Physical Insights

An independent scientist’s observations on society, technology, energy, science and the environment. “Modern science has been a voyage into the unknown, with a lesson in humility waiting at every stop. Many passengers would rather have stayed home.” – Carl Sagan

Archive for the ‘coal’ Category

Clean coal project ‘will fail’ under emissions trading scheme.

with one comment

http://www.abc.net.au/news/stories/2009/01/19/2468820.htm

Opposition environment spokesman Greg Hunt says a major clean coal project in central Queensland will fail unless the Federal Government changes its emissions trading scheme.

ZeroGen is working to develop a low emissions plant but says under the proposed carbon pollution reduction scheme it may be forced to buy permits.

If this “clean coal” is so clean, and actually does not have any significant emission of carbon dioxide to the atmosphere, why are GHG emissions permits any significant issue at all? Any and all technologies which are truly “clean” obviously have a competitive advantage under the emissions trading scheme – so how exactly is the coal industry able to complain about a financial disadvantage faced by “clean coal”?

Of course they should be forced to buy permits – as should every power station – corresponding to their quantitative greenhouse gas emissions. If you don’t want to sink money into GHG permits, then you deploy low-emissions or zero-emissions technologies.

Even after what is basically an admission that “clean coal” is still associated with very high emissions of carbon dioxide to the atmosphere, more than natural gas and more than essentially any other energy generation technology with the exception of conventional coal-firing, the coal industry is still expecting even more handouts for the government for purported “clean coal” – and the government will probably give in, since “clean coal” is the only example the Australian Government has that they can try and meaningfully show as evidence of their supposed commitment to the management of anthropogenic greenhouse gas emissions. If Big Coal threatens to walk away on the “clean coal” projects if they don’t get the additional taxpayer-funded pork they demand, the government is left with nothing to show off.

In a letter to Resources and Energy Minister Martin Ferguson the company said it should be exempted from buying carbon permits as it is a research and development project.

It has warned that if it has to buy permits the project may become unviable.

The Queensland Government has provided $100 million for the project and Prime Minister Kevin Rudd has voiced his support for it.
Mr Hunt has accused the Commonwealth of “turning its back” on clean energy.

“The project will fail under Mr Rudd’s regime,” he said.

“Very clearly ZeroGen, clean coal, the future of Australian clean energy will fail under Mr Rudd’s regime.”

What a bunch of ridiculous rhetoric.
Given that we’re seeing so much government money being handed out to the coal-fired generation industry in relation to coal and emissions trading, and so many exemptions from emissions trading and the issuing of free permits, it might almost come as a surprise that there is interest in “clean coal”, when there is no real significant economic disincentive to the use of conventional coal-fired technology. The answer does indeed seem to be that these mendaciously small-scale “clean coal” projects seem to be an attractive source of easy government handouts for Big Coal.

Mr Hunt says the Government’s stance on emissions trading has already hurt the company.

“We’ve learnt that there are already job losses at ZeroGen,” he said.

The entire business development and corporate affairs section has been sacked in the last few days, the company is already winding down.”

A spokesperson for Mr Ferguson says the minister will address the issues raised in ZeroGen’s letter in “due course”.

Last year the Government allocated $100 million to the formation of the Carbon Capture and Storage Institute.

About 80 per cent of Australia’s electricity is created by coal-fired power generators.

Under the proposed carbon pollution reduction scheme, all revenue from the sale of permits will be used to compensate households for rising costs.

The Government’s climate change adviser, Professor Ross Garnaut, had urged the Government to allocate about a third of collected revenue to clean energy research and development.

Advertisements

The environmental footprints of coal and uranium mining.

with 9 comments

Here’s something worth thinking about.

This is a coal mine. Specifically, it’s the Blair Athol coal mine in central Queensland, Australia, but there’s no special reason why I chose this specific example of a coal mine. The mine produces 12 megatonnes of coal per year. (This is just a satellite image taken from Google Maps, which anybody can of course easily access.)

Coal has a thermal energy content of about 25 MJ/kg, and therefore 12 megatonnes of coal corresponds to a primary energy content of about 2.9 x 1017 J.

This is the Ranger uranium mine, near Jabiru in the Northern Territory of Australia. Again, nothing special about this specific uranium mine, it’s just an example.
All these satellite images are at a consistent scale factor, or zoom level/resolution.

In 2007-2008, Ranger produced 5273 tonnes of U3O8.

A conventional, relatively inefficient low-enriched uranium fuelled LWR with a thermal (primary energy) power output of about 3 GW requires approximately 200 tonnes of U3O8 to be mined to fuel it for one year, assuming that newly mined uranium is used for all its fuel.

Therefore, the annual uranium output from Ranger corresponds to about 2.5 x 1018 J of primary energy, or about 8.6 times the primary energy content supplied by the coal mine.

