|28 forum posts|
Its not model engineering but its steam and coal and engineering at its best.
During my career I was lucky to visit many of these sites and the photos brought back many memories
|not done it yet||17/01/2021 19:37:02|
|5628 forum posts|
Personally, I think that wind and turbines stuck on a huge lollipop stick are equally ‘engineering at its best’. These modern machines are expected to run 25 years without too much more than regular attention.
4235 forum posts
The cost has been very high, power bills went through the roof to pay for it all
|Roger Best||17/01/2021 20:19:48|
|216 forum posts|
These systems are over 50 years old, a sign of quality that we struggle with nowadays.
I recall that the dash for gas was a big investment too, that reduced acid rain so it has some purpose even if we still needed to invest in wind afterwards.
My favourite is tidal flow turbines, i.e submerged turbines with no barrage. There is flow somewhere around the UK all the time and the moon is pretty regular. No calm winter day worries.
|Robert Atkinson 2||17/01/2021 20:28:29|
904 forum posts
Title is slightly misleading. Article refers to coal and oil fired power stations. Gas is going to be used for a long time and is a fossil fuel. Unless there is some unforseen storage solution we are going to need new nuclear for base load.
|Oven Man||17/01/2021 21:41:39|
106 forum posts
All these redundant coal fired powered stations should be the ideal location for the small modular nuclear reactors that Rolls-Royce are developing. All the infrastructure is in place, just need to knock down the old boilers. Might even be possible to use the existing turbines and generators.
|not done it yet||18/01/2021 10:17:24|
|5628 forum posts|
Agreed, watching that development with interest. If they could use Thorium, it would be better...
Aussies are installing a huge battery storage system at a coal-fired power station - ready to operate at full power when the power station closes down its coal generation. Nearly a third of the size of Dinorwig in energy storage. Could be used for grid stability or deliver 750MW for 4 hours.
5200 forum posts
Interesting articles and beautiful pictures. Thanks for posting. I always thought the several power stations I worked in/on were works of art in some ways. From the curves of the cooling towers that give the strangest circular echoes if you shout out inside them when they are empty to the 500 foot stacks. And an 80 ton main steam turbine rotor dangling from the gantry crane with hundreds of chrome moly blades catching the sunlight from the windows is pure sculpture. As are those modern wind generator turbines gently churning away on the hills where I ride motorbikes too.
On the other hand, working on coal fired boilers, coal crushers and conveyors can be the dirtiest, grittiest, noisiest and hottest job you can imagine. Good riddance to that lot! And the there is the ash removal system....
|9 forum posts|
The coal fired power stations / boilers were inefficient (~ 22%) with the current design, mainly the boilers were old fashioned, there were attempts to improve them and make them cleaner but alas they couldn’t compete with the 62% efficiency of the CCGT systems which were dual fuel, gas or oil, the gas turbine is connected to the alternator on the same shaft as the steam turbine, the heat from the gas turbine is sent through the HRSG (Boiler) to recover the heat and use it to make steam for the steam turbine, tuned in by computers, everything electronically controlled for optimum tuning, not much waste, emissions are controllable, cost of the station is paid back in 2 to 3 years, happy days, the old coal boilers would take hours to warm the steam drum slowly before bringing to base current, the gas station is up in half an hour, everything is thinner wall thickness so it warms up quickly, another win win situation when your forced to supply at peak demand, thus skimming the best prices.
The Dogger Bank project will incorporate the GE Haliade 13 megawatt wind turbine, it is a design which runs the alternator straight from the shaft, blade to alternator without a gearbox, screamingly new technology, let’s hope it’s viable, but it won’t bring down the cost, no sir, not on your nelly.
6878 forum posts
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:
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...
|Mark Rand||18/01/2021 12:55:38|
|961 forum posts|
I've only done any work at 8 of the stations on that map, but I would humbly point out that Grain and Littlebrook D power stations on the linked map map were oil fired, not coal fired.
Edited By Mark Rand on 18/01/2021 12:55:54
|262 forum posts|
Read this article on BBC News a few months ago and found it hard to understand the reason for it.
Can someone explain How 7,000,000 tonnes of wood pellets get to Drax power station and not using fossil fuels. The trees cut down in America and to be pelletised no doubt they used products from the Oil Industry which suprise suprise is a Fossil Fuel. The transport accross America then the Atlantic. Put on rail to Sheffield all Fossil Free?? All paid for by the consumers. All done with No damage to the environment where the trees are harvested from complete with a regeneration program in place maybe???
