Editorial - VGB PowerTech Journal 8/2016

Appropriate and reliable framework for CHP plants urgently needed

This issue of VGB PowerTech covers industrial power stations and CHP plants, steam generators and construction technology for power plants. By way of introduction to these topics I would like to describe my impressions from the VGB Technical Group “Industrial and Cogeneration Stations, CHPs”, which deals with similar issues. Through this Group, the VGB offers plant operators a platform where they can meet twice a year to discuss and exchange experiences and solutions. Members of the Group support each other, which benefits their clients by leading to greater security of supply and lower running costs. They also share insights into occupational health & safety (currently, for example, on rescuing people from confined spaces), discuss repairs and plant optimisations and advise one another on avoiding damage. The Group compiles technical standards, e.g. on the mothballing of plants, and helps to launch research projects such as the Novalis, a system for diagnosing burner-induced vibrations on boilers. An added benefit for Group members is the possibility of coming up with joint, ad-hoc solutions in critical situations, e.g. following damage to a boiler circulation pump. Every other year the Group also organises the “Steam generators, industrial and cogeneration stations” symposium, which informs a larger public about technically attractive solutions and fosters professional dialogue. In this context it has proven effective to invite policymakers to the lectures to engage in dialogue with them and encourage mutual understanding.

The members of the Technical Group represent a large number of CHP plants that supply municipalities or industry with heat, process steam and power. Cogeneration is known to be a reliable and extremely efficient energy supply solution that uses around 90 % of the primary energy, reducing waste heat, which is around 40 to 60 % in separate generation processes, to about 10 %. In practice, this means that cogeneration exploits an energy source that would otherwise be wasted and avoids the release of large quantities of carbon dioxide into the atmosphere. Heat, process steam and electricity are generated close to the point of use, resulting in much shorter transmission and transport distances. In the case of fluctuating demand the generation of electricity can be readily adjusted. Depending on the technology used, this can be extended well beyond local demand, so that ancillary services can be provided for grid operators and network loads reduced. Cogeneration shows clearly how a local, highly efficient energy supply solution can contribute to an effective and efficient national and European energy supply concept. In VGB PowerTech issue 7 (2014), Jörg-A. Czernitzky coined a distinctive phrase for this: “All power is glocal”. At the same time, CHP plants support the goals of the German energy transition by lowering CO₂ emissions, reducing primary energy use and relieving grid capacities.

Some of these possibilities are also being mirrored by the plants represented in the Technical Group “Industrial and Cogeneration Stations, CHPs”. For example, there is now a move away from the heat-driven mode of operation towards electricity market-driven operation. The mode of operation of the plants has become much more flexible with many plants providing control reserve. This has imposed new requirements on staff and thrown up new issues relating to lifetime consumption and the maintenance of plants. Control systems have to be adapted to the requirements associated with load changes, and operators have to be able to evaluate the impact on the plant and the service life of the components to prevent long-term damage to the facilities. This issue of VGB PowerTech contains interesting articles on these and other topics, including an article on the flexibility of an industrial power plant, which provides a good example of how cogeneration is actively contributing to grid stability and highlights ways of tackling the wear and tear in CHP plants.

Unfortunately, it appears that an existing or newly occurring local energy demand does not necessarily result in a new CHP plant or an upgrade of an existing facility. Cogeneration can be understood as a method that – regardless of whether it is used with gas or biogas, oil or bio-oil, wood or waste – makes more efficient use of the energy source and therefore necessitates a more sophisticated plant technology and a greater investment. However, for quite some time now the underlying conditions for investments have been favouring heat-only steam boiler systems, and not just in isolated cases. Older facilities that could be upgraded to improve their efficiency are even being threatened with shutdown. One of the most efficient processes available is being neglected, not just because higher investments require a long-term calculation basis, but also because cogeneration is being hit particularly hard by the increasing burden on on-site electricity generation, the uncertainty about the consent of the European Commission to the act of CHP generation, and the charges for avoided grid-use. Moreover, the reward for reducing emissions is only minimal at present. As a result, opportunities to make more efficient use of energy, cut emissions and reduce grid load are not being exploited.

Nevertheless, combined heat and power generation can make a significant contribution to furthering the goals of the German energy transition. To be able to take advantage of these opportunities, the urgent support of policymakers is required to once again establish a long-term, reliable and appropriate environment for the construction and operation of CHP plants.