That is, that one uranium mine supplies the same amount of energy content as nine of the coal mines – one seemingly quite small uranium mine, which is about a third of the size of the coal mine, supplies the same amount of primary energy content as this. (I won’t embed that image in the post, since it will probably completely destroy the formatting of the page.)

Written by Luke Weston

January 9, 2009 at 7:24 am

Fischer-Tropsch fuels and carbon dioxide mitigation.

with 7 comments

“The good news is that there is no need to build new nuclear power plants to provide for the projected energy needs of the future. Indeed, it would be possible, using other forms of electricity generation, to close down most of the existing nuclear reactors within a decade. Many kinds of alternative solutions are currently on the drawing board because of the extreme urgency of countering global warming. For instance, the conversion of coal to a synthetic fuel, which can be used for transportation and which would contribute much less to global warming than petroleum, is actively being championed by Governor Brian Schweitzer of Montana.”

That’s a quote from the perhaps infamous Nuclear Power is Not the Answer. However, this post isn’t really a criticism directed at Caldicott, specifically. The bold is mine.

The production of synthetic of petroleum-like liquid hydrocarbon fuels through Fischer-Tropsch synthesis using coal as a feedstock is not environmentally sound at all, it is not an efficient use of energy resources and it is not at all a useful technology in the slightest degree to contribute towards the mitigation of anthropogenic carbon dioxide emissions from energy systems.

The first step in Fischer-Tropsch synthesis of liquid fuel from coal is the reaction of coal, which is mostly carbon, with steam under elevated temperatures and pressures, to yield a mixture of gaseous carbon monoxide and hydrogen, known as synthesis gas. This requires mining the coal, adding water, and supplying a significant input of thermal energy, intrinsically reducing the efficiency with which the energy content of the coal can be utilised – where does the thermal energy come from?
From burning more coal?

C(s) + H2O(g) –> CO(g) + H2(g)

We may wish to consider the small amount of hydrogen, about 4% by mass in typical bituminous coal, giving the coal an empirical chemical formula of something like C2H. However, the presence of this small amount of hydrogen in the coal makes essentially negligible difference, other than to marginally increase the H2:CO ratio in the synthesis gas mixture.

2 C2H(s) + 4 H2O –> 4 CO(g) + 5 H2(g)

It’s essentially the same as the previous reaction, above.

For the sake of simplicity, we might ignore, for now, the presence of sulfur, hydrogen, oxygen, nitrogen, metals and heavier elements in the coal, and focus on the carbon content. One notable advantage of Fischer-Tropsch fuels, however, is that the sulfur content of the fuel can be removed altogether, resulting in a fuel, such as diesel fuel, with negligible sulfur content, and hence with negligible emissions of sulfur dioxide into the atmosphere when the fuel is burned.

At the heart of the Fischer-Tropsch process is the use of an appropriately engineered catalyst and reaction conditions to convert the synthesis gas mixture back into a mixture of liquid hydrocarbons with an average molecular weight and composition which is usable as a fuel for vehicles. Suppose, for example, that we’re interested in the production of petrol for passenger cars – however, you could apply the same analysis equally to diesel fuel, for example, or any other particular kind of liquid petroleum fuel that you’re interested in.

Typical liquid hydrocarbon fuels, such as petrol or diesel fuel, contain about 13-15% hydrogen by mass – significantly greater than any possible abundance of hydrogen in the coal. As such, the addition of additional hydrogen into the reaction is necessary. Suppose that we’re interested in the production of petrol for passenger cars. For the sake of simplicity we can say that octane, C8H18, is representative of the overall chemical composition of the petrol.

When the coal is reacted with water to form synthesis gas, the synthesis gas is then reacted with more steam in order to increase the H2:CO ratio in the gas mixture, using water as the source of hydrogen, and producing carbon dioxide. This gas mixture can then be used to form the desired heavier hydrocarbons, using a Fischer-Tropsch catalyst.

25 C(s) + 25 H2O(g) –> 25 CO(g) + 25 H2(g)

9 CO(g) + 9 H2O(g) –> 9 CO2(g) + 9 H2(g)

16 CO(g) + 34 H2(g) –> 2 C8H18(g) + 16 H2O(g)

Hence, we have an overall chemical reaction which is equivalent to this:

25 C(s) + 18 H2O(g) –> 2 C8H18(g) + 9 CO2(g)

Traditionally, we extract crude oil from the ground, fractionate and refine the oil into products like petrol, and run our cars on the petrol. If we combust 2 mol of octane in an engine, we’ve emitted 16 mol of fossil-fuel-derived carbon dioxide into the atmosphere. However, if that 2 mol of octane is produced from coal via a Fischer-Tropsch process like we’ve elucidated above, then 25 mol of fossil-fuel-derived carbon dioxide is emitted into the atmosphere, for the same amount of energy output in the car’s engine. Does this “contribute much less to global warming than petroleum”?

