A Year Of Solar Panels

[fluffy666]

Because people like numbers.

Got Solar panels (2.76kWp) a year ago.. after a year of operation:

The salesperson predicted 2304 kWh of generation. The actual result was 2710 kWh. Even with a poor summer.

Edit: Most important bit: This is equivalent to turning off the Drax power station. For 2.43 seconds.

Metered electric usage in the year before installation was about 4000 kWh. In a year with panels, 2650kWh.

Return:

FiT + payments for electric supplied = £1245 (1205 +40)

Electricity savings = £185

Total - 16%.

I've been unable to detect any drop-off in performance, so it seems that they don't need cleaning.

So.. so far it seems like a good investment. Given the drop in costs over the past year, I could have got a 4kWp system now, and the figures would be fairly similar. Note that the non-FiT return is about 2.5%, effectively index linked to energy costs. That would be much higher for anyone installing now - if you have a 4kWp system for £6k, that should be giving about £330 a year BEFORE FiT is considered - i.e. about 5% index linked and tax free.

[Gigantic Purple Slug]

Because people like numbers.

Got Solar panels (2.76kWp) a year ago.. after a year of operation:

The salesperson predicted 2304 kWh of generation. The actual result was 2710 kWh. Even with a poor summer.

Edit: Most important bit: This is equivalent to turning off the Drax power station. For 2.43 seconds.

Metered electric usage in the year before installation was about 4000 kWh. In a year with panels, 2650kWh.

Return:

FiT + payments for electric supplied = £1245 (1205 +40)

Electricity savings = £185

Total - 16%.

I've been unable to detect any drop-off in performance, so it seems that they don't need cleaning.

So.. so far it seems like a good investment. Given the drop in costs over the past year, I could have got a 4kWp system now, and the figures would be fairly similar. Note that the non-FiT return is about 2.5%, effectively index linked to energy costs. That would be much higher for anyone installing now - if you have a 4kWp system for £6k, that should be giving about £330 a year BEFORE FiT is considered - i.e. about 5% index linked and tax free.

Thanks for the figures, very interesting.

Ignoring the practicalities of demand timing, I estimate 13 million households would need to do the same in order to shut down Drax completely.

If I ever get a place I might get some, because it looks like a good investment from the figures you give and it must be fun evaluating them and doing the metrics. Not sure though about their potential impact as an alternative energy source though.

Was thinking the other day about petrol stations. Interestingly they normally have large flat rain shelters above them. Ideal for laying panels out onto, and completely invisible from the ground.

[Nuggets Mahoney]

Because people like numbers.

Got Solar panels (2.76kWp) a year ago.. after a year of operation...

Thanks for that. It's reminded me to get stuck back into a little project that's been parked for a while.

The appeal of solar to me is not strictly financial. There's a (partial) energy independence element to it. If the financials aren't insane that helps.

[fluffy666]

Thanks for the figures, very interesting.

Ignoring the practicalities of demand timing, I estimate 13 million households would need to do the same in order to shut down Drax completely.

If I ever get a place I might get some, because it looks like a good investment from the figures you give and it must be fun evaluating them and doing the metrics. Not sure though about their potential impact as an alternative energy source though.

Was thinking the other day about petrol stations. Interestingly they normally have large flat rain shelters above them. Ideal for laying panels out onto, and completely invisible from the ground.

Given the ROI, any decent sized factory/office, especially one that had high electricity demand, would do well out of adding them, even without FiTs.

As far as alt-energy goes..

If we had 10 million installations at 3kW each, that's a thereotecal peak of 30GW. Since it's all daytime when demand is typically higher than nightime, it does present less of a backup problem than wind. The big problem is really in Nov-Jan; a mid-december day with overcast skies may give you no more than a couple of GW for a few hours.

And yes, I have continuous monitoring of supply and demand.. and a spreadsheet..

[swissy_fit]

Given the ROI, any decent sized factory/office, especially one that had high electricity demand, would do well out of adding them, even without FiTs.

As far as alt-energy goes..

If we had 10 million installations at 3kW each, that's a thereotecal peak of 30GW. Since it's all daytime when demand is typically higher than nightime, it does present less of a backup problem than wind. The big problem is really in Nov-Jan; a mid-december day with overcast skies may give you no more than a couple of GW for a few hours.

And yes, I have continuous monitoring of supply and demand.. and a spreadsheet..

