ZEB house retrofit: less PV instead of more ! *

As I wrote more often, the Netherlands is focused on developing zero energy retrofits. Most of these initiatives address the whole house, packed in thick prefab elements, and powered by PV panels for the ( reduced) heating demand plus the full household demand. I have my doubts about this extensive package, due to the shift for materials impacts, but now there is a new phenomenon: Creating extensions to the houses for extra roof surface and PV panels. There are even prize contests organized for creative solutions.

Extensions, for more roof surface? The intentions are good, no doubt. But I can’t neglect this anymore: Its counter productive: extra living space, more material input, larger surfaces , more heated area ( no doubt) . Thats a lot of rebound effect. Its an example of running forward: filling one hole with creating another.

Its attractive of course: Selling a ZEB with extra space, a veranda, or greenery, and due to the larger roof surface more abundant energy available for use, even if its renewable energy. But that was not the question, at least when we talk energy and climate measures. In that case the intention is less. Of anything. Less energy, and less resources as the first task. While this is only more! Just like so many initiatives in the recent past, this only leads to increased comfort, at the expense of climate and resources.

When the Netherlands discovered large gas reserves, back in the sixties, a huge transition took place : not only the switch to gas heating, but since it was abundant and cheap, we decided to switch from heating one room, and mainly only when someone was at home, to heating the whole house, and 24 hours a day. Thanks to gas we started living in clover.

Now we want to phase out gas again, ( and the other fossils) , but not giving up pour luxurious,  and as we know now, disastrous way of life , giving resource availability and climate change effects.

We want to remain living in clover. And  not even that, we want to extend our houses, and using the known problems even as argument for that!

Undoubtedly this will succeed, since we are rich and will make sure we have ourselves organized when problems get really harsh. We will have the ocean full of wind turbines, and every roof full of PV , driving fancy electric cars , and have our dyke’s raised, like a fenced country. But we will have used a disproportionate share of the maximum remaining CO2 emissions. The rest of the world will have to see for themselves how to cope.

The trend should be, to avoid rebound effect, to live smaller, to lower the heating temperature, to limit the heated area, to have less energy demanding equipment, and less demanding behavior, use of mainly renewable resources, and organize things in a way that requires less transport, and retrofit vehicles for electric driving in stead of building new cars. Which is supported by some international CO2 explorations, showing how much of the remaining CO2 budget is available for the built environment, and what can be done with that. That turns out to be very limited.**

Main problem is that things are calculated in money, which has proven not to work, since the current financial economy stimulates resource consumption. . Its the core of the system. Thats why we are in trouble, with resource scarcity and climate change.

Its about time to have a CO2 budget allocated to every person,  a fair share for every global citizen, so that people can decide how to spent that budget: for a holiday, a house (-extension), or some heating or cooling.

The average budget for a continued sustainable CO2 situation should be 1 ton CO2 /cap, while there is some CO2 emissions budget left to invest in adaptations of lifestyle, to prepare for that yearly budget .

The remaining budget to invest , is around 110 ton CO2 per capita . That can be spent in 1 year, or 30 years, but is the max. After that its 1 ton CO2 /cap per year. At least is we want to stay below the 2 degree warming , for all of us, globally.

So then what is the CO2 spending currently in The Netherlands? It is 10 tons per cap-year. Without any action, its gone in 11 years. And there will be nothing left to invest, only a 1 ton CO2/cap-year budget to live from. Knowing this, not only adapt the whole house but to even extend it, is exactly the opposite to what we want to achieve. To put it very mildly.


* Picture: Climate-KIC, the EU’s main climate innovation initiative

This article has previously been published as column in the Dutch building and construction magazine Cobouw: 23 Mai 2017,  https://www.cobouw.nl/bouwbreed/blog/2017/5/meer-pv-op-het-dak-liever-minder-101248929

** find some detailed analyses at the new launched website: www.buildingscarbonbudget.org


Author: ronald rovers