Molgrips

Getting better mileage this time of year at the moment.

5 miles per kWh, will drop in the colder weather to somewhere around 4 or 3.5 as the heater will be on etc.

Don’t keep an accurate tally of mileage driven, so would estimate about 150 miles that week maximum, at least 100 miles though.

DC homes are expensive (say £2-3k per property) but allow other things to be done

Why expensive, and what else does it allow to be done?

I’m just imagining a camper van type system, with cables run through the house to a few charging locations, for low voltage stuff. Independent of mains supply.

@Denis – 100 miles a week is a reasonable amount – at least a tank of fuel a month at that rate, so £50/mo.

Moly – full 15-18kW DC supply to the home home to get to that cost. You need that to get some of the benefits.

Agreed that you could do other things – but you can’t boost the mains voltage to increase capacity without going down that route.

PS – cost also varies with how long you want kit that runs constantly to last – 5, 10 years? If you want 25 the price will rise.

Yes, we were spending about £50 to £60 a month on diesel when we had the Skoda.

Driving habits and usage hasn’t changed that much, so something like £50 a month that we were spending is now being provided by the panels and battery, will drop off in the worst four months of the winter, but for eight months of the year will pretty much cover the motoring costs.

Ah, this old chestnut. Accusing people who find problems in your ideas with having the wrong ‘mindset’. Better than actually addressing their points, and also denigrating them at the same time.

You don’t NEED to address point if it works…
Specifically though the point is engineers spend a lot of time doing exactly that .. it’s their job and that’s fine… My last 3 projects have all been met overwhelmingly with “it’s not possible” or “we’ve been trying to do that for 3 decades” .. with only a very small contingent of people like IGM supporting the project at the beginning.

The last 2 year one just successfully completed .. but to start with 90% of the engineers were negative and the CTO told them to co-operate… and if it came to nothing then fine.
Throughout the project we then did address points but incrementally as needed and the engineers all incrementally got onboard. By the final review the BIGGEST supporters were the originally pessimistic engineers.

For what it’s worth, I considered this concept many years ago,

Thats pretty much what most of the engineers said!

but then thought it wouldn’t be worth anyone’s time and effort. Power supplies are very efficient these days (ever notice how a charger for an old Nokia was pretty heavy, and a modern one is no bigger than the three pin plug it needs and weighs hardly anything? They aren’t transformers any more) and also very cheap. I can’t see that there’s going to be much of an advantage. It would be better to do what now seems to be catching on which is putting USB sockets or similar in power sockets.

The low voltage solar idea though – that would be decent. All your low voltage devices powered from a small solar installation, with a cheap lead acid battery. But how much power would that really save?

You’re still missing the point…. which is to separate the “must work” from the “can have downtime”
If I am up in the dark its very highly preferable my lights work… I often work at night so my computer “needs” to work… and the food in the freezer will spoil if its off too long… and my CH pump works.

However, if I’m working at night and the kettle doesn’t work I can boil water on the gas… or in my system draw from a battery.. (indeed I can walk down to the bike shed and use the travel kettle if I must)

A large proportion of our bill is due to electricity being available within specifications 99.9999% of the time. Hence over capacity in both the grid and generation.

A Samsung S7 has a 3.6Ah battery. Say there are 60m phones in the country (accounting for folk who use two), that would mean 780MWh to charge everyone’s phones overnight. Given it takes say three hours to charge a phone that would be 250MW or what, 1/6-1/8 of a power station’s worth.

Something like what, 25m households in the UK? Let’s say the solar charging setup could be sorted for ooh, £500 all in. That would cost £12.5bn installation and zero running costs. How much does a power station cost to build and run?

Ask the French and Chinese…. how much a power station is…
But again this is simply about reducing that can’t fail side and thus reducing required capacity.
In order to make sure you can plug your samsung in to charge (which lets say is a necessity) then you and several million also get the ability to turn on your kettle at 2AM and do the ironing because the F1 in in another timezone.

