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1. Analysis
of
“Hybrid”
Renewable
Energy
Technology
“SolarMill®”
versus
“Solar-­‐Only”
I recently spoke with Dan Bates, CEO of Windstream Technologies ,about his company's
hybrid small wind solar systems and asked why a hybrid versus straight solar for energy
production. After a lengthy discussion with Dan he sent me a 10 point discussion on
solar wind hybrids and his Windstream solar mills. It is quite compelling and I am
adding his discussion in whole versus summarizing. Enjoy! - Kevin Woodbridge
1. SolarMill®
technology
has
higher
energy
density
–
maximizes
investment
in
renewable
energy
by
doing
more
with
less
space
• Three
solar
panels
with
a
total
maximum
capacity
of
750
Watts
takes
up
52
square
feet
versus
the
SolarMill
“3P”,
which
in
the
same
52
square
foot
space
produces
a
maximum
capacity
of
1.75
KW
2. SolarMill®
technology
maximizes
investment
with
more
consistent
energy
generation
• The
chart
below
shows
the
annual
wind
and
solar
resources
in
the
Philippines.
Note
the
divergence
between
the
two
during
seasonal
changes
–
In
the
winter
months,
when
solar
radiation
is
waning,
the
wind
resource
is
increasing.
The
same
can
be
said
for
the
daily
change,
as
wind
picks
up
daily
during
temperature
change
at
dusk,
overnight,
and
dawn.
In
order
to
maximize
an
ROI
on
a
renewable
energy
investment,
the
greater
output
and
the
lower
LCOE
will
prove
best.
5.9
6.4
6.9
6.9
6.1
5.3
4.8
4.2
4.8
5.3
5.4
5.4
6.7
5.6
5.1
4.1
3.6
4.8
4.5
5.8
4.5
5.0
6.6
7.4
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Month
Annual
Solar
and
Wind
Resources
Monthly
DNI
(kWh/M2/Day)
Monthly
Average
50
M
Wind
Speed
(m/s)

2. 3. SolarMill®
technology
has
lower
LCOE
(levelized
cost
of
energy)
than
solar
• The
levelized
cost
of
energy
is
the
Total
Life
Cycle
Cost
(includes
accessories,
wiring,
etc)
divided
by
the
Total
Lifetime
Energy
Production.
The
chart
below,
from
the
Energy
Information
Administration
(USA)
shows
the
relative
LCOE
across
several
energy
resources
• According
to
Lazard
Freres,
the
LCOE
(unsubsidized),
is
$149
to
$204
per
MWh
for
solar,
and
$97
to
$129
per
MWh
for
microturbines.
By
using
both
technologies,
SolarMills®
have
an
overall
LCOE
which
is
less
than
solar-­‐only
solutions
4. SolarMill®
technology
produces
more
Watts
per
square
foot
than
solar
• The
average
solar
installation
produces
between
10
and
13
Watts
per
square
foot
versus
The
SolarMill®
“3P,”
which
produces
33
Watts
per
square
foot
$0.00
$0.20
$0.40
SolarMill
Solar
1
sq
ft
1
sq
ft

