Part 2 of Part II: Coal

Here is Part 2 of Part II: Coal, and a look at the latest "clean" coal technologies:

As We Have Seen Over The Last Few Years With Fuel Prices Climbing Ever Higher, Oil Dependency Has Become Hazardous to Our Economic Health!
Over half of the oil that fuels America's economy is now sold to us from foreign sources . Growing Foreign Dependence, But these sources may not always be reliable.
In 1973 and 1979, America experienced dual "oil shocks" -- cutoffs of supply that provided an important warning about our vulnerability to foreign disruptions. Those crises should have served as lessons about dependence on unreliable offshore sources. Instead, our dependence on foreign sources stands at an even higher level today than it did during the embargoes that plunged America into serious recessions in the past.
Today, America is vulnerable.

An Important Step
Toward Reducing Our Vulnerability
One logical alternative is coal. American coal and waste coal reserve estimates vary wildly . World Recoverable Oil Resoucres~~Pennsylvania, a prime coal state, is estimated to have 34 billion tons of in ground reserves.
But until recently, environmental concerns about coal posed a large obstacle to attaining greater U.S. self-sufficiency in energy. The environmental impact of mining and burning more coal was considered by many people to be too great to justify.
Today, new technology has made it possible for us to turn back to domestic energy sources -- and to do it cleanly. Coal gasification/coal liquefaction will now allow us to tap the abundant energy stores within our own borders -- without compromising our standards of environmental quality. In fact, these technologies may be our best hope for environmental progress in future years.
Using more of our domestic energy reserves would free us from reliance on potentially unstable sources and the economic drain that results from buying oil from overseas. It would result in greater stability in fuel pricing, jobs and job security, and enhance our national security by lessening our dependency on foreign sources.
The "US Geological Survey estimates the total identified coal resources as being 1,600 billion tons. Another 1,600 billion tons of unidentified resources are postulated." Currently the US produces approximately 1.06 billion tons of coal annually.
If the US were to produce, from coal alone, the amount of oil equivalent to what the US imports, the US would consume an additional .912 billion tons annually.

Total coal production/consumption would then = 1.972 billion tons annually. (Not even considering the benefits of energy efficiency, biomass, renewables, high mileage vehicles etc., all of which would significantly extend our energy reserves.)
1,600 billion tons of coal / 1.972 = 811 years of fuel reserves.
Given these new conversion technologies the US is, in effect, sitting on a minimum of 811 years of worth of fuel reserves.
To the extent this message becomes clear to off shore oil suppliers, the perception of a sellers market should diminish and the US would be positioned to purchase oil on its own terms.
Coal Gasification/Liquefaction Link
Coal conversion technologies - - such as Coal Gasification / Liquefaction Coal Gasification/Liquification-- are process technologies adapted from proven production methods that have been in use for decades.
In sum, the process utilizes carbonaceous matter -- coal, coal waste, biomass, refinery waste and other materials -- to produce liquid fuel products that are environmentally friendly, known as Ultra Clean Fuels.
Ultra Clean Fuels are zero-% nitrogen, low in aromatics
with a high cetane (energy density) number.
Fuels meeting these criteria are already required in some areas of the country with strict emissions standards. Ultra Clean Fuels would not only be plentiful, they could also play a large role in helping us meet the new goals for energy efficiency and cleaner air.
In addition, the production process extracts sulfur and other materials which can be used for other manufacturing and commercial purposes.

Economic Benefits Of
Choosing Ultra Clean Fuels Technology
Making a commitment to Ultra Clean Fuels Technology will have substantial and long-lasting benefits, according to a study by the Center for Forensic Economic Studies. Among them:
Adoption of Ultra Clean Fuels Technology would re-energize the domestic coal production industry (Anthracite, Bituminous, Sub Bituminous, Lignite).

Construction and operation of Ultra Clean Fuels production facilities would create high-quality jobs, improve job security and productivity, and result in numerous spin-off benefits throughout the economy.

Reliance on domestic coal resources would revitalize communities in coal producing regions across the country.

Lessening dependence on foreign oil sources would improve the U.S. balance of payments dramatically and reduce the outflow of dollars to overseas suppliers.

