A thought to kick-start the week.

[ProDave]

2 minutes ago, epsilonGreedy said:

 

The people decided 30 years ago that E7 + storage radiators is a failed concept, why waste brain cycles on this? Normal humans do not want to be cooked at 3am and shivering by 8pm.

 

A previous 1930's house I owned had storage heaters and they were just like that, the house leaked heat so fast it needed constant heat input when you wanted it to be warm, something which storage heaters were useless for.

 

But has anyone tried them in a modern well insulated house?  e.g our house when you turn the heating off, it is several hours before you notice.  So storage heaters warming up over night and releasing their heat slowly it would not matter if they have run out of heat by 6pm. the house would not go cold before bed time.

 

I suspect you would not want the full 7 hour charge, so time them to come on at say 4AM.  to adjust the heat input as the season gets colder, adjust the start time.

 

I suspect it would work very well.  Even better of course would be put them on an E10 tariff where there are more (but shorter) cheap periods so the storage time needed is less.

[epsilonGreedy]

14 hours ago, SteamyTea said:

I take it you could not be bothered to read the report I posted up. Why let facts and figures get in the way if an opinion.

 

 

We live in a world drowning in "facts" that support a spectrum of opinion on any subject. Opinion shapes the destiny of human civilization, facts are just the cattle-feed that provide fodder for the lemmings who follow the thought leaders who craft new ideas.

[markc]

The reduction in power station output is now being bolstered by stand alone generators housed in containers - makes no sense at all.

A local company is churning these generators out as fast as they can produce them and tankers are going around constantly re-fueling them.

All this waste and burning diesel just so they can say that power stations and being shut down.

[dpmiller]

8 minutes ago, ProDave said:

A previous 1930's house I owned had storage heaters and they were just like that, the house leaked heat so fast it needed constant heat input when you wanted it to be warm, something which storage heaters were useless for.

 

But has anyone tried them in a modern well insulated house?  e.g our house when you turn the heating off, it is several hours before you notice.  So storage heaters warming up over night and releasing their heat slowly it would not matter if they have run out of heat by 6pm. the house would not go cold before bed time.

 

I suspect you would not want the full 7 hour charge, so time them to come on at say 4AM.  to adjust the heat input as the season gets colder, adjust the start time.

 

I suspect it would work very well.  Even better of course would be put them on an E10 tariff where there are more (but shorter) cheap periods so the storage time needed is less.

 

Aren't pipes in slab just a different name for a storage heater tho.

[epsilonGreedy]

16 minutes ago, dpmiller said:

 

Aren't pipes in slab just a different name for a storage heater tho.

 

Just the point I was going to make, an UFH slab is just a 50mm thick storage radiator. The issue the country faces is the majority of housing stock leaks heat too fast to benefit directly from surplus overnight energy.

 

As the Daily Mail pointed out we will need a 4x increase in wind power to squash our natural gas consumption for electricity generation and get us through winter days when the weather stops. The problem of surplus overnight wind generation will rise dramatically, we need to do something useful with that capacity. Hydrogen production is one answer.

 

 

[epsilonGreedy]

40 minutes ago, markc said:

The reduction in power station output is now being bolstered by stand alone generators housed in containers - makes no sense at all.

A local company is churning these generators out as fast as they can produce them and tankers are going around constantly re-fueling them.

All this waste and burning diesel just so they can say that power stations and being shut down.

 

More likely a response to perceived grid supply instability? What KwH unit cost do these container generators deliver?

[pdf27]

47 minutes ago, epsilonGreedy said:

An ASHP is barely viable in a house built to a scraping 2013 regs pass.

Only if they use the original radiators. Fit correctly sized radiators and it's fine.

 

40 minutes ago, ProDave said:

A previous 1930's house I owned had storage heaters and they were just like that, the house leaked heat so fast it needed constant heat input when you wanted it to be warm, something which storage heaters were useless for.

 

But has anyone tried them in a modern well insulated house?  e.g our house when you turn the heating off, it is several hours before you notice.  So storage heaters warming up over night and releasing their heat slowly it would not matter if they have run out of heat by 6pm. the house would not go cold before bed time.

 

I suspect you would not want the full 7 hour charge, so time them to come on at say 4AM.  to adjust the heat input as the season gets colder, adjust the start time.

 

I suspect it would work very well.  Even better of course would be put them on an E10 tariff where there are more (but shorter) cheap periods so the storage time needed is less.

