Coal phaseout at Stuttgart-Münster

The goal of climate neutrality is neither achievable for individual companies nor entire states in a single step. With regard to heat generation in particular, renewable energies are not yet in a position to fully replace fossil fuels in the short term. Replacing coal with natural gas is therefore a sensible intermediate step and significantly reduces carbon emissions. In the long term, the gas infrastructure also makes it possible to use “green gases” – such as hydrogen produced with electricity from renewable energy sources (by means of electrolysis, for example).

The goal of climate neutrality is neither achievable for individual companies nor entire states in a single step. With regard to heat generation in particular, renewable energies are not yet in a position to fully replace fossil fuels within a few years. Replacing coal with natural gas is therefore a sensible intermediate step because it can roughly halve greenhouse gas emissions compared to coal in the short term. This is especially the case when indirect emissions generated by mining and transport are taken into account. That’s because the fuel switch also avoids indirect emissions associated with coal mining and transport, such as emissions of mine gas, which has a high methane content. The nice thing is that a natural gas power plant does not stand in the way of the ongoing journey toward climate neutrality. The gas turbines used are very flexible and can be converted to burn “green gases” in the future, including hydrogen, which is produced by means of electrolysis using electricity from renewable energy sources.

Accordingly, the switch to natural gas represents a bridge on the way to green gases, with which complete climate neutrality can then be achieved by 2035.

If work begins in the first quarter of 2023, the new building should be completed in mid-2025.

The project is currently going through a staggered approval process. We received a preliminary approval decision and the first partial approval in January 2023. The second partial approval is expected to be submitted in February 2023. The so-called scoping meeting was held at the start of the approval procedure, during which the scope of the environmental impact assessment was discussed and defined.

There are still buildings on the planned site of the new plants. For one thing, Stuttgart Netze GmbH operates a substation on the site. This is being replaced by a new building to the west of the planned power plant, which has already been commissioned. Cables supplying it are currently being rerouted. As things currently stand, we expect this work to be completed in May 2023 and then the former switchgear buildings can be dismantled.

The workshop for EnBW’s Stuttgart Münster and Stuttgart-Gaisburg power plant facilities is also located on the relevant site. Here, too, plans are currently being drawn up for a new building. Irrespective of the new construction project, this will have to be replaced within the next few years as it no longer meets specifications in line with the latest technology and EnBW intends to continue maintaining a significant part of its power plant portfolio itself in the future. The new workshop has been completed, with smaller outstanding work still being carried out there. Demolition work on the old workshop will be completed in March 2023.

Once the new plants are supplying district heating, the coal dump can be taken out of operation. A decision is yet to be taken as to how the areas will be used in the future.

The confined location of the power plant site inevitably means that the construction work will be felt in the surrounding area. However, EnBW will endeavor to keep the impact to a minimum and remain in dialog with local residents.

For example, an engineering firm has already been tasked with drawing up a traffic management concept to keep the construction site traffic separate from the flowing traffic. The new traffic management concept is described in the “Project diary” section.

Construction work will mostly take place during the day, with heavy loads being transported at night wherever possible. All construction measures will be carried out and observed as per the approval process in close consultation with Stuttgart Regional Council and the city of Stuttgart.

Various expert reports need to be commissioned as part of the approval process, which also consider any impact on the residents. Among other things, sound reports and air pollutant immission forecasts are compiled, which consider the impact of the new building on the surrounding area and the environment:

• Noise control: Once the new plant has been commissioned, the old plants – including the coal boilers, the coal storage facility and the flue gas cleaning system for the coal boilers – will be shut down. Besides the waste boilers and their auxiliary systems, these have been one of the sources of noise at the site until now. The new plant will be equipped with state-of-the-art sound absorbers, sound traps, etc. in order to stay within legal limits as specified in noise control guidelines (TA Lärm). In addition, there will no longer be any disposal of residues or delivery of additives associated with the coal boilers’ flue gas cleaning system, which will in turn reduce the volume of traffic and the resulting noise.
• Water pollution control: The newly built power plant facilities do not require any additional withdrawal of cooling water from the Neckar. Instead, the gas turbine CHP plant is cooled by heat exchangers installed on the roof of the building in a separate water-glycol system. They permanently reduce the heat discharged into the Neckar via the cooling water. Particularly when temperatures are high in the summer and the demand for district heating is lower than the amount of heat produced in the continuous waste incineration operation, the water currently has to be discharged into the Neckar via the cooling water system. In the future, the heat discharged should be kept to a minimum by the new heat exchange system in order to counteract warming in the Neckar. Particular care is being taken here to ensure that the units are both efficient and quiet.
• Immission control: Due to the location of the boiler, the urban area in particular is exposed to pollution caused by industry, traffic and residential buildings – especially particulate matter and nitrogen oxides. The switch from coal to gas at the Münster site will have a significant positive impact here. Based on initial calculations, nitrogen oxide emissions will be reduced by more than 45% and particulate matter by about 88% compared to the coal boilers currently in operation. Emissions of heavy metals are also reduced to almost zero as a result of the fuel switch. The reduction is partly attributable to the highly efficient combustion technology used in gas turbines, but also due to EnBW’s planned use of SCR technology, which involves using catalytic converters in the flue gas system of gas turbines, thereby reducing emissions of nitrogen oxides (NOx) to a greater extent than required by the already strict legal requirements for gas turbine plants.

Until all new power plant and district heating facilities have been fully commissioned, the coal boilers will remain available for supplying district heating. By taking this approach, we will ensure that supplies in Stuttgart and the surrounding region are reliably guaranteed at all times.

Private households as well as industrial companies and public institutions will be supplied with district heating in Stuttgart. You can check here whether district heating is available in your area. EnBW regularly examines the connection of new city districts.

By using district heating for their heating and hot water, citizens can play a key role in mitigating climate change. District heating is produced with combined heat and power plants, which cuts carbon emissions and increases the efficiency of the plant. Less space is required due to the compact nature of the stations, because a boiler, tank and flue gas system, including chimney, are no longer needed, thereby also eliminating the costs associated with them.

Throughout the project, EnBW will keep people regularly updated on its progress and report on milestones on the website www.enbw.com/stuttgart-muenster. On 13 April 2021, a public online information event was held, during which the project was presented to citizens. People who took part were able to put questions live to those present in the studio.

However, you can always send any questions, suggestions or criticism by e-mail to stuttgart-muenster@enbw.com.

The project falls under Number 1.1 of Annex 1 of the Fourth Regulation on the Implementation of the Federal Immission Control Act (Regulation on Plants Requiring Approval, 4th BImSchV). Pursuant to Annex 1 Number 1.1.1 Column 1 in conjunction with Section 3b of the Environmental Impact Assessment Act (UVPG), there is a duty to carry out an environmental impact assessment. The environmental impact assessment is an integral part of the approval process pursuant to BImSchG (Section 1 Paragraph 2 of the Regulation on the Approval Process (9th BImSchV)) and is conducted by Stuttgart Regional Council as the competent approval authority.

The project is set to be approved in a phased approval process with a preliminary decision on the approval requirements pursuant to BImSchG and environmental law and a further decision on the release of greenhouse gases (carbon dioxide) pursuant to the Greenhouse Gas Emissions Trade Act (Treibhausgas-Emissionshandelsgesetz or TEHG) and two partial permits for the construction and operation of the Stuttgart-Münster fuel switch plants.