Philadelphia architect KieranTimberlake has won the competition to design the new US embassy in the UK.

Called New London Embassy, it will be built at Nine Elms beside the River Thames.

The building replaces Eero Saarinen's embassy is Grosvenor Square, which was completed in 1957 and which was recently listed as a Grade II historical building.

Timberlake beat architets Pei Cobb Freed & Partners, Morphisis and Richard Meier & Partners to win the project.

Here's some text from KieranTimberlake:

New U.S. Embassy in London

23 February 2010

The United States Department of State announced today that KieranTimberlake has won the design competition for the New London Embassy. In statements given at a press briefing today in London, U.S. Ambassador to the United Kingdom, Louis B. Susman, and Acting Director of the Bureau of Overseas Buildings Operations, Adam Namm, remarked, "KieranTimberlake's design meets the goal of creating a modern, welcoming, timeless, safe and energy efficient embassy for the 21st century. Their concept most fully satisfied the requirements outlined in the design competition's mission statement. The concept holds the greatest potential for developing a truly iconic embassy and is on the leading edge of sustainable design."

Concept

• The concept for the New London Embassy is the result of KieranTimberlake's efforts to resolve, in architectural terms, what an embassy aspires to be and what present realities dictate it must do.

• The expressive challenge is to give form to the core beliefs of our democracy - transparency, openness, and equality - and do so in a way that is both secure and welcoming. At the same time, the building must confront the environmental challenges all nations face with leading edge sustainable design.

• The team included Olin as Landscape Architect; Arup for Sustainability, MEP/FP and Civil Engineering; Weidlinger Associates for Structural and Blast Engineering; Gensler for workplace design; Davis Langdon for Cost Consulting; and Sako & Associates for Technical Security.

Urban Park

• The design places the embassy building at the center of the Nine Elms site and develops the surrounding area into an urban park. The new embassy meets all the required security standards while honoring the English tradition of urban parks and gardens as the context for many civic buildings. The new embassy, with its gardens, will establish a strong framework for the urbanization of the Nine Elms redevelopment zone.

• There are two major east-west pedestrian and vehicular paths, one existing and one to be improved, and the other proposed as part of the enabling infrastructure for the Nine Elms development. The existing infrastructure is along the south Thames embankment and is composed of a river walk paralleled by Nine Elms Lane. The proposed new infrastructure to the south of the embassy site is a pedestrian greenway that will connect the embassy site to Vauxhall Station, the nearest tube stop to the east, and on to the proposed new Battersea developments to the west. Poised strategically midway between these parallel paths, the embassy becomes part of an urban park that connects the Thames embankment to the new pedestrian way to the south.

• The paving about and within the embassy site utilizes the familiar limestone used in many London walks and parks. London Plane trees provide shade and form at the perimeter and along Nine Elms Lane as well as the proposed new walk to the south that connects the site to Vauxhall Station.

• Seen from the north along the Thames embankment and Nine Elms Lane, the new Embassy Park contains a pond with walks, places to sit and landscape along its edges, all open to the citizens of London.

• Trees near the pond are to be North American species, such as the Weeping Willow and the Bald Cypress. Others, while native to North America, were long ago brought to England and are now common to the English landscape.

• Viewed from the north at the proposed plaza, the embassy grounds will provide the prospect of an open park, a landscape of grasses rising gracefully to the new embassy colonnade, with the required secure boundaries incised into the hillside and out of view. Instead of a perimeter-walled precinct, the site to the north and south is a welcoming urban amenity, a park for the city that fuses the new embassy to the city of London. Alternatives to perimeter walls and fences are achieved through landscape design.

• The spiraling form of the landscape is expressed through grading, walks and plantings in a way that simultaneously opens out to the city beyond and spirals inward as it envelops and then moves up into and through the embassy building. As a choice of form, the spiraling garden is meaningful as it represents connections of site to landscape to building.

• The connections to the surrounding urban context, both existing and proposed, begin in an open geometry well beyond the site at the Thames embankments and the proposed Vauxhall-to-Battersea pedestrian way.

