Algae power - how much greener can you get?

BIQ House at Hamburg’s International Building Exhibition

Two pieces of dramatic news out of Germany, in a single issue of Inhabitat today.  The first that Germany has quadrupled its energy surplus over the last two years, and the second that the world’s first building with prototype algae facade panels has opened in Hamburg.

News about the power surplus may not sound particularly like a win for green, until one pauses to think that it is occurring at the same time as Germany winds back the use of nuclear power, which might have been expected to result in a shrinking generation capacity.  Actually, it has spurred a spectacular growth in renewables, both wind and solar photovoltaics. Current surplus power is sold to neighbouring countries, but clearly it also affords Germany the luxury of further lowering its dependence on fossil fuels.

One example of the remarkable effort Germany is putting in to explore and implement renewables comes again from Hamburg’s International Building Exhibition.  Engineering firm Arup worked with Germany’s SSC Strategic Science Consultants and Austria-based Splitterwerk Architects to develop BIQ House, as a test-bed for an integrated louvre facade system which relies on living algae for a self-regulating degree of shading, and for active power production.

One also doesn't want to be an arm-chair critic in the face of the scientific prowess such august team would have invested in developing the technology. Technical details available on the internet are sketchy, so it's altogether a bit dangerous to try to infer how such a system might perform.  But precisely because as usual, the press releases are repeated so uncritically, a little bit of scrutiny doesn't go amiss.

Detail of louvres

My first impression is that the variable density of the algae in response to more intense sun is not strictly the first line of deference for the interiors; the limited imagery on an earlier post suggests that function is rather performed by rotating the louvres.  Equally, the information on the mode of power generation is a bit sketchy.  Implied is that the panels include a mechanism for harvesting the biomass for conversion to power by burning.  Whether the heat is used directly for heating, or to run absorption refrigeration, or whether it is used to generate electricity, is not mentioned anywhere I have yet found.

These are baseline questions one must ask to define the grounds for comparing the proposed technology to possible alternatives.  The facade represents a surface with a specific maximum energy budget, especially in terms of the solar energy falling on it.  That solar energy can be absorbed and converted to useful form by a number of alternative means, each with different efficiencies, and producing different grades of energy.  For instance, photovoltaics might be only maximum 20% efficient at the moment in producing electricity, but that electricity is the highest grade energy used in the building.  And combined with heat recovered from behind the PV panel at temperatures useful for direct heating or domestic hot water, or even running absorption chillers, the yield of such a wall might be considerably higher.  We would need a comparable overall efficiency evaluation of the algae panels, to know whether the effort is worthwhile, because the disadvantages of the relatively complicated construction and conversion (if I infer it correctly, may be simply too great to justify it as an energy technology.

The original post doesn't identify whether this is a photo or a rendering

That there is some potential in the technology is reinforced by a separate post about another new urban algae demonstration project in La Defense, near Paris.  Ennesys, a Paris-based energy systems company and OriginOil, an American algae harvesting company have prototyped a system that harvests energy from algae present in wastewater while filtering the wastewater for use as graywater. The rationale for this application ties it firmly to satisfying incoming regulations for limited release of contaminated water from sites, which clearly multiplies the benefits far beyond a calculation based on energy balance alone.

Meanwhile, the appearance of BIQ House adds new meaning to the much abused term 'green building'.  It's very green indeed.  Working in there will either be extremely calming (think 'green rooms' for actors before a performance), or your colleagues will look like they are about to be violently ill.  I am eagerly anticipating the interior photographs, and indeed further technical information.

Read more in Inhabitat:  

The World's First Algae-Powered Building Opens in Hamburg | Inhabitat

New Urban Algae System Generates Energy While Cleaning Wastewater in Paris | Inhabitat