Inside Cestas

300 MW Cestas project 300 MW Cestas project
Photos Krinner
The foundations for
Europe’s heavyweight
Mounting systems: An array the size of Cestas requires a sophisticated approach
to process optimization when it comes to installation. Working from the ground
up, Germany’s Krinner was able to provide valuable input into the build out and to
develop a solution to the high water table.
As Europe emerged from winter in 2015,
76 year old Klaus Krinner found himself
flying weekly from Bavaria to the Bordeaux
region in southwestern France. The
reason was that the company Founder
liked to survey the progress at the Cestas
site. And quite a sight it was too.
With an east-west orientation and
closely packed rows of multicrystalline
modules, Cestas is notable not only for
its size, but for its innovation. The project
allowed the Krinner team to roll out some
new machinery, techniques and installation
control software during execution.
The project has brought together some
of solar’s heavy hitters, with modules
being supplied by Chinese giants Yingli,
Canadian and Trina, and the electrical
conversion chain and grid connection by
Schneider Electric. So how then did Krinner’s
eponymous and family-owned company
get involved?
“It’s simple: We’re the best,” says Klaus
Krinner displaying some of the chutzpah
that allows a mid-sized firm, a prime
example of Germany’s economic engine
room – the so-called Mittelstand, from
Germany’s south to compete on the
global solar stage.
“We’re a family business and we always
try and see the project from the investor’s
perspective,” adds Christoph Krinner,
Klaus’ son.
Working on Cestas meant delivering a
solution that is both competitive on cost
but also durable. Krinner supplied all
of the ground screws from its own production
site in Germany and sourced all
of the steel mounting structure components
from within the country also. Klaus
Krinner says that it allowed the company
to closely control for quality and also to
prevent component bottlenecks and
potential delays.
“The reason why speed is so important
is partly to stick to the client’s time
schedule,” explains Klaus Krinner, “but
for the owner and investor, every day
with sunshine for a project this size is
worth roughly €200,000 ($220,000) in
revenues.” Even before the final contract
for the project had been signed, Krinner
began preparing components and shortly
afterwards shipping to the site to ensure
that components were in place, in temporary
storage facilities, in sufficient quantities
to ensure installation teams were
not left short at any stage.
Robotic installation
The Krinner team employed a number
of new robotic pieces of equipment on
the project. The KRD 60 was designed to
install the ground screws on Cestas. It uses
GPS positioning to automatically determine
the exact positioning of the screw. It
also determines the density of the earth to
ascertain whether ground hammering is
required. It automatically logs its activity
so it can be monitored off-site, in fact back
in Bavaria, by the Krinner team.
The marking of the ground was also
carried out by a new machine. Krinner
employed a surveying robot to precisely
locate the layout of the ground screw
placement and to pre-drill where necessary.
“As far as we know, it is the only
machine worldwide that is capable of
doing that,” says Klaus Krinner.
As the installation took place partly
over winter, something that is often
avoided in colder parts of Europe, the
installation teams had to potentially deal
with large amounts of rain. A new tool
featuring thin wheels to cut into the top
soil to allow it to drain, however not to
form deep trenches, was employed. The
machines also had to ensure that they
did not place too much pressure on sodden
earth while at the same time keeping
components off the ground. Special trailers
were designed to transport the modules
through the tightly packed rows.
The high energy density of the array
was one of the inputs that Krinner had
into the project. The team realized a
design in which one hectare of land can
be equipped with 1.15 MW of modules.
Special installation equipment had to
be designed to operate in the confined
spaces. The east-west module configuration
does lend itself to the high density,
but it was chosen for its more stable production
profile, including its production
in the morning and evening.
In terms of cost, the Krinner team
reports that it was able to be competitive
with Asian suppliers, even with components
being produced in Europe. While
Krinner was not the cheapest provider,
the family team learned after being
awarded the project, it was the additional
inputs that Krinner’s engineers
and machinery providers themselves
delivered that set them apart.
“We don’t only see the cost of the material
up until the completion of construction,
but we also see the 20 to 25 year lifetime
of the array,” says Michael Krinner,
Klaus’ nephew. “So taking that all into
account, it is cheaper to produce in Germany.”
Klaus Krinner says he has seen
arrays in Germany where module degradation
has been as little as 0.02% annually.
“The limiting factor to a project’s life
is usually the module, so we want the
mounting systems to exist for far longer
than the panel,” says Klaus Krinner. “In
case it should stay there for 100 years, it
can be done.” It is hard to imagine such
a vast project as Cestas being in place for
quite such a long time, but time will tell.
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