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EricMears

Solar panels don't generate at night

Of course they don't but that isn't the test one should apply. What you really want to know is how much load on the grid they're saving and it's not zero !


During the winter, I buy electricity to run my dishwasher. Not entirely sure how much power that uses but there's a biggish heating element that runs for 10 mins or so at start of cycle, a small electric motor or two running throughout the cycle and another heating cycle for last few minutes. For arguments sake, let's call it 2kWh I'm buying. When there is 'free' electricity available, I run the dishwasher around Noon so the load on the National Grid that night will be a couple of kWh less than it might otherwise have been.

zeupater

EricMears wrote: »

Of course they don't but that isn't the test one should apply. What you really want to know is how much load on the grid they're saving and it's not zero !

During the winter, I buy electricity to run my dishwasher. Not entirely sure how much power that uses but there's a biggish heating element that runs for 10 mins or so at start of cycle, a small electric motor or two running throughout the cycle and another heating cycle for last few minutes. For arguments sake, let's call it 2kWh I'm buying. When there is 'free' electricity available, I run the dishwasher around Noon so the load on the National Grid that night will be a couple of kWh less than it might otherwise have been.

Hi

Same here and probably true in a good proportion of properties with renewables technologies such as pv too!.

What I find totally implausible is that such a simple concept can possibly be overlooked/dismissed without the root cause being heavily embedded in a mischievous personality disorder, political mischief or corporate mischievousness.

Z

silverwhistle

zeupater wrote: »

Same here and probably true in a good proportion of properties with renewables technologies such as pv too!.

Too right! I've generated almost 12.5kWh today and, blow it, I'm exporting as the hot water tank is full. The dishwasher isn't full yet but I've plenty of laundry so you've just reminded me to do that. I'll also get the electric chainsaw out for prepping next winter's wood.

My overnight base load is 52w, and annoyingly I can't get that down even with turning off the office power block. It then jumps to 87w when something else kicks in? If I'm sat quietly reading of an evening there may be a watt or two from the LED reading light. My friends with the recent new PV system realised the principle immediately but there are certain people who either ignore demand side supply or find the concept too difficult.

Incidentally Martyn, are there any aggregate figures for the impact of this effect or is it too difficult to quantify?

Martyn1981

silverwhistle wrote: »

Incidentally Martyn, are there any aggregate figures for the impact of this effect or is it too difficult to quantify?

Hi ho Silver.

I don't know. Zeup is pretty good at finding stuff like this, but I'm not sure if it's possible at the moment because:-

1. During the BST months, not too important, as PV systems, especially west ones are generating up to 7pm and later. Perhaps not much at times, but mine in the summer will make 1kW (from 2kWp) past 7pm. So direct benefit, as well as indirect, such as that you and Eric point out.

2. In the GMT months, there will be little direct PV after 5pm, but measuring any reduction in demand, is I suggest impossible, as the demand trend is falling anyway due to higher efficiency lights, tellies, fridge/freezer compressors etc etc. So spotting/isolating a PV impact during a falling demand may be too hard ...... but as I say, I really don't know, but logically, if we had 5m households with PV, and most used devices via timers etc during the day, then you'd expect to see some effect.

Personally, we use a slow cooker quite a bit, not just because of PV, but because they are so good. I suppose cooking at low watts most of the daytime, would help reduce evening cooking loads throughout the year.

The effect of PV on demand has already been noticed by the National Grid. Their 2016 Summer Outlook Report discusses the impact of embedded PV on the demand curve. See pages 30 onwards in the PDF. Just a point, but the graph on page 24 (fig 12) has a large variance as demand on a Sunday is about 8-10GW lower than the other 6 days. Without PV, it would be roughly 40GW midday Mon-Sat and 30GW midday Sun.

Mart.

ajbell

In April I took 70kWh from the grid and generated 463kWh.
Over half of it exported.

Martyn1981

LG brings its first bifacial module to UK market

LG Electronics has released its first bifacial solar module – the LG NeON 2 BiFacial – to the UK market, pledging to increase energy yields by as much as 25%.

Tech bits

They are claiming higher efficiency, better poor weather performance, and improved temperature coefficient.

Interesting.

Mart.

Alan_Brown

I love these panels. I'd be interested if there are any UK suppliers. We have a spot in the garden where we eat in summer under a sun brolly, but I'd love to have a permanent roof over the area, especially one that generates electricity.

http://www.phatenergy.com/phatport/

ASavvyBuyer

Martyn1981 wrote: »

Hi ho Silver.

I don't know. Zeup is pretty good at finding stuff like this, but I'm not sure if it's possible at the moment because:-

1. During the BST months, not too important, as PV systems, especially west ones are generating up to 7pm and later. Perhaps not much at times, but mine in the summer will make 1kW (from 2kWp) past 7pm. So direct benefit, as well as indirect, such as that you and Eric point out.

Personally, we use a slow cooker quite a bit, not just because of PV, but because they are so good. I suppose cooking at low watts most of the daytime, would help reduce evening cooking loads throughout the year.

Mart.

We also have a West facing system (4kw) and yesterday it was generating upto 8:45pm, with over a 1kw at 7:30pm. It was installed last August and from the records on the Solaredge inverter was regularly generating until 9pm last August & September. However, we still usually get over 1kw from about 10am onwards on bright but cloudy days.

Since having the panels, we tend to use the slow cooker more often and have cooked meals during the day. The washing machine & dishwasher only get used during daytime now. Therefore, shifting our main load from evening to daytime, to make best use of the power generated.

Martyn1981

Alan_Brown wrote: »

I love these panels. I'd be interested if there are any UK suppliers. We have a spot in the garden where we eat in summer under a sun brolly, but I'd love to have a permanent roof over the area, especially one that generates electricity.

Keep an eye out, and keep on googling, as there should be more and more options as we move forward.

You don't necessarily have to have 'traditional' PV panels. You could go for PV glass, it is less efficient, but horses for courses.

Have a look at the roof of the bus shelter in this link:

Canary Wharf Debuts Solar Glass Bus Shelter

Something to think about, would be to kill two birds with one stone, and try to place any such structure where it will block some summer sunshine (high sun), but allow the low angle winter sun to sneak underneath and add solar gain to the properties heat.

Mart.

Alan_Brown

Martyn1981 wrote: »

Keep an eye out, and keep on googling, as there should be more and more options as we move forward.

You don't necessarily have to have 'traditional' PV panels. You could go for PV glass, it is less efficient, but horses for courses.

Have a look at the roof of the bus shelter in this link:

Canary Wharf Debuts Solar Glass Bus Shelter

Something to think about, would be to kill two birds with one stone, and try to place any such structure where it will block some summer sunshine (high sun), but allow the low angle winter sun to sneak underneath and add solar gain to the properties heat.

Mart.

It doesn't come across well in the photo that I posted, but those PV panels are glass, letting light through the clear bits and blocking with the blue PV bits. Just what I want above our seating area because I want a nice amount of light, just not too much of it, especially when I'm eating.

While I'm here, I just thought I'd say how pleased I am with our solar install. We just got in by the skin of our teeth before the FIT payments fell in January. I've been amazed by the success of the panels, they have totally exceeded my expectations.

I attached a diverter to the water cylinder immersion heater and its just recently started turning off saying that it's 'hot'. We have a blanker lower down the cylinder where I'm going to fit another immersion (I have the iboost+ which caters for two immersions). Another success