Following the inaugural ceremony of the Coal Power Plant in Davao City last Friday, January 8, 2016 which stunned the public with “sili” emissions from President Noynoy Aquino’s lips — What if there’s no wind? What if the clouds are overcast? And the solar efficiency is down? What if we do not have enough bio mass?— an effusion of contra-sili questions and remarks arose, most especially in the social media. One such counter-remark asks “What if the President has no brains?”
And the cerebral fray continues and the quality of the air in the resultant debate has gotten hotter and hotter, there’s a need to let the atmosphere cool down. It’s good to reflect on the lessons of experience and peer into the facts offered by studies and researches that revolve around the subject of contention.
Out of this, the commitment of our environmental advocates and activists will be fortified as they continue to monitor the effects and impact of the Coal Plant in its operation through the days ahead. And so, here is an article to provide cold facts about Coal from the experience of the most wanton user of Coal in the last century or so.
COAL FACTS
We are at a crossroads with coal. On one side of the global debate, we hear that greater reliance on coal is essential to addressing a so-called energy crisis. It is argued that with more government funding and private investment, we can make coal far cleaner, and cleaner coal more affordable.
On the other side, we hear that so-called “clean coal” merely continues reliance on the most polluting source of fossil energy. Continued coal use is a principal reason we breathe dirty air, acidify streams, lakes and forests, contaminate them with mercury and other toxic pollutants, and risk potentially devastating global climate disruption.
The term “clean coal” has been attached to coal technologies under development that would cost more, but could sharply reduce emissions of certain pollutants. But coal technologies, such as IGCC with carbon capture and storage, that could produce similarly steep reductions in mercury emissions and carbon dioxide, the main global warming gas, remain elusive and potentially far more costly.
If we factor in the true costs needed to make coal-based electricity even approach the low emissions and impact levels of other resources and technologies – such as natural gas, biomass, wind, or industrial energy efficiency — coal would likely price itself out of most energy markets. (This fact is evident when you consider how global coal prices soared in 2004.) Even then it remains unclear whether some of these coal “clean-ups” – such as carbon capture and storage — are technologically or financially feasible, reliable and without serious environmental concerns of their own.
Coal plants, in the US, are the electricity industry’s principal source of pollution. They account for 92% of that sector’s sulfur oxide emissions, 85% of its nitrogen oxide emissions, 76% of its carbon dioxide emissions, and 99% of its mercury emissions.
Coal plants are the single leading source of all mercury pollution in the US, accounting for a third of all airborne mercury releases. Mercury is a powerful nervous system toxin, and has already contaminated over 50,000 lakes and streams in the US. Coal-fired power plants emitted 46 tons of mercury in 1990, an amount that is expected to increase 33% by 2010 as coal use increases, and yet they are the only major mercury sources that are unregulated. Coal power plants released roughly 4,000 tons of toxic metal compounds to the air in 1998, many of which are known carcinogens and neurotoxins, yet whose emissions are largely uncontrolled.
The ABCs of Clean Coal
FBC: In fluidized bed combustion (FBC) technology, limestone is mixed with the fuel during combustion to binding with sulfur. This reduces SOx emissions, and also enables the use of low quality, high-sulfur, fossil fuels. However, FGD reduces overall conversion efficiencies, and therefore actually increases CO2 emissions. Also, both FGD and FBC sulfur abatement uses calcium carbonate, which itself releases CO2 as it is consumed. The use of high sulfur coals in FBC requires high limestone consumption, which results in increased CO2 emissions.
IGCC: An integrated gasification combined cycle (IGCC) is a power configuration in which the fuel is gasified so that it can be fed to a high efficiency combined cycle, rather than a steam cycle. Only IGCC reduces both SO2 as well as CO2 emissions. A key ongoing area of development is the high-temperature cleaning of coal gas, which is necessary for its combustion in a turbine. An added benefit of coal gasification is that sulfur can be removed before the combustion stage, rendering flue gas desulfurization (FGD) unnecessary. Typically, more than 99 percent of the sulfur pollutants are captured and converted into sulfuric acid or elemental sulfur, both salable by-products. Nitrogen oxide emissions are about one-tenth those of a conventional power plant. IGCC is, unfortunately, still too expensive for widespread commercial use. This technology remains in the experimental phase.
“Clean Coal”: oxymoron or achievable goal?
