8. It costs $15,000 for a fully installed rooftop solar system with battery storage so you are mostly "off grid". You currently pay an average of $1440/year for electricity (12,000 kWh at $0.12/kWh). Ignoring the time value of money, how many years would this take to payback? 9. From questions 8, if the panels last 25 years, would you get your money back? 10. Now assume that through technology enhancements and mass production, the cost of the system came down to $10,000 for the household. Also assume there is a tax on carbon and the cost to produce coal went up so your bill is now expected to be $2,000/year. Now how many years would this take to payback? 11. From question 10, if the panels last 25 years, would you get your money back