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Electricity Prices.

Old 5th Jul 2022, 16:30
  #61 (permalink)  
 
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Originally Posted by Xeptu View Post
The good news about an energy crisis is that it brings together the best minds focused on a consolidated solution. there is no doubt that the future portable fuel is hydrogen and historically the cross over from fossil fuel to alternatives is about $2.00 a litre. Once the technical obstacles of fusion, storage and recovery are resolved and the infrastructure is in place then that marks the end of fossil fuels. We are on the precipice, provided the oil and gas industry doesn't sabotage it. In the mean time I have never understood why we pay for our own gas and coal to power our own power supply, it's not like we have to import it. There is little doubt we are being screwed for absolutely no reason that impacts upon Australia.
For mass-sensitive application perhaps, though I suspect the other synthetic liquids will win for aviation in this respect (they are volumetrically better, and an easier drop-in replacement). For pretty much everything else that is not mass-sensitive the various flavours of lithium ion batteries seem already to have won. The path-dependency in technology strategy terms is now so strong that I cannot see hydrogen conquering many niche applications beyond some steel and petrochem ones. Just imho.

(Fully agree with you re O&G sabotage, and I was in O&G for a decade, before two decades in renewables & grid.)

(Renewables can do it on their own. If fusion ever arrives that would be the cherry on top).
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Old 5th Jul 2022, 20:19
  #62 (permalink)  
 
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I agree with you for aviation use, there's nothing really that can replace jet A1 yet unless we can find a way to store huge volumes of hydrogen in a small container and able to extract useful volumes quickly. I f we can't do that then perhaps back to lighter than air airships powered by electric motors or electric motor driven turbo props.
I think the next 50 years will be interesting to see which way we go. I do think there is a place for batteries, but I cant see them being the first go to solution.
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Old 6th Jul 2022, 00:31
  #63 (permalink)  
 
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Originally Posted by Ninthace View Post
Sand battery


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Old 6th Jul 2022, 08:43
  #64 (permalink)  
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Interesting though the options being discussed are, seriously, they are very much long term.

Unfortunately, they won't alleviate the potential devastation to millions of us with this prediction

Household energy bills to hit 3,000 per year - BBC News
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Old 6th Jul 2022, 11:15
  #65 (permalink)  
 
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Originally Posted by Krystal n chips View Post
Interesting though the options being discussed are, seriously, they are very much long term.

Unfortunately, they won't alleviate the potential devastation to millions of us with this prediction

Household energy bills to hit 3,000 per year - BBC News
I live in a row of basical identical Victorian terraced housing, all built in one run in approx 1900, which happen to be almost exactly the definition of the average UK house in price, energy use, space, and are 3-4 bedroom in size depending on loft conversions etc.

My two neighbours have an annual energy bill of 2,836/year. To be precise one is at 2,709 and the other at 2,963. My house's net energy bill is only 1,036/yr.

The same number of people live in these houses, there is no magic in that respect. My house is the warmest of the three in winter, again no magic in that respect. I buy my imported energy from Good Energy, who charge a premium as they are 100% green, so again no magic cheap deal for me.

Currently we are all dual fuel, i.e. gas and electric. If I remove my gas supply and fit an air source heat pump instead (ASHP) and battery then my projected net bill will increase to 1,415/year (that is assuming I make zero profit from energy trading). I'm likely to do this anyway, simply to get the satisfaction of stripping the gas supply out (and remember I'm the person who has worked offshore and run oil & gas platforms, reservoirs, etc for a living for many years).

My house has a B energy rating. Everyone else in the street of approx 30 houses has a D, E, F or worse.

