Author Topic: The beginning of the end for coal  (Read 16568 times)

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Offline Marco

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Re: The beginning of the end for coal
« Reply #25 on: August 21, 2016, 04:43:16 pm »
The part that is really missing is storage at an competitive price.  It's only the first about 25 % renewable that are easy, as this can work without much extra storage.

I suspect that if the cost of PV electricity drops low enough this will solve itself. I can't imagine high temperature thermal storage in concrete being very expensive, with recovery simply by pumping water in for steam turbines, it's just that the round trip efficiency is going to be poor.

To keep round trip efficiency high they end up with batteries, flywheels and closed loop systems. These are hard to make cheap.

And you too can clean and polish the solar panels when it produced a sand storm on desert, because if the wind blow little strong ,the sand can scratch the panels you imagine a storm.

Non concentrated PV doesn't care much about scratches. The mechanical cleaning is going to scratch too, meh. When it becomes too bad buff them out.
« Last Edit: August 21, 2016, 04:48:55 pm by Marco »
 

Offline SeanB

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Re: The beginning of the end for coal
« Reply #26 on: August 21, 2016, 04:56:25 pm »
Who says coal is mostly carbon. Anthracite for sure, a good coking coal and almost pure carbon. Most power stations however will use a much lower grade coal, which is going to have a lot more contaminants in it, like galena ( lead sulphide) , other sulphides and all sorts of dense metals and metal compounds. These do not burn well, leading to either ash or to needing to scrub the exhaust gas with a precipitator and a wet scrubber to get the output cleaner.

Gas as well has contaminants, though most are removed at source rather than at the power station, so the gas field owner has to dispose of it instead, just allowing a lower level through to go in the gas.

But the biggest thing is either to change to a power source that is more intermittent, or to develop either local storage or grid level storage. Neither is cheap though.
 

Offline firewalker

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Re: The beginning of the end for coal
« Reply #27 on: August 21, 2016, 05:16:02 pm »
Become a realist, stay a dreamer.

 

Offline vodka

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Re: The beginning of the end for coal
« Reply #28 on: August 21, 2016, 06:25:43 pm »


So ,i see more problems:

When the wind blows a few  strong , the generator must stop  :-DD

They don't tell us how many  CO2 produces the manufactured of the generator structured(gondole, post, and helix).

They too  don't tell us how many  CO2 produces the displacement of the generator parts to localization where it will be installed(special trailers, special cranes and helicopter).

They too don't tell that the localization where it will installed must clear the terrain and adapt to vehicle(Cut the forest for making the roads,relevel the terrain etc)

And it  never  would  produce as the thermal ,nuclear or hydroelectricall  plant, but clair that is ecological  :-DD :-DD


 

Offline Nauris

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Re: The beginning of the end for coal
« Reply #29 on: August 23, 2016, 06:27:00 pm »
Just go and plant a tree. Burn it when you need power. That is the simple, cheap and most practical way to store solar energy in any significant quantities.

Of course not possible everywhere as that needs lots of suitable free space.
 

Offline Marco

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Re: The beginning of the end for coal
« Reply #30 on: August 23, 2016, 06:52:15 pm »
Just go and plant a tree.

They don't grow very well in deserts.
 

Offline Kjelt

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Re: The beginning of the end for coal
« Reply #31 on: August 23, 2016, 09:32:35 pm »
Yes they need a lot more than just solar energy to grow.
Since the law of conservation of mass is still valid, I wonder how much % of the mass of a tree came from the photons of sunlight ?
 

Offline bicc1306

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Re: The beginning of the end for coal
« Reply #32 on: August 24, 2016, 07:11:08 am »
Great!
Good for UK. I haven't seen something like this before.
 

Offline Simon

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Re: The beginning of the end for coal
« Reply #33 on: August 24, 2016, 04:45:56 pm »


Err no not really, the heavy inertia will stop gap the time between high demand and more power being put in by the energy source. The guy does not know what he is talking about.
 

Offline DenzilPenberthyTopic starter

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Re: The beginning of the end for coal
« Reply #34 on: August 25, 2016, 10:18:20 am »
Err no not really, the heavy inertia will stop gap the time between high demand and more power being put in by the energy source. The guy does not know what he is talking about.

