Lisbon city hall shows the perils and payoffs of
energy upgrades
Achieving a 55 percent reduction in emissions by 2030
means addressing the most energy-hungry buildings now.
By AMERICA
HERNANDEZ 10/11/20, 7:07 AM CET
The number
of solar panels was limited to prevent marring the city's panoramic view | ©
Lisbon Municipality
She was
undeniably gorgeous — but very high-maintenance, and fiendishly expensive to
keep up with.
At well
over 100 years old, Lisbon's prized neoclassical Paços do Concelho city hall
was an aging dame stuck in the past, holding back the capital's plans to speed
toward a carbon-neutral future.
The
building ranked among the top five most energy-consuming properties owned by
the municipality, which decided to make it a flagship green renovation project
in 2016.
Lisbon
officials had no idea what they were in for.
Europe's
historic buildings are terrible when it comes to energy efficiency: They
consume huge amounts of electricity to light thousands of meters of floor space
and cost a fortune to heat — while letting much of that hot air escape through
gaps in window frames.
They're
also immensely tricky to renovate, given strict heritage codes regulating what
can and can't be modernized.
Lisbon
chose its iconic city hall as a flagship green renovation project in 2016 | ©
Lisbon Municipality
But if the
EU hopes to meet a new higher target of a 55 percent reduction in emissions by
2030 — now under discussion — governments will have to tackle the bloc's
historic palaces, city halls and other public monuments to bring down energy
consumption.
"Most
savings would need to come from buildings," the Commission acknowledged in
its assessment of where emissions reductions will have to occur by 2030.
"To fully tap into this potential for improvement would require the
renovation rate, which is around 1% today, to double and more in the period up
to 2030."
To force
upgrades on the worst-performing buildings, Brussels also said in the 2030
assessment that it might implement minimum standards that would prevent a
building from being rented out or sold until it was renovated to be more energy
efficient. It would also potentially extend the EU carbon market to put a price
on the CO2 emitted when heating buildings. Details will be in the Renovation
Wave Strategy set to be unveiled October 14.
Such
punitive regulatory and financial measures could hit governments hard if they
own many old buildings.
That makes
projects like Lisbon's city hall renovation especially crucial, given that at
least 35 percent of buildings in the EU are 50 years or older, according to the
Commission.
Learning to
compromise
Portugal's
Directorate-General for Cultural Heritage, charged with protecting the
country's historic treasures, soon gave the city a reality check.
"There
were a lot of constraints," said Carlos Varela Raposo, project manager and
energy coordinator at Lisboa E-Nova, Lisbon's energy and environment agency.
Deep
renovations — energy efficiency retrofits that provide the most consumption
cuts — usually start by sealing the building. That means maximizing insulation
and ensuring that heat doesn't seep out.
But
insulation material was ruled out for being deemed too ugly for the building's
facade, and too complex to stuff anywhere inside the richly gilded walls and
ceilings.
Finding
places to stuff insulation in the walls and ceiling was deemed too complex | ©
Lisbon Municipality
That meant
the energy conservation benefits would be considerably lower.
Then
"when the municipality was trying to replace windows that were made in
wood and trying to do it with aluminum or PVC, which are more beneficial in
terms of energy consumption and thermal comfort, [the cultural heritage
authorities] raised a red flag immediately," Varela Raposo said.
The
original wood had to stay, and could only be restored, not replaced.
Double- or
triple-glazed glass panes, which help trap heat, were also out of the question
for being too thick to fit in the original window frames.
Heritage
authorities forbade any external insulation or window frame replacement | ©
Lisbon Municipality
"They
had to compromise — in the end the result was a more thick [single] glazing
than the original, which allowed a little more energy savings and thermal
comfort," Varela Raposo said. "In terms of public procurement that
was probably the biggest challenge to overcome, because it's the kind of job
that not all companies are prepared to do, so for sure it was the most
expensive."
