Nothing works without energy , not even a 0-energy building: is has transferred all impacts to additional materials, that require energy to produce, maintain and restore. The main obvious part is Embodied energy in the linear proces of production: mining processing transporting and using materials. Now, besides our attempts to create 0-(operational) energy buildings, , can we create 0-emboded energy buildings?
Since we have to reduce CO2 emissions fast and large, everything counts and so does Embodied Energy (EE) in buildings materials and buildings. That is, 0-fossil embodied energy, since nothing works without energy. We have to eliminate fossils from production, and at the same time limit the embodied energy overall, since whatever energy we will use, it will requires investments, even in renewable energy conversion devices. Besides, if we would retrofit all houses in The Netherlands to a ZEB standard, the total investments in material alone, and related CO2 emissions, add up to above the the allowed emissions under the 1,5 degree global warming scenario! [1]
But then, 0- (fossil) embodied energy buildings , do they exist? What would a 0-embodied building look like, do we have any reference in history? A basic example avant la lettre of a 0-embodied energy building , is a cave house. Nature has formed the functionality, and no additional input is required. Just to enter and inhabit, the pre squatting movement. Though not with a modern day living standard…. Manmade constructions are the next historical development: The igloo is a most beautiful example: constructed only from labor investment, from material that formed itself under local climate circumstances. In many cases transporting the blocks is by man himself, sometimes with the use of some sleigh hounds. The energy invested is human/animal, with food-energy locally generated. Similar examples with local available materials can be found in other climates: like tents for Mongols or Indians : comprising a few nature formed poles, some animal skins, and/or palm-tree leaves for instance. Anything that can be found nearby, and has been intrinsically produced or compensated already.
Besides 0-embodied energy these housing forms also have a low if not 0 embodied energy. And its no wonder we find the lowest embodied energy houses emerge as a historical building documentary: its how houses developed over time. The next evolutionary step is mudbrick/adobe houses: usually erected on the spot where the loam is available, formed by labor1 into blocks and dried by the sun.
A similar development took place in climates where no loam was available, but for instance wood : until a few centuries ago hand cut and sawn by windenergy driven saws. But even more so for bamboo . Bamboo is a wild species, that re-establishes its forest after cutting the branches. So building a house from raw bamboo poles, binded together with natural rope, again is a 0-embodied energy basic construction. (even with the materials compensated included, the restore part of a materials closed cycle).
The basics of these concepts is 0-embodied energy, however over time building parts have been introduced that have their own embodied energy : like iron for door hinges . The energy embodied for these parts in the early days however was provided by handcraft and biomass energy, for harvesting and processing the ore . They added energy invested to the function, but not fossil energy. Nowadays this is of course exclusively fossil fuel related.
In the past 150 years or so, embodied energy invested in buildings has exploded, and even more energy from fossil origin , with ever more technologies and processed materials involved. The awareness of energy invested in materials and products has diminished, uncoupled of actual work investment, the labor. They roll out of a factory anonymously in a continuous flow. Nowadays, due to the increased awareness of scarcity of materials, and the impact of production of materials by fossil fuels, the interest is growing again, and research increasing.
The IEA EBC annex 57 working group just finished its project, bringing together many data and insights on the use of embodied energy data. [2] However, also concluded was tat many definitions used differ among case studies, and in anew Annex 72 these will be addressed. If you are interested you can find many documents and case studies at the website of Annex 57. [3] The IEA work is building on recent attention and publications on the subject. As an example, The European Union (EU) Construction Products Directive has recommended embodied energy as a key factor in the selection of building materials or construction products [4]. Other Directives and Communications refer to this as well, like the ones related to recycling, the biobased materials (economy) and development of material alternatives. [5]
Hammond and Jones at Bath university developed a overview of data available on embodied energy, while calculated mean averages . [6] Their database is widely used for general calculations, besides the more detailed data in the lca related databases like Eco Invent. Based on their findings Hammond and Jones calculated around 14 (new) houses and came to an average of around 5,3 GJ per m2 floor for contemporary building [7]. Which is close to Dixit, reporting 5.5 GJ. [8] Interesting is also Abanda, who calculated the embodied energy for two Cameroon houses, one in cement blocks and another one in Mud brick construction: 3,0 GJ.m2 and 2,0 GJ /m2 respectively [9]. *
The most extensive analyses of houses and embodied energy so far has been carried out by Berggren et all. Some 150 projects were analyzed, and most interesting conclusion is that from a total life cycle point of view its better to design/build net overall Zero energy buildings in stead of low energy building, for a better overall energy performance [10].
