According to Architecture 2030, in order to achieve a net zero, or simply a zero building, the first step is to design using passive strategies.  The second step is to use non-fossil fuels, which are free of fossil fuels.  According to the National Renewable Energy Laboratory, (NREL), at the end of the day, a net zero energy building needs to generate renewable energy on site that will equal to, or exceed, its annual energy consumption. The 2030 challenge is a great idea, but how can it be feasible?