POWER May 2023 - 34

SOLAR POWER
Floating PV System Provides
Smart Energy and Savings for
Wastewater Plant
Installing floating photovoltaic solar panels on a water reservoir provides Kelseyville
Wastewater Treatment Plant with low-cost, clean energy, reduces algae growth,
minimizes bank erosion, and lessens evaporation.
SolarEdge Technologies
T
he Environmental Protection Agency
reports that drinking water and
wastewater systems account for
approximately 2% of total energy use in
the U.S. due to the electricity required
to pump large volumes of water. It's
estimated that this adds more than 45
million tons of greenhouse gases to the
atmosphere annually. For many local
governments, drinking and wastewater
plants account for up to 40% of their total
energy consumed.
The Challenge: Rising Electricity
Rates and Limited Space for Solar
Many California electric utilities have
been forced to raise electricity rates in
recent years for a variety of reasons.
Meanwhile, the increased frequency
of wildfires in Northern California could
exacerbate the situation, as expensive
countermeasures
and
grid
enhancements
add to costs that must be passed
on to end-users.
Lake County Special Districts is the
water and wastewater agency of the
County of Lake, California, which is about
130 miles north of San Francisco. Leadership
for Lake County Special Districts
knew the solution to controlling wastewater
treatment plant costs was turning
to cheaper renewable sources of electricity.
However, they were concerned
that the property they had available did
not have adequate land or rooftop space
to install a photovoltaic (PV) solar system
large enough to offset consumption.
After issuing a request for proposals
(RFP) and reviewing the bids, Lake County
Special Districts selected North Coast
Solar, a pioneering energy consulting and
contracting firm based in Santa Rosa, to
implement its proposal to install a solution
from Ciel Et Terre-well-known developers
of the Hydrelio floating solar
power system (Figure 1).
Turning to Water for Solar
" A lack of roof and ground space put our
creative minds to work, ultimately driving
the floating solar concept, " said Brian
Hines, president of North Coast Solar.
The 252-kW solution includes 720 Canadian
Solar modules rated at 350 W each.
It also utilizes one SE100K and two SE66K
SolarEdge three-phase inverters with
Synergy technology, and 360 SolarEdge
P800s Power Optimizers (Figure 2).
The system was engineered to cover
1. Lake County Special Districts opted to install
a floating solar power system to reduce
its energy costs. Courtesy: SolarEdge
34
much of the plant's annual energy usage,
and projected annual electricity savings
of $90,000, which is expected to grow
over time as Pacific Gas and Electric
(PG&E) rates increase while monthly
lease payments remain constant. And,
with the innovative municipal lease financing
arranged by North Coast Solar,
only minimal upfront investment was
required, allowing Lake County Special
Districts to generate positive cash flow
in the first year of operation.
Floating solar power plants improve
energy production by keeping the solar
system cooler, which prolongs the lifetime
of the PV system and improves performance.
This cooling factor is an even
bigger benefit in Lake County where
summer temperatures can reach 106F.
Utilizing the pond surface for a solar
plant also reduces algae growth (Figure
3), bank erosion (through reduced water
movement), and evaporation, while
www.powermag.com
Battery Energy Storage
Adds Value to Solar
Power Systems
One of the drawbacks of solar power
systems is the lack of production when
the sun sets and on cloudy days. However,
battery energy storage systems
(BESSs) are helping to alleviate that
problem. In fact, most new systems
being installed today are incorporating
BESSs into the design.
In January, SolarEdge Technologies
Inc. began shipping its new line of
nickel manganese cobalt (NMC) pouch
cells, manufactured at Sella 2, the company's
new battery cell manufacturing
facility in South Korea. SolarEdge says
the new cells have been optimized for
energy storage applications for the
residential, commercial, and utilityscale
segments. The cells support high
cycle life (up to 8,000 cycles), high energy
density, high power throughput,
and a wide temperature range without
compromising operational life. This enables
the battery solution to support
a broad range of use cases, including
demanding grid-stability applications.
" The global stationary storage market
is estimated to grow from approximately
45 GWh in 2022 to 164 GWh
by 2030, " Ronen Faier, Chief Financial
Officer and general manager for the
Edge Energy Storage division with
SolarEdge, said in a statement. " SolarEdge
is focused on supporting this
critical segment. Owning key processes
and cell chemistries will allow us
to further secure the resilience of our
supply chain and provides us with the
flexibility to produce cells optimized
for various energy storage solutions. "
generating virtually free energy. Benefits
also include reduced greenhouse gas
emissions, offsetting 131 tons of CO2
per
year-enabling the county to meet specific
carbon reduction goals (see sidebar).
POWER | May 2023
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POWER May 2023

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