Since dense urban areas usually amplify the impact of high temperatures due to a phenomenon known as the “urban island effect,” cities are more vulnerable to extreme climate events. Now, a team of researchers led by Lund University in Sweden has found that large investments in electricity networks will be necessary to protect us from heatwaves and cold snaps.
“Unless we account for extreme climate events and continued urbanization, the reliability of electricity supply will fall by up to 30 percent. An additional outlay of 20-60 percent will be required during the energy transition in order to guarantee that cities can cope with different kinds of climate,” said co-author Vahid Nik, a professor of Building Physics at Lund.
The experts designed a modeling platform tying together climate, building, and energy system models. The goal was to facilitate the simulation and evaluation of cities’ energy transition in order to secure their resilience against future climate changes while densification of urban areas is increasing.
“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 percent while the wind speed falls by 61 percent. 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,” said co-author Kavan Javanroodi, an assistant professor of Building and Urban Physics at Lund.
This new framework relates future climate models to buildings and energy systems at city level, while taking the urban microclimates into account, revealing that peaks in demand in the energy system increase much more than previously thought when extreme microclimates are considered.
“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 percent,” Javanroodi explained.
Although an increasing number of countries are currently concerned by the relation between extreme weather events, energy issues, and public health, there are still no accurate methods of quantifying the effects of climate change and devising appropriate adaptation strategies. Future research is needed to investigate the relationship between urban density and climate change in energy forecasts and to develop more innovative methods of increasing energy flexibility and climate resilience in cities.
The study is published in the journal Nature Energy.