Question: How many years does it take for a typical government / green investment to pay off?
Mesa got $1 million in federal stimulus money to replace 2500 traffic lights with LED's. That's $400 a light which probably includes the cost of installation. Once they are operational, Mesa expects to save $0.028 million per year in electricity costs. At that rate, it will only take 35.7 years of savings to get the $1 million back.
Nine turbines from seven manufacturers, including Reno's Windspire, are being installed to test their performances in different environments. The first turbine was installed at the sewer plant in Stead and the second at Mira Loma Park.The nine turbines and several solar projects together are a $3.5 million investment, before $1.7 million in energy rebates are applied to reduce that cost. The projects are expected to save 788,932 kilowatt hours a year for an annual savings of $91,000 a year [a 38-year payback].
The latter example actually over-estimates the payback, because it ignores the substantial maintenance costs of wind turbines (what percentage have you actually seen running?) as well as the systematic over-estimation of their power output. Incredibly, the SF Chronicle's green writer/blogger actually brags up the Reno boondoggle.
Postscript: In the comments of the wind turbine article I added, in response to the projects green credentials:
But, you say, its not about return on investment but CO2 reduction. OK, lets look at that, forgetting for a minute whether Reno taxpayers should be paying extra for electricity to reduce global temperatures by 0.00000000001C.
Let's consider an alternate investment in gas turbine electric generation, and assume it and the wind turbines are displacing coal-fired power. Per Kw-H, gas turbines are going to, even including the fuel, produce power for a fourth or less the cost of wind with these relatively small turbines. And gas is plentiful and most of it comes from the gold old USofA (or at least North America).
But it's not zero emission you say. OK, but if it is 1/4 the cost that means that it can displace four times as much coal power for the same investment. And it is as low of CO2 emissions per btu as you can get in a fossil fuel. In fact, 4X of gas generation would reduce CO2 emissions more than 1X of wind. So even in terms of CO2 emissions, wind here is a bad investment.