Now don’t get me wrong.. its nice and convenient but how much is it worth in cost???
Just a theoretical percentage (as this will change according to the type of generation etc.) but lets say you got told you could buy electricity for 50% of the cost BUT in may be unavailable for 1 hour a night any time between 2am and 4am….

This really isn’t different to server requirements … when a client wants guaranteed 24x7x365 they pay through the nose. If they accept an hours non-availability over a month its a fraction of the price.

Or on my last project trial the client wanted me on call 24×7 for 3 weeks… they paid through the nose and I was the only one in the office at weekends except for 1-2 hours … and had zero calls after midnight…and paid for a hotel for 3 weeks (though the cost of the mar riot was pretty minor compared to my cost)

On the latest trial they just said “work from home as we are moving office” they actually got a better service and reporting at a faction (20%) of the cost.

Their whole perception of what they needed 24×7 was just skewed… I had set up automatic monitoring that called my mobile … should it be needed there was simply no need to physically check a screen every hour. It was also much more pleasant for me!

Why expensive, and what else does it allow to be done?

I’m just imagining a camper van type system, with cables run through the house to a few charging locations, for low voltage stuff. Independent of mains supply.

Yes…. except campers CAN have fridges and kettles and lighting…
Of course then your camper needs to recharge the battery …. which in its case is plug-in or run the engine…

I’m simply changing the engine part to solar if you view it that way.

except campers CAN have fridges and kettles and lighting…

Yes but not on battery power. Even the small old type fridges draw 8A, modern ones much more. And you can keep naff all in one. So your battery would last about a day. It’s prohibitive for camping, possibly not for a house. But that’s only a dinky little absorbtion fridge which would be crap for home use.

Similarly our little two cup kettle draws 900W, which would drain the battery in 26 two-cup boils or about a day and a half if you’re my parents.

A 110Ah leisure battery can be had for less than £100, so you could easily buy three or four. So you could probably use one for your kettle. IIRC people boiling kettles at the same time is a significant issue for the national grid – so perhaps this would help?

Their whole perception of what they needed 24×7 was just skewed

Indeed, and that’s why I am in favour of state intervention.

By the final review the BIGGEST supporters were the originally pessimistic engineers.

Pessimism is an emotion, and there’s no place for emotions in engineering. What there is however a place for is a thorough exploration of the pros and cons of an idea and their relative merits. It seems like engineers are the kind of people who can get attached to a technical idea and couple emotion to it. It’s this ‘mindset’ that needs challenging. Not every idea is a good one – that goes for you as well as your engineers Steve!

I still want to know what problem this low voltage DC house main is solving. Is it overall mains usage? Smoothing supply? Making solar installation cheaper and simpler?

steve – where to start. You’ve clearly thought about this, but there really are swings and roundabouts here.

Yes the redundancy required to keep people on during faults costs money (it’s mainly about faults).
But the diversity of connecting a load of different folk to the same source saves money – effectively you get to use the capacity that was installed for your neighbour.

electricity for 50% of the cost BUT in may be unavailable for 1 hour a night any time between 2am and 4am….

There already is less electricity available overnight. There’s also less available in the summer.
The cost is really tied up in the peak which is the third Thursday in December at 1800 (roughly). System peak is generally dominated by domestic load at a time when PV is not available – lots of storage maybe?
Asking people to switch off at they get food ready, go Christmas shopping, go out for the works do etc is a little more difficult than at 0200 in July.

There will be changes to the system (interestingly a lack of electricity at 0200 may be one of them – but a lack at that system peak is also one) but they aren’t necessarily simple – if they were I’d be out of a job of course.

Yes but not on battery power. Even the small old type fridges draw 8A, modern ones much more. And you can keep naff all in one. So your battery would last about a day. It’s prohibitive for camping, possibly not for a house. But that’s only a dinky little absorbtion fridge which would be crap for home use.

Weirdly this is the biggest progress on home fridges (according to the PDF I linked earlier)

Similarly our little two cup kettle draws 900W, which would drain the battery in 26 two-cup boils or about a day and a half if you’re my parents.

A 110Ah leisure battery can be had for less than £100, so you could easily buy three or four. So you could probably use one for your kettle. IIRC people boiling kettles at the same time is a significant issue for the national grid – so perhaps this would help?

