Gather a year of utility usage if available. Monthly dollars are a useful starting point; kWh gives the design team a clearer picture of energy demand.
A typical project moves through site review, design, engineering, permitting, utility review, installation, inspection and permission to operate. Timing depends on approvals and site conditions.
Cash and loans generally give you system ownership. A lease or PPA generally leaves ownership with a provider. Compare long-term costs, escalators, SREC rights and home-sale terms.