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LowNSlow
11th Mar 2018, 12:44
As at 12:40 on 11-Mar-2018, according to G. B. National Grid status (http://www.gridwatch.templar.co.uk) the UK is providing power thus:
1. CCGT (Closed Cycle Gas Turbine) - 17.87 GW - 48.05%
2. Nuclear - 6.53 GW - 17.56%
3. Coal - 4.02 GW - 10.81%
4. Solar - 2.97 GW - 7.99%
5. French ICT (International Cable Transmission) - 1.5 GW - 4.03%
6. Biomass - 1.37 GW - 3.68%
7. Wind - 1.31GW - 3.52%
8. Dutch ICT - 1.0 GW - 2.68%
9. Pumped Storage - 0.45 GW - 1.21%
10. Hydro - 0.16 GW - 0.43%

I was surprised that nearly 50% of our power is still generated in gas fired power stations and even more suprised that Solar accounted for nearly 8%.

Given our aged nuclear plants and our continuing dependence on Dutch and French power imports why are still closing down perfectly serviceable coal powered stations instead of installing carbon capture technology?

jolihokistix
11th Mar 2018, 12:58
Maybe there is a hint hidden somewhere in the word security? No tsunami on the horizon. Chinese nuclear? Good to see the unthinkable, that solar and wind have overtaken coal!

LowNSlow
11th Mar 2018, 13:10
Given we are now starting to import gas directly from Russia in addition to the gas that comes indirectly via the European pipeline system plus the 2.5 million tons of coal from them, roughly 20% of our coal consumption, how are we going to cope if Putin tells us to get lost in the future.

vapilot2004
11th Mar 2018, 13:30
Other than the usual slight of the French* (probably deserved), it would appear natural gas pipelines and LNG tankers would be key targets if one were so inclined to turn out the lights.

https://www.britishgas.co.uk/the-source/dam/jcr:4fb88c87-770a-4402-83c0-eb2d5b8096a0/uk_gas_570x330.jpg

Ah, but Mr. Putin...

No worries, Americans likely can come up with a(n advantageous to US business and terribly expensive for the UK government) deal of great convenience for you.

Gertrude the Wombat
11th Mar 2018, 13:36
Given our aged nuclear plants and our continuing dependence on Dutch and French power imports why are still closing down perfectly serviceable coal powered stations instead of installing carbon capture technology?
'Cos CCS is firmly in free-rainbow-coloured-flying-unicorn territory? - first catch your unicorn, then ask it how to do commercially viable CCS at scale. Do let us know the answer.

Sallyann1234
11th Mar 2018, 13:40
The sooner we can increase domestic gas production by fracking, the better. :eek:

vapilot2004
11th Mar 2018, 13:46
No one will fund the only technology that can save the US coal industry, according to a new Moody’s report - Quartz 25 JAN 2018 (https://qz.com/1189272/moodys-report-on-coal-mining-only-carbon-capture-and-storage-can-save-the-industry/)

VP959
11th Mar 2018, 13:49
The sooner we can increase domestic gas production by fracking, the better. :eek:

I'm not sure we can. AFAICS, we can probably get shale oil out of what we've got, but not the large quantities of shale gas that the US is getting.

If we could get large quantities of shale gas then I suspect we'd find more pressure being applied to go for fracking. I also suspect that the financial returns for UK fracked oil are probably marginal at best right now.

Some of the earlier estimates of UK shale gas potential have dropped a lot in the last 12 months. Apparently the most promising shale gas locations were disturbed by tectonic action around 55 million years ago, according to research done towards the latter part of last year, which may well explain why the topic fracking doesn't seem to crop up as often as it did.

Danny42C
11th Mar 2018, 13:57
Google: "Severn Barrage Power Generation" > Severn Barrage Tidal Power | REUK.co.uk
Severn Barrage Tidal Power | REUK.co.uk (http://www.reuk.co.uk/wordpress/tidal/severn-barrage-tidal-power/)

Do the sums.

Slack water? Use your gas fired stations for a couple of hours twice a day.

Forget about wind (absolutely unreliable - remember '62-'63?) and solar (gets dark at night).

Won't happen (Oh, the poor little dicky birds!)

Use your noggin.