Absolutely not – quite the opposite, in fact.

Even if all the carbon dioxide created during the synthesis was captured at the Fischer-Tropsch plant, liquefied, and sent to geological sequestration – which assumes that geological sequestration of the enormous quantities of carbon dioxide associated with fossil fuel energy systems is practical, which is extremely doubtful indeed and is at best completely unproven – then, at best, assuming that none of the additional energy inputs into the process come from fossil fuels, then the combustion of the synthetic fuel is associated with exactly the same quantity of carbon dioxide emissions as the
combustion of fuel derived from petroleum.

Synthetic fuel production, as exemplified by the Fischer-Tropsch process, is not advocated for reasons of the mitigation of anthropogenic carbon dioxide emissions – it is advocated by people including but not limited to Brian Schweitzer as a means to contribute to a secure domestic supply of liquid petroleum for the United States – helping to end the United States’ present dependence on foreign oil.

Fischer-Tropsch chemistry provides a particularly attractive means to keep our petroleum-fuelled vehicles in operation, using abundant, ubiquitous and secure domestic supplies of coal, where the security of foreign oil supplies are threatened by strategic or geopolitical considerations – as was the case in Nazi Germany and in South Africa under Apartheid, where Fischer-Tropsch fuel production was first well developed on a large, industrial scale.

Of course, perhaps it’s also possible Schweitzer also wants to see Montana’s abundant lignite coal utilised for the production of these synthetic fuels – bringing income into the state, and perhaps helping to keep the coal extraction industry in business in a society where it is increasingly widely accepted that coal is our number-one environmental enemy. That’s no secret.

Written by Luke Weston

November 25, 2008 at 1:21 am

The fallacy of currently operating “clean coal”: Part 2

with 3 comments

Next up we might look at what the coal industry calls “a world-leading low-emissions coal power plant for Queensland” – the ZeroGen project.

Through a staged deployment program, the project will first develop a demonstration-scale 120 IGCC power plant with CCS, with a gross electrical power output of 120 MW. Again – only a gross electrical output of 120 MW, and a net electricity output to the grid which will be significantly less than that – it’s a tiny demonstration-scale plant, which is feebly small by the standards of most coal-fired power stations.

“The facility is due to begin operations in late 2012 and will capture up to 75% of its carbon dioxide emissions. Some of the CO2 will be transported by road tankers for partial geosequestration in deep underground reservoirs in the Northern Denison Trough, approximately 220 km west of the plant.”

(Quoted straight from the NewGenCoal website.)

Again, only some of the CO2 is captured, and only some of that CO2 which is captured is transported, for partial geosequestration.

To facilitate more rapid uptake of the technology at commercial scale, ZeroGen will concurrently develop a “large-scale” 400 megawatt IGCC power plant with CCS. Due for deployment in 2017, the facility will be “one of the first of its kind in the world” and will capture up to 90% of its CO2 emissions. It will be located at a site in Queensland as yet to be determined by a feasibility study. Of course, capturing 90% of CO2 emissions does not mean geosequestration of 90% of CO2 emissions, and in any case, 400 MW of electrical power output is not really a “large-scale” power station at all.

There’s an interesting paper here which provides a realistic analysis of the implementation of retrofitted CO2 capture for an existing pulverised coal power station. Of course, this is a pulverised-coal system under consideration, and not IGCC as the ZeroGen plant(s) are proposed to use, but it is very interesting material nonetheless.

This paper examines the retrofit of a 400 MWe pulverized-coal fired plant, emitting 368 t/h of CO2, to enable CO2 capture while maintaining 400 MWe output, where 90% of the CO2 emitted from the coal plant is captured and sequestered. To do so, the extra energy input required for capturing CO2 was supplied by natural gas-fired gas turbines.

I’ve quoted the key points from the paper below. I’ve applied some minor editing and collation, but most of the material is straight from the paper cited.

Even when CO2 emitted from the gas turbines is not captured, the overall process still have some impact in reducing CO2 emissions, corresponding to an overall reduction in carbon dioxide output to the atmosphere of between 60-70%, with atmospheric CO2 emissions of between 110 and 138 t/h, compared to 368 t/h for the original coal combustion plant, at the cost of a natural gas requirement of about 1350 GJ/h.

When CO2 from the gas turbines is captured, the reduction in CO2 emission is between 68 and 77%, or CO2 emission to the atmosphere of 86-113 t/h. However, a considerably large amount of natural gas is required (around 3140 GJ/h), which is certainly not reasonable.