Nope, he knows exactly what he's talking about. As do National Grid who are taking steps to deal with this exact problem. See my thread about this here:

https://www.eevblog.com/forum/renewable-energy/it's-happening-the-power-grid-is-changing/

And some copy-paste from the National Grid's website:
http://www2.nationalgrid.com/Enhanced-Frequency-Response.aspx

Background
The changing generation mix in GB is reducing the contribution that synchronous generation makes
to the energy market, which in turn is reducing the level of system inertia, particularly on low demand
days. Lower system inertia affects the ability of the System Operator (SO) to manage the system
frequency within normal operating limits. This in turn will drive the procurement of larger volumes of
the existing frequency response products. NGET is therefore investigating alternative solutions, one
of which is the creation of an enhanced frequency response service. The aim of this service will be to
improve management of system frequency pre-fault, i.e. to maintain the system frequency closer to
50Hz under normal operation, however performance in post-fault conditions is also of interest.
NGET believes that the most appropriate way to develop this new service is to run a tender for four
year contracts for enhanced frequency response capability. This will give NGET experience in
integrating enhanced frequency response into the suite of system management options, as well as
providing a competitive route to market for new technologies. Whilst a number of the energy storage
solutions currently available have the ability to provide frequency response in these enhanced
timescales, NGET welcomes the participation of any technology types which can meet the required
parameters.
 

Offline arlipscomb

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Re: The beginning of the end for coal
« Reply #35 on: September 08, 2016, 05:38:27 pm »
Planting trees for fuel is not a horrible idea. Most of the time when wood is burned it is done in a very inefficient way. Just using the byproducts from manufacturing can generate a lot of energy from what was once wasted material.

For solar, you can sometimes look to adjust the timing of tasks that can be done during peak sunlight. For example pumping water can be done during the day with reserves stored above ground. When needed in later hours you can use gravity feeds. If you don't "waste" the water you can repeat a cycle many times to reduce energy use.
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Offline LabSpokane

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Re: The beginning of the end for coal
« Reply #36 on: September 08, 2016, 05:49:33 pm »
Planting trees for fuel is not a horrible idea. Most of the time when wood is burned it is done in a very inefficient way. Just using the byproducts from manufacturing can generate a lot of energy from what was once wasted material.

It's been an interesting week chatting with colleagues over beers in the UK. We all do this for a living, and virtually everyone I work with agrees that biomass power is a niche solution and replacing coal fired power plants with biomass is simply impossible.

However, it makes great sense to use waste wood and garbage to generate power.one just needs a LOT of it to fuel a power plant. The notion of harvesting trees solely for power generation is simply a bad, bad idea. The only exception to this may be eucalyptus in certain locales which is fast growing and has excellent heat value. Even that is a niche solution and not scalable to replace coal or nuclear.
 

Offline arlipscomb

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Re: The beginning of the end for coal
« Reply #37 on: September 08, 2016, 06:56:23 pm »
However, it makes great sense to use waste wood and garbage to generate power.one just needs a LOT of it to fuel a power plant. The notion of harvesting trees solely for power generation is simply a bad, bad idea. The only exception to this may be eucalyptus in certain locales which is fast growing and has excellent heat value. Even that is a niche solution and not scalable to replace coal or nuclear.

I have seen a number of products for producing home heat from wood, from logs to sawdust pellets. For example I saw a wood burning boiler that provided heat for the home, hot water for the plumbing and heated an outdoor pool; all using a very modest sized log over several days time. I agree that using wood for a power plant would not be economical in the vast majority of cases. Heating with mains power is fairly inefficient most of the time when all things are considered. I recall antique stoves that would provide heat for cooking, heat the house and provide hot water. In regions where wood was scarce you found ways to be efficient. I think part of the answer is to have as many workable alternatives as possible and use what makes sense.
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Offline Jeff_Birt

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Re: The beginning of the end for coal
« Reply #38 on: September 08, 2016, 07:18:46 pm »
I have seen a number of products for producing home heat from wood, from logs to sawdust pellets. For example I saw a wood burning boiler that provided heat for the home, hot water for the plumbing and heated an outdoor pool; all using a very modest sized log over several days time. I agree that using wood for a power plant would not be economical in the vast majority of cases. Heating with mains power is fairly inefficient most of the time when all things are considered. I recall antique stoves that would provide heat for cooking, heat the house and provide hot water. In regions where wood was scarce you found ways to be efficient. I think part of the answer is to have as many workable alternatives as possible and use what makes sense.

