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Member postings for SillyOldDuffer

Here is a list of all the postings SillyOldDuffer has made in our forums. Click on a thread name to jump to the thread.

Thread: Flash Removal Tool
20/01/2021 21:40:35

I solved 'Bad Referer'* by installing the Firefox 'Referer Modifier' add-on. It allows the user to override the browser's privacy policy, which have all been tightened recently to strip information out of URLs when a web request crosses a security boundary. An example would be a secure website (https) serving a link to an insecure http website, a mistake that compromises the user and the secure website. I don't understand what rule is being broken between me and www.mydigitalmagazine.co.uk, but telling Referer Modifier' to send the full referer URL to them opens the archive,

Opening an old Model Engineer magazine had the expected result - error message because I don't have Adobe Flash. So I activated Ruffle and tried again. It attempted to open the magazine, but said:

swf.jpg

So promising, but Ruffle doesn't work yet,

Dave

PS * 'referer' isn't my spelling mistake. It was misspelled in the Standard and accidentally became official!

Edited By SillyOldDuffer on 20/01/2021 21:45:48

20/01/2021 17:55:55
Posted by JasonB on 20/01/2021 16:33:07:

SOD, have a look at Dominic's post in this thread which gets rid of Bad referrer

Thanks Jason, didn't work for me unfortunately.

Connecting with wget, says:

--2021-01-20 17:46:03-- https://www.mydigitalmagazine.co.uk/magviewer/popup.php?token=moogzfgikdlklksltkdhjibkleuycswy
Resolving www.mydigitalmagazine.co.uk (www.mydigitalmagazine.co.uk)... 79.99.147.137
Connecting to www.mydigitalmagazine.co.uk (www.mydigitalmagazine.co.uk)|79.99.147.137|:443... connected.
OpenSSL: error:1414D172SL routines:tls12_check_peer_sigalg:wrong signature type
Unable to establish SSL connection.

Found a web page linking this to an SSL version mismatch and another suggesting a digital certificate issue, either of which mess up https.

Got some things to try. Why is nothing ever easy?

Dave

20/01/2021 16:18:03

Posted by Neil Wyatt on 20/01/2021 15:15:41:

...

If you search 'flash player replacement for Windows 10' you should be able to track down an emulator (e.g. Supernova or Ruffle add-ins for Google Chrome) that will play flash content in some browsers, but as I haven't tried any of these I can't make a specific recommendation.

...

I tried yesterday to read a Digital ME and it failed with the dreaded 'Bad Referrer' error. Digging deeper suggests it might be an SSL Authentication Problem, and nothing to do with Flash. Might be a problem at my end, but it effects Firefox on Ubuntu and W10, and Edge on two different machines. I'm investigating!

However, I was hoping to try ruffle, which is a Flash emulator, to see if it coped with a digital magazine. Ruffle's a complete rewrite and doesn't have the deep security problems that bedevilled real Flash. (Though it may have some new flaws of its own!) Unfortunately I haven't been able to try it because I can't connect to the digital magazines at all.

A quick overview may help if anyone else wants to give it a go.

Three versions, only number 3 is worth trying at home:

  1. A command line utility that plays downloaded swf files (Shockwave Flash Movies). I don't think it helps with Digital magazines because they can't be downloaded, and aren't movies!
  2. A web-server utility that converts flash content before serving it to customers. It requires all the web pages containing flash to be modified to download some Javascript to the users. This is one for a web-site developer to investigate; I've no idea how much work it might be, or if it would fix our problem.
  3. A browser plugin for Firefox, Safari, Chrome and Edge. This is the one to try. However Ruffle isn't production ready yet and is likely to be buggy and have missing features.

As ruffle is still experimental the plugin can't be loaded through the Browsers usual plug-in/extensions menu. Instead:

  • The plug-in is downloaded manually (easy to do)
  • And activated using the Browser's developer mode. (Not difficult)
    • Navigate to about:debugging.
    • Click on This Firefox.
    • Click Load Temporary Add-on...
    • Select the .xpi that you downloaded.
  • And Chrome is very similar. (Not sure about Edge & Safari)

Browser Developer mode loads plug-ins temporarily for the current session only for test and debugging. As a early version plug-in might be faulty, it's not installed permanently and has to be manually loaded each time the Browser is restarted. (If bad code crashes the browser, the next restart will be clean.)