The point here ii only use battery for a kettle in extremis
To take the camper .. when your plugged in at a site… knock yourself out and make 22 cups… but if you don’t want to pay for hookup right now then go easy on the kettle or use gas…
(Lets say electrical hookup is £10/d and you arrive at 10PM …. you might decide screw it… I just want one brew before bed and the battery is charged from the drive…. I’ll pay from tomorrow)

My suggestion in the house is the kettle isn’t required 24×7 … there is always gas or battery for the odd cup…but usually you’d just use it… only in the case of a blackout would you need to rely on battery/gas…

it but can be connected all the time but you’re getting cheaper electric that might (not will) be unavailable for the odd hour or may not be up to scratch in terms of quality (your brew might take a bit longer).

Your fridge stays plugged in … it is just if the blackout/brownout occurs it gets switched over to battery so nothing is ruined.

The main thing is that stuff like lights and your CH pump are essentially running on a UPS… its just the iron/kettle that may not be available if you don’t have enough battery stored up.

Indeed, and that’s why I am in favour of state intervention.

Unfortunately since the 70’s successive governments have shied away… no-one wants to be the one where the lights go off. Back in the 70’s lights were 100W incandescent jobbies not 4w LED’s though and fridges used a lot more power and battery technology was not where it is today.

What’s changed is that the near necessities for most people are low power necessities.(a 100W lightbulb so granny can do to the loo in the night isn’t needed).. we don’t need to fire up a CRT for a TV or computer… keeping he lights on (literally) meant Kw/house… and domestic power was a fraction of industrial anyway… however very little has changed in the way people think about “keeping the lights on”….

So, I *think* what you’re trying to say is that you could have battery storage for some appliances for far less than Tesla &co if you had a low voltage battery backup charged by solar – yes?

So, I *think* what you’re trying to say is that you could have battery storage for some appliances for far less than Tesla &co if you had a low voltage battery backup charged by solar – yes?

Partly ….
Both solar AND grid …for charging but using a cheaper lower uptime grid but that’s really the icing on the cake.

The main saving (which os bob environmental and £££ is the ability to survive comfortably on a much lower specified grid…. I can imagine at some point in the future the grid could be used for a couple of hours a day in winter for example just to provide additional capacity and also charge/top up the batteries.

The camper is an example …. I can run a few hints just off battery for a limited time.
Say I turn up and they say “you can connect to this mains supply for £5 a week but it is only guaranteed to be on 1/2 time each day .. it might be more but we sometimes disconnect it to power the swimming pool pumps… (it’s just an example) OR you can plug into this one for £50 a week and we guarantee it’s always on.

If I know I can power everything comforatbly off the battery for 24 hours I know I’m pretty safe taking the £5 option … if I don’t have a battery at all and I have some expensive luxury perishable items (like a half eaten jar of beluga caviar though that would be unpleasant in the fridge) I might want to pay for the gold plated power with diesel backup….

To put that in context what we as consumers are buying presently is the gold plated version ….but with some small changes to appliances and a battery (even without solar) we could easily use the bronze rated power.

The wider adoption the more scope for savings…. it’s not inconceivable to say purchase power for only 4 hours a day on a KwH basis … so I could have a contract allows me x Kw over say 4 hours a day when I top up any solar deficits and also do the ironing/vacuuming and use an electric oven….
Someone else might be happy without the extra capacity and just want a top-up and someone else might want near 24 hour availability…

Looking at mobile phones as an analogy you can have a subscription including the battery and solar and then pay for extra power …. or own your own (PAYG) and just pay or top ups. etc.

So when I said partly the point is in the options….
i.e. I could use PV heated water in the washing machine if I could buy a washing machine that mixes hot/cold… I could run the pump and motor from battery or from mains … and if the PV is lower than idea also heat the water say from 35-40C… etc.

So it’s not just about cheaper than Tesla its about having the option to buy a dual input washing machine in terms of both water and voltage (at least presently inverters and step up are the most unreliable part) … the ability to buy standard E10 or similar LED’s with 12VDC not 230VAC (and the irony of needing a AC/DC stabiliser to run a diode)!

