Ordinance amending Planning Code Section 226 to require that power plants in M-1 and M-2 zoning districts obtain conditional use authorization, adding Section 226.1 requiring additional findings; amending the Administrative Code to add Chapter 29A to require the Board of Supervisors consider the criteria of Planning Code Section 226.1(c) prior to taking City power plant approval actions; making environmental findings, and making findings of consistency with the General Plan and priority policies