3. 5. SolarMill®
is
an
“integrated”
solution
maximizing
installation
investment
• As
opposed
to
the
standard
installation
of
a
solar
array,
SolarMills®
work
off
of
a
single
set
of
electronics
and
a
single
bus.
The
overall
operational
performance
of
the
system
is
maximized
and
the
costs
are
minimized.
6. SolarMill®
technology
saves
money
by
extending
battery
life
• Battery
life
is
dependent
on
the
number
of
charge
cycles
and
the
depth
of
discharge
• Solar
charges
only
during
daylight
hours
• SolarMill®
charges
24
hours
a
day,
limiting
the
“depth”
of
discharge
of
the
battery
• Batteries
may
last
up
to
30%
longer
in
a
SolarMill®
installation
reducing
the
LCOE
and
the
ROI
over
time.
7. SolarMill®
technology
has
lower
service
degradation
over
time
(de-­‐rating)
than
solar
• According
to
homepower.com,
the
average
grid-­‐tied,
rooftop
solar
array
will
lose,
or
“de-­‐rate”
by
44%
of
their
generation
capacity
over
its
life
expectancy.
Tier
2
and
tier
3
panels
have
been
known
to
degrade
by
as
much
as
60%
over
their
forecasted
25-­‐
year
functional
life.
Quality
is
a
real
issue
as
shown
in
the
chart
below
from
an
audit
conducted
by
SolarBuyer:
• SolarMills®
use
only
the
highest
quality
German-­‐made
tier
1
panels
which
are
re-­‐
tested
locally
before
integration
into
the
hybrid
system.
Further,
SolarMills®
still
only
derive
a
portion
of
their
power
from
the
solar
panels.
In
the
3P
model,
more
than
half
of
the
forecasted
generation
comes
from
its
micro-­‐wind
turbines,
which
suffer
NO
service
degradation
over
time.

4. 8. Lower
grade
solar
panels
fail
within
only
a
few
years,
negating
any
ROI
• According
to
the
NY
Times
in
a
May
2013
article
on
the
quality
of
PV
Panels,
one
testing
service
reported
the
defect
rate
of
panels
inspected
in
Shanghai
jumped
from
7.8%
to
13%
between
2011
and
2012.
Another
said
defect
rates
ranged
from
5.5%
to
22%
in
audits
of
50
Chinese
factories
in
the
last
18
months.
WindStream
Technologies’
hybrid
system
not
only
integrates
the
highest
quality
panels
but
also
its
patented
US
manufactured
vertical
axis
wind
turbines.
9. Mandates
are
now
calling
for
“Hybrid”
solutions
–
• According
to
Indianpowermarket.com,
all
telecom
companies
in
India
are
mandated
to
ensure
that
at
least
50%
of
all
rural
towers,
and
20%
of
all
urban
towers,
are
powered
by
Hybrid
power
by
2015.
10.SolarMill®
System
Performance
is
improved
with
use
of
micro-­‐inverters
• Typical
solar
arrays
are
installed
with
the
use
of
string
inverters,
wherein
a
single
panel
failure
will
cause
a
significant
if
not
complete
loss
of
electrical
supply
from
the
remaining
string
• SolarMills® are
configured
with
micro-­‐inverters,
wherein
a
single
panel
or
turbine
failure
will
not
impact
any
other
component
and
overall
productivity
continues.
SolarMill®
panels
may
be
oriented
individually
to
maximize
performance
• If
there
are
tall
buildings
or
trees
near
the
roof,
shading
may
become
an
issue.
When
solar
installations
use
a
string
inverter,
if
one
or
two
panels
get
shaded
it
can
affect
the
entire
string
by
as
much
as
half
of
its
total
performance.
With
SolarMills®,
the
micro-­‐inverter
allows
that
while
the
shaded
panels
may
be
that
affected,
the
rest
of
the
system
keeps
performing.
See
below,
from
solarenergy.com:
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
Power
output
(Watts)
Time
period
(Years)
SolarMill
&
Solar
Power
-­‐
Time
Hybrid
Power
Solar
Power

5. • Micro
inverters
allows
for
easier
system
expansion
• MPPT
–
For
a
solar
panel
to
work
at
its
most
efficient,
one
of
the
considerations
is
for
the
voltage
to
be
adjusted
based
on
the
amount
of
light
hitting
the
panel.
Voltage
is
handled
by
the
inverter.
This
means
that
the
performance
of
the
solar
panel
is
reliant
on
accurate
Maximum
Power
Point
Tracking,
or
MPPT,
by
the
inverter.
So
it
follows
that
MPPT
performed
at
each
panel
by
a
micro-­‐inverter
will
yield
better
overall
system
results
than
MPPT
done
by
1
string
inverter
for
the
whole
system.