Diversifying our sources of energy would reduce the threat of war or economic blackmail by foreign powers that control a portion of oil reserves, with potential savings of billions of dollars and thousands of lives.

Environmental Benefits Of Choosing
Ultra Clean Fuels Technology
Ultra Clean Fuels are cleaner both in production and consumption than standard fossil fuels.

Utilizing Ultra Clean Fuels would reduce the overall amount of greenhouse gases introduced into the atmosphere.

Ultra Clean Fuels are generally more environmentally friendly than the production of electricity for electric "non-polluting" cars.

Coal wastes that have blighted the landscapes of coal producing regions for decades would be utilized for production, resulting in wholesale reclamation of those regions.

The Private/Public Partnership
Moving Ultra Clean Fuels Technology from the drawing board into production will require an enormous effort and sizable startup costs. For this reason, the Private / Public Partnership for Ultra Clean Fuels Technology represents the best means for making Ultra Clean Fuels Technology commercially viable in the near future.
In this partnership, private industry would be responsible for financing and construction as well as operation of the production facilities.
The public sector role would center around adoption of tax incentives that help offset the enormous capital expenditures required to make plants operational. This step will ensure a more reasonable level of risk for commercial financing purposes.


Conclusion
The benefits of applying Ultra Clean Fuels Technology are substantial:
better utilization of domestic coal and other carbonaceous feedstock

an alternative to continued dependence on unreliable oil imports Energy Dependency

rebuilding our energy industry Energy Independence

creation of new high-quality jobs

reclamation of the nation's coal regions

economic benefits of lessening foreign debt burden incurred from imports
These factors are only the highlights of a program that will have an enormous positive impact on the living standards and quality of life of the American people.
Implementing Ultra Clean Fuels Technologies through a Private/Public Partnership represents a true "win-win" for the economy and the environment.
The time to act is now.