One thing that will need care - the insulation on the storage heaters needs to be much better than in ones that were made historically, otherwise you're likely to have issues with overheating early in the heating period and under-heating later. Once the insulation is good enough, you can probably get away with direct heating when power is cheap rather than storage heating - and the window between storage heaters not working and not being necessary is probably quite narrow.

 

38 minutes ago, markc said:

The reduction in power station output is now being bolstered by stand alone generators housed in containers - makes no sense at all.

A local company is churning these generators out as fast as they can produce them and tankers are going around constantly re-fueling them.

All this waste and burning diesel just so they can say that power stations and being shut down.

Probably maintenance rather than refuelling. Peak demand on the grid is actually very peaky - the last GW only needs to be provided for a few tens of hours per year - and diesel generators and/or batteries are a very good solution to this. They're unlikely to be constantly refuelling them though - maintenance is possible, but even that should be pretty limited. The economic attraction compared to power stations is that they're pretty much fit-and-forget, so the man-hours needed to keep them going should be pretty low.

 

30 minutes ago, dpmiller said:

Aren't pipes in slab just a different name for a storage heater tho.

In a well insulated house, yes - provided that the  time constant of the house is long enough, you can use the whole house as a storage heater. Essentially that's what TerryE is doing.

[epsilonGreedy]

10 minutes ago, pdf27 said:

Only if they use the original radiators. Fit correctly sized radiators and it's fine.

 

 

The discussion has moved on, we are talking about what to do with surplus overnight wind power. Wind was peaking at 11 to 12 gW last week. A Conservative estimate is that over the next decade it will double again.

 

Fitting ASHPs to old housing stock just compounds the problem of keeping the lights on at 6pm in 2025 on a slow weather day in mid winter as nuclear capacity declines.

[pdf27]

29 minutes ago, epsilonGreedy said:

Fitting ASHPs to old housing stock just compounds the problem of keeping the lights on at 6pm in 2025 on a slow weather day in mid winter as nuclear capacity declines.

Not especially - burning hydrogen in CCGTs is a much simpler solution than burning it in domestic boilers, since the ASHPs in the middle reduce the total hydrogen demand by a factor of ~3. Infrastructure costs on the grid are vastly lower too, while ASHPs aren't vastly more expensive than domestic boilers. At a system level, it's probably quite a bit cheaper.

[epsilonGreedy]

14 minutes ago, pdf27 said:

Not especially - burning hydrogen in CCGTs is a much simpler solution than burning it in domestic boilers, since the ASHPs in the middle reduce the total hydrogen demand by a factor of ~3. Infrastructure costs on the grid are vastly lower too, while ASHPs aren't vastly more expensive than domestic boilers. At a system level, it's probably quite a bit cheaper.

 

 

Fitting ASHPs into Victorian or 1980s housing stock does not deliver a COP of 3 because they work too hard and then need to waste electricity on defrost cycles.

 

Next you need to build loads of new hydrogen power stations to generate the gigga watts of energy currently delivered by natural gas pipes to homes. Even if natural gas heating is maintained at current levels we will struggle to keep the lights on by 2025. Your plan for mass retirement of gas central heating boilers in favour of ASHP will plunge us into sustained blackouts.

 

An ASHP with capacity to heat an old house is 5 times more expensive than a 25kw gas boiler.

 

You want to move too fast, we need an extra 40 years to implement your vision.

[SteamyTea]

@epsilonGreedy

You really don't understand heat pump sizing, and how they are designed to run do you.

 

Shame you don't like facts. Show me where were have breached the grid generation capacity recently, like in the last 20 years. Not counting that unfortunate incident a few years back which was a management failure.

 

I suspect that natural gas us going to fill most of the missing generation over the next 30 years, they are quick and cheap to build, reliable, fast acting and I think the UK will wiggle out of its environmental promises.

[epsilonGreedy]

3 minutes ago, SteamyTea said:

@epsilonGreedy

You really don't understand heat pump sizing, and how they are designed to run do you.

 

 

Neither do the people who install these things or those who promote the technology, hence their poor reputation outside a few specialist internet forums.

 

5 minutes ago, SteamyTea said:

Show me where were have breached the grid generation capacity recently, like in the last 20 years.

 

 

My predictions are just that. https://dictionary.cambridge.org/dictionary/english/prediction

 

8 minutes ago, SteamyTea said:

Not counting that unfortunate incident a few years back which was a management failure.

