This is an extended version of a previous post on linked in, which had a lot of reactions.. {april 2019}
When it comes to Embodied Energy, we are used to normalize this over the lifespan of a building ( or a product) , and in that case it does not look that bad.
However , I want to bring forward the discussion about this normalizing over a certain period. As a reference I refer to the discussion going on over the use of wood as carbon neutral biofuel: Its assumed that that we can burn wood for energy, since the wood is replanted and in 40 years or so the CO2 is again stored in the regrown tree. This is true of course, but only works if we are in a stable climate position, and can plan over 40 years. But in 40 years its 2060, and we should already be a at near-0 CO2 emissions by 2050. And actually: to cut the trees now and burn them, causes CO2 emissions now, today. Biofuel contributes to increased global warming, despite the (delayed) uptake of CO2 in forest growth.
In fact we have the same problem with Embodied energy: This energy is invested today, and contributes today to global warming! And if we normalize over the lifespan of the building or of the building element, we neglect the fact that these are actual missions today. Besides, most buildings use 50 or 60 years of lifespan to normalize, which already goes way beyond our 2030 or 2050 targets.
So in fact we should be clear about embodied energy: it contributes today to Global warming, in the total invested for the building ( or the retrofit, or any other product, like new (e-)cars). Just like bio-energy. And therefore we should abandon normalizing over lifespan .
But if we do so, the situation about sustaining our built environment becomes completely different. Since investments in building materials for a new building, can, in the worst cases, be as much as 50 % of total life cycle emissions,[1] in other words in total the same as operational energy emissions over the lifetime. And to eliminate emissions from operational energy we invest in renewable energy devices, like Solar panels, which as such increase the embodied energy investments, with immediate emissions today.
All buildings newly constructed as of ’today’, are counter productive in our attempts to meet climate targets, even so called sustainable buildings. With potentially one exception: wooden buildings: Wood in fact is captured CO2, and by using it for long term construction its fixed CO2, CCS-Captured Carbon and Stored so to say. Except for a minor fraction that was invested to harvest and transport the wood. It must be stated however that this is not yet an accepted viewpoint, the debates about CO2 and plant based resources is continuing, as described at the beginning. Of course a wooden building is not completely made from wood ( not yet that is, see the wooden nails now available [2]) , so there is might still be other materials adding to the embodied energy ie embodied CO2 emissions.
The emissions from building materials is of course also an issue in maintaining buildings or retrofitting buildings for 0-energy or low energy performance. Which cant be normalized over the lifetime and are immediate contributions to climate change The profits , if there are at all, are only later.
The consequences again are huge: regardless how we treat this issue: If we neglect this and normalize over lifetime, CO2 emissions will rise , and nobody realizes how come. But even If we skip normalising and count as actual contribution, the consequences for the building sector are enormous, as well as for policies on new construction needs, and retrofit programs.
In any case , calculations will have to be inclusive of embodied energy effects, and the actual CO2 emissions.
Which is still a separate discussion form the fact oif we should calculate in CO2 anyhow. CO2 is an end of pipe effect, not a cause. Which is illustrated by the fact that when shifting to renewable energy to avoid CO2 emissions, will result in large investment in resources for windturbines, Solar panels, and related chain technologies like batteries. These secondary effects cause CO2 emissions as well, besides depleting resources in an accelerated manor. For that reason its better to calculate purely in embodied energy (MJ), which then should be lowered (supposing operational will be 0 as a target). Reducing CO2 on one side, and reducing the need for renewable energy investments on the other side.
Its a pity that the update ICE database, [3] used by many to have averaged agreed data on embodied energy, is now only available with Embodied CO2 data, not with EE data. It would be a major contribution to these developments if some independent organization would invest in developing a public Embodied energy database wih latest research findings. Which makes it very easy at the start of project to have a quick insight in embodied energy consequences of choices.
Since , as we started this article, Embodied energy is now. Immediately. Not in 2050.
[1] http://www.ribabookshops.com/item/targeting-zero-embodied-and-whole-life-carbon-explained/86504/
and
[2] https://www.beck-lignoloc.com/en
[3] ICE: http://www.circularecology.com/embodied-energy-and-carbon-footprint-database.html
