A “polished stone,” a “frozen wave” and a “beached whale” are some of the metaphors inspired by a hydroelectricity plant on the bank of the river Iller in Kempten, south-west Germany.
The arching concrete forms of the new hydroplant were designed by local firm Becker Architects in order to replace an ageing building from the 1950s. The new plant produces enough power to provide electricity for 3,000 homes and was initially planned by the specialist engineering company RMD Consult. Becker Architects were then briefed to design a structural envelope that responded to the “sensitive natural environment of the Iller” and the listed industrial buildings that are grouped on its left bank.
“Our starting point was the symbolic representation of water moving through turbines and generating electricity,” says practice principal Michael Becker. “This, together with the odd-looking eroded rock formations close to the plant’s site.”
The resulting design links the two end points of the power plant with a single envelope – essentially a reinforced concrete tunnel, 100m long by 23m wide. Becker describes it as “a softly-shaped, amorphous volume” in which openings were purposefully minimised for a “homogeneous feel”. The exterior was spray-coated with gravel particles that give iridescent surface reflections, changing with the light and weather.
In contrast to its smooth exterior, the concrete of the shell’s hollow is shuttered with rough-sawn boards and stabilised by transverse ribs that lend the interior structure a skeletal feeling. The ceiling height “pulsates between dome-like proportions and intimate scale,” says Becker, “as a way to create an exciting interior sequence.” At night the plant can be seen to glow, with light allowed to seep through movement joints in the concrete and the inlet and outlet mouths of the structure itself.
Aside from the plant’s aesthetic delights, conserving the river’s ecology and contributing to the neighbourhood were also major concerns. A 46m-long fish ladder reduces the barrier effect of the plant on fish migration patterns, allowing them to move upstream assisted by a series of low concrete steps. At bank level, a new pedestrian and bike path have been integrated alongside the hydroplant as a gesture to blend itself in with riverside activities.
It might be tricky to decide which organic metaphor suits the structure best, but for Becker ambiguity is the desired effect. “The perception of the viewer is always amazing – almost everyone experiences it in their own, very personal image.”
credit Brigida González