The process of converting electricity to heat (resistively) is very efficient, i.e. a very large percentage (most) of the energy is converted to heat. Converting coal to heat then converting the heat to electricity, then transmitting the electricity for long distances, then converting the electricity back to heat is inefficient and costly as you have gone though a number of conversions form one form of energy to another and their associated losses to create heat in your home.

Before moving into town about 14 years ago we lived out in the sticks and all we had for heat was a wood burning stove. It takes a LOT of wood to heat a house even modestly in the winter even in the more mild winters in Missouri, USA. I spent a LOT of time cutting wood and chopping wood and carry wood. It is also very messy, you can cause bug infestations in your house if you are not careful and it is DANGEROUS! The outdoor furnaces that heat water are nice, they still require cutting, chopping and carrying a lot of wood, but they do regulate the fire to get the most use out of the energy (it is a bit tricky as you can't let the fire just smolder all the time, you have to burn it hot enough, often enough to burn off the soot and creosote.

All forms of wood burning require a LOT of effort, and maintenance and skills that most people could not or would not do. 
 

Offline arlipscomb

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Re: The beginning of the end for coal
« Reply #39 on: September 08, 2016, 07:31:12 pm »
Your description of the process of going from coal to home heat was what I had in mind when I said "all things considered"  :)

I understand the work involved to process wood. Living in Florida means I don't have to deal with it, but I understand it from time spent up North. There is a reason you used wood, despite the work. It was available, economical and for the most part simple to process. If we could produce an economical wood product (such as saw dust pellets) to eliminate the manual labor, as well as many of the negatives sited, it could remain useful to people where using electricity may be less desirable and something cleaner, like natural gas, is not available. 
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Offline CatalinaWOW

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Re: The beginning of the end for coal
« Reply #40 on: September 08, 2016, 08:16:08 pm »
Planting trees for fuel is not a horrible idea. Most of the time when wood is burned it is done in a very inefficient way. Just using the byproducts from manufacturing can generate a lot of energy from what was once wasted material.

For solar, you can sometimes look to adjust the timing of tasks that can be done during peak sunlight. For example pumping water can be done during the day with reserves stored above ground. When needed in later hours you can use gravity feeds. If you don't "waste" the water you can repeat a cycle many times to reduce energy use.

These ideas are simple, and they work.  They aren't widely used.  Why?  Is it a conspiracy?  No, it is because they have problems of their own and for individuals and municipalities under existing cost structures they don't make sense.

Storing water that is pumped at free energy times requires resources.  Gravity feed is time honored.  But most people like their water at 30+ psi (apologies to the metric folks, you can do the conversion easily using info from the following sentence).  This translates to a water tower 70 or more feet tall (call it 20 meters).  If you don't have a convenient hill on your property, or in your town if you are doing this on municipal scale you are talking about a serious permiting and construction problem.  Remember that the storage tank needs to store at least a days water usage, so it is pretty good size.  On the order of 100 gallons (400 liters) for a family size installation. 

Pressurized bladder storage is another option.  These are also somewhat pricey in the required size range and have limited lifetimes.  They also require periodic maintenance.

The best alternative is to totally re-arrange your life to minimize energy consumption and optimise time of use.  Forget reading, soldering or testing after dark.  Go back to annual baths whether you need it or not.  Wash clothing while you are bathing.  Bundle up in winter and sweat in the summer.  Against that backdrop many of the alternatives do start sounding good.
 

Offline LabSpokane

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Re: The beginning of the end for coal
« Reply #41 on: September 08, 2016, 08:38:46 pm »
The issue with biomass is getting enough biomass.  Virtually every one I speak to who is outside the industry, grossly underestimates the volume of wood that is required to fuel a plant.  Typically, it is a challenge to get enough fuel to fire a 50MWe net plant.  It is only economical to source the fuel in a 50 mi radius.  For a city that had a 1000MWe coal plant, it would obviously require 20, 50MWe plants to replace it.  There is simply nowhere that I know of that this is possible without engaging in massive deforestation - or trucking in wood from such a distance that the power plant merely becomes a way to greenwash petroleum consumption.

The amount of wood required to fire a power plant is staggering.  A good rule of thumb is that 1 short ton of wood per hour will generate approximately 1MWe of power, thus to replace a coal plant would require 1000 tons per hour of wood.  A typical Douglas Fir tree here is about ten tons in mass, so a coal-fired plant replacement requires 100 - 50m tall trees per hour to operate.  Basically, we're talking about clearcutting large forests just to fuel one power plant.  This should give an idea of just how many thousands/millions of years of accumulated biomass (peat) is represented by a coal deposit.  There just is no way to grow the material on an annual basis that would replace the fossil fuels that currently power our society.

