"Going green" can be a successful economic strategy that leads
to sustainable growth, the jury said at the presentation of one of
those awards. That accurately sums up the vision of Casey
Houweling, owner of the company. "What sustainability is to us
is a combination of caring for our planet - which we will leave to
our children - and commercially viable solutions for growing
healthy, delicious tomatoes," says the grower.
In this family, the innovative entrepreneurial spirit is passed
from generation to generation. His father, a Dutch immigrant, built
a horticultural company in British Columbia with years of hard
work. Son Casey continued where his father left off and now has
locations in Canada and the USA. While the company may now be
significantly larger, one thing has not changed: the ambition to be
in the vanguard of sustainability and produce top quality
Semi-closed Ultra Clima greenhouse
The location in Camarillo has 125 acres of greenhouses, with
around 40 acres' worth of the semi-closed type that have few
windows that open and instead have air handling units to regulate
the greenhouse climate. "This type of system makes use of many fans
which requires considerable additional electricity," says Richard
Vanderburg, energy and water conservation manager. "That is why we
installed five acres of solar panels over the water basins in 2008.
This was attractive because the State of California provides a 50%
Until then, the heat required for the greenhouses had been
provided by gas boilers, but that is not the most efficient use of
energy. "With a combined heat and power (CHP) system, because it
simultaneously produces heat, electricity and CO2, you
can utilize practically 100% of the energy. There is no longer any
waste. We have Casey Houweling's enthusiasm to thank for the fact
that we now have three 4.4 MW CHP units."
The cogeneration technique is still not all that common in the
USA. The technique has been used for the combustion of gas
extracted from garbage dumps and waste-water treatment, but it is
virtually unheard of in horticulture.
Selling back to the grid
Purchasing the CHP system was the easy part. "Much harder were
the negotiations to sell the generated electricity back to the
grid. The regulatory environment was difficult. It took us three
years to win that battle," says Vanderburg.
Another challenge was the interplay of boiler, combined heat and
power units, solar panels, heat storage and assimilation lighting.
"At certain times, exporting to the grid has a strong commercial
position - in the summer the peak rate period is between noon and
six in the evening - so we run the CHPs at their maximum and we can
make good use of the produced CO2 at that time. Export
is therefore given priority over our own use, for lighting as an
example. The heat is stored in the buffer. The buffer charging must
be done in such a way that the CHPs can run at full capacity during
the lucrative hours. If, on the other hand, the heat demand cannot
be met entirely with the CHPs, the boiler has to kick in," he says.
Designing a system to control all this is very complicated, and
therefore Houweling's called in world-class specialist Priva. The
choice was made for a very user-friendly solution. Everything is
presented graphically on the computer screen; this insulates the
operator from most of the complex process coordination taking place
in the background. "There is very little that has to be done
manually," the manager realizes. "And the system stores all the
data, which is useful because we not only need it for our own
analyses but also for the energy subsidy. Working with Priva has
been a pleasure. Project engineer Richard Zeeuw found smart
solutions to meet all of our needs and made it very easy to
To integrate all the new technologies, John van der Wilk of
Priva Business Solutions was closely involved in discussions with
the local power company and the contractor.
Houweling's is not only very progressive in its approach to
energy but also in how it handles water. "Water scarcity is a major
and ever-growing problem in California. We do have our own well,
but we are only allowed to extract a limited amount of
groundwater," says the manager. "Therefore we capture as much water
as possible. We harvest rainwater from the roof, and we collect the
condensation water from the CHPs. We don't waste a drop here."
The plants get the water they need: with the Priva computer we
can dose the water based on the measured evaporation, enabling us
to provide the exact amount of water needed. The evaporation is
measured through continuous monitoring of the weight of the
substrate mats. The drain water is recirculated to the extent
possible, and potential contamination issues are ruled out by
disinfecting the return water before reuse.
This efficient use of water has also played a role in the
sustainability awards the company has received. "We do everything
possible in the current situation," tells Vanderburg. "But we are
already pursuing a new initiative: obtaining purple water from the
treatment plant three miles away. That water is currently being
discharged to the ocean after treatment, but we could put it to
good use. With reverse osmosis we can make it suitable for
cultivation. In time, this could completely offset the water we
currently extract from the well."