Traditional location ... progressive technology

STEAG has been generating energy from hard coal in Herne, North Rhine-Westphalia, for 57 years.

Now the success story is being continued with a fuel change: From 2022 onwards, the Herne 6 gas and steam combined cycle power plant will generate electricity and heat.

“The decision was a hard one to take,” says Joachim Rumstadt. “Working at the same place for decades creates relationships that go beyond the world of work.” This is another reason why the planned gas and steam combined cycle power plant (CCGT) is of particular relevance to the Chairman of STEAG’s Board of Management. “We are continuing our success story at the Herne site with the construction of a new combined cycle power plant. And with a view to the recommendations of the Commission on Growth, Structural Change and Employment and the planned phase-out of coal in 2038, we are creating an additional generation option.”

Environmentally friendly, quiet and one of the most efficient power plants in the world with 85 percent efficiency
STEAG sought out a competent and experienced partner for the implementation of this project: the Siemens Group, which with its highly specialized power plant division has decades of experience in the construction of energy generation plants of all sizes. “We are convinced that Siemens is the right partner for this important and forward-looking project,” says Joachim Rumstadt. “The group – and we know this from joint projects – has outstanding expertise in the construction of power plants.”

Following approval by the antitrust authorities, STEAG and Siemens, which set up a joint venture company specifically for this project, began preparatory work at the beginning of the year: Initially, the area between Rhine-Herne canal and Hertener Strasse will be cleared and earthworks performed to make it ready for construction. After this construction site preparation, construction of the power plant is due to begin in autumn 2019 at the latest, as soon as the necessary official approvals have been obtained.

„With the construction of a new combined cycle power plant, we are continuing the success story in Herne.“

Joachim Rumstadt, Chairman of the Board of Management, STEAG

Herne and STEAG – a long-standing connection: In 1962, two units with a capacity of 150 megawatts (MW) each went into operation on Hertener Strasse in the Baukau district. This was followed in 1966 by a third unit with a capacity of 300 MW, and finally in 1989 by Unit 4, which still has an output of 500 MW today. In times of full capacity utilization, the Herne power plant generated 5.2 billion kilowatt hours (kWh) of electricity and 0.8 billion kWh of district heating, which was fed centrally from there into the Ruhr district heating network. However, as a result of the energy system transformation, STEAG’s management decided to remove units 1, 2 and 3 from the grid for economic reasons. Since the summer of 2017, only Unit 4 has been generating electricity and heat from hard coal.

On completion, Herne 6 will generate an electrical output of 630 MW with a natural gas powered turbine. The power plant will also generate up to 400 MW of district heat. Herne is the central infeed point for the Ruhr district heating trunking line. Tens of thousands of households, hospitals and office buildings in the three Ruhr district cities of Gelsenkirchen, Essen and Bottrop are supplied with environmentally friendly district heating via a 37 kilometer pipeline system. “With the combination of electricity and heat generation, the CCGT will achieve an overall efficiency of 85 percent,” explains Joachim Rumstadt. “This will make Herne 6 one of the most efficient, environmentally friendly and also quietest plants in the world.”

In Herne, too, the construction of the ultra-modern CCGT, in which STEAG and Siemens are investing a sum in the mid-hundreds of millions, is awaited with enthusiasm: “We are happy about the economic gains, and about the people who are coming to Herne during the construction phase, as a place of job security, but also of resource-saving innovation,” says Dr. Frank Dudda, SPD mayor of the 160,000 population town.

“Future security of supply will depend on gas-fired power plants and storage technologies.”
But the Herne combined cycle power plant will also become important from the point of view of security of supply: According to the recommendations of the Commission on Growth, Structural Change and Employment (popularly known as “Coal Commission”), a total of 12 gigawatts of capacity from lignite and 15.7 gigawatts from hard coal fired power plants are to be taken off the grid in Germany by 2030. By then, 65 percent of the country’s electricity requirements will be covered by energy from renewable sources. By way of comparison, electricity generated from solar, wind, hydro and biomass currently accounts for 35.2 percent of total electricity production.

„We are happy about the economic gains, and about the people who are coming to Herne during the construction phase, as a place of job security, but also of resource-saving innovation.“

Dr. Frank Dudda (SPD), Mayor of Herne

On the one hand, this raises the question of whether the expansion of renewables can succeed to the extent planned. And on the other hand, the question must be answered as to how security of supply can be guaranteed after all nuclear and coal-fired power plants have been shut down, even on days when the wind does not blow and the sun does not shine. These questions are also the driving force for Patrick Graichen, director of the think tank Agora Energiewende, which provides politicians and businesses with new ideas for the energy transition: “In these times, security of supply must be ensured by a mixture of storage and gas-fired power plants. Following the recommendations of the Coal Commission, however, I can see that many investors in new gas-fired power plants are now finally safe.”

This is also the case at STEAG, which is driving the Herne 6 project forward with all its energy. This is because the energy company intends to apply for additional subsidies under the Combined Heat and Power Act for such high efficiency and low emission plants.

But Joachim Rumstadt has not the slightest doubt in that respect: “Our technical team is experienced, and we have a strong partner in Siemens. I am confident that we will be able to go into continuous commercial operation with the Herne 6 combined cycle plant by the end of 2022,” says the CEO of STEAG. “That would also be a good time in terms of grid stability. By then, the last nuclear power plants in Germany will have been shut down and 30 percent of the output of coal-fired power plants will no longer be on the grid. Then we will be dependent on a modern combined cycle power plant like Herne 6 for a secure power supply.” The final investment decision is to be made by summer 2019.

In combined cycle gas and steam power plants, gas is used twice as a so-called primary energy source. These power plants are therefore more efficient than coal-fired or nuclear power plants, for example: First, electricity is generated by a gas turbine. The resulting exhaust gases, which can reach temperatures of up to 650 degrees Celsius, are fed into a downstream heat recovery boiler, which in turn acts as a steam generator for the steam turbine, which also drives a generator to produce electricity. And the heat generated in both processes is fed into the district heating system.