How to convert a grey building into a green building ? [An interview with Engineering Firm Deplasse & Associates]

  • Deplasse & Associates is a firm of engineering consultants specialized in supporting the energy transition of buildings using maintenance policies and state-of-the-art proptech solutions.
  • The firm provides industrial and civil engineering, construction, commissioning, and maintenance control services for a wide range of organizations, and their Plaine 11 project has proven to be a case study in the energy transition of existing buildings.

  • Deplasse COO Thomas Deville discusses the flagship project.


Tell us about Deplasse & Associates : 

“ From an engineering firm specialized in heating systems, our company has grown and is now doing technical studies and consulting to fully support the energy transition of buildings.”

“ We now have about 45 full-time employees working for our company, with headquarters in Luxembourg and Brussels.”

“ We offer our experience and expertise to accompany you through all steps of your project – providing both in-depth guidance and technical support through your works. In addition, we most of all offer long-term monitoring and maintenance control services.”

“ Our company has the specificity of making a long-term commitment because we want to support the proposed solutions until their results. We are committed to supporting you in the energy transition of buildings, a transition that is becoming increasingly urgent.”

How did you improve Plaine 11?

The Plaine 11 building
(Image Credits : Deplasse)

One of our faithful customers was interested to buy this aging building (from 2001) and asked us “how much would it cost to improve the CO2 building in order to make it more sustainable in the rental market?”. We acted as the technical advisor from this moment (technical due diligence) until today.

The project’s located next to the ULB Plaine site, along the rails. It presented some challenges due to this particular, partly sunny location on the south side and the outdated facilities that came with it. 

The building had, like many office buildings, a chiller. But it was at the end of its life, which caused many problems of discomfort.”

“ So we chose instead a comprehensive four-pipe HVAC system [*a centralized heating, ventilation, and air conditioning system], which can cover cooling needs and partly those in heat: it is thus a mixed and fairly innovative solution of heat recovery.”

“ It was more expensive than replacing the old machine with another of the same type – but we convinced the client that the investment would pay off in the long run.”

“ To that end, we signed a 10-year contract in which we are united with the maintenance company to guarantee savings of 25,000 euros per year.

If that amount isn’t reached, we both have a penalty that pays back the difference. If, on the contrary, we exceed the promised amount, we have a bonus that allows us to reward the extra efforts.

Plaine 11 is equipped with a 4-pipe HVAC system (Image Credits: Deplasse)

So it’s a win-win solution for both parties.” 

“ And finally, our work around Plaine 11 and its evolution have given a real added value to the building. We increased the building comfort of the tenant and reduced the operating expenses. Most of all, the building reached a B- BEP label and a very good Breeam In-Use which generates a bigger valuation of these assets”.

“ We are all very satisfied with this project: we have met our commitments – and even exceeded them a little.”

“ In concrete terms, this means that we have managed to reduce gas consumption by 60% and electricity consumption by 10%. 75% of building heating is provided by renewable sources”

“ Finally, this project was a true partnership, where we worked hand in hand with each stakeholder: the client, the operator, and us, the engineering firm. And it’s a long-term project because we signed a 10-year energy performance contract.

What lessons can be drawn and used for your next projects? 

“ We are very proud of this unique and innovative project.”

“ We have only one regret: we haven’t been able to take sufficient account of private spaces, because our mission was focused solely on common building spaces.”

“ But as Plaine 11 is a multi-tenant building, we would have liked to do more at the private level (office lighting, office automation), which could have increased our energy savings.” 

“Notwithstanding, thanks to this long term contract, we’re discussing with the asset manager to work on those items during the next years to improve the building each year in the spirit of  ISO 50001”

“ For future projects, we will therefore look at the building as a whole, including private spaces. We also want to go further by suggesting green leases on occupants, in order to further influence the behavioral aspects.”

“We notice that the acceptability of some light constraints to reach environmental goals gets bigger and bigger.”

What are your biggest current challenges?

“ We want to reconcile the very ambitious long-term objectives with the reality on the ground (e.g. phasing out fuel oil by 2025, phasing out gas by 2030, and reducing carbon emissions by nearly 85% by 2050). These are very ambitious long-term goals, but they are too far away to be followed by very concrete facts daily. So for us, this is where the real challenge lies.“

“ In the short term, of course, there is also the Covid impact, which causes people to rethink the way they design office spaces, which creates uncertainties, but I think that will be resolved rather quickly.”

What’s your medium and long-term vision? 

“ Right now, most buildings aren’t energy efficient. But obviously, it is neither possible nor realistic to level them all to build new ones. So we’re thinking about ways to give existing buildings a second life – just like we did with Plaine 11.

So we want other buildings to follow in Plaine 11’s footsteps. But that doesn’t mean we’re done with this project. On the contrary, we are already thinking about its next steps.”

Plaine 11 - Deplasse & Associates
The Brussels-based Plaine 11 building is an example of a successful energy transition

“ Plaine 11 was a perfect example of teamwork. Now we want to continue to support clients in the energy transition of their buildings, both in terms of energy and maintenance. We want to ensure that buildings are properly exploited by technical operators and that energy consumption is under control.”

“ Ultimately our goal is to have the most impact on the buildings around us. And we believe we can do that by replicating the philosophy behind Plaine 11 to other buildings.”

Thank you. Would you like to add anything in conclusion?

“ We look forward to continuing to convert buildings in the same way as we did with Plaine 11 and expanding our footprint across the region.”

Deplasse & Associates

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Liuba Diederich