I'm not a complete naysayer for solar in the UK, but it's a fairly pricey way of enabling them to turn down the gas generating stations a bit during the day. If someone invents a cheap 40kwh house battery, then that will change the game....

[Kurt Barlow]

Because people like numbers.

Got Solar panels (2.76kWp) a year ago.. after a year of operation:

The salesperson predicted 2304 kWh of generation. The actual result was 2710 kWh. Even with a poor summer.

Edit: Most important bit: This is equivalent to turning off the Drax power station. For 2.43 seconds.

Metered electric usage in the year before installation was about 4000 kWh. In a year with panels, 2650kWh.

Return:

FiT + payments for electric supplied = £1245 (1205 +40)

Electricity savings = £185

Total - 16%.

I've been unable to detect any drop-off in performance, so it seems that they don't need cleaning.

So.. so far it seems like a good investment. Given the drop in costs over the past year, I could have got a 4kWp system now, and the figures would be fairly similar. Note that the non-FiT return is about 2.5%, effectively index linked to energy costs. That would be much higher for anyone installing now - if you have a 4kWp system for £6k, that should be giving about £330 a year BEFORE FiT is considered - i.e. about 5% index linked and tax free.

Thanks for posting.Thats about 1200kg of Co2 based on UK fuel mix.

[AThirdWay]

Given the ROI, any decent sized factory/office, especially one that had high electricity demand, would do well out of adding them, even without FiTs.

As far as alt-energy goes..

If we had 10 million installations at 3kW each, that's a thereotecal peak of 30GW. Since it's all daytime when demand is typically higher than nightime, it does present less of a backup problem than wind. The big problem is really in Nov-Jan; a mid-december day with overcast skies may give you no more than a couple of GW for a few hours.

And yes, I have continuous monitoring of supply and demand.. and a spreadsheet..

Did you consider air/ground heat pumps?

[Rare Bear]

I'm not a complete naysayer for solar in the UK, but it's a fairly pricey way of enabling them to turn down the gas generating stations a bit during the day. If someone invents a cheap 40kwh house battery, then that will change the game....

Now I have never thought of batteries in the sense of house batteries. I would reckon that most of the research money goes towards lightweight batteries for laptops, tablets, phones and cars. But who cares if a house battery weighs five tons provided it has sufficient capacity, lasts a long time and is affordable. Something like a NiFe cell based thing maybe?

[fluffy666]

I'm not a complete naysayer for solar in the UK, but it's a fairly pricey way of enabling them to turn down the gas generating stations a bit during the day. If someone invents a cheap 40kwh house battery, then that will change the game....

To some extent, yes.

However, if that £6k, 4kWp system - already yielding 5% without FiTs - comes down to £4k or less, then it becomes worthwhile for homeowners regardless. Mostly because it's competing with domestic electricity costs. That was the idea of FiTs in the first place.

If anyone wants an invention idea.. I have a couple:

First, a device that can detect when a household supply is generating more than it is using, and can 'dump' the surplus into an immersion heater (or electric fan heater). So you'd save on hot water/home heating.

Second, a small UPS style system that can supply some of the electric circuits in the house; for example, the lighting circuit which shouldn't need more than a few hundred watts. This will charge itself when the panels are on and generating surplus electricity, and provide 'free' power at night when you'd otherwise be using the grid. Won't work for high-power devices, but it could shift most of your continuous, low power loads to solar-only.

Between these, you'd end up using more of the power generated and less off the grid, and it should be a lot cheaper than a full backup system. Plus youd have some power during an electricity cut.

[Rare Bear]

To some extent, yes.

However, if that £6k, 4kWp system - already yielding 5% without FiTs - comes down to £4k or less, then it becomes worthwhile for homeowners regardless. Mostly because it's competing with domestic electricity costs. That was the idea of FiTs in the first place.

If anyone wants an invention idea.. I have a couple:

First, a device that can detect when a household supply is generating more than it is using, and can 'dump' the surplus into an immersion heater (or electric fan heater). So you'd save on hot water/home heating.

Second, a small UPS style system that can supply some of the electric circuits in the house; for example, the lighting circuit which shouldn't need more than a few hundred watts. This will charge itself when the panels are on and generating surplus electricity, and provide 'free' power at night when you'd otherwise be using the grid. Won't work for high-power devices, but it could shift most of your continuous, low power loads to solar-only.

Between these, you'd end up using more of the power generated and less off the grid, and it should be a lot cheaper than a full backup system. Plus youd have some power during an electricity cut.

