Efficiencies of large power plants

Hi Chum, I work in a large coal fired power plant vary near Didcot in Oxfordshire, It's around 32% efficient, but this can be less if it has to warm up for a short shift. Smaller generators can cut in and out much quicker, and may be the way forward.

Here is why I ask (and please take this wih as large a grain of sodium chloride as necessary) I'm working with a group that has a device--this device, it would seem (and I've seen it demonstrated so I do believe the general concept and process is true) is able to produce 5000 watts of electrical output, for one hour, based on the input from one pound of compressed propane [i.e, a one-pound bottle of Coleman^® fuel]--what I'm seeking is some comparison. As I understand it, based on the btu/h converted to kWh, this device achieves 79% efficiency, meaning it turns 79% of the input btu/h into kWh output.

Question--is it more efficient to use natural gas (or coal or even nuclear) to fire a boiler to create steam to turn a turbine generator to make electricity? or, given a figure of 79% efficiency on propane, is that significantly more efficient? Again, I'm speaking of a device that takes heat input and gives electriocal output.

I'm convinced of the workability of our generator--what I'm seeking to do now (in addition to just proving it will work as stated) is put together the remaining pieces so it will do this based on collected solar energy; since I speak of heat, what I'm storing is heat, not electricity like a lead/acid battery--observers of this blog will hopefully recognize some of my previous posts--I think we have a significant advance, one that is not based on some zero-point energy scheme, one that is not based on a mis-interpretation of physical laws--it does require application of semiconductor materials for which there is high competition. It does require the ability to store large amounts of heat (750C to 1500C--we know how to do this) If anyone seeing this feels they can poke holes in it, please do so--if you think there is something to what I say, help me!

Go For it, As a power engineer, it kills me to think we heat up huge power plants to sometimes provide capacity for the grid, that sometimes even isn't even used, so we throw away 100s of tons of fuel, to heat up the huge power station, only to let it cool down again! With fast acting technology, we can replace large power generation with wind power, and use fast acting technology such as yours, to back up the grid when the wind slows, or when an atomic or coal plant cuts out.

Dear Sir,

It is a fine idea to replace large power stations with wind energy generators.

But will it be feasible?

Say a major thermal power station having capacity of 500 Mega Watts.

Just count the generating capacity of a small wind power generator and then workout how much such generators you will need?

Secondly cooling down of major thermal power stations is a necessary evil and totally inevitable state; as unless the major power plant is not cooled down we will not be able to send the army of maintenance staff to undertake the preventive maintenance.

So for every issue two sides are existing and through all pros and cons we should arrive at the best solution considering all the logistics involved.

Regards,

Ulhas Pradhan

What a daft off topic reply, the power plant doesn't need maintaining twice a day! Yes we needs lots of generators, like we need lots of electricity towers to carry the wires all over the countryside, but to a modern industrial society, the manufacture of large scale renewable energy systems, of which wind is just one, will not be a problem.

As for the original question, the coal plant I work at is about 32% efficient, the combined cycle gas fired plant is around 55% efficient.

The concept of peak loading and the rotating capacity required to ride through it seem totally foriegn to a large portion of the population. If the public understood, media stunts such as "Earth Hour" would get laughed into the ground. The fools who came up with it either don't know or don't care how the system works. Being forced to vent steam for an hour with all sets rotating knowing that as soon as the stunt finishes there is going to be an inrush load must be rather frustrating.

As you are obviously aware fast startups not only blow efficiency to hell, but drastically increase maintenance, unless someone has suddenly made bullet proof turbines and non expanding metals.

