"Clean coal" versus liquified natural gas



article_image

By Dr A.C.Visvalingam
President, CIMOGG
www.cimogg-srilanka.org
acvisva@gmail.com


From the early 1970s, the highly-committed senior engineer Carlo Fernando lobbied sincerely, knowledgeably and forcefully to press the governments of the time to build one or two medium-sized coal-based power stations and not to go in for gas turbine or diesel engine-powered electricity generation. The thrust of his logic was that (1) Sri Lanka’s hydropower potential was limited and would soon be fully exploited, (2) the volume and timing of rainfall could not be accurately predicted, (3) the "base load" electricity demand would be best met by resorting to thermal power which is ideally suited for that purpose but hydropower, on account of its limited availability, should be employed only to meet peak loads over and above the "base load", (4) coal power stations from reputed sources are robust and have a long life, with relatively simple maintenance requirements, as compared to petroleum-fuelled engines and gas turbines, (5) nuclear power was far too complex for Sri Lanka to handle, quite apart from its radiation dangers in the event of an accident, (6) wind power was highly variable and too expensive, (7) solar power could be effective during daylight hours but was expensive and inflexible because the electricity generated could not be stored economically for night-time use, and (8) coal was plentifully available and relatively cheap whereas liquified natural gas (LNG) was far more costly at that time. Wave power, tidal power, ocean thermal energy conversion, hot dry rock heat extraction etc were still far from reaching industrial application status. As things stood then, from a practical point of view, coal power was the choice that could be considered to have been the most suited for Sri Lanka.


During that time, there was relatively little strength in the hands of the environmental lobby and consequently the proponents of coal power wielded greater influence, although not so much as the petroleum lobby, in which greedy politicians had a "quick-return" interest, and still do. Meanwhile, coal power boiler manufacturers were working hard in a genuine effort to make coal more acceptable by finding ways and means of limiting the volumes of dust, sulphur dioxide and nitrogen oxide that would emerge from the power station chimneys. Dealing with heavy metals like cadmium, lead and mercury was not considered to be economically feasible and was, therefore, not given much attention. The population of Sri Lanka then was very much less than it is now and, hence, it was possible to identify a few sites in sparsely populated, protected, coastal locations where coal could be unloaded and stored conveniently, where a good cooling water supply was available, and the spreading of coal dust from the point of unloading from ships to the releasing of the treated flue gases into the atmosphere could be expected to affect only a limited area with a small population. In this scenario, the "raw" cost of coal power generation was shown to be much lower than the costs associated with the alternatives then available, including LNG. However, the ground situation has greatly altered over the past 30-40 years and we need to examine this issue afresh.


One very important change that has taken place since the 1970s and 1980s is that the population has grown substantially and spread into areas that were sparsely populated three or four decades ago. A second significant factor is that there are now several individuals and organisations that are much more knowledgeable and vocal about the types and scale of the damage caused to our environment by power projects. Most of the recent newspaper articles inveighing against the promotion of "clean coal" have been written by scientists, engineers and environmentalists who have taken the trouble to study the physical and chemical analyses of the products of coal combustion to underpin their case, which is a strong one, against those who advocate the use of "clean coal". The third matter that one cannot ignore is the unwelcome spread of coal dust during transport, handling, storage and combustion, against which nuisance there are currently several petitions filed by the public at Norochcholai, which make it clear that this is an issue that cannot be glossed over. We are not aware whether any detailed analyses and costings have been done on the environmental damage caused by coal dust and the removal of such dust to whatever extent may be practical. If even an approximate cost of the environmental degradation and public annoyance caused by coal during the various stages of transferring it from ships to boilers could be worked out and added to the "raw" cost of coal power, a fairer economic comparison may be made with sources of power that have fewer negative features, particularly LNG.


In the case of LNG, its shipping, unloading, transport, handling and combustion do not spread unwelcome oily black particulate matter over the surrounding countryside although the amount of carbon dioxide that is released would be of the same order as in the case of coal. Furthermore, burning LNG does not produce unwanted sulphur dioxide, nitrous oxide and heavy metal combustion products.


Another key consideration is that Sri Lanka has no coal of its own and will forever be dependent on whichever sources are identified as producing the particular type of coal that is required for the particular design of the steam boiler that is selected. In contrast, over the past three or four decades, LNG has become more readily available from several sources and the design of the burners and boilers is not sensitive to the source of the LNG. Of the greatest relevance is the fact that Sri Lanka’s marine resources are known to include substantial natural gas reserves which, if developed with reasonable expedition, would be a fuel source that cannot be monopolised by cartels of foreign suppliers working in concert in the international markets to keep raising their prices as and when they please.


We need also to recognise that working out a cost for environmental degradation and public annoyance caused by the transporting, handling and burning of coal does not remove these undesirable effects. Avoiding these negative impacts altogether, ab initio, even at a higher cost by going for a cleaner fuel would be far better than creating these adverse impacts in the first place. In other words, minimising pollution from the outset is better than polluting first and trying to clean up the mess later.


Even the "solution" offered by planting trees to compensate for carbon dioxide emissions suffers from the same flaws whether the fuel be coal or LNG, namely, the large area of land required and the many years it would take for the trees to reach a size at which they would be effective, during which the power plants would have spewed out colossal amounts of carbon dioxide. Needless to say, renewable sources of power would be better but, as things stand at the moment, they cannot be relied upon to provide solid "base load" power any time soon.


It should be remembered that the government committed itself, as recently as in April 2016, to the international community by undertaking to base her development on a fossil-free agenda. We also understand that the Cabinet has already approved a Long Term Generation Plan for electrical power, covering the period 2017-2038. It was not many months ago that the public were informed that a firm decision had been taken to work with LNG and not coal. That decision must have been taken after a careful study and it is, therefore, surprising to learn that the government is being pressurised to go back to the plan to build two "clean coal" power plants. Whilst there are honest engineers who believe that coal power should be selected over LNG because they give a different weighting to the relative advantages and disadvantage of these two sources of heat energy, there may be some crooked political heavyweights who favour coal because it could prove to be a long-term godsend that would keep on yielding golden eggs for many years without leaving room to exploit our natural gas resources for power-production purposes. Taking all factors into account, the Citizens’ Movement for Good Governance (CIMOGG) is of the view that LNG should prevail over "clean coal" until we get our renewable sources of energy fully mobilised, which, however, will take more than a decade or two of sustained effort.


 


 
 
 
 
 
 
 
 
 
 
animated gif
Processing Request
Please Wait...