If you obtained all of your energy from a diesel generator, how much diesel would you save per year by switching from incandescent to CFL? Diesel has an energy density of 36 MJ/L and your generator operates with 40% efficiency. Incandescent bulbs consume 60-100W, while CFL consumes 15-25W.
1 Kwh 3.6 MJ. If you use each light 4 hours per day, and each was 100 watts, that is 4 x 100 x 10 x 365 1,460,000 watt hours per year. That requires 1,460 x 3.6 MJ 5,256 MJ. / 0.4 efficiency 13,140 MJ. So you need 13,140 / 36MJ/L 365 Liters of diesel. If you used CFLs, at 25 watts, the answer is 1/4 of that, so 365 / 4 91.25 Liters of diesel. So the savings is 365 - 91.25 273.75 Liters savings. At $1.25 per liter, that is $324.19.
