Green Roof Policy Optimization Algorithms and Microsimulations Benefits and Downsides of Green Roof Incentives and Mandates in San Francisco

As the 21st Century progresses, developers are becoming more aware of their environmental footprint. As the Green Economy slowly gains its footing, developers will be expected to change current building practices to reflect the increasing demand to adapt to sustainability challenges. One such methodology used by LEED to evaluate the sustainability of a building is the implementation of a green roof, the installment of vegetation on the top of a building. There are many socioecological benefits that justify the implementation of a green roof, which explain why in recent years municipalities have enacted new policies to mandate or incentivize their implementation. Four optimization algorithms were developed to determine the size of a green roof delivering maximum Net Present Value (NPV) based off raw economics, San Francisco policy, Chicago policy, and Toronto policy. The models were then tested on a sample of 2001 random buildings in San Francisco and the results analyzed. The major findings are that incentives as described by the Chicago policy do not increase the amount of green roofing installed, and mandates as enacted by Toronto and San Francisco do not apply to enough buildings to be meaningful.