Gertrude the Wombat
11th Mar 2018, 14:10
Forget about wind (absolutely unreliable - remember '62-'63?) and solar (gets dark at night).
Gosh and one would never have imagined that there are vast industries building up around storage and time and space shifting both generation and demand.

Gertrude the Wombat
11th Mar 2018, 14:13
Google: "Severn Barrage Power Generation" > Severn Barrage Tidal Power | REUK.co.uk
Severn Barrage Tidal Power | REUK.co.uk (http://www.reuk.co.uk/wordpress/tidal/severn-barrage-tidal-power/)
The real worry about this project of course is how much it would slow the moon down.

sfm818
11th Mar 2018, 14:27
Why would a country with 11,000 miles of coastline, invest in tidal power, when it can afford to build the worlds most expensive power station (Hinkley C) :E

Meanwhile, across La Manche.

https://www.youtube.com/watch?v=jNXiwcZYMpU

Highway1
11th Mar 2018, 14:57
I can remember about 40 years ago there used to be regular items on Tomorrows World showing all these power from tidal schemes - and here we are still dreaming about it..

radeng
11th Mar 2018, 15:09
Good to see the unthinkable, that solar and wind have overtaken coal!

Regrettably, with massive pollution of the radio spectrum from the inverters with minimal filtering on them. Even more generating capacity will be needed if the predictions for the number of electric vehicles in Europe are anywhere near correct. If you allow 50% usage of power spread out over 24 hours because of diversity, it looks something like another 50 or 60 GW will be needed throughout Europe. Or around another 20 Hinckley Points. The currently inadequate infra structure to accommodate this is another problem...

Nemrytter
11th Mar 2018, 15:18
Forget about wind (absolutely unreliable - remember '62-'63?) and solar (gets dark at night).I'm not sure if you've noticed (JetBlast does live in the past, after all) but it's not the sixties any more. In fact, we've (the real world, not the Daily Mail unicorn-land that exists on JB) had several decades of progress since then.
Then again, it's good that we have such highly intelligent people such as yourself to point out that it goes dark at night. I'm confident that the people behind solar power have never considered that before. But most of the feeble-minded individuals that infect jetblast seem to think that the UK inhabits a world in which the sun never sets on the British Empire, so perhaps you dimwits can generate unlimited solar energy after all.:=

Gertrude the Wombat
11th Mar 2018, 15:33
The currently inadequate infra structure to accommodate this is another problem...
Yes, the intelligent dynamic optimisation that's needed has to factor not only when and where the generation, storage and demand are but also what grid capacity there is for moving power from one place to another at various times (eg it doesn't use up much grid capacity if your washing machine is being powered from your neighbour's electric car).

There is a debate as to what extent this should be solved by putting up more pylons and to what extent it should be solved by putting in clever software. And in the latter case the industry seems to be taking more of an interest in the ability of Russian hackers to crash the grid than is normal for IoT applications.

sitigeltfel
11th Mar 2018, 15:58
I'm not sure if you've noticed (JetBlast does live in the past, after all) but it's not the sixties any more. In fact, we've (the real world, not the Daily Mail unicorn-land that exists on JB) had several decades of progress since then.
Then again, it's good that we have such highly intelligent people such as yourself to point out that it goes dark at night. I'm confident that the people behind solar power have never considered that before. But most of the feeble-minded individuals that infect jetblast seem to think that the UK inhabits a world in which the sun never sets on the British Empire, so perhaps you dimwits can generate unlimited solar energy after all.:=

They could solve all the power problems by strapping solar panels to Corbyns arse. That's where the Lefty loons think all the sunshine comes from.

ETOPS
11th Mar 2018, 16:25
OK I admit it - I'm a Gridwatch junkie :eek:

It's actually fascinating to watch the controllers balancing demand and supply. At the macro level it would appear to simply be wind against coal - the other sources being run relatively constant. The interplay between the overseas electricity cables appears more complex with occasional " reverse flow" against a U.K. demand.

If you remember there was a gas shortage warning a couple of weeks ago during the v cold weather. That was the first time they ran OCGT units that I've seen.

With demand only likely to rise and wind/solar not being a reliable source we are going to need a properly thought out Governmental energy supply policy.....

Oh heck :{

LowNSlow
11th Mar 2018, 16:35
Vapilot2004, I wasn’t having a dig at the French just pointing out that we take up to 2 GW from them as well as up to 1 GW from the Dutch. This is not necessarily one way traffic, we do send ziggy volts over to them as well when the demand reverses.