“At the current time, at least 15 separate regulatory actions dealing with SO2, NOx, and mercury are now either pending at the Environmental Protection Agency or are in litigation. These actions are based on the faulty premise that an increase in coal means an increase in emissions. This is simply not true.”
Brett Harvey, Chairman and CEO for CONSOL Energy, Inc., testifying on behalf of the National Mining Association, before the House Committee on Energy and Commerce’s Subcommittee on Energy and Air Quality, March 14, 2001.
Expectations for “clean coal” often rest on such wishful hyperbole. It may be possible to eventually produce electricity from coal with low emissions and limited impacts across its fuel cycle. The technologies to increase combustion efficiency, to remove most pollutants, to mine in a low-impact fashion, and to recycle or reuse the waste products of the coal fuel chain, are either identified or within reach in the coming decade or two. Of course, these could impose quite substantial additional costs on coal use. And, to be realistic, we must always consider true costs.
Carbon dioxide is more difficult to control than other pollutants. To burn coal with near zero carbon emissions will require a combination of high efficiency and carbon capture and storage technologies (CCS). Even if the high cost of such technologies were not an issue, doubts remain about the impacts and security of most options for CO2 storage, to ensure it is permanently kept out of the atmosphere.
This raises three big questions. How much will coal-based electricity cost once all these factors are taken into account? How long will it take to get to low impact coal, and how much irreversible damage will occur before we get there (i.e. climate impacts from the billions of tons of carbon dioxide emitted in the meanwhile, tons of mercury and other toxic pollutants released, streams and habitats destroyed, etc.)? How does this path compare to one that invests instead in available zero or low carbon alternatives?
The federal government has thus far invested nearly $2 billion in taxpayer funds in the Clean Coal Technology (CCT) program. It has yielded some important innovations, like lower-cost low-NOx burners, which has helped 50% of all plant capacity to install NOx controls. It has also helped to lower the cost of sulfur dioxide controls. However, it is still far short of its ultimate goal of a nearly carbon and pollution-free low-cost coal power plant with efficiency over 60%. It has also been plagued by mismanagement, and has been the target of seven GAO investigations over its 16-year life, largely as the result of project bankruptcies and overruns Advanced coal technologies, like integrated gasification combined cycle (IGCC) and fluidized bed combustion (FBC), have been piloted through the CCT program, and appear to offer potential for very low air emissions of criteria air pollutants like SOx, NOx, and particulates, but not CO2. (See Box) IGCC, which promises the greatest reductions in criteria, CO2, and toxic pollutants emissions, has yet to be taken up by the private sector without substantial subsidies. It remains to be seen whether developers of the next generation of merchant and utility coal plants will make the necessary additional investments. Even the US DOE recognizes that “despite the performance and emission advantages of these technologies [IGCC and FBC], high capital costs threaten competitiveness in the utility market.”
Reduced emissions from coal combustion: many tough challenges remain
The Clean Air Act and other environmental regulations, along with the control technologies promoted by the Clean Coal Technology program, have yielded important progress in the reduction of criteria pollutants. But success in addressing CO2, toxic emissions, and local environmental and health impacts has been far more limited. And, the leading greenhouse gas is carbon dioxide.
The steady improvement in NOx and SOx emissions for newer plants from 1970-1997 is evident (in available data). Sulfur dioxide and, to a lesser degree, nitrogen oxide emissions have clearly declined for newer plants. Still, the older dirtier plants dominate overall generation. (And, these are the plants that are often sold second hand to developing countries.) Moreover, coal-fired power plant efficiencies have not improved. The addition of power-consuming emission control technologies and evaporative cooling towers, have more than offset any technical improvements in combustion efficiency, and as a direct result, the rate of carbon dioxide emissions, has actually increased slightly. Mercury emissions have decreased somewhat across the period. Nonetheless, absent new regulations, it is still possible that even new plants, could emit at relatively high levels.
Coal and carbon dioxide: the ultimate challenge
The greatest challenge to making coal clean is to reduce or eliminate its carbon dioxide emissions. Ultimately, climate stabilization will require that homes, offices and factories shift to highly efficient energy using equipment, and that electricity comes largely from energy resources and generating technologies with no carbon dioxide emissions, such as wind, solar, geothermal and biomass.
Two factors largely determine a power plant’s CO2 emissions – its efficiency and the carbon content of the fuel. Compared with natural gas, coal is well behind on both counts.