There is nothing wrong with Tesla (apart from price perhaps) except the requirement to have an inverter to run appliances and then convert back to DC… and still have to heat the water for the washing machine by electricity even if I have a supply of heated PV water

That’s why I think it needs to start at the appliance end… a small way as you say would be charging all the 5V appliances.(but that’s not going to save much it’s more a PoC)… but I could run the bike shed like this…and even charge some of the 18V stuff kept in the bike shed… but its not really getting to the crux of being able to purchase lower uptime electricity…

I can imagine at some point in the future the grid could be used for a couple of hours a day in winter

Yes, but which two hours? There’d still be times when everyone wanted to use the grid at once. For that to work you’d have to ration the power centrally. But people need power at different times – if you work an afternon/evening shift, you might want your electric shower at 12pm; if you have solar HW then great, if you don’t (live in a flat or have a north facing roof etc) then you might want the grid for that. You’d have to apply to get a slot, but if the factory next door is doing something during the day you’d be out of luck. No showers for you.

It would work for stuff like electric car charging though. You sign up to a particular cheap tariff that requires you to charge your car overnight. Smart car chargers can be told to switch on for three hours between 11 and 2, or 2 and 5 and so on.

except the requirement to have an inverter to run appliances and then convert back to DC

Pretty sure inverters are quite efficient.

As for hot-fill of washing machines – can’t you just pipe both hot and cold water into a T piece with a non-return valve on each?

The grid currently costs about £10 a month for a domestic customer to connect to.

The generation and supply costs a bit more.

Some very interesting and progressive views expressed, a good read..

I would observe that the views of many consumers differ from this (currently) and they see their energy and its availability (100% uptime!) as a right. And they do not get much past ” my iPad won’t charge”, my freezer is off… They generally see energy as a grudge purchase and have little understanding of the current UK market with network operators, suppliers etc.

They generally do not link their “entitled” view to the mechanisms that provide it.. That being extensive legacy networks that were designed and built to be passive and also “fat at the source and thin at the ends”. i.e not that great at generation input . Along with the regulatory framework that works in several year chunks – more in the current one that make the sector slow to react / adapt. Who pays… when consumers generally think it is too costly already.. Work does take place on the low carbon and future technologies and this is included within the price controls / ofgem stuff. However, the scale of this when compared to the rest of the established networks is small.

The move to consumers essentially having their own capital assets and all of the associated risk, maintenance and periodic replacement would be lost on many. And for most this would almost certainly still need to be augmented with a standard supply which as IGM mentions above costs x pounds per month and is unlikely to be less for an occasional user.. (network operators would still need to offer the levels of resilience to this person and factor them into the diversity sums also mentioned earlier) ..maybe it would be but the demand side management stuff required to differentiate between them and their fully reliant on the grid neighbour is perhaps a little way off. Pay as you go!

I think that “community” scale projects might have merit where the associated capital costs, maintenance and risk are spread across a greater number of consumers – maybe a scheme shared with a few neighbours could work as this would step towards the diversity benefits and asset utilisation that a network operator enjoys albeit pocket size…

As mentioned in pre posts this is a cultural and economic challenge as much as an Engineering one.

Yes but not on battery power. Even the small old type fridges draw 8A, modern ones much more. And you can keep naff all in one. So your battery would last about a day. It’s prohibitive for camping, possibly not for a house. But that’s only a dinky little absorbtion fridge which would be crap for home use.

My camper has a proper 60L compressor fridge which runs off a battery and a 180w solar panel… lasts pretty much indefinitely even in the uk.

Agreement breaking out on STW shocker!

Work does take place on the low carbon and future technologies and this is included within the price controls / ofgem stuff. However, the scale of this when compared to the rest of the established networks is small.

0.5-0.6% of turnover. Turnover is roughly one seventeenth of modern equivalent asset value (MEAV is roughly equivalent to the cost of the network)

Agreement.. – it will never catch on 😉 Nice stat – i did say it was small 🙂

Agreement breaking out on STW shocker!

