Posted by Earth Stove on November 3, 2016coal, discussion, reader, responds, Wooden
In our Oct newsletter, we reprinted a column by Cory Hatch from the Jackson Gap Information & Information.  We located it to be a thoughtful piece by a individual grappling with energy alternatives and making an attempt to pretty weigh their costs and positive aspects.  We received a great deal of positive comments about the write-up but one reader, a previous professor of thermodynamics believed it was critical ample to clarify anything the writer said.
The column produced numerous great details, and concluded:
“Right after you factor in the strength and connected emissions it takes to extract, refine and transport fossil fuels, wooden begins to seem quite excellent once again. If you harvest trees close to home, firewood is reasonably effective and renewable, even if storing that carbon once again takes some time. Sadly, woodstoves have neighborhood impacts, as well. Chimney smoke includes particulates, nitrogen oxides and other gasses that can degrade air good quality and cause well being difficulties, particularly for individuals with respiratory or cardiovascular condition.”
The author also noted: “according to the Sierra Club, burning coal for electric power is only about 35 per cent successful, whereas a contemporary wood stove is about seventy five %.”
Professor Gael Ulrich took concern with that:
” It is correct that wooden is superior in that it is renewable and not a fossil gas, and it does not have sulfur or other aspects that can be problems in coal stack emissions.  But his assertion, attributed to the Sierra Club, implying that wooden combustion is 2 times as productive as coal combustion is incorrect.  The difference is refined and not appreciated by someone with out a background in thermodynamics, but I will try out to make the cause obvious.
Changing fuel strength to heat and then to electricity can never be completed with a hundred% efficiency.  Even the most contemporary efficient power vegetation seldom be successful 40%.  Historically, that basic principle was elucidated by Carnot, and the theoretical maximum feasible is recognized as the Carnot effectiveness.  In brief, electrical power or “saved work” is a greater sort of strength than heat.  Converting “heat” to “work” constantly signifies an vitality decline manifest as “waste heat.”
Coal electrical power plants possibly do not do a lot much better that 35% as recommended, but wood-fired electricgenerators are even less productive (for factors that would call for much more rationalization).  Converting the vitality articles of coal to heat can, on the other hand, be carried out with high effectiveness, matching or exceeding that of biomass combustors.
Thus, the assertion as worded in Hatch’s column is misleading.  His arguments relating to international warming, and many others. are okay.
I believed you might be fascinated in the error in case someone else has not presently referred to as it to your focus.”
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