Coal contains 70% more CO2 per unit of energy input to electricity generation, and new natural gas power plants are 30-50% more efficient. Together these two factors make coal-based electricity more than twice as polluting, in greenhouse gas terms, as natural gas-based electricity.
Lowering the carbon emissions from coal to natural gas levels, and below, will require progress on two fronts:
• Making coal plants more efficient. Notwithstanding its gains in NOx and SOx control technologies, the Clean Coal Technology program has failed to achieve major improvements in coal plant efficiencies. State-of-the-art pulverized coal plants are approaching their peak efficiency potential, at about 45% for supercritical boiler units. Fluidized bed plants also seem to be inherently limited to at the 45% level. This compares with nearly 60% for state-of-the-art combined cycle natural gas plants, and much higher efficiencies for natural gas co-generation plants. So, if carbon emissions are to be controlled via efficiency improvements, the future of coal ultimately lies in gasification technologies, which, linked with combined cycle units or fuel cells, could potentially exceed 50% efficiency. However, demonstration plants have yet to come close to these levels, and this new technology is still many years from full commercialization in the US. Even then, carbon emissions per kWh of electricity would be far higher from coal plants than advanced natural gas plants and, of course, renewables and efficiency, which are carbon-free.
• Capturing and storing the carbon. If one places faith in coal as a fuel of the future, all roads inevitably lead to this approach. There is simply no way of achieving meaningful climate stabilization with continued coal use, unless the carbon is somehow kept from entering the atmosphere. Carbon could potentially be “captured” either before burning the coal or afterwards. With conventional solid coal combustion technologies, the carbon must be removed from flue gases, an expensive proposition given that CO2 is typically a small constituent (9-14%) of a large stream of gases. A more elegant approach is to apply a front-end process like the “steamshift reaction,” which involves mixing coal with steam in the presence of a catalyst to ultimately produce CO2 and hydrogen gas. After stripping out the CO2, this hydrogen gas could then be burned cleanly in combined cycle or fuel cells. The IEA estimates that CO2 capture would increase the cost of coal electricity by 50-70%, depending on whether gasification or post-combustion technologies are used.
The more difficult and unresolved challenge is figuring out a safe and reliable way to store the captured CO2 on a long-term basis. Possible storage sites include deep saline aquifers, ocean depths, depleted oil and gas reservoirs, or un-mineable coal beds. There is substantial scientific uncertainty about the potential environmental impacts of deep ocean storage, and about the long-term integrity of each of these storage options.
For instance, little is known about whether earthquakes could trigger sudden or slow releases of stored CO2. IEA estimates the overall cost of CO2 capture and storage today at $40-60/tCO2. This alone could more than double the costs of electricity from new coal plants and more than triple the costs of generation from existing plants. Two things remain clear. CCS is not going to be applicable everywhere in the globe. It will be site specific and dependent on the type of rock that exists. It may be dangerous in earthquake prone areas. With CCs, more costs would be incurred, in order to reduce the other human and environmental impacts along the entire coal-to-electricity fuel cycle. Such costly measures are not faced by natural gas, renewables and efficiency. It remains easier, and cheaper, to simply promote renewable energy technologies.
Conclusion
Coal is made mostly of carbon, and burning it inescapably produces carbon dioxide. Our huge fleet of existing coal-burning power plants is pumping carbon dioxide into the atmosphere, and building new coal plants will just intensify the risk that we are dangerously disrupting our climate.
If the objective is truly clean electricity, the least-cost path today involves turning away from coal and instead towards a combination of energy efficiency, natural gas, wind, cogeneration, and other lower-emission resources. Natural gas, geothermal, mini-hydro, biomass, wind, industrial energy efficiency and wind backed up by natural gas units (for when the wind isn’t blowing) are all significantly less expensive than “clean coal”.
A coal-focused national energy strategy would be fundamentally misguided. Closer and clearer examination of available information reveals that there is a long way to go before coal will be truly clean, if ever, and an even longer way before it would be competitive.
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SOURCES:
COAL: America’s Past. America’s Future?
President Bush’s Plan and the Risk of Global Warming
A Study for: The World Wildlife Fund
Prepared by: Stephen Bernow, Michael Lazarus, Sivan Kartha
Tellus Institute, Boston, Massachusetts
May 2001