 

 

The unfortunate incident highlighted another problem. This country will have to build dummy power stations that consume energy to spin large heavy armatures to provide grid stability which is diminishing as trad power stations go offline.

 

11 minutes ago, SteamyTea said:

I suspect that natural gas us going to fill most of the missing generation over the next 30 years, they are quick and cheap to build, reliable, fast acting and I think the UK will wiggle out of its environmental promises.

 

 

Well yes if we abandon CO2 reduction targets then many power generation headaches go away. Now we can find a new subject to debate, let's talk about the future of the NHS and assume no adults have a BMI over 25 and that they go to the gym 3 times a week and never drink alcohol.

[SteamyTea]

6 minutes ago, epsilonGreedy said:

The unfortunate incident highlighted another problem. This country will have to build dummy power stations that consume energy to spin large heavy armatures to provide grid stability which is diminishing as trad power stations go offline.

I could show you some research that shows the contrary, but you will just dismiss it.

[ToughButterCup]

Dismissal? Depends on the quality of the argument. Why not wait and see what is written?

[epsilonGreedy]

29 minutes ago, SteamyTea said:

I could show you some research that shows the contrary, but you will just dismiss it.

 

 

At a point in time the stability of the grid is a function of the total kinetic energy in the weight of the bits spinning in power stations at 50hz. I know this because the man who the Government sent out to Bosnia to rebuild the war shattered grid over there, told me so at the pub. That nugget of information lodged in my brain for 20 years until I started reading reports by informed people who expressed concern that the regional summer trip-out 2 years ago can be explained in part by the lack of trad power stations providing that kinetic inertia for the grid.

 

You are claiming loss of kinetic energy does not represent a problem so the onus is on you to support that claim.

[jack]

44 minutes ago, epsilonGreedy said:

At a point in time the stability of the grid is a function of the total kinetic energy in the weight of the bits spinning in power stations at 50hz. I know this because the man who the Government sent out to Bosnia to rebuild the war shattered grid over there, told me so at the pub. That nugget of information lodged in my brain for 20 years until I started reading reports by informed people who expressed concern that the regional summer trip-out 2 years ago can be explained in part by the lack of trad power stations providing that kinetic inertia for the grid.

 

You are claiming loss of kinetic energy does not represent a problem so the onus is on you to support that claim.

 

If all you have providing power is turbines that spin at a highly controlled rate, there's an element of truth in this. But when you start bringing online significant numbers of power plants that can output AC at an arbitrary frequency (as is the case with all wind turbines, for example, given that they use power converters), the issue becomes less one of frequency stability, and more one of a lack of available power. The solution is to provide a deeper power reservoir from which to smooth brief transients. 

 

Pumped gravity-based hydro is one way of achieving this, although it isn't fast enough for very high-rate fluctuations.

 

Grid-scale batteries are another that could well be a useful addition to the grid in the short to medium term. Smart grids using car batteries and grid-connected home batteries are almost certainly in the mix longer term, although the complete farce that is the smart meters roll-out to date suggests it's going to be a long time before we're capable of doing this properly.     

[ToughButterCup]

?

[SteamyTea]

1 hour ago, epsilonGreedy said:

 

You are claiming loss of kinetic energy does not represent a problem so the onus is on you to support that claim.

Posted it up last week, now it is up to you to find it.

 

If you, @epsilonGreedy, claim many extraordinary thing from well connected men in pubs, I suggest you get a copy of 'Tales from the White Hart".

I have always considered you a Harry Purvis.

[jack]

Just learned that there's a name for power converters via which non-synchronous power sources supply power to the grid to support frequency stability: https://en.wikipedia.org/wiki/Synchronverter

[pdf27]

1 hour ago, jack said:

If all you have providing power is turbines that spin at a highly controlled rate, there's an element of truth in this. But when you start bringing online significant numbers of power plants that can output AC at an arbitrary frequency (as is the case with all wind turbines, for example, given that they use power converters), the issue becomes less one of frequency stability, and more one of a lack of available power. The solution is to provide a deeper power reservoir from which to smooth brief transients.     

Not exactly - it's more of an issue that the mechanical inertia in a wind turbine is fairly small. Good article explaining it here - https://spectrum.ieee.org/energywise/energy/renewables/can-synthetic-inertia-stabilize-power-grids . Combined with batteries it's likely to produce a good solution.

Note that it's also possible to have a synchronous wind turbine if you really want it - go for something like a doubly-fed induction generator and you can tie the main stator directly to the grid. There are reasons it isn't the preferred architecture, but it isn't a dead duck.