One: Wind Turbines such as these http://www.energycurrent.com/index.php?id=3&storyid=10905

"BroadStar's AeroCam delivers a 250kW machine for US$250,000 and is claimed to be the first turbine to break through the $1/watt cost barrier". GE Power offers http://www.gepower.com/prod_serv/products/wind_turbines/en/36mw/index.htm 3.6 mW turbines--assume one mW per turbine and it isn't too farfetched to say they could replace a 500mW coal or gas-fired plant. Yes, there are space considerations--more importantly, the obvious drawback that the wind doesn't blow consistently--hence our desire to deploy our generators for that purpose--we have a design (but no prototype as yet) for a 250kW version--four would do a megawatt, and that leads to the second point:

Two: Put the power as close as possible to where it's needed--here in Texas the PUC has signed a proposal of $4.6 Billion for roughly 2300 miles of new transmission lines, mainly to support growing windfarm generation in West Texas and the panhandle, to support cities in central [Dallas/Ft. Worth, Austin] and south Texas [San Antonio]; Austin Energy http://www.austinenergy.com/ has just signed a 20 year, $2.3 Billion proposal for a 100mW biomass power plant--in both these cases, the power is generated well away from where it will be most needed (by the way, I find it interesting that the biomass plant is considered carbon neutral because the forest-waste products used only give up previously sequestered carbon--this whole business of carbon offsets and carbon trading seems ripe for global business shenanigans)

What we want to do is place our units in one to five MW "bundles" or, have stores like WalMart and H.E.B. put up parking lot shelters that A) provide shaded parking and B) can support generators, heatstores and collectors--this could provide power to run the store with excess generation for local neighborhoods--up to 20mW. These could tap into existing transmission lines--in some cases right into the powerpole transformers--and/or at existing substations.

We approached Boone Pickens Capital https://www.bpcap.net/welcome.asp but they declined as they want solutions that are already running, not in development.

We Can Solve It http://www.wecansolveit.org/ is part of The Alliance for Climate Protection http://www.climateprotect.org/about Al Gore's front--not to be confused with Picken's Plan http://www.pickensplan.com/?c=Google&a=Pickens-Keywords&k=wecansolveit Boone Pickens' wind farm scheme

Yes, to get back on point, it is feasible for small, distributed generation--homes, businesses, transportation could all be run on electricity derived from renewable sources--oil is much more valuable for plastics and such, burning it is insane.

What's the efficiency of that turbine in average wind speed? Most turbines are about 33% efficient, meaning they will put out on average throughtout the year 33% of the rated capacity. so a 1.5mW turbine puts out 500kW for every hour of the year. The cost your turbine is $1000 per kW but it's $3000 per actual yearly average out put, where as the other companies turbines are about $3500 per kW, but that's for large turbines like 1.5mW, the economy of scale will make your actually cost per kw what?

I use average wind speeds of 6.5-7 m/s.

I wonder if you added installation, and grid connection to your price?

Oh and that Austin biomass plant seems to cost $23,000 per kW! maybe my math is bad right now, but really? That's if it runs at full capacity all the time?

Plan is that Austin Energy will pay $2.3 billion over twenty years = $115,000,000/year--the proposed output is 100mW, to come online sometime 2012

http://www.austinchronicle.com/gyrobase/Issue/story?oid=oid:663310

"This 100 megawatt biomass contract is very expensive, about $6,000 per customer," he said, which "would pay for enough rebates for 500 megawatts of local solar installations."

Of course, its not quite fair to say $23000/kW--assume 100mW, 24/7/365--thats 873,600 mWh per year--over a year thats $131.64 per megawatt hour or 0.1316/kWh--very competitive if you're charging your end-users 0.22/kWh or more

Oh, and they don't own the plant

I'm dancin' just thinking about it!

by that logic if I payed for a 3 million wind turbine over 20 years it would cost $150,000 per year, and put out 500kW. 500kWx24x365=4380mW. Now $150,000/4380=$34.25 per mW! or $0.034 per kW. See this method is fucking stupid. Finding cost per kW, which is continuous throughout the life of the project, using the capital cost is just dumb. I don't know why it's the most popular method.

Yes, I understand what you're saying--in terms of output capacity, it would cost $23,000 per kilowatt of capacity--and the comment that it works out to about $6,000 per customer (roughly 383,334 customers) is another valid way of figuring--I think it is the most popular method because it helps demonstrate what the power generated has to sell at, over the life of the contract (or bonds or whatever) to pay off in that time--most people relate to what they pay for their service--that's why you see propaganda from Austin Energy that it will "only" add about $2.50/month to the "average" bill.