The total amount of natural gas required is between 3100 and 3300 GJ/h. To put this number into perspective, this amount of natural gas would generate about 460 MWe when used in a combined-cycle gas turbine plant without CO2 capture. The relative emissions are between 23% and 32% of the original coal power plant, which has a significant impact on the reduction of CO2 emissions.

The current industrial price for natural gas, as of August 2008, is USD $9.95 per thousand cubic feet, according to the EIA’s natural gas market page. One thousand cubic feet of natural gas corresponds to a heating value of about 1.09 GJ.

If a plant consumes 1350 GJ/h of natural gas at full output, then that is a fuel cost of 108 million dollars per year – leading to a significant increase in the operational cost of the plant.

For a nameplate capacity of 400 MW, and a capacity factor which we may assume to be, say, 85%, carbon dioxide emissions of between 86 and 138 t/h correspond to CO2 emissions to the atmosphere of between 253 to 406 gCO2/kWhe generated.

The results from this study certainly paint a less optimistic assessment of the carbon dioxide emissions intensity of “clean coal” than the 80-90% reductions estimated by the IPCC. It is not at all “clean coal”.

Indeed, such levels of carbon dioxide emissions intensity are not much better than existing high efficiency combined-cycle natural gas fired gas turbine power plants. Given that the carbon dioxide emissions aren’t grossly worse, and given that gas turbine plants are already established, mature technology which is likely to remain far more economically competitive with this expensive, immature, unproven future technology, it is easy to envision that natural gas will be the main focus of the fossil fuel combustion energy industry over coming years, as opposed to the development of CCS technology, even where emissions trading is introduced.

The exception to this, of course, is where there is a vested interest in keeping the existing coal-fired power plants, and enormous coal-mining infrastructure, even if it is a less than sensible choice on many different levels. Natural gas turbines are of course, along with nuclear power, by far one of the biggest “threats” to the coal mining and coal-combustion electricity generation industry.

Additionally, that’s only considering greenhouse gas emissions from combustion at the power plant – without any consideration of whole-of-life-cycle analysis of coal mining and natural gas production – the enormous scale on which coal is mined, along with the fugitive emissions of methane associated with the production and handling of coal and natural gas, and so forth.

At the Munmorah Power Station in New South Wales, a research-scale pilot plant will capture up to 3000 tonnes of CO2.

“It is hoped the Munmorah project will provide the foundation for a $150 million post-combustion capture and storage demonstration project in NSW, planned for operation by 2013, capturing up to 100,000 tonnes of CO2 each year.

The CO2CRC (the Cooperative Research Centre for Greenhouse Gas Technologies) Otway Project is Australia’s most advanced carbon dioxide storage project. Launched in April 2008, the project involves the extraction, compression and transport and storage of 100,000 tonnes of naturally occurring CO2. The CO2 is being stored in a depleted natural gas reservoir two kilometres below the earth’s surface.

3000 tonnes of CO2? 100,000 tonnes of CO2? That’s nothing. It is just not enough to make any difference to anything. The Munmorah power station emitted 2.1 million tonnes of CO2 to the atmosphere in 2007. Even if 100,000 tonnes of CO2 was captured and sent to geological sequestration, the remaining 95.24% of the CO2 is still going into the atmosphere as usual. Capture and geological sequestration of this 4.76% of CO2 is probably indistinguishable from normal variance in the plant’s total energy output and total CO2 emissions from year to year. You wouldn’t even notice any quantitative difference in the emissions.

In 2007, Eraring power station in New South Wales emitted 13.8 million tonnes of carbon dioxide, and in 2006, Loy Yang Power in Victoria emitted 19.3 million tonnes of carbon dioxide. For there to be any chance of “clean coal” to become a reality in any honest, meaningful way, these are the kinds of quantities of carbon dioxide which must be practically, safely and economically sent to geological sequestration, in their entirety.

There are at least two Cooperative Research Centers in Australia dealing with coal-based energy technology – the CRC for Coal in Sustainable Development, and the CRC for Greenhouse Gas Technologies (The “CO2CRC”.)

As far as I’m aware, there is not one CRC dealing with solar energy, wind energy, nuclear energy, or geothermal energy. There is not one, dealing with any such technologies. We do have industries who want to invest in these technologies as commercial enterprises in Australia, and we do have plenty of good scientists and academics who believe in all these different technologies, and yet, astonishingly, surprisingly, it is only the coal industry which has a showing in the CRC program.

The large energy requirements of capturing and compressing CO2 significantly raise the fuel costs and operating costs of CCS-equipped fossil fuel power plants, with the fuel requirement of a plant with CCS being increased by about 25% for a coal-fired plant, and about 15% for a gas-fired plant.