 

1 hour ago, jack said:

Grid-scale batteries are another that could well be a useful addition to the grid in the short to medium term. Smart grids using car batteries and grid-connected home batteries are almost certainly in the mix longer term, although the complete farce that is the smart meters roll-out to date suggests it's going to be a long time before we're capable of doing this properly.     

There is an issue with response time for batteries - grid inertia produces an inherently instantaneous response, which is quite difficult given the battery chemistry. It's less challenging but non-trivial to achieve the same with non-synchronous sources like wind turbines.

Having said that it's quite likely that giant flywheels may be the cheapest way to add what is effectively inertia to the grid - they're cheap up front, cost peanuts to run and reduce the system costs associated with providing the inertia a long way away from your loads.

[jack]

You're obviously way more knowledgeable than me, but my main point was just that there's more to frequency stability in modern and future grid systems than the rotating mass of turbine-based generators. 

 

I hadn't followed it after the initial launch, but the Tesla grid-tied battery in Adelaide I linked to above appears to have been a roaring success technical and financial success. Worth a read of the short Wikipedia article. 

[newhome]

8 hours ago, ProDave said:

But has anyone tried them in a modern well insulated house?  e.g our house when you turn the heating off, it is several hours before you notice.  So storage heaters warming up over night and releasing their heat slowly it would not matter if they have run out of heat by 6pm. the house would not go cold before bed time.

This is sort of the approach I take with my UFH. I set it to come on overnight. It heats up the thermal store and the UFH. Once up to temperature the UFH doesn’t come on again until the following night. Other than during the coldest days the temperature of the room doesn’t drop enough to notice by the time I go to bed. I started doing it that way to see whether I could make the system work with a flexible rate tariff that had the cheapest tariffs overnight and concluded that I could. I imagine you could make this work with storage heaters too but can’t see that anyone would bother to install that technology these days if they were building from scratch. 

[epsilonGreedy]

21 hours ago, jack said:

the issue becomes less one of frequency stability, and more one of a lack of available power. The solution is to provide a deeper power reservoir from which to smooth brief transients. 

 

 

I agree and thought I was saying that. As we convert to wind the national grid progressively looses the reservoir of kinetic energy that provided an instant automatic reserve to keep the grid frequency within limits as the operators scrambled to bring quick start reserves online. Pumped Hydro is one example I assume.

 

Your Wiki link on the subject of Synchronverter contains references that illustrate more enlightened countries than the UK are mandating that Wind generators must also provide additional reserved power for frequency stability to replace the inherent stability that the old power provided before they were retired.

 

The science and problem is clear to all except @SteamyTea, the solution either requires some new hi-tech wizardry or as @pdf27suggests old fashioned heavy spinning flywheels might be cheaper and more reliable.

 

 

[dpmiller]

doesn't the synchroinverter just imply grid-tied tho?

 

Surely then the more reliance there is on inverter-based generation, the *more* stable the frequency becomes as inverters are current sources and would fight to hold-up the speed of any remaining rotational gennies.

Swich off all the rotating devices and tie the all required DC-AC machines to a single centrally-located stable frequency source. 

[jack]

2 hours ago, epsilonGreedy said:

I agree and thought I was saying that.

 

Not as I read it:

 

On 13/04/2021 at 12:51, epsilonGreedy said:

This country will have to build dummy power stations that consume energy to spin large heavy armatures to provide grid stability which is diminishing as trad power stations go offline.

 

My point is just that you were focused solely on inertial storage, when there are many other ways of supporting the grid over various time periods. 

 

2 hours ago, dpmiller said:

doesn't the synchroinverter just imply grid-tied tho?

 

I believe a synchroinverter adds voltage at a phase that tends to stabilise the frequency, rather than merely remaining in phase with whatever the grid is doing. A grid-connected PV inverter would be an example of the latter.

 

2 hours ago, dpmiller said:

Surely then the more reliance there is on inverter-based generation, the *more* stable the frequency becomes as inverters are current sources and would fight to hold-up the speed of any remaining rotational gennies.

   

I think that's right to a point, but you still need sufficient available power for this to happen. If that power isn't available, all the inverters in the world won't help you. 

 

I did a bit of digging around yesterday and was surprised to find that grid-scale storage projects are already well along the development pipeline for the UK. See this link for an example of a very large-scale battery in the works, and a discussion of some of the existing battery storage projects.