When I was working solar photovoltaic, the rule of thumb was 0.25/kWh--if a customer was paying less that that (most of them) it just wasn't cost-effective (so one needed an additional reason(s) for going solar)--once "time of use" metering gets fully implemented and people start having to pay peak prices for peak usage, incentive for something different will be much greater...

Of course,

once Big Dick Cheney and his alter ego are out of office, maybe that will help too....

Hello Clamrod,

Your remarks about storing heat are spot on, I have being doing work on that and found salt with added nagnesium is great for storing and giving back the heat.

When salt gets hot enough it melts into liquid and holds the heat (2000 C) for many a day depending upon the heat draw.

A mob called Cotrol-tech.com have taken over CSIRO work on the same thing, you can find them on internet search, they are located at Archerfeild Brisbane Australia.

Sorry I am not up to speed on computers or I would post their Web site adress.

Cheers

Peter

I've seen the work the lads at CTI have been doing with salt and graphite and of course the spherical mirrors to heat the stuff. They have several ideas on the boil to re-extract the energy, they certainly have kept an open mind. Hopefully Clamrod's method works well in this area.

Does the use of magnesuim you mention help with the expansion rate? Did you see the other CSIRO project using Silicon ingots?

Hello Emjay4119

No I've only seen the tank with five tonne of salt, after CSIRO had finished with it in porducing a mine rescue machine.

I understand the magnesium was not so much for exansion assistance but heat retreival back from the boiling salt. I may been wrong in magnsesium and should in fact be saying graphite.

Control-tech did have a information folder they gave me on it but unfortunately I cannot relocate it.

Everything went hush hush at Control-tech after they took on Das Energy gas/hydro turbine and replaced parts with a computer program and mechanical valving so not to cross to Patent. I do not know if they have moved forward from like us from our original steam model into Co2.

Since election of new prime minister CSIRO have been instructed no more dealing with the public, but love to know more about silicon.

Cheers

Peter

Peter,

There have been staff and ownership changes at CTI and they are so busy with electronic design and manufacture work the side issues seem to have stalled. CSIRO seems to be out of money too. I think you will find the mines rescue gear was a seperate effort. The amount of intellectual property CTI have developed is incredible, Wolfie is a whizz kid.

The turbine trails showed more movement than promise I feel.

Theoretically at least if almost pure silicon is used as a heat store, successive melting and solidifying of the ingot leads to seperation of the impurities to the top and bottom where they can then be sawed off. If it works it would assist the cost structure no end.

Thank you Emjay 4119.

I have been out of contact with CTI since change of ownership, the engineer Jim is the person who I was mainly dealing with, but he left the company. Your information on silicon was most helpful.

I am an invalid pensioner so money for investment in development is pitifull but over six years I have managed on my own to get to that I posted previous.

Whilste some reward for my work would be nice its not the driving factor, but more so a better Earth for my children that will come with less Carbon in the atmosphere.

Happy for others to copy but not seek Patent without enough changes to no longer resemble my work.

I guess the true irony of it all is that it was the Ammonia absorption fridge that first got me going. The original design works by putting the Das valve, a simple pipe and ball aperatus into the vapor line between the boiler and condensor.

This works quite well but the Ammonia does not have the pressure to heat of Co2.

Would dearly love to have speaks with someone who can speak the language of business people and engineers.

Even without the use of Co2, natural gas combustion causing flash heat steam outdoes any piston engine of the same fuel.

Having only one moving part doing nothing but revolving puts the efficiency way beyound piston engines, but a lot of peoples lifestyle is dependant on the piston engine, and a better engine having no piston is a big no no to them.

Cheers

Peter

NETL

The Department of Energy's central focal point for all DOE Unsolicited Proposals is the National Energy Technology Laboratory (NETL).

The "Guide for the Submission of Unsolicited Proposals" (PDF-120KB) provides more information on the unsolicited proposal process.