Above cited publications all refer to new houses. The situation becomes different when an old house is evaluated for embodied energy related to renovation. In that case the reduction in (fossil) operational energy should be compared to the invested embodied energy to see if the energy retrofit makes sense, and what will be the best strategy: insulate more or produce more, since in all cases it can be 0-energy, and the embodied energy is then deciding for the fossil fuels impacts. . [11,12,13]
From a modern world perspective, it seems hardly possible to create 0-embodied energy houses, or get close to that target. But when we make an inventory about global housing a different picture occurs. It happens that some 2 billion people still live in adobe based houses [14], and another 1 billion in raw bamboo constructed houses[15]. Add people living in houses in slums, assumed to be made from recycled material [16], plus wooden houses ( estimated from data in countries with wood-house culture) and those living in tents, it turns out that 2/3 of the global population lives in (near) 0-embodied energy houses: made from local raw and renewable material, with mainly labor or solar radiation and heat as energy investment. This puts another light on our industrialized worlds practice, and makes us aware this should be a prime target for us as well2. If only for the fact that the other two-thirds of the world is entitled to a larger share of the remaining CO2 emissions as us, living in a society built on guzzling CO2 emissions.
[1] iiSBE (2017) CO2 explorations for the Built environment , iiSBE Academic Forum publications, conference presentation COP22 Marrakesh, November 2016, www.buildingscarbonbudget.org chapter 1.
[2] IEA Annex 57, 2017 : if you are interested in more background on embodied energy, see the reports of the work in the IEA EBC annex 57 workgroup, with many case studies, and the papers published . http://www.iea-ebc.org/projects/project?AnnexID=57
Book and some recent papers analyzing buildings embodied energy:
https://www.sciencedirect.com/science/article/pii/S0378778816319132
https://www.springer.com/us/book/9783319727950
https://www.sciencedirect.com/science/article/pii/S0378778817321576
https://www.sciencedirect.com/science/article/pii/S0378778817325720
more papers from Annex 57 at: http://www.annex57.org/?page_id=239
[3] to follow the just started work in annex 72, lifecycle energy and environmental impacts. See http://annex72.iea-ebc.org/
[4] EU COM(2011) 571 Roadmap to a Resource Efficient Europe, Brussels, 20.9.2011
[5] EU COM(2012) 60 Innovating for Sustainable Growth: A Bioeconomy for Europe, 13.2.2012
and EU COM (2014) 297 On the review of the list of critical raw materials for the EU and the implementation of the Raw Materials Initiative, 26.5.2014
[6] ICE : http://www.circularecology.com/news
[7] Hammond, G. P. and Jones, C. I. (2008) Embodied energy and carbon in construction materials. Proceedings of the Institution of Civil Engineers – Energy, 161 (2). pp. 87-98. ISSN 1751-4223
[8] Dixit, M. et all, Need for an embodied energy measurement protocol for buildings: A review paper , Renewable and Sustainable Energy Reviews 16 (2012) 3730–3743
[9] Abanda F.Henry et all, 2014, Embodied Energy and CO2 Analyses of Mud-brick and Cement-block Houses AIMS’s Energy : Volume 2, Issue 1, 18–40.
[10] Berggren Björn ,Hall Monika, LCE analysis of buildings – Taking the step towards Net Zero Energy Buildings , A technical report of subtask A Annex 52 , May 26, 2013 , Lund university Sweden
[11] Rovers R.; Ritzen M.; Gommans. L., Reducing energy demand –or producing more energy? Research report RiBuilT March 2013, available at : http://www.sustainablebuilding.info/maxergy/ ; and: Ritzen, M. et all (2016) Environmental impact evaluation of energy saving and energy generation: Case study for two Dutch dwelling types, in: Building and Environment 108 ·July 2016
[12] Rovers, R., Beyond 0-Energy: Paradigm shift in assessment , Buildings, special issue low Carbon Building design, 2015 Volume 5 page 1-13
[13] EU H2020 More Connect, research paper: Embodied energy as a decisive parmater, June 2017: https://www.researchgate.net/publication/318340957_ZEB_retrofit_embodied_energy_as_descisive_parameter_and_proxy
[14] see 10 Abanda
[15] State of the worlds forests, 2005 , FAO, report, isbn 92-5-105187-9
[16] UN Habitat https://www.cordaid.org/en/news/un-habitat-number-slum-dwellers-grows-863-million/
1 A special element in the “embodied energy related production chain” is labor. Labor is of course a energy conversion technology, leading to invested energy embodied in the product of function delivered. However, labor is by definition a 0-embodied energy element, since the energy delivered comes from food, which is produced by renewable energy and by the time of use has already been generated: Otherwise the people would not have food, and would not be able to deliver that energy. And the without human life we would not even have a problem. In other words labor/food based is one of the 0-emb energy processes by definition. Or nowadays we better say “can be’, since we have introduced green houses and mechanised processing of food, requiring large amounts of ( non renewable) energy.
2 One of the issues here is that all the people living in adobe , recycled and bamboo pole houses, when becoming more wealthy, (will) strive for western style houses, in which all the materials have huge amounts of energy embodied.