Next came
the battle over rooftop solar panels — a retrofit that helps buildings produce
their own power and in sunny places like Lisbon drastically reduces utility
bills.
This time
the cultural authorities' protests were on aesthetic grounds.
Cultural
authorities were initially against installing PV panels for aesthetic reasons |
© Lisbon Municipality
"There
was a long conversation over two or three years with this institution — mainly
they were very worried these PV panels would be seen when walking in the
street, or from the belvederes where you can get the panoramic views of the top
of the city when sightseeing, or from ships coming down the river, and that it
would be bad for the image of the building," Varela Raposo said.
Eventually,
the heritage protectors were persuaded that tastefully arranged solar panels in
a dark color similar to the rooftop wouldn't mar the view.
The number
of solar panels was limited to prevent marring the city's panoramic view | ©
Lisbon Municipality
The third
major intervention was an overhaul of the lighting and a replacement of the
heating, ventilation and air conditioning (HVAC) system.
Swapping
out chandelier bulbs for lookalike LEDs in 2,000 lamps was the easy part.
Chandelier
bulbs in 2,000 lamps were swapped out for LED lookalikes | © Lisbon
Municipality
The latest
power savings technology calls for sensors to be installed in each room so that
lights can shut off automatically in empty ones; the city didn't go down that
route.
Instead, an
energy management system allows municipal officials to see the last 15 minutes
of consumption for the whole building and for several individual electrical
circuits, and be able to manually adjust usage as needed.
The HVAC
system does allow central management of heating and cooling, with timers to
program scheduled automatic shut-offs — plus an option to have the water
heaters turn off during peak electricity hours if they're not being used to
avoid drawing pricey power.
Tangible
results
All in all,
the retrofits cost €893,000 and were expected to last from May 2017 to December
2019, but due to a delay on the window work, restoration is expected to wrap
next month.
Despite the
lags and compromises, energy consumption was still reduced by 50 percent from
2016 to 2019, resulting in avoided emissions of 84 tons of CO2-equivalent,
municipal data shows.
The solar
panels provided about 9.6 percent of the building's total energy consumption
last year.
Varela
Raposo recommended other cities contemplating historic renovations to start
with a building assessment clearly laying out the baseline energy performance,
along with what can be done and what the cost savings would be. He also
suggested involving all national engineering or heritage authorities from the get-go
to avoid bureaucratic surprises mid-process, and to ensure all procurement
requests have the right details and restrictions.
Financial
details
The total
investment is expected to be recouped in about 20 years. That is slightly
longer than expected because the unusually expensive window retrofits made up
more than half the cost — and window retrofits don't provide as quick a payback
as the other installations that directly reduce energy consumption.
The actual
funds paid out from the municipal budget came to about €420,000 — which will be
recouped in a decade.
The EU's
Horizon 2020 Sharing Cities program provided a grant of about €168,000. A
financing instrument with a private company covered the rest.
Such hybrid
public-private arrangements — in which a government entity creates a special
purpose vehicle to raise private capital — is an option being increasingly
promoted for the upcoming Renovation Wave, as it allows local authorities to
reduce the amount of cash they put in, while private investors can count on a
steady, long term repayment stream with rates of return higher than government
bonds or other traditional investments.
That's
important, given a May 27 Commission document estimating there would be an
investment gap of €185 billion per year in energy efficiency-related building
construction that private investors would need to fill to reach 2030 goals.
That was before the emissions reduction target was raised from 40 percent to
the current proposed 55 percent.
"New
European Commission proposals to double building renovation rates are due this
month, and organizations like the European Investment Bank are already using
their own investments to attract institutional investors," said Brook Riley,
head of EU affairs for the insulation and ceiling manufacturer Rockwool group
and vice chair of the Renovate Europe campaign. "They do this by offering
AAA rating with above-average returns on investment, a bonanza in today’s world
of negative interest rates and bond yields."
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