Improving Coal Power Flexibility for Better Grid Integration of Renewables

On 22 April, GIZ hosted the Sino-German Online Conference on Coal Power Flexibility. As more and more variable renewable electricity feeds into the grid, flexibilization of existing conventional power plants plays an important role for ensuring adequate system stability in the short to medium term. The event attracted over 60 attendees from both countries’ government institutions, research and industry. The conference provided an information platform for exchanging on the status quo, challenges and solutions for the flexibilization of coal power in Germany and China and connecting German and Chinese decision makers from politics and industry alike. The event was supported by China Electric Power Planning and Engineering Institute (EPPEI).

One of the event’s highlights was the launch of the Chinese language version of VGB Powertech’s toolbox on coal power flexibilization. The flexible operation of coal-fired power plants requires suitable technologies, skilled staff and leadership with foresight. The Flexibility Toolbox provides a collection of numerous proven technical measures for the flexibilization of coal-fired power plants, practical tips and recommendations for training as well as references for management issues. Minimum load, ramp rates and start-up and shutdown time are typically used to describe power plant flexibility. By applying flexibilization measures, very advanced hard coal power plants have been able to reduce their minimum load to 10%, increase their ramp rate to 9% and shorten their hot start-up time to one hour. The report is divided into four sections – Retrofit, Operation & Maintenance, Training, and Management, and covers measures in the areas of combustion, water-steam cycle, turbine, I&C system and auxiliary systems optimization.

Click here to download the Chinese version of toolbox on coal power flexibilization.

Further notable findings from the conference include, amongst others：

With the right incentives and market mechanisms in place, coal flexibilization generates additional revenue. In an example shared by Huaneng Dandong Power Plant, one of the first batch of the country’s national flexibilization pilots, data showed that plant flexibilization, including the decoupling of heat and power generation, resulted in additional revenue from the pilot ancillary services market. However, initial revenues have since fallen as more companies entered the market. The discussions showed that the introduction of incentives and market mechanisms is crucial for introducing power sector and coal plant flexibility.

No universal solution for coal power plants. The examples of German and international power plants revealed that each power plant is unique and requires specific recommendations. Often, plant owners believe that their plant cannot be made more flexible, but small changes and careful experimentation make further flexibilization possible. E.g., improving automatic coal mill handling can address the problem of flickering flames at low minimum load. Several specific measures and experiences were shared by German companies RWE Technology International, Siemens Energy, and ProCom.

Coal power flexibilization is the most cost-effective method for improving power sector flexibility in China. Though China has very modern coal power plants, more can be done to improve flexibility, which will likely accelerate as more renewables enter the market and spot market/ancillary services markets accelerate.

The “Sino-German Online Conference on Coal Power Flexibility” was hosted by Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH in the framework of the Sino-German Energy Transition Project and the Sino-German Demonstration Project on Energy Efficiency in Industry between the German Federal Ministry for Economic Affairs and Energy (BMWi), the National Energy Administration and the National Development and Reform Commission (NDRC), respectively. The event was supported by China Electric Power Planning and Engineering Institute (EPPEI).

Both projects will continue to work closely with Chinese stakeholders to further facilitate technical exchanges on coal power and power sector flexibilization, build connections between businesses in both countries, and accelerate the energy transitions in China and Germany.