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<\/p>\nThe elusiveness and malleability of embodied carbon calculations have been the subject of much criticism. Nolan Lindquist, director of the Center for Active Stewardship, in The Financial Times, called embodied carbon a \u2018vanity metric\u2019 with little relation to fundamental decarbonisation. He argues that carbon counting can mask a lack of profound change behind a headline figure that is being massaged slightly downwards. <\/p>\n
We believe that serious ecological action within the buildings sector is being retarded by over-reliance on carbon figures, as opposed to energy figures. Of course, carbon dioxide and other greenhouse gasses are driving the biggest of the ecological crises that threaten our species. Reducing emissions is critical. But, on their own, headline carbon figures can offer false reassurance. Amid so much discussion of carbon reduction, the reality is that the built environment is \u2018lagging behind all other sectors\u2019 in addressing climate change, according to IPCC report author Yamina Saheb.<\/p>\n
The power of energy<\/p>\n
So how can energy-accounting help? Firstly, compared with carbon accounting, it is easier and more precise. Energy, whether diesel, electricity, coal or biomass, has a billed cost and therefore is already tracked in the normal run of business to a very high degree of accuracy. <\/p>\n
Secondly, energy figures tell you much more about fundamental processes: the amount of energy it takes to produce a brick, a plasterboard or a steel beam tends to be stable for decades, unless production processes themselves change. Embodied carbon, on the other hand, has to be recalculated every time a coal power plant is replaced by a wind farm. An embodied carbon figure is particular to a certain time and place, quickly outdated and different in every part of the country and the world. This makes embodied carbon figures incomparable across differences of just a few years or tens of miles. <\/p>\n
<\/p>\n
New Farm Loch Community Centre in Kilmarnock, East Ayrshire, by O\u2019DonnellBrown, a 1970s building transformed through an energy-focused retrofit<\/p>\n
In this sense, a far better picture of fundamental reductions in architecture\u2019s environmental harms would be achieved by calculating embodied and operational energy, in addition to embodied carbon. The change we propose is easy and cheap to implement and gives the insight that is needed to genuinely reform the built environment away from environmental harms. This may sound rather technical and modest \u2013 one extra column in a consultant\u2019s spreadsheet. In fact, though, energy is a game-changingly revealing and robust metric.<\/p>\n
The weaknesses of \u2018carbon counting\u2019<\/p>\n
Carbon counting, and claims of net zero, are troublingly opaque. Many built environment professionals rely on proprietary software for speedy construction carbon calculations; but these programs tend \u2013 as part of their business model \u2013 to withhold the sources of their data.<\/p>\n
Carbon figures frequently include offsetting schemes, though these are often dogged by corruption and overreporting. <\/p>\n
They also rely in many cases on electricity metrics based on paying slightly higher tariffs for nominally greener electricity. Yet double-counting and failure to use the increased tariff to provide additional renewables infrastructure, mean these tariffs often fail to deliver the claimed reductions in fossil fuel consumption. <\/p>\n
Some changes which chip away at headline carbon figures are actually investments in ongoing fossil fuel dependence. Lindquist gives the example of relining a coking-coal furnace. This can drop carbon emissions by a certain percentage but actually represents an investment in sticking with highly polluting production processes.<\/p>\n
Embodied carbon figures tend to be calculated as a part of \u2006\u2018Life Cycle Assessments\u2019 (LCAs) that rely on unverifiable assumptions about future energy consumption and nominal figures for a building\u2019s life span that vary between LCAs, making them substantially less comparable project to project. <\/p>\n
Carbon calculations neglect the long-term environmental impact of nuclear power plants, which currently provide about 15 per cent of the UK\u2019s electricity and produce waste that must be stored for thousands of years to avoid environmental devastation. Nuclear electricity has been designated as \u2018green\u2019 by the EU since 2023, after much lobbying, thus suggesting it to be not only a safe but also an economical form of energy. <\/p>\n
