Retired Landfills Become Solar Infills

For years, Atlanta commuters driving up I-675 and then turning west toward Hartsfield Airport were greeted by the sight of an enormous “Mount Trashmore” on their left, DeKalb County’s Hickory Ridge landfill.


That mountain having reached its optimum height, Republic Services was stuck with the task of trying to keep it stable and get some use out of it. This week it would have made a great ski hill. In August, maybe a water slide?


Armed with $2 million from the 2009 federal stimulus Republic is turning Hickory Ridge into a “solar park.”


Global Energy Holdings of Atlanta has contracted with Republic to harvest the natural gas seeping out of the mountain. Carlisle Energy Services will install a “Spectro PowerCap”  to contain the gas and provide solar power.


Carlisle will first grade the hill, then lay down a 60 millimeter sheet of thermoplastic polyolefin (TPO) over it. It will place Unisolar  solar panels on top of the membrane and connect them up.  The company estimates the cost of the total system as being no more than a standard landfill closure.


Unisolar systems are not efficient power generators. Prices have been falling quickly.  But the TPO membrane keeps gas from seeping out, so it can be taken out in a controlled way, and it keeps dust from blowing around. The solar power is a bonus.


The final system is expected to have a capacity of 1 Megawatt (MW), with the electricity being sold to Georgia Power for the bargain price of 15 cents per kilowatt hour.


Republic engineering manager Tony Walker admitted to the Atlanta Journal-Constitution that Georgia Power doesn’t pay much for renewable energy, but the gas is valuable, the closure costs no more than a standard solution, there’s $2 million in government money to pay for it, and there’s all that publicity to be gained.


The Georgia Solar Energy Association is proud that it recently convinced the Georgia PSC to double the amount of energy Georgia Power buys for its Green Energy Program, by 1.5 MW, at a price of 17 cents per kilowatt hour for smaller projects, and bigger projects like the Republic plan taking a lower price. GaPower hopes to sell 5.4 MW of power under the plan. They’re not trying and still doing well.


Would this have happened without the stimulus? Maybe not the solar panels. But maybe so, given the positive spin the garbage company is getting. The only real cost is the panels and connection – everything else makes enormous economic sense.


What lessons do you take from it?

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Dana Blankenhorn has covered business and technology since 1978. He covered the Houston oil boom of the 1970s, began making his living online in 1985, and launched the Interactive Age Daily, the first daily coverage of e-commerce, in 1994. He has written for a host of off-line and online publications including The Chicago Tribune, Advertising Age, and ZDNet. He has covered PCs, networks, telecommunications, cable technology, Internet commerce, the Internet of Things, Open Source and Health IT, He began covering alternative energy at his personal blog,, in 2007.

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