Full instructions & download links on Ruffle's Web Page.

I haven't been able to test if the plug in works with digital magazines or not. I'll report again if I can get past my 'Bad Referrer' problem.

Dave

Thread: Model boiler safety calculations
20/01/2021 10:33:46
Posted by Tony Wright 1 on 19/01/2021 22:53:14:

ps has anyone ever known a model boiler actually explode !!!

Model boilers are unlikely to explode, and the few attempts to do it deliberately have been disappointing. They split and leak rather than go bang, though one soft-soldered example popped the end off and rocketed into a tree. (One of my earlier posts has the reference to an ME article: one of the clubs destroyed 4 or 5 boilers, including at least one Inspector reject. )

Steel boilers are more likely to go bang than Copper, but in model loco sizes even they aren't scary. Bigger boilers are another matter entirely. Mythbuster's have a couple of episodes featuring what happens when a large US style domestic water heater is completely sealed and all the safety measures are bypassed. Spectacular and very dangerous. Don't try this at home folks!

Despite chemicals, electricity, cutting tools, burners and steam boilers Model Engineering is a safe hobby. Far safer than woodwork! Amateur radio is far more likely to be lethal than boilers because people fall off roofs or touch power lines whilst erecting aerials! Apparently real men play with radios, not trains!

smiley

Dave

Thread: Chemically cleaning brass - gently
20/01/2021 09:57:13

Just a thought, but is the petrol old, perhaps kept in a can next to the generator? Ethanol won't damage brass, but Ethanol absorbs water which does. If it's an older engine, also possible the ethanol is attacking a plastic, and the product of that is corrosive.

Petrol might be watery out of the pump if the supply chain is wonky. Most likely suspect is an elderly roadside tank - they collect muck have to be changed periodically. Petrol taken from the bottom of an nearly empty tank can be filthy. Is there an oil refinery in New Zealand? In my part of the UK petrol has few opportunities for being mucked up because it comes from a local refinery. If New Zealand petrol is imported, the chance of contamination en-route across the Pacific to Kiwi's generator is much higher.

The ethanol in clean petrol gradually absorbs moisture from the air even if the can is closed because water molecules are smaller than petrol molecules and diffuse through the seal.

At first water absorbed by ethanol in petrol goes harmlessly into solution. But as more is absorbed, water drops out of solution and sinks to the bottom of the tank. There's a distinct risk that the end of a fuel can left standing will almost pure water, definitely bad for engines!. Also that simply draining the engine will leave a lot of water behind. I suggest:

  • Use new petrol, and minimise storage time. (Perhaps monthly burn aging generator petrol in your car and refill the generator. )
  • Before pouring the end of a can into the engine make sure it's not watery.
  • Don't drain the carb, instead run the engine once every few weeks to warm it through and stop wet fuel settling.
  • If draining for long-term storage, rinse the engine thoroughly and try hard to exclude water by wrapping etc,

Dave

Thread: Advice for surface finishing
19/01/2021 22:09:46

Before worrying about where the insert came from what size and shape is it? Inserts come in bewildering variety because they are race tuned to suit industry whose goal is to remove metal as fast as possible whilst getting a good finish at the same time. Usually means a fast powerful rigid machine with the insert carefully chosen to match the material. Typically inserts are driven much faster and deeper than a hobby machine can manage, and the effect is spectacular - rather than producing swarf in spiral ribbons, smoking hot chips come off in a spray.

To get performance inserts are rather blunt and the finish improves with more speed, faster feedrates and.deeper cuts, which isn't always possible.

On a slow hobby lathe, it pays to use inserts of the sharper type, which is why Dave suggested using an insert desiged for Aluminium on mild-steel -being sharper they work well on steel at hobby speeds.