The answer is literally already in our own hands.
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Old 6th Jul 2022, 13:47
  #66 (permalink)  
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Petit. You seem to know your onions with this subject?
I live in a 4 bed detached house facing due south in northern Europe.
I have a heat pump but it is different to most. It uses internal air to reheat water. It is very economical. I have underfloor heating driven from this too. I have no gas. My yearly electricity hits 1800 euros. This is my only energy bill. For this part of the world this is unheard of. Most people pay 4/5 times what I am paying. I am very happy with it.
But it is going up 4 fold. So my 1800 euros could become 7200 euros. That is crazy! Hence why i am looking at alternatives.
I have quite a lot of trees in front of my house and have been advised that they would idealy need to be pruned back severely to get the best from my south facing roof solar panels. I don't think that would be a problem.
But are the numbers quoted earlier realistic? I am prepared to accept a "fudge factor" Whereby I don't get the 10,000 kw/hrs a year I consume but something comparable?
My guy here is saying I can expect total bills of just a few hundred euros a year! Really?
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Old 6th Jul 2022, 15:54
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Originally Posted by happyjack View Post
Petit. You seem to know your onions with this subject?
I live in a 4 bed detached house facing due south in northern Europe.
I have a heat pump but it is different to most. It uses internal air to reheat water. It is very economical. I have underfloor heating driven from this too. I have no gas. My yearly electricity hits 1800 euros. This is my only energy bill. For this part of the world this is unheard of. Most people pay 4/5 times what I am paying. I am very happy with it.
But it is going up 4 fold. So my 1800 euros could become 7200 euros. That is crazy! Hence why i am looking at alternatives.
I have quite a lot of trees in front of my house and have been advised that they would idealy need to be pruned back severely to get the best from my south facing roof solar panels. I don't think that would be a problem.
But are the numbers quoted earlier realistic? I am prepared to accept a "fudge factor" Whereby I don't get the 10,000 kw/hrs a year I consume but something comparable?
My guy here is saying I can expect total bills of just a few hundred euros a year! Really?
I am pretty sure you have a plain vanilla Air Source Heat Pump (ASHP) just the same as the one at my GF's. That is external air. It has to be external air as the air that goes in one side at ambient temperature comes out the other side much colder, and you wouldn't want that air in your house in wintertime. The energy extracted from the air is then transfered into the hot water that circulates through a wet loop, whether it be radiators, underfloor, or both. Please correct me if I am wrong.

My personal opinion is that we are seeing a transient spike in oil & gas prices that will only (!) last a few years. So the spike from c.$60 to c.$100/bbl will pass to a significant extent once Ukraine/Russia is in the rear view mirror whenever that is. Probably not completely pass, but reduce to low enough that it is not too attractive to frac the US shale (say in the range $60-$80 might be where the Saudis and other Opec members will likely aim for). The gas prices are spiking even more than this doubling, but again I expect that to ease in a few years. However I am also expecting further price transients - both up and down - to wash through the system : they always do. This is by way of saying that people should not make too many hasty (investment) decisions that don't stack up on a longer term rational analysis. So the investments I have made over the last decade in my personal energy situation have always been at best economically justifiable, or at worst economically neutral but directionally beneficial in global warming terms (as that is going to be a significant longer term policy driver, and that tends to mean tax pain). I have learnt from bitter experience that if one is too far ahead of general adoption then this tends to be economically very bad, but a mild bit of early adoption tends to pay off. The payback right now is my sticking 2k extra in my pocket each year compared with my neighbours, or in my case putting it into the "save for a battery" stash.

Translating this to your circumstance means don't go too wild, too hastily, as you seem to be in a better situation than many who are bewailing their situation. Without knowing your precise location; and factors like the visual amenity you value of the trees at the front of your property; and your local regulatory context (net metering; net billing; FIT schemes; grant schemes; etc) I can't give any context-specific guidance. However I would seriously contemplate reducing tree height, fitting solar PV, and coupling that with an LFP battery. If you have a battery-to-PV ratio of about 2kWh of battery per 1kW of PV then that will tend to support the vast majority of a dwelling's electricity consumption for approx 9-months of the year in temperate latitudes. The other 3-months of the year one needs to grin-and-bear the electricity import costs, and vote for politicians who are rational enough to prioritise installing wind turbines that will generate electricity during the grim winter darkness. (The battery : PV ratio is important to get right.)

But start with a personal energy audit. Where exactly is that energy going ? If it is mostly into winter heat then maybe more insulation is a better payback for you. As with all these things, context-specific data will give you the facts to make better decisions for yourself. When/if you know more feel free to ask for a second-opinion.

(For info this week we are installing approx 100mm of internal insulation on the inside of the external walls in my GF's large living room (5m x 7m*) which is pretty much the culmination of a long-term 10-year upgrade programme we began many years ago. It began with her eying up a very smart new blumotion Golf car, fluttering her eyelashes at me, and sayng "wouldn't it be good for the environment if she bought one of those". To which my response was "let's figure out the sums" .... which in turn led to my pointing out that she bought more oil (basically diesel) to heat her house than she bought oil (diesel) to run her car - and that a house was an appreciating asset whereas a car was a depreciating asset - so it made sense to focus the investment on the house rather than the car, at least to begin with. She is now fluttering her eyelashes at me and conspicuously eying up very smart Teslas !)