• The walks and landscape forms begin their inward spiral at the outer boundaries of the site. They sweep past the pond to the entry court that opens to the Main Lobby for staff and their guests. At the opposite side of the Main Lobby, the Gallery spirals down to the north culminating in the large Multi-Purpose Hall that merges with the grade of the spiraling Consular Walk above.

• At the main entry, the site spiral continues beyond to the great arc of the Consular Garden, carrying the visitor up the Consular Walk and into the Consular Lobby and promenade overlooking the pond and the Thames embankment to the north.

• The visitor continues this spiral within the embassy, revolving about the core and up to the consular floor above, pausing along the way to overlook the Main Lobby, a significant moment where the necessarily separate worlds of the embassy - consular visitors and staff - visually intersect.

The Chancery

• Internal gardens continue vertically within the new embassy as the spiral continues upward about the core toward an ever more focused, secure and enclosed center atop the structure. These gardens provide places to meet and additional vertical circulation. The plantings for each garden are chosen for their capacity to thrive in specific orientations, for their representation of the diversity of the American landscape and for the appropriateness of each type to its use.

• The chancery is a transparent, crystalline cubic form atop a colonnade. The crystalline form is simultaneously efficient and evocative.

• It represents the optimum ratio of maximum volume within minimum perimeter with resulting cost and energy management benefits. Its precise dimensions have been selected to afford the optimum distance for visitors and occupants to daylight and view.

• As a pure geometry, the cubic form is an ancient signifier of solidity, strength and permanence, all qualities of our democracy.

• Its surface is given form through the interface between a faceted external solar shading and collection system and the blast resistant glazing.

• This crystal-like ethylene-tetrafluroethylene (ETFE) scrim has been optimized to shade interiors from east, west and south sun while admitting daylight and framing large open view portals to the outside. Its pattern visually fragments the façade while it intercepts unwanted solar gain and transforms it into energy by means of thin film photovoltaics positioned in the ETFE foils. The design of this scrim works vertically, horizontally and diagonally to eliminate directionality from the building's massing. The scrim also renders the largely transparent façades visible to migratory birds to discourage bird-strikes.

• At each façade, an ETFE enclosed pressurized air pocket further insulates the glazing from thermal transfer.

• The top of the building is sheathed with a crystalline photovoltaic array on the entire roof, screening mechanical equipment from view. The total array of crystalline and thin-film photovoltaic on the building measures 8,300 square meters with a significant output of over 345,000 kWh of energy.

• A four-sided colonnade forms the base of the building. Through both custom and the openness and accessibility of its sheltering form, colonnades have long evoked the architecture of democracy.

The Diplomacy of Art

• Luminous ‘light art' wraps the core wall in a prominent location behind the colonnade.

• At the Main and Consular Lobbies the art inside is visible through glazing from the main entry court and the pond. To the south and southwest are external art walls. As it unfolds about the central core, the art can be experienced both within the major public spaces and from the outside as part of the continuum of spiraling walks and landscape form.

• In the Main Lobby, the art wall stops at the center to inflect toward a stone wall in which the names of prior ambassadors to the Court of St. James are inscribed.

Landscape

• Rather than employing a plinth to accommodate the large programs located at the lowest levels of the building, the colonnade sits atop a gently rising earthen mound. Within this landscape form are parking garage ramps and basement service and mechanical areas to the south, and the lower level of the Gallery and Multi-Purpose Meeting Space to the north and west.

• Instead of fragmenting the embassy into a plinth and tower, this strategy transforms the large footprints of the lower levels along with the entrance pavilions into earthen landscape form to enhance the prominence of the embassy colonnade and transparent building.

• The visual presence of the whole is that of a beacon that is a respectful icon representing the strength of the U.S.-U.K. relationship.

• In the form and expression of the New London Embassy, KieranTimberlake seeks a holistic fusion of urbanism with site, of building and landscape.

• KieranTimberlake seeks a new embassy that is both evocative and that performs, one that represents our democracy and our relationship with the United Kingdom and at the same time conserves and produces energy.

• All elements are purposeful in multiple ways: from image and expression to the environment and urbanism, to the productivity and comfort of the users. The architects at KieranTimberlake do not believe these objectives can be segregated. They must work together, holistically providing new synergies that make the form of the new embassy resonate deeply.

Renderings by Studio amd