Gertrude the Wombat
11th Mar 2018, 17:27
With demand only likely to rise and wind/solar not being a reliable source we are going to need a properly thought out Governmental energy supply policy.....
The policy at present looks like tweaking various short term and long term pricing policies and algorithms so as to get the market to automagically produce the right mix of new power stations, cleverer control systems, ect ect.

Andy_S
11th Mar 2018, 17:33
Why would a country with 11,000 miles of coastline, invest in tidal power, when it can afford to build the worlds most expensive power station (Hinkley C) :E

Don't the environmentalists get a bit upset? Upsets coastal wildlife or something.....

longer ron
11th Mar 2018, 17:40
We should be ok as long as we do not have to power gazillions of electric vehicles in the future :hmm:

KelvinD
11th Mar 2018, 18:31
Radeng: Speaking of inverters; what is the logic behind this? The various interconnectors generate A.C., flatten it and transmit it as D.C., then turn it back into A.C. with massive inverters. In my basic electricity training, we were taught that A.C. was more efficient than D.C., yet in the one example I have seen close up (Scotland to North Wales), the power is D.C. all the way to a massive inverter installation at Shotton..
Re coal: There has been a number of sleights of hand with this over the years. Fiddlers Ferry power station (between Widnes & Warrington) was built in the late 60s. A pretty big station, capable of producing up to 2 GW, it was cleverly sited close to the River Mersey (lots of water) and on the edge of the South Lancashire coal field. Starting with "you know who", that coalfield was eventually closed down so the problem arose of what to burn in the power station. Here's part of the answer:
Ship Photos, Container ships, tankers, cruise ships, bulkers, tugs etc (http://www.kelvindavies.co.uk/kelvin//details.php?image_id=19967)
Ship Photos, Container ships, tankers, cruise ships, bulkers, tugs etc (http://www.kelvindavies.co.uk/kelvin//details.php?image_id=19976)
In the first image, umpteen thousand tons of coal are inward bound to Liverpool from the US (can't remember if it was Houston or New Orleans).
The ship in the 2nd picture runs a regular schedule between Hunterston (Clyde) and Ellesmere Port (Mersey) carrying imported coal, generally also from the US.
Along a similar vein, Drax power station was built to take advantage of the huge Selby coalfield in the late 1960s. Privatisation saw an end to that, despite the proven reserves being at around 2,000 Million tons. So, the power station now relies on ship borne imports from the usual suspects; USA, Australia, Poland and others.
Meanwhile, the much vaunted Carbon Capture & Storage plan was pretty much torpedoed by the current government in 2015 when it was decided to renege on a £1 Billion investment.
I suppose the power generation industry has been condemned to join others:
"Trains? We don't build trains in the UK"
"Tankers for the FRA? We don't build tankers in the UK".
"Aircraft? We don't build aircraft in the UK".
The list goes on and on...

TWT
11th Mar 2018, 18:48
Kelvin, re using (HV)DC for transmission, there are some points in this article :

Technical advantages - Why choose HVDC over HVAC | ABB (http://new.abb.com/systems/hvdc/why-hvdc/technical-advantages)

VP959
11th Mar 2018, 18:51
DC is more efficient for long distance power transmission by a fair bit, even allowing for the inverter losses. If our National Grid was DC, rather than AC, it would have significantly greater capacity. Unfortunately it's not at all easy to switch existing wiring, otherwise I think there would already be a programme of work to do this.

We only used AC because at the time transformers were a relatively cheap and easy way to change voltage. Now we have high power inverters that can be as efficient as transformers so AC no longer has that advantage.

Jetex_Jim
11th Mar 2018, 19:43
We should be ok as long as we do not have to power gazillions of electric vehicles in the future :hmm:

That's not a problem. All we need to do is stop turning oil into petrol.
Here's a comprehensive breakdown of a complex topic.

https://greentransportation.info/energy-transportation/gasoline-costs-6kwh.html

longer ron
11th Mar 2018, 19:53
Oh dear Jimbo - it falls down on almost the first paragraph LOL

My car does 57 - 65 mpg (winter/summer) ;)

I will have a wee look through the rest tomorrow - I am just about to start a real nice bottle of wine :)

Jetex_Jim
11th Mar 2018, 20:00
Oh dear Jimbo - it falls down on almost the first paragraph LOL

My car does 57 - 65 mpg (winter/summer) ;)

I will have a wee look through the rest tomorrow - I am just about to start a real nice bottle of wine :)

That's good to know but not every car in the country does as well as yours.