* that's about the same size as the main bit of my terraced house !
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Old 6th Jul 2022, 18:17
  #68 (permalink)  
 
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Originally Posted by FullOppositeRudder View Post
Our 3 Kw solar system caters pretty effectively for our basic domestic electricity requirements over a calendar year. This includes supplying the electric stove, oven and water heater. We even manage to export some in some months (our feed-in rate is excellent). This all goes out of the window when we run the central ducted airconditioner (I think it's called a heat pump in some countries). It's not quite so bad in summer when the sun favours our side of the equator - it still costs something. However come winter when the days are shorter, the sun favours the northern parts of the globe, and it's cloudy - as it been for the past three days (8/8) - our heating costs make for very unpleasant contemplation. The ducted system suffers in both instances from the effects of heat - or cold in the ceiling cavity through which the ducting tubes are located. In summer, our ceiling temperatures have reached as much as 70C on occasions. Even though the ducting is manufactured to minimise unwanted heat loss (or gain), this surely has an effect of the efficiency of the overall system on those 44C days. I speculate now about doing away with the ducted system when something major gives out, and replacing it with three dedicated split system units. We need only run the unit(s) specific to our activities at any given time rather than attempting to heat (or cool) the entire house.

I'd also choose a different location for our solar panels if we were starting a new installation tomorrow. We chose a less than optimum orientation for aesthetic reasons having been assured the the compromise would have minimal effect on the overall efficiency. That was not altogether correct, and we would now go for the northern placement, and the hell with what the neighbours might think. Even so, our present installation earns nice money for us we go away for a few weeks for a holiday. Unfortunately it's never enough to pay the holiday expenses.

One of my ingenious friends engineered a sun tracking installation for his solar installation. Each day the array of six panels faithfully track the sun's path through the sky from east to west and the system actually also tilts in elevation over the year to present a 90 degree angle to the sun as it drops closer to the northern horizon in our winter. All automatic - he designed and built it himself - the bloke's a genius.
Don't know what your construction is but if it is standard trusses or beam and rafters have you considered having a "warm" attic. Spray foam the underside of the roof and then your ducts will be in a warm zone in Winter and cool zone in Summer.

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Old 6th Jul 2022, 18:36
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I have recently had a solar installation carried out, 14 panels and a 9,6kw battery, I will do a write up on my experience of this shortly for the benefit of my fellow PPRuNe'rs.

However, in the meantime, could anyone explain to me why I can heat a tank of water from 40c to 65c with 3.1Kw of electricity, but takes 9.2Kw of gas to do the same same . Hopefully it is not a dodgy smart meter.

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Old 6th Jul 2022, 19:29
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Originally Posted by WB627 View Post
However, in the meantime, could anyone explain to me why I can heat a tank of water from 40c to 65c with 3.1Kw of electricity, but takes 9.2Kw of gas to do the same same . Hopefully it is not a dodgy smart meter.
Not specifically, without knowing your exact system, but here's a few starters, as I found a similar situation, although a smaller difference than you found.

1. Most immersion heaters tend only to heat from a higher level in the cylinder than the coil for the boiler, so you'll be heating up more water, and suffering larger heat losses once it's heated. Few immersion heaters are anywhere close to the lower level of the coil. That could account for 15-40% difference

2. Electric immersion heaters are essentially 100% efficient, whereas boiler heating is likely to be closer to 70% if you're lucky, because:

a) Few boilers ever achieve close to 90% efficiency, as most people set boilers (even condensing boilers) to a flow temperature so the return is above 53Celsius, so there will be NO condensing whatsoever. Ideally run the boiler with the lowest flow temp possible, the slowest pump possible, so the return difference is as great as possible (ideally >20Celsius), for the coolest return (ideally 40Celsius), to give a condensing boiler any chance of condensing, and achieving closer to 90%+ advertised efficiency. This will need much longer heating times than a boiler whacked up to max (75-80 Celsius flow).

b) Heating with a boiler and coil in the cylinder will be inefficient because of all the pipe losses. Insulate the pipes wherever you can see them. Those pipe losses could account for a further 10-15% loss during operation.

c) Check whether your gas system heats the water to higher than the 65 Celsius you state for your immersion heater. Do you really need your water that hot? Would 55Celsius do? Or compromise on 60Celsius. Beware of Legionella though, a high temperature is required from time to time to prevent that.

d) A boiler system will always have extra losses associated with starting (heating the 'heating' water up from cold to start with, then losing all that heat once stopped), irrespective of how well the pipes are insulated. The 'heating' water in the pipes will inevitably go cold before the next HW heating cycle 24 hours later, and need that energy to heat it back up to do its work. That could account for a further 5-10% loss OVER AND ABOVE the operating loss described from pipes in b) above.

