Estonia’s ambitious dive into seawater heat
Baltic Sea: A New Source For Urban Heating
As global temperatures continue to climb and the demand for sustainable energy grows, the oceans are becoming recognized as valuable sources of renewable resources that have yet to be fully explored. A recent study from the Copernicus programme, titled “Ocean State Report 8,” highlights the swift and often severe transformations taking place in oceans around the world. Notably, in 2023, marine heatwaves affected 22% of the Earth's ocean surface.
Despite these difficulties, new opportunities are arising. A notable initiative is taking shape in Estonia, where scientists at Tallinn University of Technology, commonly referred to as TalTech, are investigating the Baltic Sea as a potential source of thermal energy for heating in urban areas.
"Is Baltic Seawater Heating The Answer?"
Scientists from the Institute of Marine Systems at TalTech have been investigating the possibility of harnessing heat from seawater in Tallinn Bay to operate heat pumps. This cutting-edge method could play a crucial role in helping Estonia achieve its energy independence objectives. It takes advantage of the fairly consistent temperatures found in the deeper layers of the Baltic Sea, even in winter when heating demands are at their peak.
In contrast to geothermal energy that taps into the heat found deep beneath the Earth's crust, seawater heat pumps utilize the variations in water temperatures. According to emeritus professor Jüri Elken, who is a primary researcher for the project, “Tallinn is one of the best places for seawater heating among the major cities along the Baltic Sea.” The water depth near Tallinn permits easy access to seawater at depths of 50 meters or more, located just a few kilometers from the shore.
Although this approach shows a lot of potential, there are significant logistical challenges. To produce enough heat during the winter, the system needs to handle vast amounts of seawater, which could mean moving several cubic meters of water per second through underwater pipes. Additionally, it's crucial to handle the environmental effects properly, especially concerning the release of nutrient-rich water, to prevent exacerbating eutrophication—an ongoing problem for the Baltic Sea.
Estonia's investigation into using seawater for heating is part of a larger global movement aimed at utilizing marine energy for eco-friendly urban living. Coastal cities worldwide are turning to the ocean to fulfill their energy needs. Take Stockholm, for instance, where seawater heat pumps have been integrated into district heating systems since the 1980s, setting an example for other northern European cities. Likewise, in Marseille, France, the groundbreaking "Thassalia" project provides heating for homes and businesses along the city's waterfront using a seawater heating system.
Estonia's approach aligns with the global context but brings distinct benefits of its own. While the Baltic Sea may be chillier than the Mediterranean, it keeps relatively consistent temperatures, which makes it suitable for heat extraction during the winter. Additionally, the close distance between the deep sea and the main consumers in Tallinn helps to lower infrastructure expenses, enhancing the economic feasibility of the system.
Although there are promising opportunities, there are still obstacles to overcome. Using seawater for heating demands a precise equilibrium between energy efficiency, environmental effects, and expenses. Senior researcher Ilya Malyutenko pointed out, "One major concern is the environmental consequences of pumping water from such deep depths." Returning nutrient-rich water to the ocean could worsen current issues, such as harmful algal blooms that reduce oxygen levels and endanger marine life.
The Benefits Could Be Huge!
Several Estonian businesses, like Utilitas AS, are starting to investigate the potential for using seawater heat in commercial settings. Initial research is currently taking place in the Hundipea district, which is being developed as a climate-neutral urban area in Tallinn. However, Rivo Uiboupin, director of the Institute of Marine Systems at TalTech, emphasized that research funded by the public sector is crucial for the success of these projects.
Uiboupin’s team is presently engaged in a project called “Marine Renewable Energy Digital Twin,” where they are charting Estonia’s coastal areas to locate potential marine energy sources. Funded by the Estonian Research Council, this effort seeks to connect scientific studies with commercial opportunities.
Although it's important to tackle the environmental and logistical issues involved, the advantages of harnessing energy from the Baltic Sea are significant. If Estonia's strategy proves effective, it could serve as a model for other coastal countries looking to alleviate the effects of climate change while satisfying rising energy needs in urban areas. In a time when our oceans face greater threats, responsibly utilizing them for renewable energy could be a key part of the answer.