Gertrude the Wombat
11th Mar 2018, 20:53
Radeng: Speaking of inverters; what is the logic behind this? The various interconnectors generate A.C., flatten it and transmit it as D.C., then turn it back into A.C. with massive inverters.
The frequencies aren't synchronised between the UK and the other ends of the interconnects.

Donkey497
11th Mar 2018, 21:02
I'm with TangoAlphad - why aren't we building a whole lot more hydro given that this end of the island gets enough of it dropping out the sky to seem like we're already partly submerged in any case?

dastocks
11th Mar 2018, 21:15
I'm with TangoAlphad - why aren't we building a whole lot more hydro given that this end of the island gets enough of it dropping out the sky to seem like we're already partly submerged in any case?

A shortage of suitable sites? This paper by Leo Smith (who runs the gridwatch site) discusses the issues:

http://www.templar.co.uk/downloads/Renewable%20Energy%20Limitations.pdf

NWSRG
11th Mar 2018, 21:23
I've worked in the electricity industry for 25 years, and it's fair to say, the change in the last 10 years has been staggering. Old paradigms have been blown away dramatically. I could not have forecast how operation of the transmission and distribution systems would have changed, and it hasn't stopped yet.

Renewables (mostly wind to date) have come far faster than most (including my own sceptical self) could have believed. The penetration here in Northern Ireland regularly tops 40%...at night, we shift significant amounts eastwards back into GB.

Small-scale renewables (the turbines that every farmer now erects) have changed the way the distribution system operates. Traditionally power flowed down through the voltages...now, it flows up or down depending on the demand at any given time.

Storage is likely the next big thing, and it might come in the form of electric vehicles. Now, I still struggle to see how a battery can be made suitably robust to charge and discharge at high speed over thousands of cycles to support the local LV network...but given the change of the last decade, I'm not going to predict against it!

Large scale batteries are already in service (Tesla recently installing a real game-changer in Australia). And this will only increase the impact of DC across the network.

As for HVDC, Western Link, shipping 2 GW down the west coast of GB, shows that this is not just an inter-system concept now...it's an intra-system approach for transferring renewables from source to end user. Yes, it creates challenges, but the HVDC sector is advancing very quickly. And of course, it supports the EU objective (and one of their better ideas) of a Europe wide grid that shares low cost energy across the continent and drives down prices for all.

All the renewables do cause knock on effects...the stability of the system is reduced, as we don't have the same inertia afforded by traditional steam turbines rotating at 3000 rpm...and this requires novel solutions to manage and ensure stability. Those HVDC interconnectors can help, by virtually instantaneously injecting power to maintain frequency whenever there's a system disturbance.

All fascinating, challenging, and certain to change more. I'll never say never, when it comes to predicting what changes might come next!

Donkey497
11th Mar 2018, 21:30
Plenty sites, just no dams.

Also, when dams have been built (E.g. Kielder) no turbines........

If HRH Phil can power substantial parts of Windsor and Balmoral from a small river turbine at each - what's wrong with micro hydro?

G-CPTN
11th Mar 2018, 21:38
Kielder Water hydro-electric turbines (https://en.wikipedia.org/wiki/Kielder_Water#Hydro_electric_plant).

Gertrude the Wombat
11th Mar 2018, 21:44
Now, I still struggle to see how a battery can be made suitably robust to charge and discharge at high speed over thousands of cycles to support the local LV network...but given the change of the last decade, I'm not going to predict against it!
One theory runs as follows

Punters don't trust car batteries to last for any particular length of time, so won't buy them
Which means that the business model is that the car companies lease the batteries to the punters ...
... and charge them by either the month or the mile, not the discharge / recharge cycle ...
... so the punters will be perfectly happy to rent their batteries out to the grid to discharge every evening and recharge in the small hours.
Not sustainable at scale, of course, as the leasing companies will be left taking the loss. It will be interesting to see how this one plays out.

