GENERATION SPECIALIST TOPIC 43 The new cogeneration plant from Vattenfall Wärme in Berlin-Marzahn proves that industrial facades do not have to be dreary: With the day’s changing light, the CHP plant also changes its appearance Source: Siemens Energy District Heating for Berlin Vattenfall Wärme Berlin has not only achieved its goal of halving CO2 emissions by 2020, but even exceeded them. A milestone in the concept of reducing emissions: one of Europe’s most modern combined heat and power plant in Berlin-Marzahn that as general contractor, Siemens Energy built – in just over three years. The history of the Marzahn cogen- 2020 Siemens Energy handed over heating in eastern Berlin area. eration plant is closely intertwined the new cogeneration plant on a Combined, the two plants serve with that of the city of Berlin. The turnkey basis after only a little over around 450,000 households – only city intends to be CO2-free by 2050. three years construction time. Soon in the eastern part of the city, by the No easy undertaking. This is why thereafter it went into commercial way, as underground the city is still the power company Vattenfall operation. divided. The eastern part has a two- Wärme Berlin committed itself in a The plant has an electrical output pipe system, while West Berlin has climate protection agreement to the of around 273 MW and a thermal a three-pipe system for district city Berlin to halve its CO2 emis- output of around 232 MW. The heart heating. sions – compared to 1990 – in the of the plant is an SGT5-2000E gas German capital by 2020. Today, this turbine manufactured at the Sie- Successful bid for interna- has been achieved. Vattenfall’s next mens Energy workshop in Ber- tional tender process target is phasing out coal by 2030. lin-Moabit – a proven and reliable An important step in this direction turbine with low capital costs and Marzahn represents a power plant was the construction of one of the long-term advantages in mainte- for the future: It has a maximum most efficient combined heat and nance and repair. Together with the fuel efficiency of over 90%; it is flex- power (CHP) plants in Europe in Klingenberg CHP plant (also gas- ible with short start-up and shut- Berlin-Marzahn – with Siemens fired), the plant in Marzahn is im- down times and can quickly switch Energy as general contractor. In May portant to the supply of district between full and partial loads. This II/2021 www.ehp-magazine.com 44 SPECIALIST TOPIC UNTERRUBRIKENNAMEGENERATION enables it to balance fluctuations, that can be a bridge to hydrogen Making sure the site is which repeatedly occur when feed- and other sustainable fuels. secure ing renewable energy into the elec- The power plant also had to be tricity grid – a necessary compo- flexible. In case of low heat de- While already had been worked in- nent for energy transition. At the mand – as in summer – it is impor- tensely on the detail engineering, same time, it reliably secures the tant to be able to run the power plant Siemens Energy also took control of needs of urban heating customers. at low partial load without stopping the site in spring 2017. Various plant Also, the gas turbine is flexible district heat production. After all, components on the site had already enough to use hydrogen – ideally heat is also needed on warm days – been dismantled in 2011 and 2012 produced with green energy – in most people want to be able to take by Vattenfall. As general contractor, the coming years. Still, this devel- a warm shower any day of the year. Siemens Energy was responsible to opment was certainly also helped This is enabled by a high degree of ensure that the site was secured by subsidies paid by Germany for automation and fast controls of all before the cornerstone was laid in cogeneration plants. They are to be components of the plant, such as: October 2017. Before taking over the paid out over the duration of 30,000 the gas and the steam turbine, the site a soil survey and an explosive full-load hours and are supporting heat recovery steam generator, or ordnance detection was conducted. to amortize Vattenfall’s investment the air condenser. This was followed by a grid sam- costs. pling to identify any soil contami- Following an international tender High degree of prefabrica- nation, which showed the ground process Siemens Energy was tion was necessary only to be moderately contaminat- awarded the contract as general ed. contractor in December 2015. For The plant’s flexibility also allows The plant’s most important build- the company, it was a given to pur- Vattenfall to take advantage of at- ings, which have no basement, sue