Twin & Earth are the sustainability consultants on our 68 King William Street redevelopment project. We recently caught up with Co-Founder Alicia Costas Freire and Energy & Sustainability Consultant Nicolae Bajenaru to discuss all things green building in London. 

Alicia, tell us a bit about your company Twin & Earth?

We think of ourselves as a boutique consultancy, relatively young and small yet working with high-profile clients. My business partner Matt Cotton and myself both came from large consultancy backgrounds as engineers. We set up our company six years ago in response to how energy and sustainability was being treated as a bolt-on to a building services package, which creates a conflict of interest. Our vision was for a fully independent consultancy businesses that could be procured independently. 

68 king william street london

Sustainability at 68 King William Street

Tell us about the work you are doing on sustainability at Black Mountain Partners’ 68 King William Street?

That will be a BREEAM Very Good rating using the ‘refurbishment assessment’ path, the first part of that refers to the building envelope and structure; the second part to the core building services; part three to tenant building services and part four to the fit-out. For 68 King William Street, the fit-out and structure envelope was not assessed as little to no refurbishment is planned for those components. We are using a version of BREEAM that is partially tailorable, so we focus on the categories of visual comfort, acoustic performance, indoor air quality and thermal comfort but not security for example, meaning there is a smaller pool of credits to play with.

What type of project and clients do you usually work with?

We were fortunate to win a series of large projects from day one such as the reconversion of the old American Embassy on Grosvenor Square into a luxury hotel. We also won the refurbishment of the former Eurostar terminal at Waterloo station railway conversion. We also do a lot of hotels and offices, such as 68 King William Street for Black Mountain Partners, and a fit-out for Investec Asset Management, BHP Billiton, and others. We work regularly with big tech companies such as Apple and Microsoft too.

How is your sustainability team set-up internally?

We originally thought we would all be building services engineers to focus on the energy side of things but we also have environmental specialists with a background in geography who are good on masterplanning, for example. I look after environmental certification while my business partner looks more at energy modeling.

Green Building Certifications

How do you advise your clients to navigate the world of green building certifications?

Well, a big client like Apple will know exactly what they want already when they approach us. For most clients though, we start by trying to find out their objectives – is the certification for marketing purposes, to help with staff retention or to improve the rental rates? Then we look at any relevant regulations, for example a BREEAM assessment is essential for any new non-residential development in London now. We also consider whether the client’s business is global and will therefore require a certain type of certification system recognized internationally. 

Real Estate Sustainability Strategy

You then recommend a certain type of sustainability strategy, is that right? 

Yes, so a strategy could be single certification (e.g. BREEAM), double certification (e.g. BREEAM & WELL) or a bespoke strategy that combines elements of different green building schemes – suitable for client occupiers who care less about third-party stamps and more about the impact on their user experience in the building. 

Green Building in London

Have you seen a growth in demand for green building schemes in recent years?

Demand for BREEAM in the UK is very solid, people are familiar with it now. Agents have a big say on certification schemes as well as they know what the market wants. Nowadays, a building can be penalized by buyers for not having a certification, losing out to another building that did go through the process. In future that could create a big wave of change, with the occupier becoming a driver of demand as they have more appreciation for building health and wellness.


What would you recommend as the priority scheme for say a commercial building in London?

If you are targeting a large corporation as a tenant, then you might want to go with LEED, otherwise you’d probably want a BREEAM certification possibly combined with WELL (Core) certification. When applied properly, the WELL Building Standard can really help to improve the quality of a building.

Environmental, Social & Governance (ESG) is a hot topic now, how does your work align with that?

ESG can be much bigger than just green building. Estates in London masterplanning a green community are looking at ways to align tenant selection with their sustainability strategy. So ESG can really be pushed a long way.