And here is how coal is seen from the prespective others, with this assessment from the World Nuclear Association:
Clean Coal Technology:
Coal is a vital fuel in most parts of the world.
Burning coal without adding to global carbon dioxide levels is a major technological challenge which is being addressed.
The most promising "clean coal" technology involves using the coal to make hydrogen from water, then burying the resultant carbon dioxide by-product and burning the hydrogen.
The greatest challenge is bringing the cost of this down sufficiently for "clean coal" to compete with nuclear power on the basis of near-zero emissions for base-load power.
Coal is an extremely important fuel and will remain so. Some 23% of primary energy needs are met by coal and 39% of electricity is generated from coal. About 70% of world steel production depends on coal feedstock. Coal is the world's most abundant and widely distributed fossil fuel source. The International Energy Agency expects a 43% increase in its use from 2000 to 2020.
However, burning coal produces about 9 billion tonnes of carbon dioxide each year which is released to the atmosphere, about 70% of this being from power generation. Other estimates put carbon dioxide emissions from power generation at one third of the world total of over 25 billion tonnes of CO2 emissions.
New "clean coal" technologies are addressing this problem so that the world's enormous resources of coal can be utilised for future generations without contributing to global warming. Much of the challenge is in commercialising the technology so that coal use remains economically competitive despite the cost of achieving "zero emissions".
As many coal-fired power stations approach retirement, their replacement gives much scope for 'cleaner' electricity. Alongside nuclear power and harnessing renewable energy sources, one hope for this is via "clean coal" technologies, such as are now starting to receive substantial R&D funding.
Managing wastes from coal
Burning coal, such as for power generation, gives rise to a variety of wastes which must be controlled or at least accounted for. So-called "clean coal" technologies are a variety of evolving responses to late 20th century environmental concerns, including that of global warming due to carbon dioxide releases to the atmosphere. However, many of the elements have in fact been applied for many years, and they will be only briefly mentioned here:
Coal cleaning by 'washing' has been standard practice in developed countries for some time. It reduces emissions of ash and sulfur dioxide when the coal is burned.
Electrostatic precipitators and fabric filters can remove 99% of the fly ash from the flue gases - these technologies are in widespread use.
Flue gas desulfurisation reduces the output of sulfur dioxide to the atmosphere by up to 97%, the task depending on the level of sulfur in the coal and the extent of the reduction. It is widely used where needed in developed countries.
Low-NOx burners allow coal-fired plants to reduce nitrogen oxide emissions by up to 40%. Coupled with re-burning techniques NOx can be reduced 70% and selective catalytic reduction can clean up 90% of NOx emissions.
Increased efficiency of plant - up to 45% thermal efficiency now (and 50% expected in future) means that newer plants create less emissions per kWh than older ones.
Advanced technologies such as Integrated Gasification Combined Cycle (IGCC) and Pressurised Fluidised Bed Combustion (PFBC) will enable higher thermal efficiencies still - up to 50% in the future.
Ultra-clean coal from new processing technologies which reduce ash below 0.25% and sulfur to very low levels mean that pulverised coal might be fed directly into gas turbines with combined cycle and burned at high thermal efficiency.
Gasification, including underground gasification in situ, uses steam and oxygen to turn the coal into carbon monoxide and hydrogen.
Sequestration refers to disposal of liquid carbon dioxide, once captured, into deep geological strata.
Some of these impose operating costs without concomitant benefit to the operator, though external costs will almost certainly be increasingly factored in through carbon taxes or similar which will change the economics of burning coal.
However, waste products can be used productively. In 1999 the EU used half of its coal fly ash and bottom ash in building materials (where fly ash can replace cement), and 87% of the gypsum from flue gas desulfurisation.
Carbon dioxide from burning coal is the main focus of attention today, since it is implicated in global warming, and the Kyoto Protocol requires that emissions decline, notwithstanding increasing energy demand.
Capture & separation of CO2
A number of means exist to capture carbon dioxide from gas streams, but they have not yet been optimised for the scale required in coal-burning power plants. The focus has often been on obtaining pure CO2 for industrial purposes rather than reducing CO2 levels in power plant emissions.
Where there is carbon dioxide mixed with methane from natural gas wells, its separation is well proven. Several processes are used, including hot potassium carbonate which is energy-intensive and requires a large plant, a monoethanolamine process which yields high-purity carbon dioxide, amine scrubbing, and membrane processes.
Capture of carbon dioxide from flue gas streams following combustion in air is expensive as the carbon dioxide concentration is only about 14% at best. This treats carbon dioxide like any other pollutant and as flue gases are passed through an amine solution the CO2 is absorbed. It can later be released by heating the solution. This amine scrubbing process is also used for taking CO2 out of natural gas. There is an energy cost involved.
