Sustainability Subcommittee approves green roofs at CCB and energy saving at Alliant Energy Center

On Friday, the Public Works Sustainability Subcommittee convened to review three applications for improving the environmental impact of two county properties. The committee began with an election of committee leadership, selecting chair Supervisor Erickson — an advocate for sustainability who helped to create the Sustainable Management and Renewable Technologies (SMART) Fund (with former District 24 Supervisor, Robin Schmidt), which supports efficient energy initiatives. I was elected as vice chair.

Three initiatives, two at the Alliant Energy Center, and one at the City County Building were recommended for approval. The applications will move to Public Works, and if approved, will go before the county board.

Green Roof at the City County Building:

Install extensive living roof systems on each of the first floor roof Sections on the MLK elevation of the City County Building (approximately 3,800 total square feet). This project is really exciting, as it will model what can be done to retrofit older buildings to mitigate urban heat islands and storm water runoff.

Green roofs help reduce the Urban Heat Island Effect, which can increase urban temperatures up to 8 degrees Fahrenheit compared to surrounding rural areas and prolong and intensify heat waves in cities. (City of Chicago, 2008) They can also lower the energy demand by assisting in internal building temperature regulation. Additionally — and related to community conversation about storm water runoff — green roofs can absorb 50-100% of storm water.

Two initiatives at the Alliant Energy Center:

Replace 348 with 308 energy efficient LED fixtures. The result is to reduce contribution to fossil fuel dependence by reducing the amount of electricity and eliminate the need to send metal halide bulbs to the landfill. This project is expected to save 60,310 kilowatt hours of electricity usage per year, which will reduce greenhouse gas emissions by 42.6 metric tons, saving $12,425 per year, resulting in a payback period of 2.06 years for this project. This request is a result of similar successful projects in the past few years.

Replace large, slow speed roll up doors with two new 14’x16’ high speed Rytec Spiral doors. This project will reduce the electricity and gas used to cool and heat the building. Slow speed roll up doors are often left open show ingress and egress in all seasons. The project is estimated to save 13,085 therms of natural gas and 11,346 kWh of electricity, annually, leading to reduction in greenhouse gas emissions of 77.4 metric tons leading to an estimated cost savings of $9,972, a payback of about 8.4 years. This project furthers the Sustainable Operations Plan goal of reducing greenhouse gas emissions generated by all county operations and facilities, and to planning for and implementing climate adaptation measures to build resilience in the face of current and future impacts of global climate change on government operations and our community.

Chicago City Hall’s green roof — temperature differences between the vegetated and non-vegetated claimed to be as much as 70°

Chicago City Hall’s green roof — temperature differences between the vegetated and non-vegetated claimed to be as much as 70°