So how could you do that, restoring minerals or metals?
It happened that last week I was participating in the “Exergy, LCA & sustainability conference, ELCAS, 5th edition, originating from a EU COST project. And I presented a paper (with co-authors) about precisely this topic, closing cycles, with the title: Circular Energy, the missing link. [1]. Science struggles already for some years on how to include depletion of non-renewables (abiotics) in the assessments. That Exergy should play a major role in this, is more or less clear, but not exactly how? As researcher Amini formulated this: “Earth is in a process of Exergy Countdown. “[2] .
In the paper it is presented a approach of “Counter Entropy” , in terms of Circular Energy. (CE) . It took some time in research before the picture unfolded . The point is, we normally evaluate a product or a service. But thats not the right moment in a cycle to evaluate. If you want to evaluate resources, you have to look at resource chains, not at products, the accidentally 1 moment in the chain of actions that something is valued by humans. Its about the resource flow in the global system to be evaluated. The principle behind this is thermo dynamics: resources within a system evolve always to a position of higher entropy: chaos in molecules increases, so to say, until the moment when resources are in complete equilibrium with their environment: the resources are not lost, but there is no work or performance to be subtracted from them. There is no distinction with the surroundings: Think of water on top of a hill, that can produce energy, but once downhill and flowing in the ocean lost that potential ( except for other effects) Same with heat: lost through the walls of a building, it mingles with the outside air. The energy is not lost, but the power to heat has gone, there is no difference anymore.
The same for solid resources. One would assume that a nail is valuable in a building evaluation, it provides strength to a construction. Thats correct. But as a resource it has already lost a lot of value: millions of nails, concentrated iron, have left the factory, and are spread over thousands of projects and even countries in our global economy: The concentration of iron has been strongly diluted in the system : just try to collect them again… And even with reuse and recycling the nails undergo a next diluting phase. And in the mean time there are lost ( in serious amounts on construction sites) others rust away dissolve din groundwater. Inevitable the quality, the potential to change, is decreasing.
Or take a car: by humans highly valued as a product, but as materials, thermodynamically, materials have already been mainly downgraded . After all, there are dozens of materials used for a car, which have been spread over millions of cars and locations: the dilution has already taken place. Not only that, but they are again ‘polluted’ with other materials : Cars are that complex, that we can regard them as mini-mines: It requires a lot of energy to re-capture all the materials, just as originally materials had to be separated from complex ores. But this time in minimal amounts. From a large and rich mine, we have created millions of small ones, and spread over the world. In other words: the resource cycle is another one a s product cycle.
So we are loosing resources, unless we counteract this process: And the ReStore step is easy imaginable for organic of biotics, but not for abiotics. But to maintain quality in the system, for abiotics as well we have to make the cycle closed, so including ReStore. If not only for reasons of Resource Racism , as previously argued. Thats the only way to create a system balance.
Practically it can be illustrated as follows: The reference is a maximum diluted resource, . For organics this is for instance a clear cut forest: Trees are gone, nutrients are gone, and there is just fallow land. This is the start of the ReStore process: seeds are brought in by the wind, nutrients by rain, and worms process this all in the right substances, so solar energy can kick start a new forest. It can be accelerated by planting young trees , but that is detail. The hectare of fallow land is the reference , and its will take say 40 years, plus the solar energy, to regrow the trees. : this provides around 5 tons of wood per hectare, per year. Or 1 kg wood requires 1 m2-year: this is the space time requirement within the earth system for the resource wood. Or the Circular Energy, CE .
Mind that large part of the performance is delivered by the sun, from outside our, for mass resources, closed earth system. ( if we would use fossil fuels to make plants grow, its from inside our system depleting one source for another: its putting the horse behind the carriage)
Thus the energy in a material chain can be described as: EE + CE (+OE) Embodied energy invested in materials to make them fit for human use, ( Which is in fact the energy that degrades the resources) and Circular Energy to counter that loss, that degradation, to Restore the cycle (stock). OE, Operational energy is only required when the function needs additional energy. ( in case of a ZEB, Zero energy Building, OE is 0, but the EE has grown due to extra material for insulation and PV panels)
For non organic resources, like metals, the arguing is the same, only the reference environment is different: in general in thermodynamics the ocean is regarded as the equilibrium reference environment : the environment with the lowest quality of metal , the highest diluted distribution of resources. To Restore the cycle, it requires to re-concentrate the metals ions, (as far as they are faster depleted as naturally re-concentrated). Which could for instance be done by filtering ocean water, just like in desalination plants fro drinking water. ( but with other filtering techniques) The required amount of energy, for pumping and filtering, is then the Circular Energy for metal. This energy in turn is related to solar energy ( to avoid depleting another source from within the system) And this leads us to the same indicator as for organics, via relating the energy for instance to solar panels: how much m2 solar panel (-land) is required ( and the output per year) to provide the Circular energy for 1 kg of iron in concentrated form. A similar way can be followed for all metals as well as minerals.
For instance gypsum, can be harvested from basins filled with ocean water : evaporation driven by solar energy does the work, and at some point, gypsum solidifies: ( after a certain period of time 1 ha of basin generates x kg of gypsum:) . Which is 2 kg/m2-year.
For metals this leads to high energy requirements, much higher as for organic or biobased materials . Which again proves that not counting for restoring or regenerating non organic materials, is very misleading picture of resource cycles. It provides minerals and metals with a uneven and unfairly advantage. It also shows that minerals and especially metals should be avoided as much as possible. ( unless maybe no alternative whatsoever is available) ( but in the building sector all aluminium and most part of iron is avoidable). For more details see the paper and the website [1][3]
It may sound theoretically, but its the only just scientific way. Of course, rocks to built with are not depleted by tomorrow, so to say. But the system degrades in an accelerated way, and its not more then normal that the effects are counted for, and fairly compared. And yes: non renewables can be renewed. Its only not done automatically by some worms and solar radiation, like for renewables, but requires some human activity in addition. Which in fact is the same: Nature makes no distinction. But we are so to say, lazy worms, not cleaning up and restoring our habitat.
Therefor, as other speak of renewable and non renewable resources, I prefer to speak of regrowable and renewable resources ( which does not imply it happens automatically, in enough quantity. For both kinds that is)
An whether a government decides to include Circular energy or not in its laws and regulations, is another question and discussion . However the underlying data on which decisions are made, should be objective and fair, and not mystifying. Other wise Maintainability of the human habitat is out of sight.
Note: The theoretic methodology requires that all resources always have to be compensated via circular energy. But the situation in practice might be less challenging as described in the paper: Michiel Ritzen, as part of his PhD research, works on a publication in which he introduces a reduction on Circular Energy, by means of including a factor for recycling and reuse, on conditions. ( nevertheless, the general trend remains the same) [4]
[1] Circular Energy: the missing link, R.Rovers et all, paper for Exergy, LCA &Sustainability conference, ELCAS 5 , Nisyros Greece, 9-11 July 2017. accesible via : https://www.researchgate.net/publication/318318419_Closing_Cycles_Circular_Energy_the_missing_link
[2] Quantifying the quality loss and resource efficiency of recycling by means of exergy analysis, S.H. Amini , J.A.M. Remmerswaal , M.B. Castro , M.A. Reuter , Journal of Cleaner Production 15 (2007) 907-913
[3] see the website www.maxergy.org , (downloads)
[4] Carrying capacity based environmental impact assessment of Building Integrated Photovoltaics , Michiel Ritzen, to be published