Additionally, increasing the overall greenhouse gas emissions intensity is increased well above what it’s claimed to be, since the gas is not captured with 100% efficiency. In addition, there are significant increases in capital costs for the plant.

The IPCC Special Report on Carbon Capture and Storage reports that:

“Available technology captures about 85–95% of the CO2 processed in a capture plant. A power plant equipped with a CCS system (with access to geological or ocean storage) would need roughly 10–40% more energy than a plant of equivalent output without CCS, of which most is for capture and compression. For secure storage, the net result is that a power plant with CCS could reduce CO2 emissions to the atmosphere by approximately 80–90% compared to a plant without CCS.”

Since 1996, the Sleipner gas field in the North Sea, the industry’s poster child for large-scale, established, operational geosequestration, has stored about one million tonnes of CO2 per year. A second project in the Snøhvit gas field in the Barents Sea stores about 700,000 tonnes per year.

The Weyburn project is currently the world’s largest carbon capture and storage project.
Started in 2000, Weyburn is located on an oil reservoir discovered in 1954 in Weyburn, southeastern Saskatchewan, Canada. The CO2 injected at Weyburn is mainly used for enhanced oil recovery with an injection rate of about 1.5 million tonnes per year.

These projects are by far the largest operational CO2 geological injection/geological sequestration projects in the world – and there are only a few such facilities in the world. Each such facility does not have nearly enough capacity for carbon dioxide geosequestration to handle the output from even just one large coal-fired power station.

Australia’s coal industry takes public relations up a notch.

with 6 comments

Did anybody else see the full page ad in The Age yesterday (Thursday 13th, I think it was page 7 or page 5) courtesy of the Australian Coal Association, telling us how wonderful CCS “clean coal” technology (i.e. carbon dioxide capture and geosequestration) is, and how it’s proven technology which is already in use, and how it’s going to solve all our problems with regards to anthropogenic CO2 emissions, and maintain active business as usual for the coal industry?

I don’t think so, personally.

You don’t see the ITER consortium taking out full-page page 5 ads in the major papers to promote their technology, do you? That option is about equally as mature and developed, and has just as much potential, if not more, for energy generation, and it’s far more environmentally sound.

I realise that, of course, those full-page newspaper spots must cost a pretty penny, so I did a little bit more investigation in the press.

Coal industry reaches out for love

THE coal industry feels unloved. Its polling tells it Australians have no idea what, if anything, it is doing to reduce its greenhouse gas emissions — and most say they’ve never heard of carbon capture and storage.

So the coalminers want to convert us. Today the Australian Coal Association launches a $1.5 million ad campaign — and a $1 million website — to tell us what it’s doing to develop what it calls “NewGenCoal”.

Association executive director Ralph Hillman predicted that carbon capture and storage would be commercially viable by 2017, and said the industry was investing $1 billion to ensure coal a future as a low-emission technology.

“CCS will work, and we’re investing in demonstrating these technologies,” Mr Hillman told journalists yesterday. “We’re working to implement them on a commercial scale by 2017.”

Back in Hugh Morgan’s day, the coal industry’s global warming strategy was to fund denialist groups. Not now: Mr Hillman said the industry saw climate change as real, and the association’s main goal was to drive the adoption of CCS to tackle it.

Coalminers now pay a voluntary levy of 20¢ for every tonne they mine into the Coal 21 Fund, raising $100 million to help finance CCS pilot plants and, in future, demonstration projects. These include:

* $68 million towards the $205 million trial of an oxyfuel post-combustion CCS system at the Callide power station in central Queensland, to be opened by Resources Minister Martin Ferguson tomorrow.

* $26 million towards a feasibility study to revive the collapsed ZeroGen project near Rockhampton.

* A proposed demonstration scale plant at Munmorah in NSW.

The Federal Government’s climate change adviser, Ross Garnaut, has criticised the industry’s effort as inadequate. In his final report last month, Professor Garnaut contrasted its research and development spending with the amounts paid by farmers out of a much lower revenue base. He said coalminers should beef up their R&D levies to $250 million a year to accelerate the adoption of CCS.

The International Energy Agency warned last month that CCS now costs between $US60 ($A90) and $US75 per tonne of emissions saved, way above the price of wind power or nuclear — and unless R&D efforts were radically stepped up, it might not be commercially viable until 2030.

There is no commercial coal-fired power station anywhere in the world at present which captures even 10% of its CO2 emissions.

The coal industry is quick to hold up their current, active CCS and “clean coal” enterprises as examples – but perhaps it’s worth looking at them a little more closely.

Firstly, we have the coal industry’s “clean coal” technology fund putting $68 million towards the $205 million trial of an oxyfuel post-combustion CCS system at the Callide power station in central Queensland. Where does the rest of the money come from? From state and federal governments, mostly, who are handing these projects lots of money in an effort to appear “clean and green”, and serious about mitigation of CO2 emissions, of course.

