District heating: has its time come?

District heating: has its time come?

Due to its reliance on renewable energy sources, district heating is becoming a preferred energy saving solution. One of the biggest challenges, however, is convincing homeowners of the long-term value of retrofitting buildings to accommodate the smart solution

From the frosty reaches of Umeå in eastern Sweden to the rolling hills of San Sebastian in Spain’s Basque Country, European cities have one refrain on their minds as the cold sets in: winter is coming and homes must be heated in a way that allows the EU to reach its goal of reducing energy consumption by 20% by the year 2020. District heating is quickly cementing itself as a preferred method to do so, as it relies on renewable energy sources and decreases greenhouse gas emissions.

Long and bitter Scandinavian winters, where buildings must be heated eight or nine months of the year, spurred the beginning of district heating in Sweden in the 1940s. According to the Swedish Environmental Protection Agency, it has gone from almost exclusively relying on fossil fuels to being 90% powered by renewable and recycled heat in 2017.

Today, Stockholm contains 2,800 km of underground pipes connecting to more than 10,000 buildings, says Erik Rylander from Fortum, energy company active in Nordic and Baltic countries. “As long as you have a water based heating circuit in your building (which basically all bigger buildings in Sweden have) the connection is easy,” he explains. “A heat exchanger is placed in the basement which connects the district heating system to the building’s heating system.” The system uses biofuels - wood chips, wood pellets and bio oil - as well as household waste and recovered heat from the city’s data centers and industries. It also draws energy from the sea using large heat pumps, Rylander adds.

Another emblematic Swedish case is Lund, where almost 90% of the heat demand in the city is supplied by district heating. Moreover, tenants living in the area of Linero, which is hosting a series of renovation measures under the European project CITyFiED, can use a free app where they can check their personal power consumption. Such measures are crucial to evolve a change of mindset and show how the role of each and every one is important.

The involvement of citizens is a key-issue for smart city initiatives, as confirmed by José Ramón Martín-Sanz García, energy efficiency engineer at Veolia, another partner of the project that worked in Spain, in the Torrelago district of Laguna de Duero, near Valladolid.

“One of the biggest challenges was convincing homeowners that it was necessary,” he tells youris.com. “It required a communication plan.”  The district heating recently won the Global District Energy Climate Awards 2017 in the category Emerging market. Some 31 buildings, or a total of 1,488 dwellings with more than 4,000 residents, have been retrofitted since 2014 to decrease buildings’ energy demands by 40%.

In Spain, even if district heating is not as widely used yet, other cities have made important forays into the technology. San Sebastian is in the final stages of installing a power plant with 7400 kW of power, with two 1400 kW biomass boilers, that will heat 1,500 new homes. The construction falls under the umbrella of the European research initiative Project Replicate, which seeks to reduce primary energy consumption by 35% through a biomass-fueled district heating system. It will be finalized by summer 2018.

“This is the first project of its kind,” says Ainara Amundarain, smart strategy and sector specialisation technician for the city of San Sebastian. Most of the buildings in the district heating area are being built in tandem with the district heating project, so retrofitting is not an issue, she explained. However, 154 buildings already standing in the zone will have to accommodate the new technology. “They’re quite old, from the 1960s, so what we are also doing is retrofitting these old buildings,” she explains.

In the event of a longer or colder winter, the city has made sure to have back-up measures in the form of boilers. “We have also included a gas energy supply with additional gas boilers in order to supply for big consumption during winter months,” Amundarain confirmed.

The initiative is keen to expand to other parts of the region. “We analysed if biomass could be generated by local resources, not just for San Sebastian but for the whole region, and it was viable. We have the local resources to do it.”

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