Regards JD.

Hello jdretired.

My Sons and I consitute DaS Energy and are a registered company in Queensland Australia. Our claim to fame is the production of new form of powering a hydro turbine.

Our first model uses a hydro turbine and a floating ball to acheive motion, this is because we cant afford an engineer to lathe out the cylinder in our second model adressed in this discussion forum.

The principal in both models is that Co2 can be both liquid and vapour, and does not require the heat of a Steam turbine.

Australia and especialy Queensland relies upon the burning of Coal to keep the ship afloat, so anything that decreases Coal burning is much wanted as diarea in a spacesuit.

Would love to speaks with person or body wishing to obtain cheaper cost and less carbon emission power generation, and or a car engine with only one moving part.

Do you know how an Aussie can approach NETL and if an Amercian Citizen is required would you or another have mind to become involved.

Cheers

Peter

Thanks for those suggestions--I'm aware of them, but the problem for me is that the "developer" (he hates to be called an inventor) of this device brought it about from technology he developed for DoD in the 1990's, mainly a kinetic "gun" using magnetic propulsion--his "proof of product" would launch a 100lb projectile to 2.5 km/sec, and with a few dozen more yards of room it would do 6 km/sec--he was turned down in the end because he didn't hire a lobbyist (and because his result was not expensive enough)--his experience with magnetic forces lead to this device--He doesn't want to go to the government on this, and I don't think we have to.

But I would like something to compare against--while we want to go solar with this, I'm wondering if these units, run on natural gas, would be more efficient than a "conventional" gas fired plant.

79% is substantially more efficient than a natural gas plant. At very best, natural gas power plants are 60% efficient, provided they are doing cogeneration, in which what would otherwise be waste heat is used.

Diesels are about 35% efficient, from fuel to electricity.

If you have a device in the 5000 watt range, I'll take one. If you really have such a device, it's worth $billions.

DaS Energy gas/hydro turbine works upon liquid Co2 being contained at 31.1 Celsius and then 0 0 0 heated further to turn the liquid Co2 into vapour which in turn forces the x x x liquid Co2 beneath it through a hydro turbine into a sealed cooling tank which cools the Co2 back down to 31.1 Celsius and back into liquid.

When the revolving valve opens the Co2 vapour escapes upward forcing the liquid Co2 back down through the hydro turbine and refills the Co2 liquid container.

The megawatt output of the DaS Energy gas/hydro turbine accounts only for a one way flow, and its two way action increases its megawatt output.

Steam turbines require water to be heated beyond +100 Celsius.

At temperature of +550 Celsius Steam has a pressure of 175 atmosphere.

A Hitachi Steam turbine at 175 atmosphere produces 350 megawatts for every 285 litres of water per second fed into its Steam boiler.

Co2 at temperature of +32.1 Celsius has a pressure of 248 atmosphere.

DaS Energy gas/hydro turbine at 248 atmosphere receiving 285 litres of liquid per second produces 5.6544 megawatts.

DaS Energy gas/hydro turbine operating at +550 Celsius produces 3,109.92 megawatts

In comparison to Hitachi turbine which produces 350 megawatts.

Queensland biggest power producer Tarong employs 350 megawatt Hitachi turbine and its boiler consumes 450 tonne of Coal per hour, and its Steam cooler evaporates to atmosphere 200 litres of water per second.

DaS Energy gas/hydro turbine 350 megawatt consumes 62 tonne of Coal per hour, and evaporates zero water to atmosphere.

Year 2012 charge per megalitre water shall be $1,986.00, and Tarong 350 megawatts requires 6,307.2 megalitres water annualy, costing $12,526,099.00

Year 2012 water charge for DaS Energy gas/hydro turbine is $0.00

Each 1 tonne of burnt Coal produces 1.2 tonne Carbon emission.

Tarong power station 350 megawatt Steam turbine emits 4,730,400 tonnes Carbon annualy.

DaS Energy gas/hydro 350 megawatt turbine emits 543,120 tonnes Carbon annualy.