Ordinary mild-steel tears and smears rather than cuts cleanly - rather like the photo. Some steels are worse than others - always suspect the material when poor finish occurs on unknown scrap. I usually cure poor finish by cutting more aggressively, but this undermines another trick, which is to sneak up on a dimension by taking fine cuts. For that a sharp insert or HSS tool is better.

I prefer inserts but they take a little getting used to. HSS is more forgiving but you have to learn how to sharpen it.

Dave

Thread: Benchtop lathe with power cross feed, looking to buy
19/01/2021 16:39:41
Posted by Gazz on 19/01/2021 16:13:54:

Placed a wanted ad,

I've narrowed it down to the Warco WM280V or Chester DB10VS, or something similar to that,

...

So i guess the 10mm stuff i have will be ok, just not as rigid as it could be?

Yes, I often use 10mm tooling on a 280. My 12mm tools are best for larger work but get a bit clumsy for certain jobs. It happens 10mm suits much of what I do. Occasionally use 6mm on small diameters. If I was only allowed one size it would be 10mm.

Dave

Thread: Ethanol
19/01/2021 16:30:06

Same answer as pgk, except IDA is industrial meths, a mix of ethanol and 5% naptha. I think 99.5% IDA is industrial meths (95/5% mix) diluted with a dash of water, not 99.5% ethanol. It's controlled because Ethanol is a recreational drug only sold under licence with much tax added!

Isopropyl Alcohol is a different alcohol with unpleasant side effects.

IDA is cheap and is widely used as a fuel or unfussy solvent - where the naptha doesn't matter.

Propanol is mainly used when a pure alcohol is needed as a solvent for medical, cosmetics, ink and such. Meths works just as well except it stinks or spoils some things! Propanol is a good fuel but is rarely used because of the cost. (It can be added to petrol as an anti-knock agent.)

Dave

Thread: Model boiler safety calculations
19/01/2021 16:08:35

Posted by Andrew Tinsley on 19/01/2021 15:20:55:

...

It would appear that most things are decided by past practice and no real calculations are involved. In a past life I was responsible for some safety critical calculations on nuclear reactor pressure vessels and I was expecting a derated version of this type of calculation. My apologies for misunderstanding the context of safety calculations in model boilers.

...

That's my perception too. Model Boiler Inspectors seem to look for established best practice and don't have to do the sums, understand materials or the engineering. The system is a little rough round the edges! Tony mentions an inspector whose hydraulic test consists of pumping a boiler to twice working pressure. OK except applying excessive test pressure to a boiler weakens it. Does this chap know what he's doing or is his twice working rule guesswork? If guesswork, the test could unnecessarily take a few years off the boiler's working life. Hundreds of pounds of the owners money down the drain on an Inspector's whim. Perhaps 1.5x working pressure is good enough? Or maybe I'm completely wrong and test pressure should be 3x? I suspect no one knows!

Apart from the possibility of quirky inspections, I feel the boiler inspector system works well though. By only allowing time proven designs clubs get the necessary insurance, engines steam in public, and everyone is happy.

Almost everyone! The loser is the guy who wants to innovate and experiment. The chap with ideas, improvements, and cost efficiencies. Today's LBSC! To get approval the builder has to prove he knows what he's doing, which involves a professional design approach that's hard to explain to anyone other than a suitably qualified engineer. Andrew has my sympathy!

Dave

Thread: Marine Engine Flywheel Fixing
19/01/2021 15:23:09

Had a look at my American Marine Engineering Book circa 1945.

Volume 1 describes the US Maritime Commission Engine of 1940 in considerable detail. Quite interesting - it's the Triple Expansion Steam engine used to power Liberty Ships. Rationale almost engineering firm could make them, and reliable simplicity, not high-performance or fuel economy. Goes on to describe Woolf Engines, Lentz Engines, Steam Turbines and Maritime Diesels. None of these engines have flywheels.

However, Volume 2 has a section on vibration, and mentions flywheels as a way of controlling it. My idea of a flywheel is a hefty beast designed to store a lot of energy to deal with varying loads. Not how this book sees them. Small, if used at all, and intended to deal with resonances.