With respect to power, the optimum use case of biomass for power is "combined heat and power" (CHP) where the biomass is used to make steam for power and the residual, low-grade heat from the turbine condenser is distributed for building heating.  Of course, this only is efficient during heating season. 

As far as heating goes, biomass heat can be very efficient.  Efficiencies of about 70% are common in pellet stoves, which are radically more efficient than the wood stoves of past.  (Open fireplaces are horribly inefficient heating devices.)

Using wood pellets for home heating, in my opinion, is an excellent way to efficiently heat a space that is efficient, environmentally friendly (if the stove has a catalyst) and truly sustainable.  The pellets are largely from wood waste from the forest products industry.  In westernized countries, the forest products industry represents sustainable biomass use in that their aggressive replanting programs ensure a perpetual supply now.  What is surprising is the amount of processing and capital equipment that is required to create the pellet, which is why pellets cost $200USD/retail instead of the $30/ton for wood chips that a power plant would purchase. 
« Last Edit: September 08, 2016, 08:40:35 pm by LabSpokane »
 

Offline RGB255_0_0

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Re: The beginning of the end for coal
« Reply #42 on: September 08, 2016, 09:01:36 pm »
Heating oil is not much more expensive here than wood pellets, doesn't rot in storage and can produce double the energy by weight and takes up less space. For remote areas there's no compromise if you have harsh winters.
Your toaster just set fire to an African child over TCP.
 

Offline Marco

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Re: The beginning of the end for coal
« Reply #43 on: September 08, 2016, 10:04:15 pm »
These ideas are simple, and they work.  They aren't widely used.  Why?  Is it a conspiracy?  No, it is because they have problems of their own and for individuals and municipalities under existing cost structures they don't make sense.

Give it time. We've only been in the situation where electricity can periodically be had for free for a short while. We need at least 20 years of that before the real innovation can start.

I have higher hopes for storage to be solved than for breeder reactors to not be a commercial clusterfuck.
 

Offline Someone

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Re: The beginning of the end for coal
« Reply #44 on: September 08, 2016, 10:42:11 pm »
I have seen a number of products for producing home heat from wood, from logs to sawdust pellets. For example I saw a wood burning boiler that provided heat for the home, hot water for the plumbing and heated an outdoor pool; all using a very modest sized log over several days time. I agree that using wood for a power plant would not be economical in the vast majority of cases. Heating with mains power is fairly inefficient most of the time when all things are considered. I recall antique stoves that would provide heat for cooking, heat the house and provide hot water. In regions where wood was scarce you found ways to be efficient. I think part of the answer is to have as many workable alternatives as possible and use what makes sense.

The process of converting electricity to heat (resistively) is very efficient, i.e. a very large percentage (most) of the energy is converted to heat. Converting coal to heat then converting the heat to electricity, then transmitting the electricity for long distances, then converting the electricity back to heat is inefficient and costly as you have gone though a number of conversions form one form of energy to another and their associated losses to create heat in your home.
Most climates can use heat pumps to provide over unity heat transfer, and the waste heat from the thermal power plant can still be harvested locally to it (farming etc). Thermal power plants are not awful when run in ideal conditions, but while fuel is cheap there is no incentive to introduce efficiency measures and in most countries they run with very poor thermal efficiency.
 

Offline arlipscomb

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Re: The beginning of the end for coal
« Reply #45 on: September 08, 2016, 10:45:29 pm »
Please note that I am not talking about a "one size fits all" solution. What makes sense in a rural community, or small town, may not scale well in large city. But a large city can justify things like atomic energy, windmill farms and hydro-electric projects. It may not make sense to burn wood in a city, but in rural areas it may make more sense than trying to have the power grid keep up with the demands.

For using solar to pump water consider this:

People use solar to pump water on farms and remote areas all the time.

In the United States most homes maintain 30 to 50 gallons of water stored in an insulated hot water tank. The better insulated tanks can keep water hot for many hours. People already put them on timers so they only heat water during the day. Some use solar energy to reduce the cost of heating the water. Common enough.

Now take a second tank and fill them both up with water during the day. Add an air tank to the mix and run the compressor during the day. Then you can get your 30 psi water pressure using the air tank.