The reality is far bleaker. Germany, which shut down all its nuclear power plants in 2023, spent over \u20ac60 million the following year on its 400-staff Federal Office for the Safety of Nuclear Waste Management. It is not expected to designate a safe final deposit site for its nuclear waste before 2074. The carbon and resource cost of such a long period of temporary storage highlights the hidden costs of \u2006\u2018low-carbon\u2019 nuclear. Meanwhile, the terrifying instability of Ukraine\u2019s nuclear plants, under attack from Russia, underline their vulnerability to bad actors.<\/p>\n
An excessively narrow focus on fossil carbon, as promoted by carbon counting, can also perversely incentivise other harms, such as the ill-fated boom in biomass-burning power stations. <\/p>\n
A focus on embodied carbon overlooks the undeniable environmental benefits of energy saving. For the foreseeable future, the UK will be operating in an environment where clean energy is a finite resource. Even a fully-decarbonised grid (which we do not have \u2013 a quarter of UK electricity was from fossil fuels in 2024) brings with it environmental costs, including extensive land use and the production and disposal of plant for renewables. In other words, even should we achieve a zero-carbon energy system, it will remain environmentally preferable to reduce energy inputs for architectural materials and processes. <\/p>\n
While our energy system is now dependent on top-up fossil fuels (which so far has been the case for every hour of the 90-year history of the National Grid), the need to cut energy use is even more pressing. Increases and reductions in electricity consumption have a much greater environmental impact than a headline carbon figure would suggest, because of how our grid operates: as much electricity as possible is generated from renewables and nuclear and this is topped up using fossil fuels. So increasing consumption, whatever tariff you are on, disproportionately increases fossil fuel consumption, while decreasing consumption saves more carbon than you would think.<\/p>\n
The UK Net Zero Carbon Buildings Standard<\/p>\n
The fact that carbon figures, in contrast to embodied energy figures, are only accurate for a particular moment in time, vary for every country and have to be re-counted with every new wind farm connected to the grid, is often neglected. <\/p>\n
The admirable Net Zero Carbon Buildings Standard, launched in 2024 as a pilot, calculates the emissions of a building over several decades and balances them against carbon offsets. We would urge the authors of the Standard to monitor figures for embodied energy alongside those for embodied carbon to allow much greater longevity and comparability for the statistics the standard reveals. <\/p>\n
How can we tell if we are genuinely improving, or learn from best practice elsewhere, if our metrics are so unstable? Zooming out from the specifics of our moment, embodied energy has huge power as a way of monitoring differences in the construction industry over time and space. It is a truism that almost all pre-modern buildings in the world were, by today\u2019s definition, zero carbon. As we have said in the AJ previously, they were built with muscle power, occasionally aided by sailboats and watermills, any heat requirements being furnished by renewable charcoal and firewood. <\/p>\n
If, instead of carbon, you ask what the embodied energy of historical buildings was, the answer is much more revealing: Khufu\u2019s Pyramid, built around 2600 BCE and the world\u2019s tallest man-made structure for almost 4,000 years, used around 22 million kWh for cutting, transporting and assembling its two million stone blocks \u2013 around 37.7 million man days at 0.06 kWh per man day. <\/p>\n
Compare this with New York\u2019s Seagram Building (completed in 1953 to a design by Ludwig Mies van der Rohe and Philip Johnson), which is about 10m taller than Khufu\u2019s Pyramid but, at 77,000 tonnes, around one seventieth of its weight and nowhere near the biggest building of its time. The Seagram Building\u2019s embodied energy, however, is 168 million kWh, more than seven times the amount for the pyramid.\u00a0 Meanwhile, at a domestic scale, the case studies in our book Form Follows Fuel show that housing produced without fossil fuels cost 100-500 times less embodied energy per square metre than those produced with fossil fuels, including two recent passive house projects we studied. <\/p>\n