Looking at the engine plans in Volume 1, although they don't have separate flywheels, they do have heavily weighted cranks. Although the main purpose of the weights is balance, they would also have a flywheel effect, maybe sufficient to not need a separate flywheel at all. There are also features like the engine / propeller-shaft couplings that must act as small flywheels. The reduction gearbox on a steam turbine looks like a hefty flywheel - might take a turbine ship a few miles to stop!

Mill engines and pumps see varying loads and for them a big flywheel must be very helpful. Maritime engines don't have the same need for a flywheel because they deliver power into a steady load for weeks on end. I suppose a ship engine's worst nightmare is when the propeller dips in and out of the sea during a storm.

Dave

Thread: Cura 4.8
19/01/2021 14:32:47

Might be more productive to explain what the actual problems are?

As slicing a basic STL model is easy-peasy with Cura I guess something complicated such as shapes needing supports. Or maybe a difficult printer/filament combination requiring the advanced settings to be fiddled with? Cura might not be the problem. My dad's car had a seriously faulty clutch that mysteriously fixed itself after I'd had several driving lessons...

Most software gets tricky when the user gets into 'not for tourists' territory. Cura seems pretty typical to me - an easy front-end for simple jobs with the option to unleash a multitude of advanced settings on anything awkward. Unfortunately using advanced settings often requires advanced skills. (Or a large dose of luck. You can guess how I know, blush!)

Dave

Thread: The demise of UK fossil fuel Power Stations
19/01/2021 13:00:09
Posted by oldvelo on 19/01/2021 09:45:53:

Read this article on BBC News a few months ago and found it hard to understand the reason for it.

Fossil Fuels

Can someone explain How 7,000,000 tonnes of wood pellets get to Drax power station and not using fossil fuels. ...

Eric

They don't at the moment because most ships and land transport systems are diesel.

But remember, whatever the answer to our future energy needs is, it is not coal and oil! So far as the future is concerned they are off the table. Over the next 20 years the cost of oil will rise sharply and in 60 years time it will be far too expensive to burn. This is because people are using oil in ever increasing quantities and there are no new sources. When it's gone it's gone. Coal lasts longer, but same problem - god isn't making any more.

Pellets only have to reduce our dependence on fossil fuels, they don't have to be a complete answer. In theory bio-fuels can be Carbon neutral, i.e. obtaining energy from the sun without increasing the amount of Carbon Dioxide in the atmosphere. In practice, it doesn't seem that a full balance can be achieved, so the system is less attractive that it might be. As all energy systems are imperfect, their value comes down to benefits outstripping the disadvantages. Not confirmed that pellets make the grade.

However, shipping wood pellets from the USA is certainly less damaging than shipping coal because burning coal can only add to Carbon Dioxide - there is no way of offsetting the effect of burning fossil fuels.

Biofuels have their place but I don't see them as a major energy source in future. My guess is electricity from nuclear, wind and solar will dominate and burning will be reserved for special cases, or which there are many. For example, heavy farm machinery is unlikely to work well on battery power, and biofuel and internal combustion look good for that. Most road transport could be electric with very few problems: most travel is short distance, and many vehicles will have plenty of time to recharge while the owner works or sleeps.

Fossil fuels are wonderful in that they provide a one-stop-shop solution to many energy problems. Be jolly nice if supplies were unlimited and green-house gases weren't damaging our living space. Unfortunately, they have altered the climate and they are about to become rare and expensive. There's an urgent need to move away from fossil fuels. We benefited from simple cheap energy; our grand-children face a different world entirely. It's time to move on.

Dave

Thread: Vertex (V4?) Rotary Table
19/01/2021 11:25:42
Posted by Michael Gilligan on 19/01/2021 10:43:32:
Posted by SillyOldDuffer on 19/01/2021 10:05:46:

If a rotary table is used regularly it pays big time to fit a computer controlled stepper motor; they are much better at maths and remembering where they are than humans. You tell it the angle or division needed and off it goes, never losing concentration or making a mistake.

Dave

.