Could pumping some water around reduce the amount of power needed to air condition buildings during the day? I remember the old water chilled air conditioners. They are not too common anymore.

What I am trying to think about is how to use the energy in different ways than to just charge a battery for use after dark. In my area the coal plants tend to be used to "fill in" when demand gets high. Find economical ways to use solar where it makes sense and you may be able to nickle and dime the plants out of existence.
« Last Edit: September 08, 2016, 10:47:13 pm by arlipscomb »
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Offline edavid

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Re: The beginning of the end for coal
« Reply #46 on: September 08, 2016, 10:55:08 pm »
The issue with biomass is getting enough biomass.  Virtually every one I speak to who is outside the industry, grossly underestimates the volume of wood that is required to fuel a plant.  Typically, it is a challenge to get enough fuel to fire a 50MWe net plant.  It is only economical to source the fuel in a 50 mi radius.  For a city that had a 1000MWe coal plant, it would obviously require 20, 50MWe plants to replace it.  There is simply nowhere that I know of that this is possible without engaging in massive deforestation - or trucking in wood from such a distance that the power plant merely becomes a way to greenwash petroleum consumption.

Enviva currently produces "about 2.3 million metric tons of wood pellets annually" without any deforestation.

Quote
Using wood pellets for home heating, in my opinion, is an excellent way to efficiently heat a space that is efficient, environmentally friendly (if the stove has a catalyst) and truly sustainable.  The pellets are largely from wood waste from the forest products industry.  In westernized countries, the forest products industry represents sustainable biomass use in that their aggressive replanting programs ensure a perpetual supply now.  What is surprising is the amount of processing and capital equipment that is required to create the pellet, which is why pellets cost $200USD/retail instead of the $30/ton for wood chips that a power plant would purchase.

The European price for wood chips for power plants is well over $100/ton:

http://ir.envivapartners.com/sites/envivabiomass.investorhq.businesswire.com/files/doc_library/file/Enviva_Investor_Presentation_Feb_2016.pdf
 

Offline LabSpokane

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Re: The beginning of the end for coal
« Reply #47 on: September 08, 2016, 11:38:20 pm »

Enviva currently produces "about 2.3 million metric tons of wood pellets annually" without any deforestation.

[2.3M tonnes * 1.1 short ton per metric ton ] / 8760hr per year is approximately a 288 MWe power plant. Like I said, it takes a staggering amount of wood to replace coal. That monumental effort would need quadrupling just to replace *one* 1000MWe fossil fuel fired power plant. Then that effort would need to be multiplied by dozens to replace the dozens of coal and nuclear plants slated for decommissioning. It's just not going to happen.

Quote
The European price for wood chips for power plants is well over $100/ton:

http://ir.envivapartners.com/sites/envivabiomass.investorhq.businesswire.com/files/doc_library/file/Enviva_Investor_Presentation_Feb_2016.pdf

Exactly. This price difference between what wood chips cost and pellets sell for has been the basis for a gold rush in exporting US and Candian biomass to Europe as a coal "replacement."  And the cost of power at $100+/ton is staggering as well, as just the fuel cost per MWh is likely $125 once one factors in moisture content, ash content, and loss due to plant parasitic load.  That likely would result in a retail price $0.35-0.50/kW-h or more to the customer once capital cost, operational expenses, transmission and distributions costs and profit is added through the wholesale and retail stages.

Biomass power is great for niche applications, but please don't let the marketing lull anyone into believing that it's a cheap and easy replacement for our current fossil fuel demands.
 

Offline arlipscomb

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Re: The beginning of the end for coal
« Reply #48 on: September 08, 2016, 11:50:55 pm »
Fossil fuels will be with us for the foreseeable future. I wish they would get their act together on nuclear power plants. I think they could be part of the long tern solution if they would focus on things like standardization.   
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Offline LabSpokane

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Re: The beginning of the end for coal
« Reply #49 on: September 09, 2016, 12:41:06 am »
Fossil fuels will be with us for the foreseeable future. I wish they would get their act together on nuclear power plants. I think they could be part of the long tern solution if they would focus on things like standardization.

Nuclear is the only current means to replace fossil fuel power generation on a MW for MW basis and have the availability we are used to.

The real problem is that we (myself included) fail to appreciate just how magically concentrated and convenient fossil fuels are and how hard they are going to be to replace. I'm not advocating continuing to accelerate our use of fossil fuel, but we have to realize just how damned good they are when evaluating replacement sources.
 


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