My camper has a proper 60L compressor fridge which runs off a battery and a 180w solar panel… lasts pretty much indefinitely even in the uk.

Lucky you – but how much power does it draw?

Yes but for example what about gas heated showers both on demand and fed from the CH and that’s just one alternative??? PV heats water pretty efficiently to shower temperatures … but you can also add heat exchangers etc and with efficient lagging hot water can be kept 10-15 degrees above ambient with very little input energy. Also in winter you are using other heating so a back boiler etc. would also heat your water.

The point is yes there are lots of exceptions you can think of but there are even more possible solutions. A lot of people already have GCH…. so the shower problem disappears for them…

As to which 2 hours then at this point (in the future) I don’t think it really matters … the 2 hours is mainly recharging time for UK winters… but taking some intermediate stage then it would balance out by pricing. The guy on night shifts would probably get the extra-boost cheaper at a more convenient time for them but everyone is paying less anyway … so call it a bit of a perk for working nights 😀

It would work for stuff like electric car charging though. You sign up to a particular cheap tariff that requires you to charge your car overnight. Smart car chargers can be told to switch on for three hours between 11 and 2, or 2 and 5 and so on.

Take step back…. what’s the difference? You are storing energy in the car battery vs in a house battery…

So simple ballpark … take a electric car capable of 300 miles and we can compare that directly to a internal combustion engines fuel… so if we say a 50 mpg diesel that’s 6 gallons of diesel which a bog standard diesel generator would give say 60KwH of energy. You can divide the 60 KwH as you like… its just a way to think about interchangeability of power sources.

Pretty sure inverters are quite efficient.

It depends what you mean by quite…. in comparison with the old 1970’s ones yes but mine still get pretty warm… same with the down stepping … the hottest part (and by far greatest failure) of the LED lighting is the voltage regulator…. In my exprience I think it’s 100% though I may have lost 1 LED in a cluster of 12 on occasion its the voltage regulator that fails. (I started keeping broken ones for a while thinking I’d take one where the LED’s failed and use the voltage regulator .. but threw em out as it never happened)

As for hot-fill of washing machines – can’t you just pipe both hot and cold water into a T piece with a non-return valve on each?

No because the modern machines lack the mixer… they can’t then decrease water temperature if it’s too high… If you had a otherwise balanced system (so the hot/cold pressure aren’t affected by the rest of the house) it might be OK… (and I guess what’s the worst that could happen) but surely the answer is just to go back to the dual input machines if you wish to buy one????

I completely agree that this is far more a cultural than engineering challenge…. at work we would class this as a Organisational Change Management…

The move to consumers essentially having their own capital assets and all of the associated risk, maintenance and periodic replacement would be lost on many.

So phone lines have to be near 24×7 (for emergency calls etc.) …
However despite this still being the case and legislated I don’t even have a phone plugged in and I’m sure I’m not alone. Every day I have to take responsibility for charging my phone…. which is my own capital asset.. I don’t need a nanny to do this… but others have accepted this as well simply because it has never been legislated that it’s someone else’s problem.

No-one fills my car up…. it doesn’t have a autofill function that takes over the driving and decides it’s going to take a trip by itself and fill-up…again because it’s never been like this… yet 10’s of millions manage this as well.

One of the major inputs into energy consumption is simply that it’s there…. if I leave the bathroom light on or oven etc. it just ticks away on my bill (that is designed so I don’t see it for anything from a quarter to a year) … the cost is deferred so my will to control it is much lower.

If on the other hand I run out of fuel in the car I’m screwed… at the best I’m calling the RAC etc. so I simply make sure I have adequate fuel… a few times I’ve been in a rush and been low on fuel and just been more economical as the time penalty for filling up has been in my guestimate more than just driving more carefully/economically)

they do not get much past ” my iPad won’t charge”, my freezer is off… They generally see energy as a grudge purchase and have little understanding of the current UK market with network operators, suppliers etc.

