Cities will need more resilient electricity networks to cope with
extreme weather

Date:
April 11, 2023
Source:
Lund University
Summary:
Dense urban areas amplify the effects of higher temperatures, due
to the phenomenon of heat islands in cities. This makes cities
more vulnerable to extreme climate events. Large investments in
the electricity network will be necessary to cool us down during
heatwaves and keep us warm during cold snaps, according to a
new study.


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FULL STORY ========================================================================== Dense urban areas amplify the effects of higher temperatures, due to the phenomenon of heat islands in cities. This makes cities more vulnerable
to extreme climate events. Large investments in the electricity network
will be necessary to cool us down during heatwaves and keep us warm during
cold snaps, according to a new study led by Lund University in Sweden.


========================================================================== "Unless we account for extreme climate events and continued urbanisation,
the reliability of electricity supply will fall by up to 30%. An
additional outlay of 20-60 per cent will be required during the energy transition in order to guarantee that cities can cope with different
kinds of climate," says Vahid Nik, Professor of Building Physics at Lund University and one of the authors of the article in Nature Energy.

The study presents a modelling platform that ties together climate,
building and energy system models in order to facilitate simulation
and evaluation of cities' energy transition. The aim is to secure the
cities' resilience against future climate changes at the same time as densification of urban areas is taking place. In particular, researchers
have looked closely at extreme weather events (e.g. heatwaves and cold
snaps) by producing simulations of urban microclimates.

"Our results show that high density areas give rise to a phenomenon called urban heat islands, which make cities more vulnerable to the effects of
extreme climate events, particularly in southern Europe. For example,
the outdoor temperature can rise by 17% while the wind speed falls by
61%. Urban densification -- a recommended development strategy in order
to reach the UN's energy and climate goals -- could make the electricity network more vulnerable.

This must be taken into consideration when designing urban energy systems,
says Kavan Javanroodi, Assistant Professor in Building and Urban Physics.

"The framework we have developed connects future climate models to
buildings and energy systems at city level, taking the urban microclimate
into account.

For the first time, we are getting to grips with several challenges around
the issues of future climate uncertainty and extreme weather situations, focussing in particular on what are known as 'HILP' or High Impact Low Probability events," says Vahid Nik.

There is still a large gap between future climate modelling and building
and energy analyses and their links to one another. According to Vahid
Nik, the model now being developed makes a great contribution to closing
that gap.

"Our results answer questions like 'how big an effect will extreme weather events have in the future, given the predicted pace of urbanisation and
several different future climate scenarios?', 'how do we take them and
the connections between them into account?' and 'how does the nature of
urban development contribute to exacerbating or mitigating the effects
of extreme events at regional and municipal level?' " The results
show that the peaks in demand in the energy system increase more than previously thought when extreme microclimates are taken into account,
for example with an increase in cooling demand for 68% in Stockholm and
43% in Madrid on the hottest day of the year. Not considering this can
lead to incorrect estimates of cities' energy requirements, which can
turn into power shortage and even blackouts.

"There is a marked deviation between the heat and cooling requirements
shown in today's urban climate models, compared to the outcomes of our calculations when urban morphology, the physical design of the city,
is more complex. For example, if we fail to take into account the urban
climate in Madrid, we could underestimate the need for cooling by around
28%," says Kavan Javanroodi.

Vahid Nik explains that an increasing number of countries have become interested in extreme weather events, energy issues and the impact on
public health. At the same time, there are no methods of quantifying the effects of climate change and planning for adapting to them, especially
when it comes to extreme weather events and climate variations across
space and time.

"Our efforts can contribute to making societies more prepared for climate change. Future research should aim to examine the relationship between
urban density and climate change in energy forecasts. Furthermore, we
ought to develop more innovative methods of increasing energy flexibility
and climate resilience in cities, which is a major focus of research
for our team at the moment," says Vahid Nik.

* RELATED_TOPICS
o Matter_&_Energy
# Energy_Technology # Physics # Thermodynamics
o Earth_&_Climate
# Weather # Global_Warming # Climate
o Science_&_Society
# Energy_Issues # Environmental_Policies #
Resource_Shortage
* RELATED_TERMS
o Urban_planning o Electricity_generation o Urbanization o
Smog o Hurricane o Winter_storm o Humidity o Climate

========================================================================== Story Source: Materials provided by Lund_University. Note: Content may
be edited for style and length.


========================================================================== Journal Reference:
1. A. T. D. Perera, Kavan Javanroodi, Dasaraden Mauree, Vahid M. Nik,
Pietro
Florio, Tianzhen Hong, Deliang Chen. Challenges resulting from urban
density and climate change for the EU energy transition. Nature
Energy, 2023; DOI: 10.1038/s41560-023-01232-9 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/04/230411105903.htm

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