Very true, Dave ... But : at the level of precision originally specified by Martyn, [aside from the mechanical accuracy of the worm gearing] you would need to consider both the inherent accuracy of the stepper motor and the manner in which the computation is done.

The controller may claim to be incrementing exact seconds of arc; but what is physically happening at the workpiece ? ... a situation which might be familiar from your ongoing investigation of the sprod.

MichaelG.

.

Edit: __ by my reckoning, the original requirement requires a resolution of one part in 68592 [however you choose to achieve it]

Edited By Michael Gilligan on 19/01/2021 10:59:53

Yes, computers are always let down by limited mechanicals!

Though it might be able to compensate for certain types of error, a computer can't fix fundamental mechanical inaccuracies. It's no more accurate than a careful human. A computer driven rotary table has several other advantages though. The computer de-skills operation of the table by removing the burden of doing sexagesimal and modulo arithmetic, and it eliminates many human errors like maths and scale-reading mistakes. Plus it saves time by making everything quick and easy.

Dave

Thread: Planer Blades
19/01/2021 10:26:14

HSS is just a generic description of a family of tool-steels. Means very little other than it's not carbon steel - usually a good thing.

T1 identifies a particular member of the High Speed Steel family, so the description is more complete, which is a plus. However, T1 is the usual general purpose HSS used for wood and metalwork for planer blades, twist drills, taps, dies, reamers, and lathe cutters etc. Not the toughest or most heat-proof HSS available for specialist work, but a decent performer. There's a good chance anything just described as 'HSS' is T1, though the metal could be less reputable.

Dave

Thread: Vertex (V4?) Rotary Table
19/01/2021 10:05:46
Posted by Nicholas Farr on 19/01/2021 08:11:36:

Hi Martyn, showing my dials again at 1 degree 25 minutes and 20 seconds.

Vertex HV6  RT

You will notice on the 60-0-60 scale that there is almost 13 divisions past the figure 1 lined up with the 0, so that is 25 whole minutes. you will then see the only other line that is in line with the 60-0-60 scale is the 11th line from the figure 1 and seeing that it is only one line away from the 0 on the 60-0-60 scale, makes the 20 seconds. ...

I'm indebted to Nick because I've been reading the Vernier on the wrong side. Thank goodness I've never used it in anger!

Verniers are a clever idea but take practice and thought to get right. The usual decimal scales are straightforward enough but I have to think hard about any vernier working in fractions. My HV6 clone, as in Nick's photo above, has a vernier graduated in thirds of a minute, i.e. 20 seconds. Eh? And I have a vernier caliper that registers in ¹⁄₁₂₈" which is a right pain. Good job I'm metric and can use the millimetre scale.

Back to rotary tables, I guess most of us stay safe by moving the table positively, i.e. doing a hexagon by starting at zero, and winding the handle to 60, 120, 180, 240, 300 and then to 0°. It's also possible, and sometimes necessary, to work with negative angles, which require serious concentration subtracting an angle like 19°3'12" and working the scales backwards.

Another booby trap is that many common workshop angles are divisible by 4, so the handle always finishes on 0. But watch out for angles that aren't divisible by 4, because they don't finish nicely on the dial, as in Martyn's example where he might have to crank out:

19° 3' 12"
38° 6' 24"
67° 9' 36"

Keeping track of the number of handle turns and the scale readings are both irksome. When dealing with anything other than simple angles I sit down with a calculator and work out a cheat sheet telling me how many full turns to do and what the scales should read at each end-point. Not my idea of fun!

If a rotary table is used regularly it pays big time to fit a computer controlled stepper motor; they are much better at maths and remembering where they are than humans. You tell it the angle or division needed and off it goes, never losing concentration or making a mistake.

Dave

Thread: Files - what do I need to know
18/01/2021 17:52:51

While I agree cheap files are best avoided, I'm far from convinced advice to spend big money on files is well founded. Ask yourself:

  • How much filing will I actually do? (Not much if you own a milling machine.)
  • Do I really want to own expensive tools because they will last longer than me?
  • Is there nothing else that the money wouldn't be better spent on?

