How It Works

In the heating season, with a network flow of 1000 m³/h, the valve directs approx. 600 m³ of water per hour to the geothermal plant. After heating to 75°C, the water mixes with the rest of the stream, returning to PEC at 65°C. Thanks to this, PEC reheats water to 85°C from 65°C, rather than from 45°C.

In the heating season, PEC operates in a hybrid mode: as an operator and a supplementary heat source. Geotermia provides 62.5% of annual thermal energy, so PEC burns significantly less coal than traditional heating plants. The goal of development is the total abandonment of supplementary heating in the future.

In winter, boreholes GT-6 and GT-7 (temp. 90°C) cover approx. 62.5% of the city's annual demand. Currently, this requires PEC support, but planned investments aim to achieve 100% heating coverage exclusively from geothermal energy.

In the heating season, network water must be at least 85°C. The valve mixes heated water from Geotermia (approx. 75°C) with return water here, providing 65°C at the PEC inlet instead of 45°C. As a result, the heating plant only needs to raise the water temperature by 20°C, which drastically lowers coal consumption and pollution emissions.

After the heating season, all water returning from the city is heated by geothermal energy to 75°C, eliminating the need to burn hundreds of wagonloads of coal annually. Renewable energy effectively replaces fossil fuels, which consequently do not need to enter the city.

During the heating season, efficient reinjection of brine into the five wells (GT-1 to GT-5) is crucial. Pumping to a depth of 2600–2900 meters maintains pressure in the reservoir and forces circulation, allowing the water to regenerate temperature for subsequent seasons.

The Old Town Market Square is within the range of geothermal energy. Surrounding tenements and premises are heated ecologically, which raises comfort and supports the sustainable development of the historical center.

This is the interface point between the municipal network and Geotermia. A control valve directs part of the cooled return water from the city to the geothermal installation. There, the water is reheated, gaining temperature thanks to Earth's energy, and returns to circulation, increasing efficiency without burning coal.

The historic Town Hall, the city's symbol, is today heated by clean geothermal energy. Connection to the network allows for the protection of cultural heritage in a modern and ecological way.

In winter as well as the rest of the year, heat exchangers work at full possible capacity, heating water up to 600 m³/h (part of the network flow). Energy from brine (90°C) is transferred in three isolated circuits. After releasing heat, filtered water returns underground.

The monumental Gothic Collegiate Church of the Blessed Virgin Mary Queen of the World in Stargard also uses geothermal heat. Network heating ensures stable conditions for the historic structure and limits pollution emissions in the heart of the city.

The municipal transmission network covers almost the entire city, reaching both multi-family housing estates and pre-war tenement houses. This ensures reliable heat supplies to the diverse urban fabric, regardless of building age.

The network also delivers heat to the historic center, eliminating local heat sources. This protects unique architecture and reduces pollution emissions in Stargard's most representative area.

Heated water from the geothermal plant flows directly into the municipal circulation here, constituting 100% of the energy in the PEC infrastructure during summer. The entire stream is heated by Earth's energy, allowing coal boilers to be shut down completely.

In the non-heating period, boreholes GT-6 and GT-7 (depth 2900m) cover 100% of the city's demand for domestic hot water. Brine at 90°C with mineralization of 130 g/dm³ completely replaces conventional sources, so the system operates exclusively on clean renewable energy.

Cartridge filters form the second, more precise purification stage, removing finer impurities. Behind them are injection pumps, which assist in forcing the cooled brine back into the reservoir, stabilizing parameters and protecting the system.

After the heating season, heat exchangers handle the entire network water flow, transferring energy from brine (90°C, depth 2600–2900m) to municipal water. Three independent loops guarantee full isolation - geothermal water does not mix with network water. After releasing heat, the brine goes to filters and is reinjected back into the ground.

Production pumps, installed deep within the boreholes, transport hot brine to the surface. They operate under extreme pressure and temperature conditions. Their reliability is crucial for the continuity of heat supply and system stability.

Bag filters pre-clean the brine of rock particles and mineral sediments, protecting the installation against wear and failure. This ensures stable and safe system operation even at high flow rates.

Once the heating season ends, a valve directs all network water to the geothermal plant. Heating it to 75°C via GEO fully meets the network's demand for domestic hot water. Consequently, PEC does not need to reheat the water, allowing for the total elimination of coal combustion during this period.

The geothermal reservoir in Stargard is a deep aquifer in porous rocks, acting as a natural heat store. The reinjected brine heats up there using the Earth's interior energy, creating a renewable energy source.

After the heating season, PEC acts merely as a network operator, transporting heat produced 100% by Geotermia. The process occurs passively, without firing up coal boilers, which completely eliminates the emission of harmful substances during this season.

After the heating season, we heat the system water to approx. 75°C, which fully suffices to power the water supply network throughout the city. Residents receive domestic hot water coming exclusively from a renewable source, without reheating by PEC.

Injection wells close the ecological loop, discharging brine to a depth of 2600–2900m. Five boreholes (GT-1 to GT-5, including three "J" type and two vertical) evenly distribute water in the rocks, where it is heated by the Earth's interior energy, ready for reuse.