Agree with that, Fluffy, although I would be adding solar collectors to the system to harvest the solar energy as heat when it is available and a BIG heat store.

[thecrashingisles]

Agree with that, Fluffy, although I would be adding solar collectors to the system to harvest the solar energy as heat when it is available and a BIG heat store.

I recently read up on passive solar heating designs for houses and it's incredible how efficiently you can regulate the internal temperature in both summer and winter with a good design. You need plenty of thermal mass positioned so that low angle sunlight falls on it during winter, but when the sun is high in summer, you avoid a greenhouse effect. This can be achieved with glazed panels set back behind a veranda.

[Rare Bear]

I recently read up on passive solar heating designs for houses and it's incredible how efficiently you can regulate the internal temperature in both summer and winter with a good design. You need plenty of thermal mass positioned so that low angle sunlight falls on it during winter, but when the sun is high in summer, you avoid a greenhouse effect. This can be achieved with glazed panels set back behind a veranda.

Yes, I reckon that if I were building a house from scratch I could achieve pretty close to zero for heating costs by thoughtful design and good planning. Lots of insulation, lots of thermal mass, gain as much solar energy as possible by whatever means. Possible haet recover ventilation. I haven't looked at the concept in any detail or done any research but I don't see why, given sufficient space for ducting, a heat recovery system should need a mechanical fan. Think about it.

[fluffy666]

I recently read up on passive solar heating designs for houses and it's incredible how efficiently you can regulate the internal temperature in both summer and winter with a good design. You need plenty of thermal mass positioned so that low angle sunlight falls on it during winter, but when the sun is high in summer, you avoid a greenhouse effect. This can be achieved with glazed panels set back behind a veranda.

You'd think that at £170k a pop, the average 3-bed new build would have all that as standard, as well as solar hot water and PV.

[Tuberider]

Yes, I reckon that if I were building a house from scratch I could achieve pretty close to zero for heating costs by thoughtful design and good planning. Lots of insulation, lots of thermal mass, gain as much solar energy as possible by whatever means. Possible haet recover ventilation. I haven't looked at the concept in any detail or done any research but I don't see why, given sufficient space for ducting, a heat recovery system should need a mechanical fan. Think about it.

I'm building a house from scratch right now. South facing, concrete skeleton with 20cm ytong block infil for the walls and the whole thing is wrapped in 5cm xps polystyrene (baumit system)

i'm hoping i'll be ok and won't need central heating, but then again i live in a warm climate

i left a big flat roof on the garage free for future solar panels, but no cash to install now

[Rare Bear]

You'd think that at £170k a pop, the average 3-bed new build would have all that as standard, as well as solar hot water and PV.

You would need a bit of space though for a ventilation system and outside you would need to be clear of any shading on the Southern side. Agreed though, that at current prices for new builds you get carp.

[OnlyMe]

I recently read up on passive solar heating designs for houses and it's incredible how efficiently you can regulate the internal temperature in both summer and winter with a good design. You need plenty of thermal mass positioned so that low angle sunlight falls on it during winter, but when the sun is high in summer, you avoid a greenhouse effect. This can be achieved with glazed panels set back behind a veranda.

Ageed, passive solar could have saved much, much more energy, but that is not where taxpayer's money was ploughed into.

[RiskArb]

These drink can solar heater projects are awesome, great way to recycle and generate free electricity at the same time:

If the UK government had spent the money used for the winter fuel allowance on these and installing more insulation we would probably have saved money and more importantly have less deep-frozen pensioners dead in their own homes.

[corevalue]

Now I have never thought of batteries in the sense of house batteries. I would reckon that most of the research money goes towards lightweight batteries for laptops, tablets, phones and cars. But who cares if a house battery weighs five tons provided it has sufficient capacity, lasts a long time and is affordable. Something like a NiFe cell based thing maybe?

The cycle efficiency of NiFE is poor, around 50% IIRC, compared to 80-90% of lead-acid. I wish there were better batteries than a 150-year old technology.

I have a 1kW PV array as an experiment, charging 4kWh of secondhand lead-acid batteries, hooked up to a 3kW inverter (an old UPS).

I have found:

In the summer, there is enough power for all our daytime domestic usage. The batteries in this context are only used as short-term storage. I believe Kurt also tried this and his was less successful, as he wasn't around in the daytime to use the power and had to rely on the batteries as long-term storage.

By having a peculiar orientation of the panels (one pair almost horizontal, one pair almost vertical) I get useful amounts of power even in the winter. It is not optimum for maximum yearly production though.