This is the UK today …. it’s no different to education, healthcare etc. many people see a fantastic benefit of being born somewhere as a inalienable human right… I know one person hash’t wired more than 2-6 weeks in a row for 10 years… because “there are no jobs in a single bus ride” … this would perhaps seem less pathetic if their hobby wasn’t fell walking … there are tons of jobs in a 2 hour walk (and god forbid he gets a bike)… they are just not on a bus route… (of course if they got a job they then would have to start paying for their housing .. etc. and to sum it up the whole job thing is just too much hassle for them and they would end up having to find housing … )

The point of the above is really because they didn’t start off like that but 10 years later they can’t imagine having to get up for work .. walk 10 miles (till they move) etc. and most impotently he doesn’t believe it is up to HIM to get a job…. it’s “the government’s” job in his head…

Another similar example was a young bloke from the Welsh Valleys I bumped into in Aberdeen airport…
He was working as kitchen staff offshore and getting a really good wage and lifestyle but he said what ruined it was his mates who took the piss – on one hand taking the piss because he had to work and on the other expecting he paid for the beers etc. I’m not saying this is everyone in the Valley’s… however what is striking is that a generation ago this was completely the opposite – in only a generation .

Relating that to energy …. it’s really easy to take for granted… think it’s someone else’s responsibility and spend other peoples hard earned… indeed I don’t think you can even blame the consumer … Most of them have grown up pressing a switch on the wall and the lights just working… this amazing thing is taken for granted except for the grumbling over the cost.

I honestly believe that if this is introduced incrementally as a benefit that can be used rather than forced that given the ability to control cost/usage most people will.

That might mean a small supplement on dual input washing machines/TV’s etc… but not much more than the cost of a set top digital box ??? How many people have redundant analogue receivers in their TV for example?

So forgetting the outlay, we are actually about £5 in credit, and running the car for free

For that particular week Dennis….

Unfortunately you’re on a best case scenario there as you’re not going to get more than 6-7 months a year with a PV production >200KWh. Historical figures from our 4Kwp system here.

£6000/£13 = about 461 weeks/115 months/16 [7 month] years to pay back the capital expenditure. Not great.

I love our PV, but I’ll be waiting a couple of years before I start looking at going down the storage route as by then I suspect that the capital outlay will be considerably less.

Are you still running the Immersun (think you’ve got one)? If so I think that will consume more of your surplus PV at the start of the year due to the colder water temperature needing heating up.

Steve – I think the thing you describe will raise total costs. That’s fine for the early adopters while everyone else subsidises them, but not so good for anyone later on.

PS – I may be wrong.

Steve, you are brimming over with ideas which is good; but you can’t simply accuse people of having the wrong ‘mindset’ when we examine the ideas a little more closely and try and come up with potential issues. That’s what we do, it is in fact part of my day job.

@ sharkbait

yes, I agree with you on the return on the initial outlay.

Our decision to go with the PW2 wasn’t entirely based on financial basis.

Now retired, looking to lower our outgoings and run a vehicle that is considerably cheaper than petrol or diesel. Also very good for the environment.

The decision was based on partly ethical grounds of a renewable energy, £6000 in an ISA returns about 1%, inflation running at 2.5%.

May as well spend it on something that reduces our costs, good for the environment,also improves any saleability of the house should we decide to move ( very unlikely).

Could have spent it on all manner of things, which in the main would immediately depreciate, cars, bikes, coke and hookers……

More of a ethical decision than anything else, whilst preventing the inevitable hike in energy prices over the coming years.

Fair enough! Keep us informed as I’m sure a number of us with PV are interested in the real world experience of a storage system.

Cheers,

There is a local development in Neath ( where we live), that is building homes with solar, battery storage and some sort of heat pump to make these new homes as energy efficient as possible.

The company has been in touch with me, and we will be assisting them with real world data from the panels and battery usage side of things.

So, in the coming months they will analyse the death out of this real world data vs their modelling forecasts etc.

Things are beginning to gather some momentum in terms of renewables for homes and transport , although it doesn’t address the congestion issues.

One step at a time I suppose.