If you want to cough up £30 per file for a full complement of Vallorbe's very best, go for it. My advice is to buy something mid-range.

Far more important to me than owning an expensive file that lasts for ever is having a collection of files in the sizes and shapes I need. Have a look at what Arc Euro sell - aimed at hobbyists, and well described. I have round, half-round, triangular, square and flat in large, medium and small (needle files), more than 30 in total. Mostly second cut, but I have a few rasps for quick ripping and plastics, and a few fine files (smooth cut). I keep a small set for brass only: this is because using a file on steel quickly takes the very sharp edge off, and brass likes a sharp file. When a file used on brass starts to go blunt, replace it and move the old one over to steel where it will still work well.

Horses for courses because this is a hobby! Nothing wrong with pride of ownership purchasing if it makes you happy. I'm the opposite. I think tools are to be used not drooled over. and am quite happy to replace inexpensive tools when they don't do the job. I might go upmarket if I did a lot of filing. As is, files costing about £5 to £10 each depending on size do me well. Paying £6 for a set of four big files is risky!

Never use a file without a handle. Apart from the risk of spiking oneself, the handle makes the file much easier to control.

As a youngster I was given the 'buy quality, buy once' advice by a well-meaning craftsman. Fifty years later I was proved right : my collection of ordinary tools is still going strong. (Mostly!) They've lasted because they're lightly used. A busy professional should buy tools that last, but I'm not rushing to meet deadlines, and only work when I want to. Buying better than I need is a waste of money.

Dave

Thread: Design of boilers
18/01/2021 16:53:41

I agree it's an interesting subject, but I think it would need a serious programme of testing to get to the bottom of it.

Several compromises going on at once, for example:

  • Volume of water and the thermal load due to the metal work vs the amount of heat available from the fire. (The boiler mustn't be too big for the fire or vice versa!
  • Boiler pressure (effecting steam temperature and boiling point.) vs strength. High pressure steam is best for locomotion but the mechanical build is harder to do, more weight & stress etc.
  • Surface area of the tubes relative to the amount of heat. (Lots of small tubes good.)
  • Sufficient tube volume and flow so as not to throttle the fire (Lots of small tubes bad.)
  • Flow allowing time for hot gas to maximise heat transfer from tube to water as it heads for the funnel. Excessive flow rate wastes heat. (Big tubes bad)
  • Small tubes are more likely to choke with ash. (Big tubes good)
  • Low temperatures at the smoke box end means there must be an optimum tube and boiler length for a given boiler diameter and heat source. The purpose of the tubes is to boil water, not to make the smoke-box hot, or to have the smoke-box end remove heat from the boiler.
  • Tubes shouldn't stop water in the boiler from circulating freely. Heat can't be transferred efficiently to the water if they do. A few small tubes are best.

Several contradictions! My feeling is careful design and research might produce a better boiler, but there are so many competing factors that improving one would be counter-balanced by worsened problems with the others. And undermining all attempts to do better is the unavoidable heat loss that means a small boiler can never be thermally efficient.

I wish someone would investigate though. Almost 100 years since LBSC shook a complacent hobby in the Battle of the Boilers. Reading old ME mags I get the impression boilers improved slowly in terms of construction until about 1970, and since then designs are just copied. Apart from discussions like this no-one has given thermal or physical design a good seeing to since. I've a sneaking suspicion model boilers are a good as they can be, but it would be nice to know. Not impossible: Tornado outperforms the original A1 due to modern design tweaks.

Dave

Thread: Myford ML7 4 way tool holder
18/01/2021 15:36:16

How strange. And it's come up before. In this old thread there appear to be 3 Myford 1410 tool-holder owners, all with good reason to believe they have the genuine Myford item, but different dimensions.

DC31k suggests measuring the compound slide and saddle. Maybe Myford updated their kit a few times over the years and the holder comes in various sizes to suit?

Dave

Thread: Lathe Tool Height
18/01/2021 14:06:37
Posted by Ian Mellors on 18/01/2021 10:54:02:

All sorted, ... I'll make sure I keep aquiring more offcuts etc for finer adjustment though

Classic problem, me too!

