Nation's Largest Net-Zero Mixed Use Project Planned for Philadelphia

Branden Klayko reports on the pioneering project planned by innovative Philadelphia design-build developers Onion Flats.

1 minute read

January 20, 2012, 10:00 AM PST

By Jonathan Nettler @nettsj


Planned for a site on the banks of the Schuylkill River, The Ridge is intended to become the nation's largest Passive House. Scheduled to be completed in 2014, the building will be prefabricated in a facility just outside Philadelphia.

Sustainable elements include power generated by a 200-kilowatt solar array and a completely permeable, green-roof covering the site.

The technical aspects of solving the net-zero energy puzzle are not the only challenges for Onion Flats. "What's going to be important is to demonstrate that it's easier to meet Passive House standards on large-scale buildings than small buildings," [Timothy] McDonald, [Principal] said. "We want to show that it's not only possible but also much easier to take on larger buildings without losing quality design."

Thursday, January 19, 2012 in The Architect's Newspaper

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Cover CM Credits, Earn Certificates, Push Your Career Forward

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

June 25, 2025 - Diana Ionescu

Map of Western U.S. indicating public lands that would be for sale under a Senate plan in yellow and green.

Map: Where Senate Republicans Want to Sell Your Public Lands

For public land advocates, the Senate Republicans’ proposal to sell millions of acres of public land in the West is “the biggest fight of their careers.”

June 19, 2025 - Outdoor Life

Person wearing mask walking through temporary outdoor dining setup lined with bistro lights at dusk in New York City.

Restaurant Patios Were a Pandemic Win — Why Were They so Hard to Keep?

Social distancing requirements and changes in travel patterns prompted cities to pilot new uses for street and sidewalk space. Then it got complicated.

June 19, 2025 - Diana Ionescu

Close-up of full beer glass with purple train-themed design sitting on bar between two frosty tall cans.

Platform Pilsner: Vancouver Transit Agency Releases... a Beer?

TransLink will receive a portion of every sale of the four-pack.

3 hours ago - Cities Today

Vintage red Toronto streetcar passing in front of Rogers Arena in Toronto, Canada.

Toronto Weighs Cheaper Transit, Parking Hikes for Major Events

Special event rates would take effect during large festivals, sports games and concerts to ‘discourage driving, manage congestion and free up space for transit.”

4 hours ago - blogTO

Map of Berlin with ring roads in green and red.

Berlin to Consider Car-Free Zone Larger Than Manhattan

The area bound by the 22-mile Ringbahn would still allow 12 uses of a private automobile per year per person, and several other exemptions.

5 hours ago - Streetsblog USA

Urban Design for Planners 1: Software Tools

This six-course series explores essential urban design concepts using open source software and equips planners with the tools they need to participate fully in the urban design process.

Planning for Universal Design

Learn the tools for implementing Universal Design in planning regulations.