Testing out how long power plants and water facilites last. So far power plants (coal, gas, oil) start showing 90% effectiveness around 50 years after being built (although Wind Power plants were only at 95% after 50 years) Water facilties were only down to 97% at 50 years. Waste to Energy plant was down to 92% after only 30 years (86% after 40 years).

60 years in, and the 3 basic power plants are all at 78-79% condition (a drop of 11-12% in only 10 years). Wind power plant is still at 91% condition, Water plants are at 95% condition. Around year 65 and you'll start getting messages about "Power Plant No Spring Chicken". Worse, is the fact that your costs per month to maintain the facility go up as the efficiency (condition) gets worse.

70 years - oil/gas/coal are all at 50% condition (meaning they only generate half of what they're supposed to), but costs per month have risen to $908 (oil, 3562MWh, $0.26), $605 (gas, 1528MWh, $0.40), $378 (coal, 3054MWh, $0.12). Looks like the condition drops at an exponential rate the older the plant gets (year 50-60 they lost 11-12% efficiency, year 60-70 they lost 28-29%). Wind power plant is at 83% still ($56/mo, 166MWh, $0.34). Waste to Energy is at 68% (but is only 50 years old) with monthly cost of $1296 to produce 1157MWh ($1.12). Water plants are at 95% condition still with standard monthly costs of $350 (water pump, 19066 cu m, $0.02), and $50 (water tower, 2316 cu m, $0.02).

Things of course, get worse and worse as it goes along (see my SimCity 4 Power Plants page for the rest of the tables).

75 years - coal/oil/gas down to 39% efficiency. Wind Power plant is holding at 80% ($58/mo for 161MWh). Water plants are at 95% still (but usage is only 25%, which may mean that they wear out slower.... maybe there's a calculation that says a facility can only produce quantity X before it degrades?). The Waste to Energy plant (which is only 55 years old) is $1403/mo for 1085MWh.

80 years - at this point, the advisors are screaming about the power plants getting ready to go boom. Coal/gas/oil are down to 17% efficiency. Wind Power is down to 75% ($61 for 151MWh). Waste to Energy (only 60 years old) is at 46% ($1561 for 830MWh). Water facilities same as they were at +75 (95%). Good chance that there's a different rule set for water plants.

84 years 11 months - boom. Well, one of the coal/oil/gas plants exploded and took the other 2 with it (I had all 3 types of plants sitting next to each other). The destruction radius was limited to only 1-5 blocks around the plant (took out the federal jail, caught a few surrounding buildings on fire). Waste to Energy plant is now down to 34% efficiency ($1872/mo for 593MWh).

I'll have to set this test up again in another zone (or start over in this one).