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| Plug-in
solar panels sit on
the balconies of a
building in Erfurt,
Germany. Credit:
Martin Schutt/picture
alliance via Getty
Images |
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After
Russia invaded Ukraine
in 2022, electricity
prices shot up across
Europe and consumers
looked for ways to
save. One popular
option was plug-in
solar—inexpensive and
easy-to-install
renewable energy
systems that began to
appear in store
aisles.
Now, Germany is the
global leader in
plug-in solar with
about 1 million systems in official counts and
probably many more
that utilities and
local governments
haven’t counted.
I looked to Germany
this week because I’ve
been unsure whether
plug-in solar makes
sense for U.S.
consumers, and I think
Germany’s experience
provides some clues
about what may work
here.
The benefits are
clear. An entry-level
plug-in system costs
about $500 to $1,000
and can be installed
in a backyard, on a
balcony or on a roof.
The electricity enters
your home through a
standard wall outlet,
where it helps offset
the electricity you
draw from the grid.
The low cost makes
solar accessible for
people who can’t
afford to spend
$10,000 or more on an
electrician-installed
rooftop array.
Here’s the main
downside, as I see it:
The financial benefits
are small, starting at about $15 per month in the United
States. It may make
more sense financially
to spend the cost of
plug-in solar on
insulation, air
sealing or other basic
measures to reduce
energy use.
To help weigh the
benefits against the
concerns, I spoke with
Craig Morris, the CEO
of Bundesverband
Steckersolar,
Germany’s plug-in
solar trade
association. Readers
may recognize that
name. He is a U.S.
native who has spent
his adult life working
as a clean energy
advocate and
researcher in Germany,
and he was a key
interview subject in my 2020 series about Germany’s energy
transition, and another story since then.
“The distinctive thing
about this technology
is it’s so small that
you don’t need an
electrician to plug it
in,” he said in a
video interview from
Berlin.
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| Craig
Morris is the CEO of
Bundesverband
Steckersolar,
Germany’s plug-in
solar trade
association. Credit:
Dan Gearino/Inside
Climate News |
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The
do-it-yourself nature
of the product is one
reason it’s sometimes
called “guerrilla
solar,” with people
installing it even in
buildings and
jurisdictions where
it’s not allowed.
Morris previously
worked for a nonprofit
that advised the
plug-in solar
association. As
plug-in solar grew in
popularity, the
association needed its
first full-time
manager and hired
Morris last year.
He and his members are
now working to
convince the European
Union to adopt rules
that would allow
plug-in solar across
the bloc, rather than
the patchwork now in
place. Germany and
Belgium passed plug-in
solar laws in 2024 and
other nations have
followed suit. Hungary
and Sweden are among
the countries with
restrictions.
I asked him if savings
from plug-in solar may
be too small to be
worthwhile.
He responded by
referring to an analysis his organization published this
week that serves as a
useful primer. It has
a page comparing costs
and payback periods in
six international
cities for a system
that costs about $570.
The fastest payoff is
4.26 years in Berlin,
largely because the
region has high
electricity prices,
which create more
opportunity for
savings by generating
your own power.
The slowest payoff is
9.56 years in Ho Chi
Minh City, Vietnam,
where electricity
prices are unusually
low.
Kansas City, Missouri,
the only U.S. city
listed, has the
fourth-fastest payoff
with 4.99 years. The
city has high
household electricity
consumption, which
means electricity
generated by the
panels is almost
entirely consumed
onsite, accelerating
the payback period.
This factor is offset
by the region’s
electricity rates,
which are lower than
those in all but Ho
Chi Minh City.
The payoff periods are
estimates that don’t
account for consumers’
ability to optimize
their power
consumption to
maximize the value of
plug-in solar. For
example, someone could
choose to do laundry
or other
power-intensive tasks
when the sun is
brightest. Also, some
markets offer net
metering for plug-in
solar, which
compensates for excess
electricity that goes
back to the grid.
Customers can buy
batteries to store
electricity they don’t
use right away. This
increases the upfront
cost but yields
greater savings in the
long run.
But my focus on the
payoff periods may be
missing the point.
Morris explained that
the main benefit he
sees with plug-in
solar is that
consumers are taking
greater control of
their energy costs and
becoming participants
in the transition to
clean energy. He views
this as part of
creating and
maintaining a
political consensus
that supports the
transition, which is
good for everyone.
He also sees land-use
benefits, with plug-in
solar occupying
otherwise unused
spaces in yards and on
roofs and balconies.
