Heat and power for Energiewende, Germany’s renewable energy transition

Heat and power for Energiewende, Germany’s renewable energy transition

Wärtsilä has recently been awarded contracts to develop hundreds of megawatts of combined heat and power (CHP) plants in Germany – all thanks to the flexibility, efficiency and environmental credentials of its technology.

Wärtsilä has recently been awarded contracts to develop hundreds of megawatts of combined heat and power (CHP) plants in Germany – all thanks to the flexibility, efficiency and environmental credentials of its technology.

There’s no doubt the announcement about Wärtsilä delivering an eight-engine 92 MW combined heat and power (CHP) power plant to DREWAG in the city of Dresden, the capital of Saxony, is an important step in Germany’s transition to a renewable energy future.

The facility has been ordered by DREWAG, Dresden’s local utility company, and is a milestone for Wärtsilä. It’s the first project in Germany to employ Wärtsilä 31SG engines, the company’s most flexible and efficient engines to date. In fact, the extremely high efficiency and flexibility of the Wärtsilä 31SG engine were cited as key factors in the award of the Dresden contract. Another major consideration was the power plant’s ability to deliver electricity and district heating simultaneously. The installation is set to be operational by 2021.

The Wärtsilä engines that will be used in Dresden can reach full output in a matter of minutes, enabling them to provide immediate balancing of the grid as the system uses more and more energy from intermittent renewable sources, such as wind and solar.

Technologies such as these are integral to Germany’s pioneering Energiewende (energy transition) – an ambitious change programme where the goal is a low carbon, environmentally sound, reliable and affordable energy supply. Germany is targeting an 80-95% reduction in greenhouse gas emissions by 2050 relative to 1990 levels. It also wants to produce 60% of its energy from renewables by mid-century, and phase out coal-fired power generation by 2038, and nuclear power by 2023.

Germany: A ‘showroom’ for clean technology

Integrating increasing levels of renewable power onto the grid is not without its challenges. While energy from solar and wind is intermittent, the energy system requires a constant flow of uninterrupted power.

That’s where the flexibility, responsivity and reliability of Wärtsilä’s smart power technologies for generating electricity and heat can play a key role. “Germany is a showroom for a new renewable energy-based system and supporting technologies,” explains David Szymanski, Director, Solutions, Europe West, Wärtsilä Energy Business. “It’s a great place to demonstrate what our products can do.”

Although the Energiewende will take time to deliver its vision of a 100% renewable energy system, renewable energy is already delivering baseload power. Technologies that Wärtsilä has developed such as engines and energy storage are providing the means of balancing electricity supply with demand as an ever-greater level of renewable power comes online.

In Germany, municipalities are incentivised by the government to build and maintain CHP plants. In 2016, Wärtsilä announced a deal to supply a 100 MW CHP plant to Kraftwerke Mainz-Wiesbaden (KMW) consisting of 10 Wärtsilä 34SG engines running on natural gas. In addition, a 10 MW CHP  plant featuring one Wärtsilä 34SG engine running on natural gas has been delivered to Thüringer Energie. And there will be more: Germany has committed to increasing the share of electricity generated by CHP power plants to 25% of total electricity production by 2025.

Quick-start, flexible and clean technologies

Wärtsilä’s technologies are attractive for a number of reasons: not only are they flexible, reliable and sustainable, they also start up very quickly and can be used in the electricity balancing markets. With a response time of even less than two minutes, they flex according to demand. Plus, CHP combined with heat storage technologies also means heat can be stored and released according to demand for hot water.

The German deals are significant achievements for Wärtsilä and testament to the company’s ability to understand customer needs and support an asset through its entire lifcycle. With Wärtsilä as partner, performance of customer installations can be also optimised through upgrades, modernisations, fuel conversions and safety solutions. At the end of the day, it was these capabilities that helped win the DREWAG deal, with the customer investing in Wärtsilä’s first-of-its-kind Wärtsilä 31SG CHP plant.

Added to that, the development of the 100MW KMW project means Wärtsilä has made a statement of intent in the industry: “The efficiency and start-up times of our Wärtsilä 34SG and Wärtsilä 31SG engines make them very attractive to the customer,” says Szymanski.

Wärtsilä 31: Setting world records

The Dresden plant relies on eight new Wärtsilä 31SG engines, which are even more powerful and efficient than their 34SG counterparts. In fact, the Wärtsilä 31 ranks in the Guinness Book of Records as the world’s most efficient four-stroke engine. Hence, the 31SG represents a natural evolution, taking this efficiency to the next level. “This represents our most advanced engine,” explains Szymanski, “and delivers an output in the range of 12 MW.”

The efficiency of the Wärtsilä 31SG engine helps reduce the cost of fuel. Wärtsilä guarantees operational reliability and efficiency of the engine, backed up with expert advice on optimising power plant operation and maintenance. Guidance on equipment performance and operations monitoring ensures a high performance level and maximised uptime for the plant.

Plus, the use of flexible power from Wärtsilä enables an increase in the level of renewable energy on the German grid as part of the Energiewende. “The grid relies on a stable flow of energy,” explains Melle Kruisdijk, Vice President, Europe, Wärtsilä Energy Business. “When there’s a limited amount of renewable energy online, that’s not a problem. But greater levels of renewables mean fluctuations in supply. That’s why Germany also needs highly flexible and dispatchable power generation that can respond in minutes and provide the energy that’s needed.”

The combination of flexibility and CHP opens up a new operational regime for these plants. Contrary to traditional CHP plants that mainly run in baseload mode when heat is most required, these plants will only run when the electricity market price is high, i.e. when there is fluctuation or lack of renewable power. By decoupling electricity generation from heat generation with heat storage, the generated heat that is not directly consumed can be time-shifted for later use. This new operating mode will allow more renewable energy to penetrate the power system while still delivering heat to consumers.

Other advantages of Wärtsilä’s technology include the fact that its engines are built in modules and can be readily scaled up to meet the needs of customers, such as at the KMW plant. There, Wärtsilä also has a 15-year Guaranteed Asset Performance agreement. For Dresden’s local utility DREWAG, Wärtsilä will maintain the new 92 MW CHP plant under a Guaranteed Asset Performance agreement for 10 years, with the option to extend for a further five.

A bright future in renewables

CHP isn’t the only technology that Wärtsilä is developing to help Germany move towards a 100% renewable energy economy: it’s also working on energy storage systems and hybrids combined with energy management systems. In fact, Wärtsilä’s energy management system software, GEMS, is among the most advanced in the world, using artificial intelligence and big data to control and balance multiple energy assets, including energy storage, renewables and engine power plants.

CHP looks set to play a critical role in the future, even though greater levels of renewable energy are always coming online. Ultimately, Kruisdijk envisages a future where synthetic liquid and gaseous fuels generated through ‘Power-to-X’ technology are used to power CHP plant, developing a zero emission future power system.

But whatever the future holds, there’s no doubt that as Germany makes the transition to a carbon-neutral energy system, Wärtsilä will continue to play a key role in the CHP market.

Written by
Ben Hargreaves