Oxyfuel combustion-and-CO2-capture involves the combustion of coal with virtually pure oxygen, rather than air, to fuel a power plant’s boiler. When the coal is burned in pure oxygen, the resulting exhaust gas is mostly CO2 (with a little bit of SO2 as usual, depending on sulfur content in the coal) instead of being mostly atmospheric nitrogen, with a smaller portion of CO2 as well as some SO2 and NO2 as is present when the coal is burned in air. A portion of the exhaust gas is recycled back into the boiler to regulate combustion and keep the oxy-fuel furnace from destroying itself.

Since the product of oxy-fuel combustion of coal is essentially pure CO2, (SO2 can be removed as usual via standard flue gas desulfurisation), the exhaust gas CO2 can be liquefied and sent straight to geosequestration, without the need to distil the CO2 from a mixture of other gases such as N2, hence making CO2 geosequestration easier to do.

Of course, the plant to produce pure oxygen, by compression and liquefaction of air followed by cryogenic distillation of pure O2, is required as part of the oxy-fuel combustion plant, and this is a non-trivial capital expense – and it also requires a reasonably significant energy input during operation.

However, the liquid oxygen produced (boiling at 90 K) can easily be used to liquefy the carbon dioxide output stream (boiling at 195 K), meaning that additional plant, and additional energy input, for the compression and liquefaction of the CO2 output is probably not required. It is claimed by the industry that oxyfuel combustion can be retrofitted to conventional coal power plants with relatively little modification.

There’s some more useful technical detail on the Callide oxyfuel project here. [PDF file, but it is not especially large.]

The graph on slide #4 is interesting, isn’t it – perhaps I’m misinterpreting it, but are Australia’s National Generators Forum really themselves predicting that nuclear energy will make up about 40% of Australia’s electricity supply by 2050, under a scenario achieving a 50% reduction in anthropogenic CO2 emission rates, over 2005 levels, by 2050? I’m surprised that they recognise, and indeed operate with the assumption, that nuclear energy will be the largest single technology on the electricity grid by 2050. Let’s hope that it actually plays out that way.

Then again, perhaps I’m not all that surprised – is there really any way that a 50% reduction in anthropogenic CO2 emission rates over 2005 levels by 2050 could actually be done, in the absence of a significant contribution from nuclear energy?

Back to the oxyfuel-CCS plant, anyway.

According to the table of data given in the above document, a typical 500 MW air-firing plant may have a gross electrical power output of 524 MW, a net electrical power output of 500 MW, and a net thermodynamic efficiency of 41%. Hence, the thermal power is 1278 MW. For the oxygen-firing plant, gross electrical power output is 633 MW, with a net thermodynamic efficiency of 34%, for the same net electrical power output of 500 MW. Hence, the thermal power is 1862 MW – an increase of 46% in the thermal power required from the boiler, and hence an increase of 46% in the amount of coal that needs to be mined, a 46% increase in mountaintop removal, and so forth.

At a net gas flow rate of 180 kg/s, which I assume is the exhaust gas output, from the oxyfuel plant, the 67% concentration of CO2 corresponds to a CO2 output of 868 g CO2 per kWh, or 10,420 tonnes per day (that is, ignoring any < 100% capacity factor, since a coal-fired plant should be operating with a high capacity factor, and I really have no idea what kind of capacity factor to expect from such a plant.)

The Australian coal industry’s efforts to develop and implement oxyfuel combustion with CO2 storage are currently at the demonstration phase. The Callide Oxyfuel Project team is assessing potential sites to the west of Biloela for carbon dioxide geosequestration and plans to select the final location in 2009.

The carbon dioxide will supposedly be transported in road tankers.

Road tankers? Seriously? Obviously that can not and does not work, for carbon dioxide geosequestration on any meaningful scale.

Let’s assume that the trucks leave the station, and travel, say, 50 km to the geoseqestration site. Assuming that the trucks travel at 100 km/h, and ignoring the time taken to load and unload the tankers, (obviously these assumptions are conservatively high to the point of being completely unrealistic) and assuming that one tanker holds 20 tonnes of liquid CO2, then you can move 20 tonnes per truck per hour. If you have, say, 22 tanker trucks, then you can transport the required 10,420 tonnes per day, if those 22 trucks are running non stop for 24 hours per day.

(Keep in mind that those trucks will almost certainly be running on fossil-fuelled, CO2 (and SO2) emitting engines…)

As the CSEnergy presentation notes, oxyfuel combustion, CO2 capture and geosequestration can reasonably be expected to increase the wholesale cost of electricity by between 50% and 75%.

