix is somewhat different. The advantage of solar is that they can last 25 years plus, and thus will recoup the energy in production, and are also recyclable with relatively little extra effort, as now you have the components easy to separate, if somewhat labour intensive, but still worth the energy 25 to 50 years down the line.

[alancalverd]

Average output of a solar unit in the UK is 10% of its rated power, so that's 25600 kg of CO2 to produce 1 kW for 20 years (performance falls off towards the end of life) - 175000 kWh, say 0.156 kg CO2 per kWh. That's about 2.5 times the energy per unit CO2 that you'd get by burning coal, or 1.5 times what you'd get from diesel fuel, so it's marginally economic as long as you don't need to store the electricity, in which case the climate would probably be better off with coal.

If you need to replace all your internal combustion and gas heating systems in order to use solar electricity, and build electrical  storage systems, the carbon break even period looks more like 200 years.

[SeanB]

True, but there are other places that are not UK weather wise, with rain most of the time (my current weather notwithstanding, there is a cyclone dumping over a half metre of water so far, which is leading to the area being declared a disaster zone, but normally you have at least 8 hours a day of full sun here) to drop output, so there are plenty of locations that offer better use of the panels.

[alancalverd]

normally you have at least 8 hours a day of full sun here

Somewhere on an oscillating planet? It tends to rise and set in most places.

[Petrochemicals (OP)]

. The advantage of solar is that they can last 25 years plus, and thus will recoup the energy in production, and are also recyclable with relatively little extra effort

but that means in climates of intermittent sunshine that this recoup of energy means that they are nothing but a self funding expense. If after installation and maintenance losses etcetc they only save enough carbon to produce more of themselves, solar is a major carbon expense. They are of course made in the far East where we can deny our carbon footprint.

True, but there are other places that are not UK weather wise, with rain most of the time

You must be confusing the uk with somewhere sunny. And light when it's dark outside.

[evan_au]

In Australia, we get better sun than the UK.
The bulk of electricity generation is from coal, which dumps a lot of other pollution into the air and ash ponds (not just carbon dioxide). So the sooner we can reliably decommission the coal-fired power stations, the better.

embodied carbon in those references for monocrystalline PV was 2,560 kg CO2e per kWp

Do you have an equivalent figure for construction of a coal-fired power station?

[Petrochemicals (OP)]

Average output of a solar unit in the UK is 10% of its rated power, so that's 25600 kg of CO2 to produce 1 kW for 20 years (performance falls off towards the end of life) - 175000 kWh, say 0.156 kg CO2 per kWh. That's about 2.5 times the energy per unit CO2 that you'd get by burning coal, or 1.5 times what you'd get from diesel fuel, so it's marginally economic as long as you don't need to store the electricity, in which case the climate would probably be better off with coal.

If you need to replace all your internal combustion and gas heating systems in order to use solar electricity, and build electrical  storage systems, the carbon break even period looks more like 200 years.

I make it about 7 years before they break even, but this is without transport, back up generation or the over specification for winter demand in a dark country/installation/accessories/etc. Even at present I cannot believe that it is a carbon benefit in the UK given that they are scrapped after 25 years.

[Petrochemicals (OP)]

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.mdpi.com/1996-1073/5/4/872/pdf&ved=2ahUKEwir8Z_5gJ_3AhWQfMAKHT43DzwQFnoECDIQAQ&usg=AOvVaw0EgQzRKhM5AMM_ZAyQO4P2

In Australia, we get better sun than the UK.
The bulk of electricity generation is from coal, which dumps a lot of other pollution into the air and ash ponds (not just carbon dioxide). So the sooner we can reliably decommission the coal-fired power stations, the better.

embodied carbon in those references for monocrystalline PV was 2,560 kg CO2e per kWp

Do you have an equivalent figure for construction of a coal-fired power station?

Which is ironic, far better sun yet powered by coal. Solar is vastly cheaper economically than nuclear or combustion plants if you have good sunshine, virtually free energy, Australia could do a great trade in green steel production. Plus they then have the ability to make more solar panels without using combustion sources, they are not some self perpetuating carbon expense. The carbon footprint of Nuclear power is questionable as well, a lot of concrete steel etc that is unusable again, lots of waste, difficult to process fuel.

http://large.stanford.edu/courses/2015/ph241/gerrard1/

[wolfekeeper]

Solar panels aren't scrapped after 25 years, they have about 0.5% loss of output per year, so they're still outputting nearly 90% of their original output after that. That's just the suggested lifespan, but they're clearly going to go a lot longer.

The fact that the panels are only producing about 10% of the time doesn't matter, because they DO produce during the day, when people are using more energy, that increase is mostly carried by natural gas, so it directly reduces the amount of natural gas burnt. Spoiler: natural gas is a LOT more expensive right now than solar power.

Note that solar installations have got a LOT cheaper. Payback can be as little as 5 years now, but 7 is probably more common. The actual panels are stupidly cheap at about £0.3/watt peak and still falling. What kind of investment pays back the initial investment in 7 years? A good one, that's what.

Note that solar panels work better in the UK than Australia during their respective summers, because the UK is such a long way north. We get over 14 hours of sunshine.