The Integrated Gasification Combined Cycle (IGCC) plant is a means of using coal and steam to produce hydrogen and carbon monoxide (CO) which are then burned in a gas turbine with secondary steam turbine (ie combined cycle) to produce electricity.
If the IGCC gasifier is fed with oxygen rather than air, the flue gas contains highly-concentrated CO2 which can readily be captured by amine scrubbing - at about half the cost of capture from conventional plants. Ten oxygen-fired gasifiers are operational in the USA.
Development of this oxygen-fed IGCC process will add a shift reactor to oxidise the CO with water so that the gas stream is basically just hydrogen and carbon dioxide. These are separated before combustion and the hydrogen alone becomes the fuel for electricity generation (or other uses) while the concentrated pressurised carbon dioxide is readily disposed of.
Currently IGCC plants have a 45% thermal efficiency.
Capture of carbon dioxide from coal gasification is already achieved at low marginal cost in some plants. One (albeit where the high capital cost has been largely written off) is the Great Plains Synfuels Plant in North Dakota, where 6 million tonnes of lignite is gasified each year to produce clean synthetic natural gas.
Oxy-fuel technology has potential for retrofit to existing pulverised coal plants, which are the backbone of electricity generation in many countries.
Storage & sequestration of CO2
Captured carbon dioxide gas can be put to good use, even on a commercial basis, for enhanced oil recovery. This is well demonstrated in West Texas, and today over 3000 km of pipelines connect oilfields to a number of carbon dioxide sources in the region.
At the Great Plains Synfuels Plant, North Dakota, some 13,000 tonnes per day of carbon dioxide gas is captured and 5000 t of this is piped 320 km into Canada for enhanced oil recovery. This Weyburn oilfield sequesters about 85 cubic metres of carbon dioxide per barrel of oil produced, a total of 19 million tonnes over the project's 20 year life. The first phase of its operation has been judged a success.
Overall in USA, 32 million tonnes of CO2 is used annually for enhanced oil recovery, 10% of this from anthropogenic sources.
The world's first industrial-scale CO2 storage was at Norway's Sleipner gas field in the North Sea, where about one million tonnes per year of compressed liquid CO2 separated from methane is injected into a deep reservoir (saline aquifer) about a kilometre below the sea bed and remains safely in place. The US$ 80 million incremental cost of the sequestration project was paid back in 18 months on the basis of carbon tax savings at $50/tonne. (The natural gas contains 9% CO2 which must be reduced before sale or export.) The overall Utsira sandstone formation there, about one kilometre below the sea bed, is said to be capable of storing 600 billion tonnes of CO2.
West Australia's proposed Gorgon natural gas project from 2009 will tap natural gas with 14% CO2. Capture and geosequestration of this will reduce the project's emissions from 6.7 to 4.0 million tonnes of CO2 per year.
Injecting carbon dioxide into deep, unmineable coal seams where it is adsorbed to displace methane (effectively: natural gas) is another potential use or disposal strategy. Currently the economics of enhanced coal bed methane extraction are not as favourable as enhanced oil recovery, but the potential is large.
While the scale of envisaged need for CO2 disposal far exceeds today's uses, they do demonstrate the practicality. Safety and permanence of disposition are key considerations in sequestration.
Research on geosequestration is ongoing in sevaral parts of the world. The main potential appears to be deep saline aquifers and depleted oil and gas fields. In both, the CO2 is expected to remain as a supercritical gas for thousands of years, with some dissolving.
Large-scale storage of CO2 from power generation will require an extensive pipeline network in densely populated areas. This has safety implications.
Economics, R&D
The World Coal Institute notes that at present the high cost of carbon capture and storage (US$ 150-220 per tonne of carbon, $40-60/t CO2 - 3.5 to 5.5 c/kWh relative to coal burned at 35% thermal efficiency) renders the option uneconomic. But a lot of work is being done to improve the economic viability of it, and the US Dept of Energy (DOE) is funding R&D with a view to reducing the cost of carbon sequestered to US$ 10/tC (equivalent to 0.25 c/kWh) or less by 2008, and by 2012 to reduce the cost of carbon capture and sequestration to a 10% increment on electricity generation costs.
More recently the DOE had announced the $1.3 billion FutureGen project to design, build and operate a nearly emission-free coal-based electricity and hydrogen production plant. The FutureGen initiative would have comprised a coal gasification plant with additional water-shift reactor, to produce hydrogen and carbon dioxide. About one million tonnes of CO2 (at least 90% of throughput) would then be separated by membrane technology and sequestered geologically. The hydrogen would have been be burned in a 275 MWe generating plant and in fuel cells.
Construction of FutureGen was due to start in 2009, for operation in 2012. The project was designed to validate the technical feasibility and economic viability of near-zero emission coal-based generation. In particular it aimed to produce electricity with only a 10% cost premium and to show that hydrogen can be produced at $3.80 per GJ, equivalent to petrol at 12.7 cents per litre.
