In the previous article, in which the energy and mass conversions are described at different moments in the flow of a cycle, the role of biomass as driving energy for a resource cycle was underexposed. But let me be clear about this: Biomass a energy source is no option. First of all, recent research shows that the CO2 balance by burning biomass is far from neutral, and some cases even worse as fossil fuels. One of the reasons is that biomass is harvested and burned today, but it takes 40 – 60 years before that same CO2 is captured and stored again. [1]. While that same CO2 was already stored in the uncut trees.( and then why are we talking about CCS, capturing and storing CO2, wipe the dirt under the carpet. ?) we release that CO2 to increase the global warming effect. And it takes decades to restore it again. If that will be restored, since the pressure on wood is high, and we might harvest more then is regrown. Time, is again a crucial factor ….
However there is a second and even more important reason not to burn the biomass: we need biomass as a material: if for instance we don’t use wood for construction, ( and store the embodied CO2 for long) but use it as fuel, we will have to use non-biomass, abiotic materials for construction, which have a much larger impact and global warming effect, since they are processed with huge amounts of fossil fuels and related emissions: burned stones, cement and metals. Which is putting the horse behind the carriage. Not only have we lost the CO2 stored in biomass, plus we will have a higher CO2 emissions from burning biomass , and from construction by non-biomass resources.
Conclusion: mass should remain mass: Exergetically speaking, burning biomass is a deadly sin. It makes no sense, only loosing overall potential in a system. [2]
( which counts also for most waste. Only if reprocessing waste into a useful product would require more energy ( CO2 emissions) as burning, it would be an option)
And by the way, biomass might firstly function as a material, the energy content is still there after decades: the energy potential is secured. Some years ago I made a rough calculation about that: 15 m3 of wood is enough to construct a moderate timber-frame house. If you would use the same amount of wood as energy source, to process cement for instance, you will end up with just enough cement to built half a concrete house…. 15 m3 can deliver a full house, plus CO2 storage, plus energy potential in future, or half a concrete house, with no rest value. Count out your winnings….
To use cement/concrete for houses is in fact destroying quality, ie system potential: the material potential is actively lowered, and the energy need raised, with increased CO2 emissions. That is devastating in a world in which we have to set all sails to decrease the impact from energy and materials. Besides having lost all potential energy compared to a timber-frame house or building. Concrete does not bring you very much in future, its destroyed energy , and of mass in case of biomass. ( better: destroyed exergy, the energy is still there but unusable). There will remain some concrete, in future, which has some value , but were on earth do you need demolished concrete ? With concrete as a material nothing as such is wrong, but using concrete should only be done in cases where the specific properties are indispensable, no alternative around, and should stay in use as long as possible.: Mass not only should remain mass, but also provide a function as long as possible, to reduce the impact per year of service/function. To avoid repetitive need. But there aren’t many functions for which concrete is the only and best solution…
A interesting example showing the delicate balance between material and energy potentials, comes from Japan. During the EDO period, the 17-18 th century Japan was isolated from the rest of the world, and had to live from its own resources. [3] For energy as well as materials. Interesting from that period is the choice of roofs; Just like London, Edo ( current Tokyo) suffered large city fires. Everything was made of wood, even the roofs. There were many voices to replace the wooden roofs with ceramic (burnt) tiles but for a hundred years or so this was forbidden. The roofs remained from wood ( with loam on top as a kind of protection) . I cant prove it 100%, but after studying many sources, the only explanation is that using wood for the burning process of ceramic roof tiles , would required more wood as would be required to rebuilt houses after a fire.
Only after forestry reached high levels, even growing trees on very steep hill sides, ( and Japan is still famous for its forestry knowledge) , ceramic roof tiles were allowed .
Lets not forget, as I wrote before, that resources are not equal, there is a ranking in importance , and materials come before (external) energy, for humans that is. [4] The protection provided by a house or shelter comes first, only after that comes energy. To protect against rain and storm and cold, materials provide the first defense line ( and in history also against wild animals) . If that defense works, there is the option to add energy, to make it more comfortable, by heating. So that people can have reasonable comfort even in colder climates. Nevertheless: wherever you are: materials comes before external energy.
Biomass , which is in fact also energy since formed by the sun’s radiation, ( In science mass is sometimes referred to as rest energy, or the other way around, energy as rest mass, the two are intertwined , the exergy in the system) has more potential in its material appearance as in its energy appearance , both in need, as in system potential.
So lets be clear: mass should stay mass, and not burned and destroyed, that would be cutting in our own flesh. .
How the we should fulfill our need in (external) energy is another question… some other time.
[1] Ecowatch: study: biomass more polluting then coal https://www.ecowatch.com/chatham-house-biomass-study-2288764699.html
[2] Rovers R., 2011 Exergy relativity, the role of mass and Embodied Land, paper Cost Conference Exergy, LCA and sustainability, ELCAS, Greece 2011.
[3] For Edo a good start is the Japan for Sustainability organisation JFS: https://www.japanfs.org/en/edo/
[4] Rovers R. 2012 Resources are not equal: Exploring ranking not weighting , Journal: International Journal of Sustainable Building Technology and Urban Development Volume 3, Issue 4, December 2012, pages 270-276
of blog: http://ronaldrovers.nl/ranking-resources-resources-are-not-equal/
