W
hen I joined Turner Construction Company in 2015, a green building
was mostly defined by what certification it carried. But recently, this definition has expanded to include how we build. Sophisticated clients are starting to ask contractors how they will deliver sustain- ability beyond the design specifications – especially surrounding embodied and operational carbon. In 2018, Turner was one of the first large general contractors in the United States to commit to reduce jobsite car- bon emissions and water consumption during construction. The pathway was unclear at first. What is the project boundary? Do we measure commutes? What about water for street sweeping? Over time, we standardized our process and began to require carbon and water tracking for activities within the jobsite fence on all projects over $20 million. We added tracking requirements to our subcontract language and our trade partners got used to submitting monthly fuel tickets. Anything that stays within the jobsite fence, we measure. The early years of our program taught
us many valuable things, not least these three significant takeaways relevant to California:
1) Demolition, earthwork, and foun- dations trades are the biggest fuel consumers on our jobsites. Identifying this enables us to focus our efforts on where technology and alternative fuels can help us transition off car- bon-based fuel.
2)Generators are one of the most carbon-intensive items on projects. With a carbon footprint that is nearly 20 times that of being on temporary power, getting off generators is critical to lowering carbon footprints.
3)Water consumption and carbon emissions peak when the building is undergoing testing and balancing. When MEP systems undergo stress tests to confirm performance and prior to balancing, carbon and water impacts are highest. Measuring is only one part of the equa- tion. Te adage ‘you can’t manage what you don’t measure’ is a good one. Tese three takeaways gave Turner information to pilot technologies that can help address it. A Turner project in Iowa served as a sandbox to identify and test technologies to start adopting on a wider scale, where we gathered carbon, operator experience, financial, and safety data on a wide array of equipment. Some takeaways from this pilot (and others since) include:
1)Hybrid generators are the future. In these systems, a battery is charged by a generator and serves as the primary energy source for equipment, trailers, or lighting. While the battery is in use, it turns off the generator, saving upwards of 75% of fuel savings for the same amount of power generation. Tese savings often pay off the premium for the battery, require less maintenance for the generator, and make for a healthier, quieter site.
2)Solar and hybrid light towers/ cameras/signboards are no-brainers. These hybrid or solar systems pay for themselves from saved fuel and mainte- nance. Carbon savings from a hybrid unit on the Iowa project were as much as 97% compared to conventional diesel units.
3)Getting on temporary power early, for as much equipment as possible, is key. As California works to decarbon- ize its grid by 2045, this means that any electric equipment connected to shore power will also become carbon-free by that date. Consider an early-buy of the
CALIFORNIA CONSTRUCTOR SEPTEMBER/OCTOBER 2023
17
Opportunities for low-carbon equipment grow significantly through
engaging with rental partners and connecting vendors with subcontractors.
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