5200 forum posts
Yes I have always struggled to get my head around how grinding up trees, transporting them across the world then burning them can be a green source of energy. Turns out in the link in the first post of this thread that it may not be all that green.
The linked page on the Drax biomass fuelled station here: DRAX LINK contains a section further down on "Decarbonisation" that says its opponents claim the power station puts out more carbon that the regrowth forest trees will absorb and that processing and transporting create more carbon again. It concludes:
"Drax claim their carbon emissions have been cut by 80%, but independent estimates indicate those emissions may have even increased as a result of the biomass conversion. "
But no reference to whose report/estimate so no idea how sound their methodology or agenda might be.
5200 forum posts
If we are looking at power station porn, how about this steam turbine rotor from GE. I'll leave you to calculate the tip speed of those blades when that baby is spinning at 3,000rpm. You can't tell me that's not art.
And then you have to be able to lift it in and out of the turbine casing, with a clearance around those blades about the same as what you might find in a small model engine, feeler gauge stuff. Then scrape those bearings (foreground, just like a giant Myford headstock bearing) and align that shaft to the generator shaft within one thou. That's another art in itself.
Edited By Hopper on 19/01/2021 10:47:25
6878 forum posts
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.
|262 forum posts|
you have just shot yourself in the foot
Can someone explain How 7,000,000 tonnes of wood pellets get to Drax power station and not using fossil fuels. ...
"" They don't at the moment because most ships and land transport systems are diesel""
Do you realy know about what you post.
|R Johns||19/01/2021 18:34:02|
|38 forum posts|
I remember as a child sat in school learning what things would be like in the year 2000. Aside from flying cars, electric would be so cheap to produce it would be free! Oh happy days.
|Mark Rand||19/01/2021 19:27:00|
|961 forum posts|
Eric, you are making the perfect the enemy of the good. The amount of fuel used to transport wood from the US, Canada, Europe and Brazil is tiny in comparoson with the energy content of that wood. That's how transport works.
Secondly, the wood that's used is the trash wood, trimmings, bark, etc. that are a significant by product of the primary wood use.. making trees into sheets, boards, furniture etc. is surprisingly wasteful.
|not done it yet||19/01/2021 19:38:37|
|5628 forum posts|
I suspect that Drax only makes a profit by getting subsidies from the government (from taxpayers, of course) for generating using a ‘non-fossil’ fuel. Fuel is lumped together with all biomass. Look at sites such as:
to see the amounts of CO2 emitted to the atmosphere. Less than coal (or gas) but still considerable.
The 3.6 TWh of wind turbine power generation, which was not actually generated (turbine generation was ‘constrained’ - as in ‘stopped, shut down or blades were feathered to reduce output) simply because the UK grid was deemed unable to cope with that amount of generation - due to two reasons:
1) the need to keep some sites generating as these would be needed to restart generation if there were to be a nation-wide blackout and
2) because the grid could not cope with the incoming power with the present structure (think here our circulatory system heart to arteries to capillaries - it does not work too well if the main source of blood flow was first through capillaries!). We need more/better high voltage grid lines across the country to distribute all of that energy when the turbines are operating at their full capacity. National Grid call it ‘grid reinforcement’.
until recently, gas fired generation was rarely run below 5GW as it was deemed ‘necessary’. Recently it has been reduced much lower than that.
Edited By not done it yet on 19/01/2021 19:42:15
5200 forum posts
Seems that science is split on the biomass issue, with some calling it fraud. Interesting article on it here LINK
One scientist, John Sterman, director of the Massachusetts Institute of Technology’s System Dynamics Group, is calling it "biomass accounting fraud", saying it is worse than coal and that it can take up to 100 years for the regrowth forest to reabsorb the amount of carbon released by burning the cut down trees. But biomass companies base their calculations on closer to 10 years. They also base their calculations on the wood chips coming from waste branches etc on existing logging sites. But then some naughty logging companies have been caught clear cutting old growth forest purely to make biomass pellets. Tsk tsk.
But some other scientists disagree with the fraud analysis and reckon it's all good, as long as the logging companies are carefully selective about what trees and parts of trees are used to make the pellets.
There in lies the rub. Truth is always the first victim in war -- and big dollar business.
Edited By Hopper on 20/01/2021 00:45:37
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