The key to carbon-free district heating lies deep underground

District heating and cooling (DHC) based on renewable sources is among the most promising solutions for a sustainable future. In particular, geothermal energy has enormous untapped potential for use in DHC networks. By working with leading geothermal utilities such as Izmir Jeotermal in Turkey, Diehl Metering has developed solutions that are well-adapted to the challenging environment of geothermal. Through these solutions, utilities can create new efficiencies in their network and contribute to a more sustainable world. 

The energy sector is at the heart of the global climate challenge. Across the planet, heating and cooling accounts for more than 50% of our energy consumption. Yet, just 10.2% of energy used for heating currently comes from renewable sources. This means there is a real opportunity to decarbonize the sector.

If utilities can successfully transition heating and cooling to renewable sources, they will greatly reduce their carbon footprint. In so doing, they will make a significant contribution to global climate targets such as the European Green Deal and the Paris Agreement.

The high potential of district heating

Today, one of the most promising solutions for carbon-free energy is district heating. Through a network of insulated pipes, district heating distributes thermal energy from a central location to residential and commercial buildings. According to Heat Roadmap Europe 2050, it is estimated that district heating can cost-effectively fulfill at least half of the EU’s heating needs by 2050 compared to only 12-14% today.

But the district heating systems of the future will be fueled differently to those currently in use. Coal and natural gas will need to be replaced by low-carbon sources such as biomass, renewables, excess heat, and a combination of heat and power.

Fourth generation district heating (4GDH) offers a powerful way to accelerate the decarbonization of district heating by enabling the integration of high proportions of renewable energy sources and waste heat. In addition, 4GDH distinguishes itself through its high energy efficiency because it allows heat to be stored on a massive scale.

Geothermal’s untapped reserves

Within district heating, one solution offering particularly significant opportunities is geothermal energy. Generated by the natural heat of the Earth and available year-round, geothermal is a largely untapped resource. In Turkey, one of the world’s leading geothermal power-producing countries, 12% of the geothermal potential is currently being used. And in the USA, a Department of Energy report estimates that geothermal energy could increase more than 26-fold between 2020 and 2050. 

The growth of geothermal in DHC depends on energy solutions that are compatible with the specificities of geothermal waters. One of the defining characteristics of geothermal water is that it has a naturally a high chlorine and sulfur content, which makes it corrosive. As a result, any geothermal distribution network must be capable of withstanding this aggressive environment. This is particularly important for meters within the network in order to ensure measurements remain accurate and stable throughout the meter's service life.

Optimizing efficiency and sustainability

Through its experience with geothermal utilities, Diehl Metering has developed smart metering solutions that are well-adapted to the harsh conditions of geothermal waters. The company’s SHARKY ultrasonic energy meter, designed for heating and cooling applications, has proven to be extremely robust, providing long-term accuracy and reliability in geothermal energy networks. 

As a smart energy meter, SHARKY can precisely measure multiple metrics such as flow and return temperature, flow rate, current output and energy consumption. This information can then be analyzed and interpreted by meter data management software to boost network efficiency and reduce waste. In this way, SHARKY helps to further promote the sustainability of DHC networks.

Continuous improvement

Diehl Metering has a history of supporting geothermal utilities to optimize their DHC networks. For more than 10 years, the company has been working in Turkey with Izmir Jeotermal, which operates one of the largest geothermal district heating networks in the world. Today, the utility has integrated some 30,000 SHARKY energy meters into its network, enabling it to collect meter data remotely, enhance flow rates and implement leak detection. 

Also in Turkey, Diehl Metering has recently started working with Salihli Geothermal and will be supplying the utility with SHARKY energy meters. The town of Salihli, which is about 100km (60 miles) from Izmir, is particularly interested in the potential of district heating because of its low cost, as much as 50%, compared to natural gas.

This on-the-ground experience could prove essential to Diehl Metering as the geothermal energy market continues to expand and tailored solutions are increasingly in demand. The opportunities offered by geothermal and DHC could be one of the defining trends in the years to come as the energy sector accelerates its much-needed transition towards carbon-free production and reinvents itself as a vector for sustainability.