When it comes to energy in the built environment, we have a pretty good picture of how and what. To ban fossils as source, we create Zero energy buildings, ZEB. These buildings still use energy but on site produced from renewable sources, in the Netherlands mainly solar panels. Bringing operational energy to 0-fossil is a ‘piece of cake’. More or less. And not minding cost.
However we invest a lot in materials, which are fossil energy related as well. Which is a bit more complex issue. Since the materials are made from fossil energy, and have substantial CO2 emissions. The problem has shifted, not solved.
To be “0” the operational energy does not necessarily need to be low, its finding the optimal balance between materials invested in Solar panels and materials in insulation, for instance. To find out which combination has the lowest impact in materials related energy, or embodied energy [1] The building remains 0 for any combination.
But even with the lowest impact combination of materials, there are substantial materials invested, and a fossil ie CO2 impact remains. While the 2 degrees agreement requires that we not only eliminate fossils for operations, but go down with CO2 for the whole spectrum of activities. Also for materials. That is what the climate agreement is all about.
Its a Catch 22 situation: we have a 0-energy building, but impact has shifted.
So then refrain from 0-energy buildings? Since both, 0- operational energy and 0-embodied energy is not possible. The products are not available ( except from some very front running companies that are developing (near ) 0-embodied energy products) . Only when we apply drastic measures, like making straw roofs by handwork for instance, will we be able to control the materials impact. If its up to me its an option, but I don’t see it happen in the near future. ( and I have some experience with proposing drastic solutions … It wont happen until the dikes down here are broken.)
In a recent project I stumbled upon this dilemma. The task was to not create a 0-energy or energy-neutral building (retrofit) but a climate neutral building. Which concerns all CO2 emissions: you put a fence around the project, whether a building or a city does not matter for the principle, and whatever happens inside the fence, the CO2 emissions have to go down, not up. And ultimately, on a yearly basis, to be 0-CO2, at least by 2050. And nationally for all buildings…
Which means we will have to start with this approach to apply to any building that is retrofitted from now on. We need the 34 years until 2050 to treat all buildings. And therefore, with this first building, we have to solve this, otherwise it makes no sense. And with wrong decisions the CO2 might even rise.
But then, how to solve this? We developed the following approach that could provide a way out: There is still some CO2 budget space to be emitted before the two degrees gets out of sight [2]. ( forget the 1,5 degrees) . Now , we should only use that budget to apply measures to make operational energy 0, and no longer use that for any operational energy. And not construct any new building, or retrofit a house, without the 0 target. Otherwise we will create more lock ins and will never reduce CO2. Its only more activities that at some point still have to be brought to 0.
In other words, we will use that remaining budget for the creation of a 0-energy building , with at the same time a extreme low impact shift towards materials. This counts as a one time CO2 investment. The minimal scenario is that the CO2 investment in materials should be lower as the original operational energy would have emitted during the remaining years until 2050 . If not its still shifting problems to the future. This is however the minimal requirement, in this case there is still no CO2 reduction until 2050, It only has (net) effect virtually after 2050. (compared to operations as usual)
So even better would be to have a lower shift of impact, or lesser cumulative CO2 invested. In our case the principal had defined a policy of being climate neutral in 2030. Therefore: the materials to be invested to retrofit the building ( to 0-fossil operational energy) are limited to 14 years of cumulative original operational energy, to be climate neutral after 2030. Which is accepted as requirement for this project. ( its a demonstration project for a larger portfolio, and the client is aware and willing to face the challenge) . Whatever the consequences will be , we will have to go and find out. But that the task is huge and difficult maybe clear, and will require enormous creativity. But if we dont apply it at this first building, we will run behind from the beginning and lose the battle. Even before started.
.
[1] Environmental impact evaluation of energy saving and energy generation: Case study for two Dutch dwelling types , Ritzen M , Haagen T, Rovers R, Vroon Z, Geurts C, Building and Environment 108 (2016) 73-84
[2] CO2 budget: http://www.climatecentral.org/news/two-decades-until-carbon-budget-is-eaten-through-18051
ref: http://www.nature.com/ngeo/journal/v7/n10/full/ngeo2248.html
and https://www1.ethz.ch/iac/people/knuttir/papers/meinshausen09nat.pdf