The year 2010 forecast Carbon emission tax is $20.00 per tonne.

Carbon tax annualy for Tarong Hitachi 350 megawatt Steam turbine is $94,608,000.00

Carbon tax for DaS Energy 350 megawatt gas/hydro turbine is $10,862,400.00

DaS Energy gas/hydro turbine does not require replacement of existing Steam turbine, but access to the waste heat from Steam turbine boiler to obtain full operation.

I see there is a lot of info on the internet regarding the Brayton system using supercritical CO2, particularly in regard to the next generation of nuclear power stations. Is this the same system you are referring to? on a smaller scale of cause.

Regards JD.

Hello jdretired,

I have read all I can find on the Brayton system, and the DaS Turbine does not include the Brayton system but instead reflects on how a standard electric fridge works. Our first model in fact used a absorption type fridge to prrove the idea worked. After the refriderant is heated out of the water it is at a pressure before being squeezed through a little hole to bring the refriderant back to liquid form,

Our trick was to impose a francis hydro turbine after the heater and before the sqeezy hole. The friderant gas pressure forces water through the turbine, before venting out to to squeezed through the hole by the next lot of water exiting the turbine.

Two Das valves are required in our first model to acheive constant revolution of the hydro turbine.

Cheers

Peter

Its all a bit of a learning curve for me. Thought the solar side of things sounds interesting. I have been to Tarong, could have been an operator there but decided to remain at swanbank. I'll have to do a bit more reading.

Regards John D.

Hello John D,

Good God your an Australian.

Boy could we use someone with your qualifications, as all funding aplications keep coming back asking for an Engineer to submit comment.

The figures I rely upon in my comments are quote Tarong Fact Sheet, Coal per hour, Hitachi steam turbine, steam pressure, water intake boiler and water evapouration to atmosphere.

Water evaporation to atmosphere is further quoted same by Sinclair, Night and Mertz.

The cost of water per gigalitre 2012 is quote Queensland Water Commision new charges now set in place.

I rely upon Wikipedia for my Co2 pressure at temperature.

Electric generation is from American University citing a 80% efficient hydro turbine, whilste DaS Energy uses a 92% efficient Francis hydro turbine.

Thought Tarong would jump at opurtunity for discussion as we gave Government free use of our design, but Governments continuing silence may reflect Government recent purchase of Rio Tinto coal mine to supply Tarong.

My idea was Coal could charge more per tonne, and Tarong use less and receive gains from lower Carbon emissions.

Control-Tech International Archerfeild first took up the DaS Energy design to replace CSIRO Stirling engine powered by Control-Tech new solar ring design, replacing parabola and solar trough for much less cost and greater efficiency.

Phone if you like 07-55338757.

Cheers

Peter

Hello again JD,

Sorry about my lack of comminication skills, I am on a pension after something began grazing in my mind, so I'm not so hot at putting things down in writing in a way people can readily understand, but with a little help I get there.

Hope this helps a little further, Critical Co2 liquid is held in a cylinder which has one end closed off by a revolving valve. Heat is then added to the Co2 at the top end of the cylinder, and as the Co2 turns to vapour its pressure forces the liquid Co2 (or water) out the bottom of the cylinder and through a hydro turbine, which empties into a sealed cooling tank.

The valve at the top of the cylinder rotates to open before the vapour can reach the hydro turbine. The Co2 vapour release from underneath the liquid Co2 in the sealed cooling tank forces the liquid Co2 Back down through the hydro turbine, and the revolving valve closes as it becomes full.

The Co2 vapour having left the cylinder is cooled back down to liquid in the sealed cooling tank.

As the revolving valve, hydro turbine and blower can be shaped from one cylinder with spacing for bearing housing it has only one moving part.

An added feature of DaS Energy turbine is that the gas/air mix is burnt inside the cylinder holding the Co2 thereby providing even greater forces upon the liquid Co2.

This process is more like a pulse jet but uses a hydro turbine in place of a gas turbine.

The low heat requirement of DaS Energy turbine makes far more suitable for Solar than a Steam turbine.

