energy in UK

It is better than any of the alternatives. I suspect at one point the utility companies were at break even or even making a slight loss on domestic customers when the gas price went up very high.

They compensated by hammering business users.

The "smart" meter program in the UK has been hilarious. They rolled out model 1 systems that are almost trivial for a state actor to hack. I waited for a gen 2 "smart" meter which so far has behaved pretty well. I had my own monitoring clipped onto the incoming live line so it doesn't really give me anything new except fewer meter reader visits.

There are two different comms systems in use one which works and one which doesn't. The north of England where I live has the latter. My meter actually works OK but the one in our Village Hall nearby failed within days of being installed and they have now given up on it.

A bit more info here.

That is huge. I sometimes have a small fan on from time to time but the house temperature seldom exceeds 25C in summer. Night time almost always drops below 16C (56F) so tropical nights are rare here.

Yes the 5:2 ratio is very visible in the national power output graphs.

Aren't you in desert country? I thought the overnight temperatures could drop quite low there...

It is spring here. Has been as high as 20C (64F) but yesterday was cold

That is what the aftermarket diverters allow to happen. Through a quirk in the Feed-in Tariffs it pays to do that and only export the excess.

Outdoor swimming pools are not common in the UK. It is too cold - although wild swimming in open water is on the increase since Covid.

That is still true here, but the daily standing charge went through the roof when so many stupid "electricity" companies went bust all at once.

That is a double win in a low latitude country because the double skin on the roof creates shade and delays ingress of heat. Clever backing on the panels (thin insualtion and Alu foil) can improve it further at the expense of losing efficiency of the solar panels due to increased heating.

The network stability is actually quite a tough problem. And getting tougher with the rapid removal of so much spinning generator kit which has serious angular momentum stored energy in the rotating equipment.

The problem with locally electronic phase matched output is that it will quite happily track whatever frequency is sees on the mains.

They typically have no idea and fewer skilled engineers than are needed to reconnect people in more remote areas when there is big storm damage.

Wind power you can still graze animals or grow crops underneath as it doesn't shade the ground. UK has rather more offshore windfarms than most. The blades for the bigger ones are amazing things of beauty.

I sometimes pass them on the motorway. Definitely "abnormal load" !

No. That is how the loading up with massive debt trick works. They are allowed to offset interest payments on loans against taxable profits. (and pay themselves big dividends into tax havens)

In the UK, that appeared to be the main reason the electricity compaines rushed to install them; anyone who didn't pay or disputed their bill could be threatened with being cut off without any necessity to gain access to the premises. Rather late in the day, this was made illegal and the drive to fit 'smart' meters suddenly vanished.

The drive to fit them is still there. The supply companies get penalised if they don't get enough people to upgrade to smart meters each year. SMETS2 are quite reasonable meters (at least in southern England).

They haven't pestered me for a while now. Various friends in places with no mobile 'phone signal have recently had high-pressure salesmen visit them - and they told them to clear off!

Most UK domestic premises are on single-phase 240v, with the neutral earthed at the sub-station. This means there is only one leg to disconnect, so a latching relay with one set of 100A contacts is sufficient. (I remember seeing a video of 'Big Clive" dismantling one - it may still be on YouTube somewhere.)

Most of which benefits the supplier, not the consumer.

The 'price cap' was originally set up to prevent suppliers price-gouging retail customers who weren't on fixed term tariffs. They'd end up on the default tariff which was often much higher than the shiny advertised tariff

- some of those customers had never switched tariff or provider, some not for

Then Ukraine happened and the wholesale price exploded. The price cap, being based on the wholesale price 6 months ago, did not. Because the price cap was in law the maximum price that could be charged, everyone ended up on the price cap. So it became the maximum price and, because suppliers were making a huge loss over the wholesale price, that's what they all charged. (a good number went bankrupt too)

The next update the price cap went up massively, but the government stepped in to subsidise consumer energy bills to limit the unit costs - effectively a new lower cap. That subsidy has ended, but the price cap logic (now calculated every 3 months) is still what drives the prices most people pay. Even though it was never designed for this scenario.

Businesses never had a price cap. Small businesses often sign up for energy in 3 year fixed term deals, and the ones some signed up to have very high unit rates (>60p/kWh). They had no choice to sign up because their previous deal came to an end and otherwise they'd be disconnected.

