Supply contracts may well be different to your FIT provider, Octopus however will buy excess production off you and it you can then buy it back at (potentially) cheaper rates if they are your supplier too.

Net Energy Consumption is total import less total export. It would not include consumption of your own production, you would have to work that out from your production meter and deduct exported energy.

The grid only works because of fast-responding energy stores like Dinorwig and more recently battery stores. They meet peaks and at those times there is no other capacity. Equally at the times they absorb it, demand can be so low that the price is negative. Then they're absorbing energy that has been sent into the grid that isn't wanted.

I don't believe that there has yet been or that there will be any time soon when we were generating solar energy that would not have been better to put into the grid.

Generally we only pay for grid electricity to be taken away on windy nights

this issues ive heard re PV and smart meters is regarding false readings of import.
seem PV confuse some of them for some reason.
A read around a while ago, seemed to suggest steering clear of smart meters if you have PV until its sorted.
I had one customer who had a SM fitted and started getting hideous bills , the supplier has come back and switched it for a traditional one , saying theres wasnt compatible with PV .
As to why I'm unaware.

Regarding Tony's comment , Id have to agree , sending surplus to grid seems the way to go , onsite batteries are just for those off grid or not interested in the bigger picture and perhaps over obsessed with self sufficiency or an isolationist approach.

While FIT as designed was poor value to the wider community and benefited those generating, there should be some benefit to the generator.

Storage is not just a chemical battery. A solar tank is a form of battery (i.e. it stores energy). Is that wrong too?

Im not sure FIT was poor value to the wider community as the wider community may not have had to put their hands in their pockets to build more generation capacity, because the investment by the FIT recipients added to the generation capacity on the wider communities behalf.

Whether personal PV storage is wrong depends if youre on FIT or not. If your on Feed IN Tariff then personally Id say its wrong as you are being paid to export for the wider communities benefit. If your PV is wholly self funded then its up to you what you do

Posted By: borpin

Posted By: jamesingramRegarding Tony's comment , Id have to agree , sending surplus to grid seems the way to go , onsite batteries are just for those off grid or not interested in the bigger picture and perhaps over obsessed with self sufficiency or an isolationist approach.

However, without any form of payment for the energy put into the grid, why should someone do that over storing it themselves? While FIT as designed was poor value to the wider community and benefited those generating, there should be some benefit to the generator.

Storage is not just a chemical battery. A solar tank is a form of battery (i.e. it stores energy). Is that wrong too?

i dont think batteries really add up environmentally or financially currently.
An immersion dump is simple a solution with only some small additional components involved, I guess a purist might argue in CO2 terms its better in the grid, but as ive got two 120l tanks I dump into, I wouldn't ;-)

If someone stores solar by charging a car, then discharges it to power a house, will that charge/discharge cycle use up a bit of the lifecycle of the car battery and hence of the car itself?

Yes, but not enough to matter unless badly implemented. EVs have now been around long enough for useful data on lifetimes to have been generated. Nissan just published a document that the battery on a Leaf will outlast the rest the vehicle by a large margin - they are expecting a life of about 20 years (presumably to 70% although I've not seen the doc, just reporting the Fully Charged podcast), despite the low-tech approach they have taken (which doesn't work well in very hot places like Arizona). Evidence from Tesla batteries is also of long lifetimes (90% capacity after 10 years is typical). Not using the top 15-20% is the main thing that extends battery life, and this is increasingly being built in to chargqing algorithms.

On charging efficiency it can be anything from 80% (fast charging, wastes heat) to 94% (slower charging, good charger efficiency). I measured a consistent 94% on my moped (using LiFePo (LFP) cells). 90% is typical. From a systems POV it does make sense to use diversity and have local-area batteries, rather than individual batteries, and new house-builders (the more forward-looking ones) are starting to do that, but the incentives are currently not aligned for that. We can expect rapid changes in this area.

Re the good point about all energy, not just electricity, Will is quite right that fossil is still 80-odd percent. But it's important to remember that that's _input_ (primary) energy, not useful output energy. Nearly all the fossil is being used at 20-50% efficiency so if you replace it with something that produces electricity directly (PV, wind) you probably only need about 1/3rd of the energy. Nuclear is just as inefficient as fossil (still steam generation with lots of wasted heat), but it's always measured and quoted in output terms so for the purposes of this calculation it is considered the same way as PV and wind (1GW of nuclear replaces 2-3 GW of coal/gas in that chart). This is all good because the situation is not quite as hopeless as charts like that make it look. It's pretty bad, and we have some _serious_ change to get done, but that 22% of primary electricity is actually more like half converted than the apparent one-quarter (assuming electrification of everything, and ignoring gas heating which is already ~80% efficient).

Posted By: wookeyOr you could take a very low-tech approach and use the standard 3-pin socket built-in to a Sono Motors Sion for export power (nice idea). (Available in 2021)https://sonomotors.com/en/sion/" rel="nofollow" >https://sonomotors.com/en/sion/

I really like this idea, for all it's apparent tokenism.

Was discussing it yesterday with my brother-in-law and I realised there could be a market for a long VW camper-van version. Big enough for a load of PV on the roof and could carry a decent sized battery. Park it up somewhere and charge while you enjoy a weekend of sunny camping etc. then drive home in a nicely charged vehicle. Plus you can plug in various home-comfort appliances (i.e airbed pump, hoover, TV etc.) in the meantime.

Just add sunshine...