All this could easily make the boiler heating barely 50% efficient, sometimes even worse, depending on circumstances.

Of all the things mentioned above, the biggest favour most people could do themselves is read and re-read the advice in a) above. I believe very few condensing boilers ever have the opportunity to condense, so they are barely any different from any other boiler - except double or triple the price to buy, on a promise of saving shed loads of cash:

- Set the lowest flow temp you can get away with, ideally <65C or <60 C even better.
- set the slowest pump speed. This and the above will achieve the very lowest return temp, and that is the key to economy, whether heating water or rooms (CH)
- then leave the boiler on for longer to compensate for the lower output - on continuously if you've achieved the above 2 points fully.

Just my 2p worth - hope it helps many to save loads of cash.

pm
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Old 6th Jul 2022, 19:37
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Originally Posted by WB627 View Post
However, in the meantime, could anyone explain to me why I can heat a tank of water from 40c to 65c with 3.1Kw of electricity, but takes 9.2Kw of gas to do the same same . Hopefully it is not a dodgy smart meter.
Kw? Should be kWh for a quantity of energy.

I'm assuming that the electric water heater is a resistance element rather than a heat pump type. I'm also wondering about any assumptions your energy company might be making about the heat content of a given volume of gas. Our gas metering is in CCF (hundreds of cubic feet) times an energy factor to convert that into BTU.

If it really is kW, then it's just a matter of different sized burner/resistance elements. If you are actually being billed for energy (kWh) then you have a very inefficient gas boiler. Or your energy company is rolling some taxes, assumed efficiency factors or whatnot into your rates.
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Old 6th Jul 2022, 19:59
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btw what ever happened to Economy 7 ?
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Old 6th Jul 2022, 21:11
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Originally Posted by WB627 View Post
I have recently had a solar installation carried out, 14 panels and a 9,6kw battery, I will do a write up on my experience of this shortly for the benefit of my fellow PPRuNe'rs.

However, in the meantime, could anyone explain to me why I can heat a tank of water from 40c to 65c with 3.1Kw of electricity, but takes 9.2Kw of gas to do the same same . Hopefully it is not a dodgy smart meter.
Keeping the numbers simple for people like me.

Your gas boiler is approximately 33% efficient. Two thirds of the energy from burning the gas (6kWh) goes up the chimney, leaving one third (3kWh) to heat the water. Meanwhile 3kWh of electric are darn nearly 100% efficient at going into the water. Either way 3kWh ends up in the water doing the job (work) of raising the temperature of the water.

Problem is the same efficiency issue also occurs at the other end of the electricity line where the gas (or coal) fired power station is also 33% efficient. So 9kWh of gas at (say) 5p/kWh yields 3kWh of electricity which they sell at 15p/kWh to balance the books of the various energy companies. At least it was 5p & 15p/kWh back when oil (and gas) was $40/bbl, but things have changed recently.

One can get more complicated with the numbers, adding more decimals and differing efficiencies but the principles are the same.

(The other comments are not wrong, but my explanation addresses - I think - the main issue).

(edit: mind you, it does depend on what your meter(s) are metering when trying to construct an appropriate explanation)

Last edited by petit plateau; 6th Jul 2022 at 21:33.
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Old 6th Jul 2022, 22:26
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Originally Posted by petit plateau View Post
Your gas boiler is approximately 33% efficient. Two thirds of the energy from burning the gas (6kWh) goes up the chimney, leaving one third (3kWh) to heat the water.
.... the gas (or coal) fired power station is also 33% efficient.
Wrong. You need to check your figures.
Modern condensing boilers are labelled between 92-94% efficient ErP, aka A-rated. Boilers over 25 years old can be as little as 60% efficient, or G-rated.
https://www.theheatinghub.co.uk/boil...s%20by%2030%25.
Thermal efficiency is the efficiency with which heat energy contained in fuel is converted into electrical energy. In 2020, combined cycle gas turbine stations had a thermal efficiency of 48.3 percent, which means that 48.3 percent of the energy in cycle gas was converted to electricity.
https://www.statista.com/statistics/...%20electricity.
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Old 6th Jul 2022, 22:36
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Thank you all for your replies.