Steve – I think the thing you describe will raise total costs. That’s fine for the early adopters while everyone else subsidises them, but not so good for anyone later on.

PS – I may be wrong.

It’s not that I disagree it will involve an initial ROI somewhere, more that to achieve critical mass we need more people thinking like Denis99

As Denis points out mains energy isn’t going to get any cheaper…. thinking in terms of a decade or two and a bit of speculation … at least preparing the house for alternate consumption and reducing the energy requirement doesn’t seem like such a bad choice/investment.

When I bought a house I looked at the previous years utility bills, the OH was horrified but we currently use about 1/3 the previous occupant with some fairly minor changes (like fitting a thermostat). I can get much better but that means investing in plumbing and insulation… and I’ve a plan to change the upstairs extension as planning permission continues to relax…. hence I don’t want to invest immediately in changes when they can be built in at extension time.

I really expect that energy storage cost will decrease and solar efficiency continue to increase whilst grid electricity will increase. So if I want PV storage I’d want to build in a place…and hoses even if I don’t install it immediately… it’s like say changing the consumer unit… if/when I change it it would have spare and alternate capacity… because the unit itself is cheap but rewiring isn’t…

There are some finer points on the Tesla Powerwall 2 that may be worth considering, maybe not depending on your circumstances.

Firstly, the capacity of the battery.
The total capacity is 14 kw , you can add additional batteries and diasy chain them together for additional storage.
For domestic use in the UK I think this would be a bit of overkill. Even having a power hungry EV car, the daily charge from the solar to the battery rarely gets near the max 14 kw capacity.

But could be very useful for farms and collective energy usage.

Secondly, and this is where it could hopefully save some extra money.
It is possible ( although not at the moment), to import electricity from the grid.

There are companies supplying cheap off peak electricity for 6p kw from midnight to 6am.
Charging the battery up, especially in the worse of the solar months would be of benefit.
Depending on your household demands, around 14 kw is pretty close to powering alot of homes for 24 hours ish, at roughly half the current cost per kw ( at say 12 p).

Sure there will be further developments once some impetus is achieved.

14kW or 14kWh?

Most homes around 10kWh per day.

Overnight electricity unlikely to be cheaper than day time as PV becomes more dominant.

Steve, you are brimming over with ideas which is good; but you can’t simply accuse people of having the wrong ‘mindset’ when we examine the ideas a little more closely and try and come up with potential issues. That’s what we do, it is in fact part of my day job.

My everyday job involves finding the problems and solutions … we used to have a bloke who only ever found problems… he never actually proposed what to do with the problem or what mitigation… he’d just say “but we can’t do that because”

It wasn’t that the problems were not valid but he just never had a suggestion on how to overcome them.

The point I’m making is there are lots of problems that be be thrown up but to take your bloke wanting a shower at 2AM … it’s relatively simple for him to just use the shower heated by the GCH…. it’s not a real problem – gas heaters already exist.

Of course the next question is “what if he doesn’t have GCH?” …. etc. etc. hence we end up talking about some bloke who has one leg, one eye and is deaf who is part of a minority religion that prevents them pressing buttons on Thursday’s…. (* not wanting to pick on strict Jews but they aren’t allowed to press buttons to turn on a light etc. on Saturdays)

The thing is I’m sure they are 1-2 .. but even forgetting the infirmities there is a traditional solution to this which is to employ a non Jew to turn the lights on and light the fire however this being 2017 many find it’s OK to have a timer on the heating and a motion detector on the lights etc. (or simply just think.. stuff it… I’ll just turn the light on myself….)

“but he’s living in a flat…. can’t have gas ….etc.” it’s a rabbit hole.
Most people in the UK don’t…. and there are another 101 solutions for communal energy use that are flat friendly. (e.g. where flat occupancy is high like Paris most heating and hot water is generated on a communal basis from a more efficient industrial boiler…. in the basement… indeed a mate in London lived in a place where they have this + a communal gym and communal laundry. (The commercial washing machines do take hot water input)

Some countries have communal heating supplied directly as hot water from the power generation plants. Instead of cooling stacks they pipe the hot water as heating to the nearby houses and flats.