In December 2007 Mattoon Illinois was chosen as the site of the demonstration plant. However, in January 2008 the DOE announced that it would pull its funding for project, expressing concerns over escalating costs. The DOE has said that funding would be made available to assist other projects that aim to add carbon capture and storage (CCS) to existing coal plants, but will no longer include hydrogen production as part of the project.
In the UK a competition was launched by the UK government in November 2007 to support a coal-fired power plant demonstrating the full chain of CCS technologies (capture, transport, and storage) on a commercial scale. The winning project bid will need to demonstrate post-combustion capture (including oxyfuel) on a coal-fired power station, with the carbon dioxide being transported and stored offshore. The project will have to capture around 90% of the CO2 emitted by the equivalent of 300MW-400MW generating capacity. The successful project bid should demonstrate the entire CCS chain by 2014. The winning project bid will be chosen by May-June 2009.
In Denmark a pilot project at the 420 MWe Elsam power plant is capturing CO2 from post-combustion flue gases under the auspices of CASTOR (CO2 from Capture to Storage). Flue gases are passed through an absorber, where a solvent captures about 90% of the CO2. The pregnant solution is then heated to 120°C to release pure CO2 at the rate of about one tonne per hour for geological sequestration. Cost is expected to be EUR 20-30 per tonne.
A 2000 US study put the cost of CO2 capture for IGCC plants at 1.7 c/kWh, with an energy penalty 14.6% and a cost of avoided CO2 of $26/t ($96/t C). By 2010 this is expected to improve to 1.0 c/kWh, 9% energy penalty and avoided CO2 cost of $18/t ($66/t C).
Figures from IPCC Mitigation working group in 2005 for IGCC put capture and sequestration cost at 1.0-3.2 c/kWh, thus increasing electricity cost for IGCC by 21-78% to 5.5 to 9.1 c/kWh. The energy penalty in that was 14-25% and the mitigation cost $14-53/t CO2 ($51-200/tC) avoided. These figures included up to $5 per tonne CO2 for transport and up to $8.30 /t CO2 for geological sequestration.
Gasification processes
In conventional plants coal, often pulverised, is burned with excess air (to give complete combustion), resulting in very dilute carbon dioxide at the rate of 800 to 1200 g/kWh.
Gasification converts the coal to burnable gas with the maximum amount of potential energy from the coal being in the gas.
In Integrated Gasification Combined Cycle (IGCC) the first gasification step is pyrolysis, from 400°C up, where the coal in the absence of oxygen rapidly gives carbon-rich char and hydrogen-rich volatiles.
In the second step the char is gasified from 700°C up to yield gas, leaving ash. With oxygen feed, the gas is not diluted with nitrogen.
The key reactions today are C + O2 to CO, and the water gas reaction: C + H2O (steam) to CO & H2 - syngas, which reaction is endothermic.
In gasification, including that using oxygen, the O2 supply is much less than required for full combustion, so as to yield CO and H2. The hydrogen has a heat value of 121 MJ/kg - about five times that of the coal, so it is a very energy-dense fuel. However, the air separation plant to produce oxygen consumes up to 20% of the gross power of the whole IGCC plant system. This syngas can then be burned in a gas turbine, the exhaust gas from which can then be used to raise steam for a steam turbine, hence the "combined cycle" in IGCC.
To achieve a much fuller clean coal technology in the future, the water-shift reaction will become a key part of the process so that:
C + O2 gives CO, and
C + H2O gives CO & H2, then the
CO + H2O gives CO2 & H2 (the water-shift reaction).
The products are then concentrated CO2 which can be captured, and hydrogen. (There is also some hydrogen from the coal pyrolysis), which is the final fuel for the gas turbine.
Overall thermal efficiency for oxygen-blown coal gasification, including carbon dioxide capture and sequestration, is about 73%. Using the hydrogen in a gas turbine for electricity generation is efficient, so the overall system has long-term potential to achieve an efficiency of up to 60%.
Present trends
The clean coal technology field is moving very rapidly in the direction of coal gasification with a second stage so as to produce a concentrated and pressurised carbon dioxide stream followed by its separation and geological storage. This technology has the potential to provide what may be called "zero emissions" - in reality, extremely low emissions of the conventional coal pollutants, and as low-as-engineered carbon dioxide emissions.
This has come about as a result of the realisation that efficiency improvements, together with the use of natural gas and renewables such as wind will not provide the deep cuts in greenhouse gas emissions necessary to meet future national targets.
The US DOE sees "zero emissions" coal technology as a core element of its future energy supply in a carbon-constrained world. It has in place an ambitious program to develop and demonstrate the technology and have commercial designs for plants with an electricity cost of only 10% greater than conventional coal plants available by 2012.
Australia is very well endowed with carbon dioxide storage sites near major carbon dioxide sources, but as elsewhere, demonstration plants will be needed to gain public acceptance and show that the storage is permanent.
In several countries, "zero emissions" technology seems to have the potential for low avoided cost for greenhouse gas emissions.


Tomorrow is Part III: Wind!!