Example Steam has 175 atmosphere pressure at +550 Celsius, whilste Co2 has 10,000 atmosphere pressure at +75 Celsius.

The hydro turbine converts 1 litre fliquid flow per second at 9 atmosphere into 720 watts.

This doubles with the doubling of pressure or liquid flow per second.

Example 1 litre liquid flow at 9.926 atmosphere pressure (allowing for constant 74 atmosphere pressure) delivers 794,080 watts.

DaS Energy converts 1 litre vapour pressure into 1 litre liquid at the same pressure as the vapour forcing down upon it.

Cheers

Peter

I do not believe this is possible.

You have mentioned correctly about internal combustion engines havig efficiencies of about 22% when converted to electrical power. In case of turbines, the efficiencies are somewhere around 33 to 35 percent, though I am not the expert. Please do not believe anybody claiming even 40% efficiency. This has not been possible even with worldwide efforts. Perhaps most of the R&D in the whole world would be on this subject.Study of Basic laws of thermodynamics will show you what is possible

Hello rsalaskar,

Nothing can be done untill it is, and we did it!

It took six years and a lot of thinking different, such as using a gas that needs far less heat to acheive greater pressures than can currently be supplied by Coal fired boilers producing steam.

The first trick in acheiving what we have was to ignore those who said it cant be done.

So many are expert and involved in the dinosaur technology of boiling water to steam that they dont want change and will argue till they are blue in the face its not possible to do anything else thats better at generating power, a bit like the bloke when he first saw an Elepthant spent years saying there's no such animal.

Cheers

Peter

In your system, cooling the Co2 and compressing back to original pressure would take at least three times the energy produced as per basic thermodynamics laws. In any heat pump cycle such as airconditioners, there is net energy input to compress the expanded gas in evaproator.

Hello rsalasker,

No compression is involved only cooling!.

Cheers

Peter

Please do not believe anybody claiming even 40% efficiency.

Actually, 46% is the most efficient simple cycle turbine. Combined cycle turbines (at around 60%) are reasonably, I think, considered 60% efficienct, because the output is electricity: the two turbines are acting as one. The 90% efficiency claimed for cogeneration is yet another way of looking at overall efficiency, and if there is a need for the hot water or steam, then the fuel-to-total-useful-work output can indeed be around 90%. (Granted, the portion that comes out as electricty is much lower.) (There are available home cogeneration units that are 85%-90% efficient, with the assumption that the hot water is used very soon, and not be allowed to cool off.)

That was some news for me.An efficiency of about 60% using gas turbine and steam turbine. I went through the link. Any idea how many of the power plants use the combined cycle? Or is it something new?

Thanks

Off hand, I don't know what percentage of power generated is by combined cycle turbines. In the US, I'd guess it might about 10% of the total. (About half our power is generated with coal, about 20% by natural gas, about 20% nuclear, about 5% hydro, 2% oil, and almost insignificant amounts of solar, wind, etc. -- a sad state of affairs, really: the two things we have an unlimited supply of, and which are very clean, are used least.)

Soory--I did not mean to set off a bomb or anything--DaS is interesting, to be sure--I'm not a zero-point energy guy, or a cold-fusion guy--I wouldn't believe that this device would work as advertised if I didn't see it for myself.

Right now we're working like dwarves in Snow White's diamond mines, perfecting formulas and assembly for actual manufacturing--much rediscovery and reformulation has had to be done, and as yet we have just the one working prototype.

Problem with raising funds is that most of those with the money to throw at it either want something already at the manufacturing stage, or they also recognize that it is worth billions, so they try to wrest patents away, or want obscenely unfair deals (one offered the developer two percent of net sales!) --it would be a great find if someone said "Here's two million--pay it back in one year, plus twenty percent." The best offer so far was four million, but the people offering it wanted to frontload all sorts of "salaries" for themselves and friends that there was maybe 10% of that figure left for actual development--I'm truly amazed at how much my cohort has achieved basically on his Social Security check.

Quite.

The teaching is worldwide.