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Comparisons such as these demonstrate the extent to which fossil fuels have not only produced harmful carbon emissions \u2013 they have also pushed our material choices (even for most of the buildings that are really trying to be sustainable) to a level of default energy consumption that is ecocidal. Mercifully, this level of consumption is avoidable. As the AJ\u2019s RetroFirst campaign and the advocacy group Don\u2019t Waste Buildings argue, reuse and retrofit of existing buildings must be given priority. Where we do need extensions and new structures, we can rediscover the wide palette of low-energy, local materials that produced almost all the homes, working buildings and monuments of pre-modern human history worldwide.<\/p>\n
The best of both worlds<\/p>\n
We are not arguing that embodied carbon is not an important and valuable metric. It is valuable for communicating with clients and the public. It is also crucial in avoiding underreporting the harms associated with materials like cement, around half of whose carbon emissions are from calcination of limestone, rather than fossil fuel consumption. <\/p>\n
Instead, we argue simply for another column to record energy in every environmental assessment spreadsheet. These figures could be tracked alongside carbon to allow the full advantages of both metrics. Embodied energy figures are easier than carbon figures to get your head round: about 0.8 kWh per kg of brick, about 10 kWh per kg of steel, and an enormous 50 kWh per kg of aluminium (both assuming no recycled content). They are easy to relate to everyday experience: there is about 0.07 kWh of food energy in a slice of white bread and the same amount was consumed by burning an old-style lightbulb for an hour. <\/p>\n
For now, though, the UK is moving in the wrong direction, paying less attention to embodied energy in environmental assessments. Our leading source of data on the carbon cost of materials, the Inventory of Carbon and Energy, developed at the University of Bath in 2005 and maintained since, is no longer in fact an inventory of energy \u2013 it stopped reporting embodied energy costs in its 2019 revision. <\/p>\n
In increasingly neglecting embodied energy, the UK is anomalous. Many international examples, including the Australian EPIC and German Oekobaudat databases, still contain figures for both energy and carbon cost, freely available and directly funded by organs of government. The UK\u2019s Inventory of Carbon and Energy, upon its inception at the University of Bath, was similarly publicly funded, through the Engineering and Physical Sciences Research Council (EPSRC) and the Carbon Trust. Now, however, the UK\u2019s best freely-accessible database is dependent on a mix of public and private sponsors, and the dedication of a small, committed consultancy. <\/p>\n
Without robust government backing for transparent, universal publication of energy and carbon costs, both embodied and operational, profound sustainability will remain a marginal luxury for those with exceptional ethical commitment and unusual wealth. It will never benefit from the mutual learning and economies of scale that accelerate learning and carry avant-garde improvements into the mainstream. Meanwhile, shorn of the energy data it needs, the building sector thunders on into environmental catastrophe without even understanding the true impact of buildings, let alone addressing their root causes. <\/p>\n
Barnabas Calder is head of the History of Architecture Research Cluster at the University of Liverpool. He is the author of Architecture: From Prehistory to Climate Emergency @barnabascalder.bsky.social<\/p>\n
Florian Urban is head of History of Architecture and Urban Studies at the Glasgow School of Art @florianurban.bsky.social<\/p>\n
NEW BOOK: Form Follows Fuel: 14 Buildings from Antiquity to the Oil Age (Routledge, 2025) by Florian Urban and Barnabas Calder, with drawings and calculations by John Joseph Burns<\/p>\n","protected":false},"excerpt":{"rendered":"The elusiveness and malleability of embodied carbon calculations have been the subject of much criticism. Nolan Lindquist, director…\n","protected":false},"author":2,"featured_media":262957,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[1397,90,56,54,55],"class_list":["post-262956","post","type-post","status-publish","format-standard","has-post-thumbnail","category-environment","tag-environment","tag-science","tag-uk","tag-united-kingdom","tag-unitedkingdom"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/262956","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/comments?post=262956"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/posts\/262956\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media\/262957"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/media?parent=262956"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/categories?post=262956"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/uk\/wp-json\/wp\/v2\/tags?post=262956"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}