The Callide oxyfuel project is not some important milestone in reducing Australia’s anthropogenic CO2 emissions. It is only a pilot-scale experiment designed to establish the design and operating costs for oxyfuel CCS plants, and to establish the capital and operating costs for these plants.

The project involves the refurbishment and retrofit of only one of the four 30 MW boilers are the currently-mothballed Callide A station, with the compression and purification of 100 tonnes of CO2 per day from a 20% side stream. That’s it – it’s only 30 MW of “clean coal” capacity.

How much CO2 is actually produced, and how much is actually being sent to geosequestration?

Assuming that the retrofitted 30 MW unit continues to operate with a capacity of 30 MW then, extrapolating the above numbers for the 500 MWe case, then the plant will be expected to produce about 625 tonnes of CO2 per day. If 20% of that CO2 is compressed and purified, then that’s 125 tonnes per day. OK, their quoted figures seem reasonable, so let’s work with that – 100 tonnes of CO2 compressed and purified per day. But only 50-75 tonnes per day of CO2 is transported and geosequestered.

To recapitulate: The plant will emit about 625 tonnes of CO2 per day, of which only 50-75 tonnes, 12 percent at the most, is geosequestered.

The atmospheric CO2 emissions intensity, then, is at best 764 gCO2/kWhe.

The Portland Wind Project under construction in Victoria has a nameplate capacity of 195 MW – which is over twice the energy output of the 30 MW Callide A unit, even when the lesser capacity factor of wind, at about 30% or so, is taken into account. At a cost of about 270 million dollars to construct the wind farm, which has zero carbon dioxide emissions, it is clear that even something as simple as wind energy, let alone nuclear, geothermal, solar thermal or anything else, is a far more economically attractive, and a far more environmentally attractive choice than the coal plant – and even typical wind farms generate far more energy than this pilot plant!

I really view “clean coal” in the same skeptical fashion that I treat anything else – such as solar photovoltaics or wind turbines – they can come back and sell their solutions, once they have a solution that realises actual generating capacity by the gigawatt, which can replace or retrofit existing coal-fired generators, with negligible, or essentially negligible greenhouse gas emissions. When the coal industry can capture and sequester all the carbon dioxide emissions from a conventionally sized coal-fired generator, economically, then I’m happy to reconsider the technology.

This plant is more expensive than nuclear, it’s more expensive than wind, and it’s probably more expensive than just about every low-emissions technology, with the possible exception of photovoltaics, it’s getting taxpayer money thrown at it, and it emits at least 764 gCO2/kWhe to the atmosphere.

That’s not “clean coal”; that’s… well, I won’t say what I think in polite company. I’ll leave it for you to think about.

“Nuclear Power Will Kill the Coal Industry”

with 3 comments

Many reader’s will be familiar with Australia’s Construction, Forestry, Mining and Energy Union (CFMEU) and their now-slightly-infamous “nuclear energy threatens coal jobs!” position.

But could nuclear power really “kill the coal industry” in Australia? I don’t think so.

Total production of raw black coal in Australia in 2006 was 405 Mt (million tonnes). This production represented a small increase of 1.6% over the 2005 figure of 399 Mt. After processing, a total of 317 Mt of metallurgical and thermal black coal were available for both domestic use and export in 2006.
(I’ve taken these statistics from the Australian Coal Association website.)

In 2006, Australia’s domestic consumption of black coal for electricity generation amounted to 62.4 million tonnes of black coal. Hence, domestic electricity generators consume only about 20% of Australia’s output of processed black coal. Other domestic industrial uses of coal, such as steel production, account for about three percent, with the entire remaining 77% being exported.

(The ACA’s statistics refer exclusively to black coal – however, brown coal is a much smaller resource, relatively, and since we have the statistics for black coal, I’ll limit the discussion to black coal.)

Hence, under the worst case scenario (or best case scenario), we may envisage a future in which every coal-fired generator in Australia is closed down and replaced by nuclear power plants. This would result in cutting Australia’s greenhouse gas emissions in half – at the cost of a 20% reduction in coal demand. If we were to see half of Australia’s coal fired plants closed down and replaced by nuclear energy, we will see a 10% reduction in coal revenue.

I don’t think a 10% to 20% downturn in revenue constitutes “killing the coal industry” – and I really don’t think that the coal industry has anything to worry about for the foreseeable future.

Written by Luke Weston

August 31, 2008 at 8:48 am

Switching off Victoria?

with 5 comments

I was quite impressed with myself to discover, the other day, that everybody’s favourite opinionated newspaper columnist, Andrew Bolt, had linked to and cited one of my recent posts.

That’s probably responsible, at least in part, for the significant increase in traffic I’ve seen on this blog over the last week or so – and I’m grateful for that.

Sometimes Bolt is absolutely on the money – but not always.