Gertrude the Wombat
11th Mar 2018, 21:52
All the renewables do cause knock on effects...the stability of the system is reduced, as we don't have the same inertia afforded by traditional steam turbines rotating at 3000 rpm...and this requires novel solutions to manage and ensure stability.
Which is partly addressed by the grid letting various frequency response contracts, where someone promises to have kit on standby and respond within a given number of seconds if the frequency drops below the threshold.

The "kit on standby" is up to the bidder - it can be a bunch of diesel generators, or it can be a promise to discharge a battery, or it can be a promise to reduce demand. The idea apparently being that the system just pulls financial levers, and it's up to the market to work out how to make a profit out of what's on offer.

Of course you have to take into account human nature and obvious failure modes. So you can't, for example, bid to be paid to increase your consumption if the grid frequency gets too high, because people would just turn on all the heaters and open all the windows, which conflicts with other objectives.

Donkey497
11th Mar 2018, 22:00
G-C, I sit corrected, but "only" 500kW steady load for a reservoir that's square miles in size is a bit of an underambition for construction on that scale.

The problem with this country is that we never think of trying to solve two or more big problems at the one time. We'll happily spend tens or hundreds of billions on a scheme that does one thing then at the last gasp we'll tack on something that barely pays lip service to another equal issue that could have been largely or completely solved by the same project.

ENDMODE "Grumpy"

NWSRG
11th Mar 2018, 22:09
Which is partly addressed by the grid letting various frequency response contracts, where someone promises to have kit on standby and respond within a given number of seconds if the frequency drops below the threshold.

The "kit on standby" is up to the bidder - it can be a bunch of diesel generators, or it can be a promise to discharge a battery, or it can be a promise to reduce demand. The idea apparently being that the system just pulls financial levers, and it's up to the market to work out how to make a profit out of what's on offer.

Of course you have to take into account human nature and obvious failure modes. So you can't, for example, bid to be paid to increase your consumption if the grid frequency gets too high, because people would just turn on all the heaters and open all the windows, which conflicts with other objectives.

Yep, these services are the means of dealing with much of this. But the response has to be effectively instantaneous...not reliant on people turning on their own loads...

So, batteries that can react in milliseconds, or HVDC interconnectors that can change export or import within a number of cycles (and you can bid to provide that almost immediate change).

But the stability issue also relies on other technologies...we'll be seeing solid state devices that can regulate high power high voltage networks during network events.

Gertrude the Wombat
11th Mar 2018, 22:22
The problem with this country is that we never think of trying to solve two or more big problems at the one time.
Because different projects, from different funding streams, from different policy strands, from different ministers, to different timescales. "Joined-up government" is not something we've ever got the hang of.

Gertrude the Wombat
11th Mar 2018, 22:26
Yep, these services are the means of dealing with much of this. But the response has to be effectively instantaneous...not reliant on people turning on their own loads...
I'm not working at the commercial end of this, but I gather you can bid different amounts for different services depending on whether you can react in a second or so or whether it'll take you tens of seconds? - you can, I think, bid in for a fast response service with a small battery which just takes the load until the diesels have spooled up?

The basic control technology - spot the frequency drop from the metrology and hit a relay (or fire off a message through a software interface) - is quite fast, so it's almost all down to the spool up time of the assets.

G-CPTN
11th Mar 2018, 22:27
Kielder Water was not constructed as a Hydro facility but as a supply reservoir for the now defunct steel industry on Teesside - in fact the steel industry was defunct by the time Kielder Water was completed - and would not be built today.
The regular daily discharge is minimal relative to the planned discharge for the original purpose.

Today, Kielder Water exists primarily for leisure though after the December 2015 floods in Tynedale, it has a function as a flood amelioration storage reservoir.

A secondary purpose is to supply water via the Riding Mill tunnel to Weardale and Teesside when needed,and has provided water as far south as York during drought conditions.

NWSRG
11th Mar 2018, 23:04
I'm not working at the commercial end of this, but I gather you can bid different amounts for different services depending on whether you can react in a second or so or whether it'll take you tens of seconds? - you can, I think, bid in for a fast response service with a small battery which just takes the load until the diesels have spooled up?

The basic control technology - spot the frequency drop from the metrology and hit a relay (or fire off a message through a software interface) - is quite fast, so it's almost all down to the spool up time of the assets.

