The electric grid is changing rapidly - with more intermittent, renewable energy resources contributing to the power generation supply, more dispatchable baseload retiring, and more extreme weather events causing outages. Providing uninterruptible power supply is becoming increasingly more challenging. As building designers and operators, we have the opportunity to be part of the solution by optimizing the demand side of the equation. Passive building is a design methodology that utilizes passive principles to reduce loads on a peak and annual basis. Passive buildings have inherent load flexibility, flattened peak demands, and less reliance on continuous power supply which is essential for the transition of a clean energy grid.