Generating your own energy

VfM4meplse

An ad popped up in something I was streaming earlier this evening, but was one of the few that I didn't make use of the "Skip ad" facility.

It was for photovoltaic cells to generate energy that could be sold back to utility companies, not unlike solar panels but captures energy from light regardless of the sun coming out. The advert ended with the warning to get yours now, before prices go up because demand increases (which I thought was weird, because in the current political climate, supply is unlikely to be far behind). Bizarrely it also referred to beating the October rate rise, which had been and gone.

Now I've wanted something like this for a while: I have a south facing rear garden that captures plenty of sunshine when it makes an appearance, which means that my conservatory is often unbearably hot and that energy is wasted. Obviously I'll be holding off investigating options until the election is done and dusted, given the green credentials all parties seem to have laid claim on.

I really just wanted an opinion on the tech itself: is it any good, problems with it etc? Experiences? Is there a better alternative out there?

Gerry1

Steer well clear. It's not from the magic dust panel radiator company is it? No doubt it works just as well with moonlight and starlight, and that claim would be 100% truthful.

matelodave

the benefits of the feed in tariff and selling excess leccy back to the grid ceased about 18months ago and there's not much hope that it will ever get re-instated. Even in the last few years of the FIT it wasn't really giving much of a return so the payback period was getting a lot longer than the original 8-10 years. I'm afraid that you've missed the boat

TBH the only benefit from them is that you can use the leccy they generate which will reduce the amount you consume from the grid. If you assume that you can generate £200 of useable leccy from a set of panels costing £5000, then it will take you 25 years to just break even. Dont forget that what you cant use gets wasted

What ever anyone says, they don't generate much in the winter, none at night and very little if any when its dull and overcast so they really only work effectively in the summer when the days are longer and the sun shines a bit more.

VfM4meplse

Is there anything else in the pipeline (ideally that can be stuck on my roof by next summer?).

Coldplay only announced their intention not to play live gigs on account of the carbon footprint last week: this morning we hear that scientists have found a way round it: https://www.bbc.co.uk/news/science-environment-50562183

What tech is on the horizon for home owners?

Undervalued

VfM4meplse wrote: »

Is there anything else in the pipeline (ideally that can be stuck on my roof by next summer?).

Coldplay only announced their intention not to play live gigs on account of the carbon footprint last week: this morning we hear that scientists have found a way round it: https://www.bbc.co.uk/news/science-environment-50562183

What tech is on the horizon for home owners?

Some friends of mine had a type of panel on their roof that had water flowing through then (obviously with antifreeze for the winter)! That was circulated by a small pump and helped to heat their hot water cylinder, thus reducing the gas or electricity needed for hot water.

The idea being that you still needed hot water even in mid summer plus, with a well insulated large cylinder little of the available energy was wasted as it was being stored.

I have no idea if such systems still exist or what they were called but it did seem an interesting idea.

Ectophile

Solar hot water systems have fallen out of favour since solar photovoltaic became affordable.


They give you pretty much unlimited hot water in summer, when you don't particularly need it, and very little hot water in winter. Plus, they require complicated re-plumbing of your hot water system. Often, a new hot water tank.



Instead, it's easier to get photovoltaic panels, and use a "diverter" to send any spare electricity to the immersion heater.

sevenhills

matelodave wrote: »

What ever anyone says, they don't generate much in the winter, none at night and very little if any when its dull and overcast so they really only work effectively in the summer when the days are longer and the sun shines a bit more.

They do generate when the sun is behind the clouds, not sure how much, maybe 1/3 compared to a sunny day.

Undervalued

Ectophile wrote: »

Solar hot water systems have fallen out of favour since solar photovoltaic became affordable.


They give you pretty much unlimited hot water in summer, when you don't particularly need it, and very little hot water in winter. Plus, they require complicated re-plumbing of your hot water system. Often, a new hot water tank.



Instead, it's easier to get photovoltaic panels, and use a "diverter" to send any spare electricity to the immersion heater.

Personally I shower and do the washing up with the same temperature water all year round!

But yes, I did wonder why they weren't electric panels driving an immersion heater rather than having the complexity of plumbing running up to the roof. Maybe in those days that type of panel was more efficient. They were in effect two glass tubes, the inner one had the water running through it and the outer one was half silvered at the bottom as a focused mirror reflecting the sun into the inner tube.

My friends found that they didn't need to run their boiler at all during the summer months as the system produced more than enough hot water.

[Deleted User]

Something which is overlooked is that if you have a solar panel system and an old electric analogue meter with a rotating ring such as the Sangamo Weston meter, it will run backwards on sunny days taking off units used as well as increasing the FIT meter. Suppliers and companies who fit their systems know about this but as usual in the UK nothing is done about it.. I have found hundreds of these in operation but they can only be spotted in action on a sunny day with the occupier not using much electricity .
So long as a meter reading is not submitted which is less than the previous ones , the suppliers are not concerned
These old analogue meters are still around in large numbers in the UK..Youtubers will show their video s of it if a search of "electric meter running backwards ".
My friend has one and hes so keen to keep his old meter he refuses meter fitters entry and he makes sure that one reading is not less than the previous one he will use a three bar electric heater on to use units up in the summer months ..he s with N.Power, a supplier known to be pretty sloppy !
Digital meters will not reverse, and neither will analogue meters with a backstop on them, but Sangamo Westons do.

Ectophile

I have a solar PV system, and an old spinning disc meter. But this one is designed not to run backwards. It won't rotate back more than one revolution before it hits an end stop and sits there making grinding noises.


One approach that is currently just barely financially viable is a combination of solar photovoltaic and lithium ion batteries.


When my original solar inverter failed a couple of years back, I was persuaded to buy a new one with a small battery attached. I am not sure I will ever get my money back on the extra cost of the installation, but it is nice to be running the house on free electricity long after the sun has set. My usage over the summer was less than 1kWh per day of grid electricity.


The down side is that in cloudy weather (including most of the last week), the system is not a lot of use. As a rule of thumb, even a light cloud blocking the sun will reduce the power to about 1/10 of the maximum. If it's heavy cloud, this may go down to 1/100 of the maximum. At that sort of power levels, it will barely cover the background load in the house, and won't even make a start on charging the battery.

matelodave

I investigated solar thermal ten years ago when I had my heatpump installed . In fact the hot water tank has a solar coil in it. The company that supplied it suggested that it really wasn't a very cost effective solution, especially as I'd already got a pretty efficient system already and I'd probably only save around £50 a year as the solar wouldn't provide all my hot water requirements in the winter

The cost of a solar thermal system would have been around £1500 at that time and even now I only spend around £100 a year heating my hot water. Assuming that solar thermal could provide 50%of my hot water needs it would have taken me 30 years to break even.

In the end you can pay a lot of money to try and be green, but you have to be aware of the law of diminishing returns.

Spending thousands to save pennies might make you feel better but wont help your finances all that much, so make sure that what you spend gives you the best payback and that usually means improving your insulation first because nearly everything else will cost you more and save you less