[alancalverd]

Note that solar panels work better in the UK than Australia during their respective summers, because the UK is such a long way north. We get over 14 hours of sunshine.

Not according to the folk who sell solar power systems - see the attached chart of annual equivalent sun hours. The polar regions get 24 hours of sunshine in the summer but remain covered with ice! And of course demand is maximised in winter, not summer.

The more I learn about renewable sources of electricity, the more I am convinced that their commercial success so far depends almost entirely on the flexibility of fossil fuels. If it wasn't possible to fire up a gas-powered generator quicker than coal, wind and solar would never have featured in the energy market.

[Petrochemicals (OP)]

.

The fact that the panels are only producing about 10% of the time doesn't matter, because they DO produce during the day, when people are using more energy

And they do produce during the winter when people need energy by far the most.?

[evan_au]

demand is maximised in winter, not summer.

Again, that depends where you live.
- Australia does have a winter peak of air-conditioning, which coincides with minimum hours of daylight
- but it also has a summer peak of air-conditioning, which coincides with maximum hours of daylight

[Petrochemicals (OP)]

For cloudy or hot conditions such as arizona, some sources state thin film panels are better

https://solartown.com/learning/solar-panels/advantages-make-thin-film-solar-panels-shine/

Are we rushing into solar in some locations before the technology has been  created?

[wolfekeeper]

Note that solar panels work better in the UK than Australia during their respective summers, because the UK is such a long way north. We get over 14 hours of sunshine.

Not according to the folk who sell solar power systems - see the attached chart of annual equivalent sun hours. The polar regions get 24 hours of sunshine in the summer but remain covered with ice! And of course demand is maximised in winter, not summer.

That's averaged over the entire year. Which bit of 'summer' didn't you understand?

The more I learn about renewable sources of electricity, the more I am convinced that their commercial success so far depends almost entirely on the flexibility of fossil fuels. If it wasn't possible to fire up a gas-powered generator quicker than coal, wind and solar would never have featured in the energy market.

As opposed to what? Nuclear?

.

The fact that the panels are only producing about 10% of the time doesn't matter, because they DO produce during the day, when people are using more energy

And they do produce during the winter when people need energy by far the most.?

No, but wind does.

Apparently in your heads, the UK has no electricity demand in summer, and you think that using natural gas, which gives a current electricity price of over 14p/kWh is only superior to solar which costs around 5p/kWh in the UK right now and wind that costs about 7p/kWh.

Hint: if solar panels are attached to your house, you can reduce your bills because any electricity you use only costs 5p/kWh instead of ~27p/kWh and any you don't use gets exported to the grid and reduces the electricity price.

[alancalverd]

The retail cost of electricity has very little to do with physics and a great deal to do with profits, taxes and subsidies.

Having lived through many, I understand a good deal about UK summers. Yes, the sun is above the horizon for over 16 hours in June, but the solar angle never exceeds 62 degrees in London, 59 in Inverness, which is why it is generally colder in Scotland than in England and the north pole (24 hour sunlight) stays frozen. And we do have a lot of cloud over these Atlantic islands.

The value of mains electricity and gas is 24/7/365 availability at any level from zero to the supply rating. Until the cost of renewables includes that of maintaining an adequate overnight and strategic (say 10 day) reserve, you are not comparing apples with apples.

[Petrochemicals (OP)]

demand is maximised in winter, not summer.

Again, that depends where you live.
- Australia does have a winter peak of air-conditioning, which coincides with minimum hours of daylight
- but it also has a summer peak of air-conditioning, which coincides with maximum hours of daylight

If I was in Australia and not in the outback I would certainly drive an electric car that I powered myself from solar power, there is also the space in australia for solar. What sort of weather do you get in Australian winters Evan?

[Petrochemicals (OP)]

No, but wind does.

Apparently in your heads, the UK has no electricity demand in summer, and you think that using natural gas, which gives a current electricity price of over 14p/kWh is only superior to solar which costs around 5p/kWh in the UK right now and wind that costs about 7p/kWh.

Hint: if solar panels are attached to your house, you can reduce your bills because any electricity you use only costs 5p/kWh instead of ~27p/kWh and any you don't use gets exported to the grid and reduces the electricity price.

We are discussing solar. Yes wind does, but solar is now requiring ancillary production in the UK, and that ancillary production (wind) then requires ancilliary production, all of which require carbon to set up. Australia as is in your head just as good as the UK for solar production is in my head a different kettle of fish, you would recoup the production carbon in under 2 years and the rest in under 5, plus the fact that over specification of a solar system will need to be far far less.

[alancalverd]

What sort of weather do you get in Australian winters Evan?

Not sure where Evan is, but winter holidays in Queensland were like an English summer plus heat on the coast, and continuous sunshine inland. Hence the bloody great desert

I would certainly drive an electric car

thus committing another 20 - 30 tonnes of CO2 to the atmosphere to build it.

[Petrochemicals (OP)]

I would certainly drive an electric car

thus committing another 20 - 30 tonnes of CO2 to the atmosphere to build it.

Plus the powerbank and solar panel carbon. If you do 10kmiles per year that is about 30 charges, or 3000kwh but call it 5000 for variance losses etc. A 100kwh powerbank and a 3kw solar array should keep your car in the pink.