When I talk about “mindset” what I mean is the preconceived idea we have a house .. that house gets 230VAC and Gas and has a boiler and central heating

This is just the way it is historically in the UK…. but all that aside the bloke who wants the 2AM shower is actually helping smooth the demand …. meaning the infrastructure doesn’t need to be as over specified and is cheaper for everyone. If he gets it at a cheaper rate than next door who want it at 6:30AM then that’s a good thing .. right until the neighbours complain about why they are subsidising his showers… when in reality he is subsidising theirs.

Steve – you are addressing issues in today’s terms. Throw your mind 20 years down the tracks (which you have to do in infrastructure) and the issues and answers change.
As I noted electricity is going to be more scarce over night and unless we change a few things that are coming at us more in demand overnight.

For example that was

Overnight electricity unlikely to be cheaper than day time as PV becomes more dominant.

wind generally doesn’t shut off [quite as much] at night… although I do agree with you on the possibility of cheap night time power disappearing as energy generation becomes more efficiently timed (i.e. less surplus during the night).

It is possible ( although not at the moment), to import electricity from the grid.

I thought this was available now…. hmm, that would be a deal-breaker if I was looking into storage right now.

Sharkbait – assume an EV world where people arrive home and want to charge. This will increase the evening load and smart charging to avoid the evening peak will tend to move load back – possibly in the sort term into the wee small hours.
However we are already seeing times when the demand on the grid is higher overnight than the following afternoon because of the lack of PV overnight. This will only increase.
Going a little deeper we used to consider load curves because network was roughly constant and generation was dispatchable (albeit base load stations were able to bang out cheap electricity overnight).
But in future we will have to consider utilisation curves (load curves might still be a proxy for this for network) separately for network and for generation.
Merit orders will also be interesting – not sure how that will work with guaranteed prices for nuclear.

The future is going to be different from the past (quelle surprise) and the rules of thumb of the past won’t work.

Which keeps me employed.

igm

Yes , you are correct,

say 10 kWh per day.

igm

Yes , you are correct,

say 10 kWh per day.

I should be. It’s been my life for 25 years. 😉

(As in I should be fired if I get that too far wrong)

Steve – you are addressing issues in today’s terms. Throw your mind 20 years down the tracks (which you have to do in infrastructure) and the issues and answers change.
As I noted electricity is going to be more scarce over night and unless we change a few things that are coming at us more in demand overnight.

For example that was

Possibly a bit of both ….
We have to start changing (it’s not like we really have any choice) but no-one has a crystal ball.
I’m unsurprised at the current changes to demand times (e.g. EV charging) but I’d suspect you are seeing a short term response to a new paradigm.

Just 2 things that could change this are more dynamic billing rates per KwH …. (a bit like the Amazon if you don’t need this in a rush then get some money back towards your next purchase ) – You could offer for example 1.5KwH in non peak times for the price of 1KwH…. Obviously the wording is important that they are getting a discount by not plugging in when they get home from work not being charged extra …

The other is at work charging…. specifically in the medium term many work places will be wired up for excess capacity. If I take my work office I’d imagine a lot of energy in summer is lighting (they don’t seem to spend much on cooling) and in winter it is I believe gas heating… So with the change from the old several hundred halogens we had we have probably reduced energy consumption 10 fold…. meanwhile out with the desktops and in with solid state laptops and cloud storage in the last 2 years but before that it was out with CRT’s etc.

Should suitable incentives (or at least not disincentives such as taxing it at a ludicrous rate) be available then those parking at work could charge before they go home and still have plenty of power for the next day Mon-Thursday….

My gut feeling (sack load of experience allows me that).

Network constraints won’t be the bottleneck people think.
Generation constraints will be worse than people think.
At work charging makes sense – how metering and billing is arranged will be key.

As for cheap electricity, one of the suppliers offered free electricity all weekend in exchange for a slightly higher tariff during the week – don’t think it was a success.
Economy 7 also offered two rate electricity.
So it has been done.

Variable rate tariffs make sense but truly dynamic variable rates confuse folk – which is bad.