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According to their press release, Republic Services "embarked on a revolutionary new venture"
earlier this year - apparently, they glued 1,050 Unisolar laminates on
a TPO membrane covering their landfill hoping to generate some
electricity from the Sun (here are some more pictures). ECD showcased this installation on the May-11th earnings call in a slide titled "New Applications Provide Opportunities" (see page 11 of the presentation). The installation was labeled as 132KW in that slide, although a September American Recycler article rates the system 134.4 KW DC (which makes much more sense as Unisolar do not make any PVL-126 modules, but, apparently, they do make the PVL-128
ones and probably used that rare opportunity to offload some). Anyway,
the same article provided a glowing review of the system:"The system has been working great. But keep in mind it’s only been online since April. We’re averaging about 750 kWh per day. It’s not a big system, but very reliable and low maintenance.
We have done no maintenance since we installed it. We get quite a bit
of rain so it washes down the panels for us,” said Tony Walker,
Republic’s project manager, who also pioneered the concept... "[The modules] work in very low light and we will probably be over our estimate in projected kilowatt hours by the one year anniversary date,” Walker said. Like other types of solar panels, Republic’s are performance warranted – 92 percent of minimum power output for 10 years, 84 percent for 20 years and 80 percent for 25 years... Republic reported only one outage of less than 24 hours since the system became operational.
That was caused by a major electrical storm. Lightning struck the
inverter unit, but as the unit was designed to handle lightning, it
only required changing a blown fuse." [bold mine]
The article also reveals that "Mr.
Walker, who is based in Phoenix, is able to remotely monitor the
Tessman Road system on a web-based monitoring system by Fat Spaniel, a
provider of monitoring and control systems to the solar industry."
So,
let us see whether Mr. Walker told the truth. Here is what Fat Spaniel
reports for the electricity generation from this system over the past month (the full real-time system monitor is available here):
As
you can see, nothing has been generated in the middle of September and
in the past few days (since last Thursday), and on the days the
electricity production was reported over the past 30 days, it was
always below 700 kWh a day. Here is the monthly generation data since
the system went online as of today (average daily generation has been
calculated off the reported monthly kWh generation and the calendar
days in each month, with only 13 days counted for October):
| Month | kWh | Avg Daily kWh Generation |
| April | 13,161 | 439 |
| May | 14,770 | 476 |
| June | 19,859 | 662 |
| July | 19,900 | 642 |
| August | 20,531 | 662 |
| September | 13,752 | 458 |
| October | 2,573 | 198 |
As
you can see, the system NEVER averaged more than 662 kWh a day in each
month, which is 12% below the 750 kWh claimed by Republic's project
manager. In fact, based on the reported data by Fat Spaniel, the system
is unreliable and has suffered at least two outages that have lasted a
few days.
The article also makes another outrageous claim: "Traditional
ground-mounted PV does not work for landfills because of prohibitions
against drilling into soil caps to build the foundations necessary for
steel racks to support conventional PV arrays, and the land is far too
unstable to support other heavy structures like wind towers. After long
term settlement these lands may serve as green space, golf courses or
parklands, but usage is often problematic because of the underlying
decomposition." No doubt, the author (and Republic) have failed
to consult Pfister Energy, an important Unisolar partner (at least, so
far), who installed in March of 2008 a 1,090 kW ground-mounted crystalline PV system
(or 8x as large as Republic's "science experiment") on the Pennsauken
landfill in New Jersey (see their picture on the left). And, of course,
they pretend to be oblivious of the tens of megawatts of glass PV solar installations by Juwi
all over Germany on landfills/brownfields. In fact, rack-mounted
(penetrating or non-penetrating) glass-solar-panel systems with
properly designed degrees of freedom offer the best solution for
landfills, both in terms of energy generation and reliability, and, of
course, cost. Unisolar's glued-on solution runs the risk of losing
adhesion over time as the geomembrane moves and stretches, leaving the
laminates free to fly in the wind (which they can do). Finally, one has to wonder whether Republic Services were aware that Unisolar's laminates ignited on the rooftop
of the Long Beach Convention Center in February of 2008 - because
Republic's landfill has been producing so much flammable biogas that
they actually already have a system there to collect and process it to generate electricity.
By the way, this "test project" apparently cost $1.3 million, or $9.67 per Watt, when First Solar's (and some crystalline's and glass a-Si's) ground-mounted systems could cost close to $3 per Watt. So much for Unisolar's claim, as reported by the American Recycler article, that "the payback time on investment is better than conventional panels."
