Building evaluation should change 1/2

There is a lot of discussion in the Netherlands about how to assess buildings, if you integrate material impacts in addition to energy, as well as to somehow include CO2 budgets. There is already an instrument for this, the MPG, (materials performance Buildings) but it is under discussion. Besides, in recent years I was involved in the IEA international research network, the EBC Annex 72. Together they  gave some new insights in assessment, which I am happy to share here, in two parts .

The original intent of the Annex research initiative was a focus on embodied energy, defining concepts, methods, and approaches. In the startup process, this later became “life cycle energy”. after which the focus gradually shifted even further: to life cycle carbon, (-emissions, incl what is also called ‘embodied’ carbon). So from ‘embodied energy’ to ‘whole life carbon’. Not only in this research group, a shift to ‘carbon’ is seen in many research work. [1] [2] [3]

The studies and discussions convinced me that we have a wrong approach, with respect to evaluating buildings ( and also products). In that science focuses too much on the building sectors approach and on buildings (products), instead of on a more fundamental analysis. I will list some of these misconceptions here.

Note that this is mainly about operational and embodied energy effects. Material depletion itself, (and or recovery stocks) is not yet included, that will be addressed in a yet to be published book.

Some of these topics have been covered as separate items in articles before, so I refer to those.

1. A focus on CO2 or Carbon, is a strange thing, if we want to move to a society without fossil energy. Then you should not calculate related to the old and unwanted reality, but optimize towards that desired future, so assuming processes and products without CO2. That CO2 is still temporarily in play along the way is irrelevant to the optimal end goal. [4]

2 Focus on CO2 suggests that you can dissolve the CO2 problem, and continue as before with what you were doing. Like for example apply Aluminum which e.g. has 10 x more energy impact than iron. (per kilo that is) but assuming to produce it with renewable energy, like in Iceland, and therefore can continue with aluminum, even if it is for nonsensical applications (for applications where no extreme impact material like aluminum would be needed at all), which will increase energy use. [5]

3 Obviously calculating in energy , instead of in Carbon/CO2, is preferable because we also need to reduce energy demand, otherwise we will need to build more and more wind turbines and solar panels, which is a prayer without end. Even with renewable energy, energy conservation is highly relevant.

By focusing on (embodied) energy, you tackle both, CO2 and energy demand.

4 Moreover, and not unimportant, CO2 is a consequence and not a cause, so we are again putting horse after the cart. Focusing on 1 consequence shifts problem to other areas.

So the starting point is incorrect, Besides pitfalls in the calculation itself:

CO2 storage in materials?

If you keep calculating in CO2, one consequence is that you also start thinking in terms of CO2 storage in for instance (building) materials. But then, CO2 storage in biobased materials may only count dynamically: so in the case of e.g. wood: as the project gets older (and the trees can grow), a proportional part will count. At project completion, storage is 0, and after regrowth of the trees, say 40 or 50 years, only then reaches 100%. Or in other words, only when actual regrowth has occurred in the same amount, is storage accountable [6] Better though: count in embodied energy, not in Carbon, CO2 or GWP.

This also shows that the current use of the term ‘embodied carbon’ is somewhat misleading: it should be emitted carbon. Embodied, of course, is what is then sequestered, in biobased materials, among others. (And in fossil, as long as we leave that in the ground…!).

3. Lifetime ?

1)Embodied energy or what is counted as Embodied Carbon for now, is averaged over the lifetime. This is disastrous because it is immediate , at inception, and should not be hidden by averaging over a notional expected lifetime, and thus shifted to the future. Then you are sure not to stay within CO2 budgets. See also [7] [8]

2) Anyway, a fixed lifetime is an economic concept, not a physical science concept. Physically, buildings should last as long as possible, hundreds of years, so as not to overburden the cycles. With maintenance and repair, that’s no problem at all. If every generation had to build its own built environment, no progress would be possible. [9]

M2 normalization ?

Calculating per m2 (normalizing) is perfect for comparisons between various solutions, but obviously says nothing about final absolute impacts. Because how many m2 are you talking about? And what counts as (useful) m2? It should be about providing a function: shelter, within national maximum budgets of energy ( and possibly CO2, if that is what is being calculated anyway), [10] see also:

reductions instead of absolute?

CO2 calculations are constantly looking at reduction trajectories, also for buildings, especially if lifetime becomes the great common denominator. And indeed, if every year buildings become 2.5 %-points more economical, then after 40 years the emissions from buildings will be 0. But then we are already way over our 1.5 or 2 degrees emission budget, as set by IPCC. What is needed, if any calculation is made in CO2, is an absolute budget, and staying within it. See [11]

recycling ?

1) in the future: nonsense, of course, to count with that now: in other words, we will continue with new materials, and our children may work with our waste. And they may not even count the advantages, because we have already included the benefits today. Besides, who guarantees that recycling will be done in the future*? [12] And besides: buildings should last much longer, see lifespan.

2) the use of recycled material today: in that case often only the embodied energy from the recycling process itself is counted. The original embodied energy, or CO2, has the suddenly disappeared? Nonsense, of course, (unless that has already been compensated for right at the start in some way, in a valid way). Generally, the longer something is in use, the less energy/CO2 load per unit of function per time period, but its never 0 of course. If the origin is known it can be calculated what remains, [13] , but as a rule of thumb in practice I use for reused and/or recycled materials 50% of the original impact, unless shown otherwise. ( and excl. new (recycle) process energy)

system boundary: infrastructure?

If we consider buildings, the system boundary is always taken too narrowly: a (new) building usually includes a road and other infra-technology. If that new building is on virgin land, you have to include the impact of building that road. After all, without that new construction, there would have been no road needed or constructed. The same goes for sewerage . And even for the energy grid construction. Otherwise a building is calculated far too favorably, and impacts are passed on to the community.

Lca ?

LCA is fine for scientists or researchers who know what they are doing and know the shortcomings, but not suitable for practitioners. Who should steer building sector by hard indicators to have real results. ( more in part 2/2 next time)

So hopefully it is clear that science still contains numerous pitfalls, and its time for a completely different approach to evaluation. End part 1.

(part 2:  )



* though in 50 years there will most likely be fighting to get some resources left.



[1] CIBSE:

[2] RICS


[3] reports ramboll

[4] post fossil :

[5] aluminum :

[6] CO2 storage analysis: 1/2/ and 2/2

[7] embodied is direct:

[8] climateneutral student project:

[9] lifecycle :

[10] per m2? and 2/2

[11] absolute budget :(2015:)

and (2020:)

and (2022:)

[12] future recycling:

[13] today rycling :

Author: ronald rovers