Some of those tariffs are a bit of a gimmick if you look at the numbers: while there's some variation in demand weekend v weekday, there's much more variation in supply based on the weather. Some of the operators give you a variable price based on wholesale (including free energy when it's sunny or windy) which is more aligned with the actual balance.

It's not just FITs, without FIT you might get paid 5p to export and you pay

Obviously it'd be better to store it in a battery instead (to displace 25p import during the night) but diverters are/were a cheaper alternative (or for when the battery is full). The price of batteries has fallen a lot so it's becoming more attractive to have a battery now, if you have the space.

Air to water ASHPs are the way a lot of people heat their swimming pools, as it's cheaper than gas. They run very efficiently into low-temperature water (~30C).

It would not be implausible to have an ASHP where the refrigerant is taking heat from a house and heating pool water - just need a heat exchanger of refrigerant into water not air. Could probably do it in a domestic A/C system with some diverter valves in the refrigerant circuit.

The difference is that < 3.68kW you can just install PV with no permitting. If you want to install more you need to fill in a form first. The power company could tell you to limit your export based on the capacity of the local grid, but they can't refuse you point blank (you could just do 3.67kW in the worst case).

Theo

A tiny dendrite puncturing a separator can start an ignition wave that propagates in all directions at centimeters per second and ends in a fireball fast. All a sensor might to is to tell people to RUN.

Utility-scale batteries are huge and forklifts move pretty slow.

Yes, I like the minisplit approach - we have an 18,000BTU/Hr one for a separate room and it extremely quiet and efficient. It normally only takes 200-300W with very low inrush.

Yes, we had to get the city to give their permit that involves what you mention plus features for emergency responders such as adequate access to the roof and approved means of disabling the panels and batteries with suitable signage.

In California, residential solar installations have to meet "California Rule 21" that is a specification of how the inverters control their output when the mains frequency or voltage changes.

Basically the solar output is curtailed linearly to zero as the frequency is increased from 60-62.5Hz or the voltage above 240-245V. These measures are intended to promote system stability.

kw

Interesting. I didn't know that.

Probably all of Spain has smart meters now. But the reason was, AFAIK, that here the contract limits the current you can draw. For instance, a contract can say that you can draw 15A (3450W). The meter has the ability to switch off when you try to draw 16A for a time.

Previously, al houses had a limiter switch with a lead seal. People managed to bypass that switch. By passing the meter is harder, I have not seen it done.

What would happen if the inverter on the battery pack doesn't have that peak capacity?

I mean, an inverter might simply limit the maximum peak current without destroying itself, keeping itself all the time within safe limits. Would the motor still start, albeit slowly? Or would it stall and overheat? Perhaps motors could be designed co cope. I know my AC unit has an inverter inside to control the motor, so does my fridge.

...

Our city water contractor said on radio few days ago that they would start to deploy smart water meters, and he did say that they would try to detect leaks on our premises, and tell us.

Water here is scarce, the water company is trying to conserve it (a percent comes from desalinization plants). I have seen a crew of two people (I think) open the iron lid that covers the main water valve on the street, at 3 AM, put a tool to it, and hear carefully the noise on headphones, to detect leaks; they were doing the same on all houses on the street. And then, days later, I noticed a crew coming in and opening up the pavement to repair a single leak.

Our water supply at the cabin in Truckee has a shutoff valve. It had a slow leak, and the local utility emailed me, with flow-vs-time graphs.

The smart meters are fairly recent. The water used to be unmetered.

I designed a smart meter to be used in India. Power theft there is a popular sport, so it had some specific anti-theft provisions.

I also designed a smart power strip, with metering and remote shutoff for every outlet.

I don't think either was manufactured in volume.

California also licenses and rations sunlight.

The inverter would trip and power would be cutoff until reset.

Even at night?

I think that is an Spanish only feature.

They charge us for the watts we actually take, and also a fixed monthly amount for the size of the pipe. Meaning, if we contract for a maximum of 15A, we pay for that, €/month. If we contract 30A, we pay double fixed amount per month. And the smart meter controls that we don't contract 20 and take 21.

So people try to contract the minimum they actually need.

How does some sweet little granny know what to contract for, or how to limit her peak amps?