His organization has
calculated that
widespread adoption of
plug-in solar would
meet about 2 percent
of Germany’s
electricity demand,
which would reduce the
need to build new
power plants on
undeveloped land.
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Utilities
tend to be the primary
opponents of plug-in
solar, citing safety
concerns. I’m not
going to go point by
point through the
objections, other than
to say that consumers
shouldn’t plug a solar
panel into a broken
outlet or one that’s
on a circuit that’s
already prone to
overloading.
To get a view from
closer to home, I
contacted Steven
Hegedus, an
engineering professor
at the University of
Delaware who has spent
most of his career
researching solar
power.
Like Morris, Hegedus
is someone I’ve known
for a while, a
longtime friend of my
wife’s family. He’s
also an expert in
plug-in solar who appeared last year on the radio program
Living on Earth.
Hegedus’ main concern
is that the
often-touted plug-in
solar savings numbers
may be overstated. He
has kept an informal
tally of costs and
savings for systems in
his region and has
found that some would
take 10 to 15 years to
pay off.
He thinks payoff
estimates are usually
based on systems in
markets with expensive
electricity, such as
California, which
doesn’t apply to most
of the country.
And he believes the
savings estimates are
based on systems that
have been installed in
positions that
maximize sunlight
exposure. But with the
product's
do-it-yourself
process, he argues
that not all customers
install it in the most
effective location.
He thinks the benefits
of plug-in solar
probably exceed any
concerns. The main
benefit is that
plug-in solar is
widely accessible,
creating an
opportunity for many
more people to
generate clean energy,
assume greater
responsibility for
their energy use and
feel connected to the
energy transition.
“You’re doing this for
reasons other than
just to save money,”
he said.
The legal status of
plug-in solar is
unclear in much of the
country. Bright Saver,
a plug-in solar
advocacy group, counts nine states that have passed laws or
rules allowing the
systems: Colorado,
Connecticut, Maine,
Maryland, New
Hampshire, New York,
Utah, Vermont and
Virginia. Four states
have bills that have
passed one legislative
chamber: California,
Massachusetts,
Minnesota and New
Jersey.
California is almost
certainly the leader
in plug-in solar
purchases, according
to industry
professionals, but I
haven’t found any
reliable data. The
estimates I’ve heard
are thousands of
systems, so we’re
talking about an
industry that’s just
getting started.
For more information,
Solar United Neighbors, EnergySage and Bright Saver offer resources to help
consumers answer basic
questions about costs,
savings and technical
issues.
A few years ago, it
would have been easy
to dismiss a
comparison of Germany
and the United States
as plug-in solar
markets since
electricity is much
more expensive in
Germany. But U.S.
power bills have
soared in recent years
and are likely to
continue doing so.
As this happens,
plug-in solar will
become a better deal,
and, I think, much
more popular.
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Other
stories about the
energy transition to
take note of this
week:
Tesla, Sunrun
and Renew Home Are
Teaming Up for a
Giant Virtual Power
Plant: Tesla,
Sunrun and Renew Home
have announced plans
for a 16-gigawatt
virtual power plant
that uses solar
panels, batteries and
smart thermostats to
bolster the grid, as Jeff St. John reports for Canary Media. This
is an unusually large
example of energy
companies seeking
decentralized
solutions to meet high
electricity demand
from data centers and
other large users.
Many of the solar
panels, batteries and
smart thermostats are
already installed
across the country;
the new initiative is
tying them together so
they can work in
tandem to help the
grid.
A Clean Energy
Tax Credit Deadline
Is Looming; Here’s
What That Means for
Philadelphia: Clean
energy developers are
facing a July 4
deadline to begin
construction to
qualify for the
federal investment tax
credit under the
phaseout specified in
last year’s One Big
Beautiful Bill Act. My colleague Daniel Perrin reports on how
this is playing out in
Philadelphia, where
slow-moving
bureaucracy for
publicly funded
projects is running up
against the need to
move quickly.
The Trump
Administration
Provides Money for
Nuclear Reactors: The
Trump Administration
said this week that it
would spend $17.5
billion to help cover
the costs of 10
nuclear reactors for
new power plants, part
of an attempt to
revitalize nuclear
power in the United
States and meet demand
from data centers, as
Jennifer McDermott and Matthew Daly report for
The Associated Press.
These are large
nuclear reactors, a
type that developers
are wary of because of
decades of cost
overruns, as opposed
to small modular
reactors, which many
analysts view as the
future of nuclear
power.
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