Here’s a recent blog post of Bolt’s which is somewhat agreeable, but still gets on my nerves a little bit. It’s worth reading, anyhow.

It’s utterly unbelievable that the Rudd Government should be contemplating making bankrupt the stations that provide more than 90 per cent of Victoria’s power:

Yes – it is extremely worthwhile and important to close down the extremely polluting and greenhouse gas emissions intensive brown coal fired power stations that provide more than 90 percent of Victoria’s electrical energy. That does not mean making the energy companies bankrupt – we still need that energy, it just has to come from a different source.

However, I too would have a hard time believing that Rudd would or could actually make it happen.

Although careful to respect the Federal Government’s process, Victorian Energy Minister Peter Batchelor appears increasingly nervous in his public comments. Asked if one of the state’s brown coal generators will be forced to close prematurely, he said: “It depends on the nature of the emissions trading scheme (introduced).”

The purpose of a GHG emissions trading scheme is to mitigate anthropogenic greenhouse gas emissions from our industries. Its purpose is not to raise more government revenues or to create more paperwork – its purpose, its reason for existing, is to reduce industrial, anthropogenic emissions of carbon dioxide.

Therefore, if the “mud-burning” Latrobe Valley stations are not the very first things to close down under an emissions trading scheme, then clearly the scheme is not working.

If it’s one like Garnaut actually recommends – with no compensation to power stations for wiping billions off their value – the generators are cactus. And here is Kevin Rudd’s modus operandi writ large and destructive: process over purpose. What possible good could there be to cause such an economic catastrophe in this state?

But Rudd’s guru has a solution of the kind the Soviet Union would have suggested:

In his report, Professor Garnaut said $1 billion to $2 billion of the emissions trading scheme proceeds should be invested in clean coal technologies, matched dollar for dollar by the companies. If clean coal worked, he said, the Latrobe Valley would heave a “prosperous and expansive future”. If it didn’t, money from the scheme should be used to help retrain workers and to help the valley community survive the brave new world of zero emissions.

Hey, let the Government spend a couple of billion of taxpayers’ money, and another couple of billion of the bosses’, on a yet-to-be proved “solution” many experts say is pie in the sky. And then, $4 billion later, let’s give the unemployed some handouts.

Warning: These people now have their hands all over your jobs and paypackets.

Whilst I’m interested – and many others are interested – in seeing the coal fired plants closed down, that doesn’t mean that the electricity utilities are out of business – we still need the electricity, and we will continue to need the electricity.

Ideally, what we would see happening is the construction of new lower-emissions or zero-emissions electricity generators of an energy output comparable to the coal power plants, followed by the decommissioning of the coal-fired plants. [Of course, we don’t decommission the coal plants until after the new ones are online.]

The electricity utilities are still operating lower-emissions or zero-emissions generators, there are still people employed, and we’re still getting the energy needed to support developed civilisation. This is where we need to transition to, and where an emissions trading scheme – if it’s done right – might help us transition to.

I agree that investing many billions of dollars in CCS research and development, which is considered by many to be pie in the sky, is a grave mistake. Instead, we need to consider the energy generation technologies that are mature technologies that are available and proven right now, that can replace coal-fired power plants, generating energy at a comparable scale, for less GHG emissions.

Those options are large hydroelectricity, natural gas fired turbines, and nuclear fission.

In Australia, expanding the use of large hydroelectric installations above and beyond what we’ve already got is really not a practical proposition, so we’re left with two options that really could replace coal-fired generators in the Latrobe valley, under an emissions trading scheme – natural gas and nuclear energy. Certainly, what is absolutely not sensible at all is arbitrary, unfair and exceptional, scientifically unfounded legal prohibitions on the development of nuclear power plants by the energy companies who are willing to invest in zero-emissions replacement for coal, especially when their investments may be kick started by billions of dollars in the government’s ETS revenue, which clearly needs to be put back into these zero emissions or lower-emissions technologies.

If power plant operators wish to pursue either of these options, which will finally actually put a stop to the ever-expanding use of coal-fired generators, and finally put a real dent in GHG emissions, then they are to be wholeheartedly encouraged in doing so.

Obviously the nuclear energy option is completely superior to natural gas in terms of greenhouse gas emissions – however, in practical terms, one must grant that gas turbines are already in widespread use in Australia today, and they are more politically acceptable in some political circles than nuclear power – however that may change as concern over greenhouse gases, even at the somewhat reduced levels from natural gas generators, grows.

However, that said, given the importance of making real cuts in GHG emissions within the next 3-10 years, if the generators want to build combined-cycle natural gas turbines, technologies with which they’re more familiar, straight away, then they shouldn’t be discouraged. Natural gas could offer some benefit as a stopgap measure for last-ditch replacement for coal fired plants in the absence of nuclear power.