this commission. After all, tractive electricity prices – and, if are the engine buildings for the power plants are part of the core necessary, to compensate for fluc- gas and the steam turbine, the boil- business of Siemens Energy (in 2015 tuations in other district heat sup- er building with a 67-meter-high still part of Siemens AG). Also, the ply plants or in the output of wind stack for flue gases, the feed water plant is located in Berlin, where the and solar power within minutes, pump house and the switchgear company has its gas turbine work- thus helping to make renewable building. In addition, it had to have shop and other production facilities. energies suitable for base load. a site for the control room, build- “We were convinced by Siemens The entire plant had to fit into a ings for ancillary systems, a gas Energy’s technology, important very compact package as the desig- compressor building, as well as components of which came directly nated site was not large. At the be- administration, storage and work- from Berlin”, says Vattenfall’s pro- ginning of the 1970s, the first CHP shop buildings. ject manager for the power plant, plant had been built in Marzahn, Jochen Ludwig. “Of course, Siemens which supplied energy to parts of High level of fuel efficiency Energy not only supplied technolo- eastern Berlin and Marzahn indus- gy, the company also acted as gen- trial plants. In the beginning, it was The SGT5-2000E turbine weighs eral contractor. And we were right to fired with Soviet crude oil, later also around 200 t and is about 10 m long. expect them to handle a project of with waste. The waste incineration It is mounted on a concrete turbine this complexity very well”. plant closed in 1990 and the remain- table weighing around 1,000 t at ing power generation plant was ground level. The hot flue gas from Flexibility thanks to high taken off the grid in 2010. The power the turbine is fed into a heat recov- degree of automation plant was to be built on this site – to ery steam generator. It also contains be precise, at Allee der Kos monauten catalysts in order to minimize ni- Various specifications by Vattenfall at the corner of Rhinstraße. But trogen oxide and carbon monoxide and the plant’s location framed with a total size of only 55,300 m2 emissions, which makes it possible Siemens Energy’s design in impor- this was certainly a challenge (fig- to keep emissions low even when tant ways. First and foremost tech- ure 1) – and it was clear that a high the plant is operated at low gas nology. As part of Germany’s energy degree of prefabrication would be turbine load. The water evaporating transition, a gas-fired CHP plant necessary. Regardless, Siemens in the heat exchanger tubes of the was required, as natural gas is a Energy was happy to take on the heat recovery steam generator is fuel producing low CO2 emissions challenge. then fed into the steam turbine www.ehp-magazine.com II/2021 45 Figure 1. All tightly put together: The CHP Plant in Berlin-Marzahn was built on a small site due to clever planning und plenty of prefabrication Source: Siemens Energy SST5-800, which in turn produces Another special feature of the during construction to efficiently additional electricity. plant is that hydraulically it is coordinate the site activities like This is where cogeneration comes placed at the optimal tie-in point for piping installation. Siemens Energy into play: An essential part of the district heating for eastern Berlin. also insisted on having almost steam from the steam turbine is fed But since there is no freshwater everything enclosed – for work into heating condensers, releasing cooling at the site, today there is an safety, energy efficiency, maintain- its heat to water for the district heat- air condenser to be used at ambient ability and soundproofing with ing network. The water is heated up temperatures above approx. 5 °C. special focus on ensuring high in the plant to a maximum of 135 °C This air condenser helps with con- plant availability. and in turn supplies customers with densation for excess steam that A particular challenge was the energy for heating and hot water at cannot be condensed in the district building that was to house the a maximum pressure of up to 15 bar. heat exchangers when the district steam turbine. It had to be designed Taken together, this ensures a high heat demand is low. in a way to integrate not only the level of fuel efficiency: Up to 92% of steam turbine, but also its steam the energy available in natural gas A table with a steam turbine piping, the district heaters and the is converted into electricity or heat.