City administration Acct Problem

City administration is considering refurbishing the lighting system of its administration building.       
After initial investigation, the city procument office has narrowed down the choices into the following two options:      
      
Option 1 is a Urgolight system, which costs $500,000 to purchase and instrall.       
Option 2 is a convention system, which costs $100,000 to purchase and instrall.       
The system is expected to last for 20 years      
The energe and maintenance cost for Option 1 is $20,000 and $2,000.       
The energe and maintenance cost for Option 1 is $50,000 and $10,000.       
Assume all gas costs paid at end of year.       
Real discount rate:  4%       
      
Which lighting system should the city selected based on financial consideration.       
Note: please use LCC analysis to facilitate the decision-making.