You fill a workshop with metal munching tools and then discover a few simple shims are difficult! What's needed is a common bit of scrap you don't happen to have. It's all part of the fun...

Dave

Thread: The demise of UK fossil fuel Power Stations
18/01/2021 12:49:25
Posted by Ady1 on 17/01/2021 19:38:56:

The cost has been very high, power bills went through the roof to pay for it all

Always good to put numbers on energy costs because they are changing. This lot are from Lazard, October 2020. They show investment in alternative energy sources is already paying.

From most expensive to cheapest, in US$ per megawatt hour:

  1. Solar (residential) 150-227
  2. Gas Peaker 151-198
  3. Nuclear 129-198
  4. Coal 65-159
  5. Wind offshore 86
  6. Geothermal 59-101
  7. Gas Combined Cycle 44-73
  8. Wind onshore 26-54
  9. Solar (utility) 29-42

The table is fuel for thought. Gut objections to 'Green' will focus on the high cost of residential solar, whilst ignoring utility solar which, on average, is the cheapest form of energy available. Dismiss gut and consult brain! Look deeper before deciding.

Residential solar is expensive because it doesn't achieve economies of scale. Small installations expensively engineered onto individual rooftops, few of which are optimally aligned to collect energy. Although they compare badly with large optimised solar installations (the cheapest electricity available today), the cost isn't much higher than gas peaker.

Gas peaker electricity is generated by fast response gas turbines. Their purpose is to cover peak demands to which other generators can't respond fast enough. Though coal is more nimble than nuclear, neither are well-suited to rapidly varying loads. Cranking coal up and down is liable to take longer than the peak lasts, so the system fails twice. By not meeting demand and and then wasting money as it shuts down. It's better to leave slow responding generators alone and manage peaks with a system that can stop and start quickly; guess what - Gas Peaker is expensive. But worth having!

Further down the table we find Gas Combined Cycle is about half the price of coal. Gas CC burns for maximum efficiency. The fuel is cheaper and cleaner than coal, hence the 'dash for gas', and lower maintenance, but the system is another slow responder. It's good, but imperfect, and it makes a lot of Greenhouse gas.

Nuclear is expensive to set up and even more expensive to decommission, but the energy is cheap. Nuclear power stations are best run flat out continuously. Maintenance is low compared with coal because the system runs at a lower temperature, there is no flame playing on metal parts, and no acid gases full of grit blasting through the boiler. An important advantage is Nuclear is resilient against economic and political turbulence because it doesn't depend on imported fuels. Shame about the clean up costs!

Lazard give the cost of each source of electricity as a range. This is because cost depends much on local circumstances. For example, UK coal is almost all imported from the USA, Brazil and Australia. A coal power station built next to the mine avoids transport costs and generates cheap electricity compared with came coal shipped half way around the world to be burnt in exactly the same type of power station in the UK. When the UK was a major coal producer, it made sense to generate electricity with coal here. Now coal is imported, it doesn't.

When considering energy, never wave the flag for a particular method without considering today's requirements. A system that was excellent in 1980 may not do what's needed now or be useful in the future.

Fairly obvious from Lazard's numbers why the UK has gone heavily for Wind. Onshore Wind is at least ⅔ cheaper than coal, it's cleaner, it doesn't have to be imported from abroad, and future supply is assured. Land being expensive tends to discourage large solar arrays particularly as we not blessed with reliable sunshine. Land costs also encourage off-shore wind-farms here, the downside being higher maintenance - difficult to reach and showered in salt-spray!

Also fairly obvious that none of these energy systems provide a complete answer on their own. At the moment green energy may be cheaper, but it's not reliable. There's an urgent need to find ways of storing green electricity in bulk. Last year the UK lost 3.6TWh of wind generated power because no-one wanted it and it can't be stored yet.

Fossil fuels can't be the answer to mankind's long-term energy needs because they are a diminishing resource. Coal and oil may have been cheap in our life-time but our grandchildren will suffer ever increasing fossil fuel costs. God isn't making fossil fuels any more. What worked for us won't work for them...

Dave

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