Can you build an "energy positive" office building north of sixty?

© Snohetta/ Powerhouse Telemark

Powerhouse Telemark would get a lot of attention, no matter what zero-energy standard it was built to; The building is designed by Snøhetta, and it is way up there in Porsgrunn, Norway, at 62°19'12"N a latitude where you really have to squeeze those sunbeams to get any juice out of them.

There are a lot of Net Zero schemes and standards in the world today; most work on the basic principle that the building, in the course of the year, generates more energy through renewables than it consumes. That gets harder, the further north you go, simply because you need more energy to keep warm and you get less sun.

Powerhouse Telemark from R8 Edge on Vimeo.

But there is a real kicker with the Powerhouse model that makes it the toughest Net Zero standard in the world: It not only is net-zero in terms of operating energy on an annual basis (ho-hum, boring, everyone does that now). It also is designed generate enough excess energy over the estimated life of the building (estimated here at 60 years) to pay back the embodied energy from the construction, production and transportation of building materials used to build it in the first place.

Think about how hard this is. The architects and engineers have to calculate how much energy went into every component of the building. They basically have to choose every material based on the embodied energy. They have to estimate how much energy will used to schlep it up there north of sixty.

Powerhouse roof© Snohetta/ Powerhouse Telemark

Built on a tilt

Like Snohetta’s Zero Energy house, built to the same Powerhouse standard, Powerhouse Telemark is built on a tilt to optimize the solar gain.

The form of the 11-story building is dictated by site and environmental conditions, resulting in a diamond-shaped structure optimized for capturing and retaining solar energy. A system of heat exchangers and heat pumps will also contribute to producing energy for the building.

rendering of building in context© Snohetta/ Powerhouse Telemark

Powerhouse Telemark is the first new office building built to the Powerhouse Standard, but it follows in the footsteps of Powerhouse Kjørbo, a renovation built a few years ago. That’s easier, with so much embodied material already in place. At the time, the team noted:

We believe that energy-positive buildings are the buildings of the future. An energy-positive building is a building which during its operational phase generates more energy than what was used for the production of building materials, its construction, operation and disposal. The building is therefore transformed from being part of the energy problem to becoming part of the energy solution.

Interior view© Snohetta/ Powerhouse Telemark

Does this make any sense?

But this idea is extremely controversial; many believe that concern with embodied energy is misplaced. Building science expert John Straube has written:

Scientific life-cycle energy analyses have repeatedly found that the energy used in the operation and maintenance of buildings dwarf the so-called “embodied” energy of the materials. Cole and Kernan (1996) and Reepe and Blanchard (1998) for example found that the energy of operation was between 83 to 94% of the 50-year life cycle energy use.

A new book I just read on "Positive Energy Homes" (to be released in May) devotes significant space to debunking embodied energy, suggesting that information on it is sketchy and often contradictory, that analyses of it are all over the map, that it really doesn't matter in the long run and that it is not ever lost because everything can be reused if you are careful, "the landfills of today will become the hardware stores of tomorrow."

Technically they are both probably right, but worrying about long term embodied energy does make a difference in the immediate short term. It makes sense to think about it. A decision to use low embodied energy structures like heavy timber and wood instead of concrete reduces CO2 emissions right now, as does using wood fiber or mineral wool insulation instead of foams made from fossil fuels. So far as I can tell, the PowerHouse standard is the only one in the world that really takes embodied energy seriously. The fact that they think they can pull this off North of Sixty is beyond impressive, it’s stunning.

Tags: Energy Efficiency | Norway


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