That's right Gertrude...the all-island market in Ireland is probably a bit more mature than the GB market in this respect (likely due to the faster growth in wind on this side of the water). So the range of products this side is more extensive (for the moment), starting with the 2-10s range and working out from there. There's also a range of additional multipliers available (as well as penalties for not delivering when you should)...for example, if you can demonstrate capability to operate at finer frequency deviations (perhaps 49.95Hz rather than 49.9Hz) then there's additional payments available.

ricardian
12th Mar 2018, 00:47
Orkney has a surfeit of electric power (wave, tidal & wind) and a new cable connecting us to mainland Scotland is planned (http://sse.com/newsandviews/allarticles/2018/03/ssen-submits-needs-case-to-ofgem-for-orkney-transmission-link/) which will allow the export of surplus power

oldpax
12th Mar 2018, 06:10
While GB inc have phased out almost all the LARGE coal fired stations the rest of the world continues building themand burning all the rubbish coal they can find.Only recently has China made comments that they will clean up their emmisions!So while GB has reduced coal powered and relies more on Gas(Wind unreliable and solar......well!!!).So in the last couple of weeks Coal overtook gas (well on one day !!)as supplier prices went up ,remember people its now a profit/loss business ,not run by government anymore!!!

radeng
12th Mar 2018, 10:21
(eg it doesn't use up much grid capacity if your washing machine is being powered from your neighbour's electric car).

But is the neighbour happy at the reduced life of the battery? Of course, one could envisage a scheme that automatically figures out how much came from the battery and sends a payment to the battery owner's bank account. It is then getting complex to the point where the capabilities for fraud are enormous!

Gertrude the Wombat
12th Mar 2018, 12:20
But is the neighbour happy at the reduced life of the battery?
If the neighbour

(1) gets paid for the use of his battery
(2) isn't carrying the risk of reduced life, because he's leasing the battery and it's up to the leasing company to replace it when necessary

then he'll be perfectly happy.

LowNSlow
12th Mar 2018, 15:15
VP959, Cuadrilla, Third Energy, Ineos and iGas seem reasonably confident of getting gas out of the shale rather than oil. https://www.theguardian.com/environment/2017/dec/25/fracking-start-2018-shale-gas-uk-industry-protests

There does seem to be quite a bit of both shale oils and gas in the South as well

In June 2013, the US Energy Information Administration issued a worldwide estimate of shale gas, which included an incomplete estimate of recoverable shale gas resources in the UK. The Carboniferous shale basins of North of England and Scotland, which include the Bowland Basin, were estimated to have 25 trillion cubic feet of recoverable shale gas. The Jurassic shales of the Wessex Basin and Weald Basin of southern England were estimated to have 600 billion cubic feet of recoverable shale gas and 700 million barrels of associated oil. The agency noted that the UK shale basins are more complex than those in the US, and therefore more costly to drill. On the other hand, as of June 2013, the price of natural gas in the United Kingdom was reported to be more than double the price in the US and Canada by one source[24] and three times higher by other sources.

https://en.wikipedia.org/wiki/Shale_gas_in_the_United_Kingdom

VP959
12th Mar 2018, 15:50
VP959, Cuadrilla, Third Energy, Ineos and iGas seem reasonably confident of getting gas out of the shale rather than oil. https://www.theguardian.com/environment/2017/dec/25/fracking-start-2018-shale-gas-uk-industry-protests

There does seem to be quite a bit of both shale oils and gas in the South as well



https://en.wikipedia.org/wiki/Shale_gas_in_the_United_Kingdom


Depends on the age of the info. This article from late last year suggests that the reserves aren't anywhere near as great as first thought, for example: https://www.telegraph.co.uk/business/2017/08/16/uk-shale-industry-overhyped-unlikely-deliver-geologists-warn/

LowNSlow
12th Mar 2018, 16:02
Good point there VP959, I hope the esteemed professor is wrong or that the prospectors will be able to adapt their drilling techniques to accommodate the fractured (as in disturbed) reserves.

radeng
12th Mar 2018, 16:14
I would suspect, Gertrude, that any leasing company that didn't put a limit on the number of charge/discharge cycles allowable in a given period would be going out of business. Much the same way as when a car is leased - exceed the given number of miles in a given period and there's an extra charge (pun not intended!) levied.

Plus even more electromagnetic pollution. Should it all be wireless charging or power supplying, the overall efficiency of the power transfer process would waste about 30% of the energy.