Inverters will not start large motor devices without stress, such as hoovers, washing machines, unless these have "soft start" capability, as these appliances draw several times their nameplate power consumption at start-up. I believe this is an upcoming EU requirement.

I do know of someone who built a house with a large solar collector on the roof - simply black painted domestic radiators with panes of glass in place of roof tiles. The heat was stored in a massive insulated "basement" which was actually just a slab of ground surrounded by curtain walls below the house. To extract the heat, he used a ground source heat pump. he reckoned to get a 7:1 COP which is far better than the usual ground source pumps. His store got up to 26C by late summer, and dips to 13C at the end of the winter.

[Rare Bear]

The cycle efficiency of NiFE is poor, around 50% IIRC, compared to 80-90% of lead-acid. I wish there were better batteries than a 150-year old technology.

I have a 1kW PV array as an experiment, charging 4kWh of secondhand lead-acid batteries, hooked up to a 3kW inverter (an old UPS).

I have found:

In the summer, there is enough power for all our daytime domestic usage. The batteries in this context are only used as short-term storage. I believe Kurt also tried this and his was less successful, as he wasn't around in the daytime to use the power and had to rely on the batteries as long-term storage.

By having a peculiar orientation of the panels (one pair almost horizontal, one pair almost vertical) I get useful amounts of power even in the winter. It is not optimum for maximum yearly production though.

Inverters will not start large motor devices without stress, such as hoovers, washing machines, unless these have "soft start" capability, as these appliances draw several times their nameplate power consumption at start-up. I believe this is an upcoming EU requirement.

I do know of someone who built a house with a large solar collector on the roof - simply black painted domestic radiators with panes of glass in place of roof tiles. The heat was stored in a massive insulated "basement" which was actually just a slab of ground surrounded by curtain walls below the house. To extract the heat, he used a ground source heat pump. he reckoned to get a 7:1 COP which is far better than the usual ground source pumps. His store got up to 26C by late summer, and dips to 13C at the end of the winter.

Only reason I though of NiFe cells as an example is that they have a reputation for longevity. At least, from what I rememeber of schooldays science. I was more wondering if anyone were doing any research on any type of cell where size and mass were of no importance compared with the more normal applications like phones etc.

I like your mate's idea. I had never thought of the idea of using heat pump in conjunction with a heat store. Neat.

[thecrashingisles]

You would need a bit of space though for a ventilation system and outside you would need to be clear of any shading on the Southern side. Agreed though, that at current prices for new builds you get carp.

These were built, believe it or not, by David Wilson/Barratt.

[gadget]

i.e. about 5% index linked and tax free.

That's a damn good yield.

Sure beats - 0.1%

http://www.investmentweek.co.uk/investment-week/news/2136429/index-linked-gilts-sold-lowest-negative-yield

To be fair with a linker you get your money back at the end. Whilst a 25 year old solar panel isn't going to be worth much.

But bring on grid parity.

Also how much would a solar array been worth to you in New York / Jersey the past couple of weeks?

[thecrashingisles]

Also how much would a solar array been worth to you in New York / Jersey the past couple of weeks?

Not much if it blew away.

[libspero]

Thanks for posting.Thats about 1200kg of Co2 based on UK fuel mix.

Though none was saved unless they reduced combustion based production by the same amount. Otherwise it's just 1200kg + the CO2 cost of the panels.

I know that's not the point but couldn't resist being pedantic.

On the plus side.. in another 2 to 6 years (if combustion based production were directly off-set) the panels will have saved as much CO2 as it cost manufacture them. At that point you will be truly reducing your CO2 foot print

[Guest eight]

Thanks for posting.Thats about 1200kg of Co2 based on UK fuel mix.

I thought it had got a bit cooler.

[Kurt Barlow]

Though none was saved unless they reduced combustion based production by the same amount. Otherwise it's just 1200kg + the CO2 cost of the panels.

I know that's not the point but couldn't resist being pedantic.

On the plus side.. in another 2 to 6 years (if combustion based production were directly off-set) the panels will have saved as much CO2 as it cost manufacture them. At that point you will be truly reducing your CO2 foot print

Will depend largely on what fuel the solar panels are displacing. If it is coal then the annual saving will be about 2500kg. If it is gas then the saving is about 1200kg. From what I recall it takes about 2 years to recover the energy costs of producing and installing monocrystaline solar panels. As they should last 45 years or more they will pay themselves back many times over in terms of EROEI or carbon budget.