I guessed it was probably due to inefficiencies in the boiler & heat loss in the pipes etc. but it is helpful to have that confirmed.

Yes it is kWh. My smart meter gives me gas in kWh or , I can go on line and get the readings in m3.

I am running the water in the tank (gas or electrically heated at 65c for legionella reasons; my wife is clinically extremely vulnerable and is on a chemotherapy drug so we cannot take any risks.

I must check my flow and return tempreture, but my pump is on a pretty slow setting.

The long and short of it is, despite only paying 8.4p kWh for gas, it is still cheaper to use my self generated electricity to heat the water , despite what I am being paid on the Octopus Agile Export tariff.

EDIT - I have dual rate Economy 8 but now I have a solar installation with a big battery, I am not using any electricity from the grid at night.


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Old 7th Jul 2022, 07:44
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I agree with you, WB627, I have the same decisions to make. For me, the choice is more difficult, as the pricing is more in favour of burning gas for water heating:

Like you, I have ample PV solar with battery storage, any excess sold to Octopus for 7.5p per unit. Imported electricity would be 18p, but I don't import except on the dullest of Winter days. My gas is 3.3p per unit, so do I spend aprox 6 units of gas (20p) to heat the water or 4 units of electricity which I could have exported for 30p? Obviously, burning the (inefficient) gas is cheaper.

What does make sense is the Air Conditioning that I've installed. Working on a COP of aprox 4 because I use to lowest, highest efficiency setting, each unit of electricity which costs me 7.5p (by not being exported) gives about 4 units worth of heat, saving me around 15p of gas. And on the hottest Summer days, using the same 7.5p unit of non-exported electricity to cool the house with 4-5 units of cooling feels wonderful, and worth every 7.5p spent that way! The rest of the spare electric units give the electric cars a further 4 miles or so per unit, until they're full, and then Octopus buys the remainder from me.
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Old 7th Jul 2022, 08:18
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Originally Posted by pilotmike View Post
Yes, I know that modern CCGT's are >45% efficient, however I picked 33% for explanatory purposes as it both makes the illustrative numbers easy, and not all generating units are of the CCGT type.

Regarding domestic condensing boilers achieving >90%, thank you. That is helpful indeed.
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Old 7th Jul 2022, 08:35
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Originally Posted by petit plateau View Post
Regarding domestic condensing boilers achieving >90%, thank you. That is helpful indeed.
But only if run at their most efficient, ie with return below ideally 50 Celsius.
If set as most seem to be with 75+ Celsius flow and 60 Celsius return, efficiency is likely to be about 85-88%. And that's just the actual boiler. Other losses bring it down closer to 50 - 60% , or worse, as outlined above.



https://www.urbanplumbers.co.uk/how-...nsing-boilers/
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Old 7th Jul 2022, 08:54
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Originally Posted by pilotmike View Post
But only if run at their most efficient, ie with return below ideally 50 Celsius.
If set as most seem to be with 75+ Celsius flow and 60 Celsius return, efficiency is likely to be about 85-88%. And that's just the actual boiler. Other losses bring it down closer to 50 - 60% , or worse, as outlined above.



https://www.urbanplumbers.co.uk/how-...nsing-boilers/
Thanks Mike, most helpful.

On a different point, it seems solar PV module manufacturers are now offering 40-year warranties. Quite how reliable the claims experience might be boggles my mind, but it does give a feel for how reliable this stuff is getting.
https://www.pv-magazine.com/2022/07/...-solar-panels/
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Old 7th Jul 2022, 22:03
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Originally Posted by petit plateau View Post
Thanks Mike, most helpful.

On a different point, it seems solar PV module manufacturers are now offering 40-year warranties. Quite how reliable the claims experience might be boggles my mind, but it does give a feel for how reliable this stuff is getting.
https://www.pv-magazine.com/2022/07/...-solar-panels/
Does require faith that the supplier will still be there to honor the obligation.
In electronics, that is a bit of a leap.
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