Hard coal-fired power plants between hope and trepidation

Author: Dr. Klaus Hassmann, Energy Technology Cluster (as of September 2016) The production of hard coal in Germany has declined significantly: From 2089 petajoules (PJ) in 1990 to 361 PJ in 2011 (the year of the start of the energy turnaround) to 188 PJ in 2015; based on 1990, this is just about 9%; the hard coal subsidy by the federal government will expire in 2018. Hard coal is therefore no longer a significant domestic economic factor; the employment effect compared to lignite is low.

Hard coal-fired power plants play a rather subordinate role in the discussion about the energy transition compared to lignite. In this article, the question is pursued, what contribution hard coal has in installed power plant capacity in Germany and how it is distributed regionally. In the second part of the article, primary energy consumption and power generation are discussed. For this purpose, the power plant lists of the Federal Network Agency of 16. 7. 2014 and 10. 5. 2016 were evaluated on a block-specific basis. The allocation to hard coal differs from the results of the list itself in individual aspects, but insignificantly.  

Development of the hard coal-fired power plant fleet in Germany since the start of the energy turnaround in 2011

Table 1: Power plant capacity, distribution among the federal states and age  

1) provisionally decommissioned, 2) permanently decommissioned, 3) legally prevented from decommissioning/reserve power plants, 4) seasonal conservation, 5) special cases/no allocation

Tab 1 shows important data on the development of the coal-fired power plant fleet since the start of the energy transition in 2011; it is to be updated in this form on the Bayern Innovativ Internet portal over the years. Among others, the 4 federal states with the highest shares of installed, operating, electric power plant capacity from hard coal are listed. Compared with the brown coal (see article likewise in this portal) is in Germany around approx. 6000 MW higher with hard coal fired power station achievement in enterprise.

A not too large part of the hard coal power stations is not operated exclusively with hard coal. Other fuels such as fuel oil, natural gas and waste are also fired. This category is listed as "multiple fuels" in the power plant list. These power plants are not only included in Tab 1 in the total capacity of power plants in operation; they are also found in the other features of this article.

It is noticeable that there has been a lot of movement in hard coal in the years since the beginning of the energy transition, especially in terms of closures; from 2011 to 2014, a total of approx. 1700 MW, in the 2 years after that until 2016 additionally approx. 2800 MW power plant capacity were taken off the grid; related to the power plants in operation this is approx. 17%; 80% of the decommissioned hard coal power plants are located in North Rhine-Westphalia (NRW); on average they were in operation for about 40 years. Power plants with a total of not quite 500 MW were legally refused decommissioning. All these plants are in Baden-Wuerttemberg and point also considering their age of 50 years to a "vulnerability" of the supply security of the south countries with still high nuclear energy portion.

62% of the hard coal power stations in enterprise are operated with heat extraction. In the decommissioning decision, this mode of operation plays virtually no role; both categories - with and without heat extraction - are affected. 

If one determines the global mean value for the federal states from the figures for output percentage and mean age (each row 2 in Tab 1), the result is an age of 29 years for 2014. In 2016, the value fell by 3 years; a figure that is respectable, all the more so if one takes into account that the fleet has generally become 2 years older. There are 2 reasons for this: 1. the high number of decommissioned power plants and 2. due to the new high-efficiency power plants that have come on stream in recent years. After 2011, a total of nine large (between 700 and 850 MW capacity) units have been commissioned until 2016, including 4 with a total of 3000 MW in NRW, 2 with 1700 MW in Baden Württemberg, also 2 with 1500 MW in Hamburg  and one unit  with 730 MW in Lower Saxony. Operators are usually the large electricity suppliers.

Behind the "rest" mentioned in Tab 1 with 7 federal states are, sorted by the installed capacity of power plants in operation in the 2016 list, Hamburg with 1734 MW, Bavaria with 847 MW, Berlin with 777 MW, Hesse with 753 MW, Schleswig Holstein with 672 MW and Mecklenburg Vorpommern with 514 MW. Hamburg has made a big leap forward in the ranking due to the commissioning of 2 new units. In the other states of the "rest" nothing or not much has changed compared to 2012. In Bavaria, all power plants run under the category "several energy sources".

Electricity generation and primary energy consumption

The characteristic values listed in Tab 2 were taken from the evaluation tables of the Working Group on Energy Balances.

Table 2: Electricity generation and primary energy consumption

Efficiencies, especially of old power plants, are usually not published by operators; I wonder why? However, the average electrical efficiency of the power plant fleet can be estimated from the available data; the reader can draw his conclusions. The average net efficiency can be determined from the last two lines in Tab 2 Net electricity generation hard coal divided by primary energy consumption hard coal. It is constant at 39% from 2012 to 2014 and increases to 41% in 2015. The latter is probably due to the fact that after 2014, as mentioned above, some new power plants with high efficiency around 50% came into operation and many old plants were decommissioned. Nevertheless - in 2 years an increase of the average efficiency by 2 percentage points at an installed capacity of more than 25000 MW is a surprisingly high value. 

The available data also allow an estimation of the average number of full load hours per year; for this purpose the primary energy consumption in Tab 2  was increased by the share of other energy sources fired in addition to hard coal; data on their use cannot be found in any of the energy transition portals. In 2014, other energy sources were fired at approx. 4460 MW or 17% of the power plants listed under hard coal, in 2016 at only 3674 MW (10%). If one increases the gross power generation in 2014 assigned to hard coal in Tab 2 by e.g. 5% to 125 TWh, this would result in approx. 4600 full load hours for the year 2014. This figure seems realistic and means that mainly depreciated hard coal power plants should be in the money at the power exchange. For new plants, as commissioned in the last two years, the economic situation is probably borderline. 

Conclusion

One question is quite crucial: how long will Germany, a high-tech country, still afford to keep an aged, some would say senile, fossil fuel-fired, mainly coal-fired power plant fleet in operation. In the case of hard coal, as explained above, there have been some changes in the last 2 years. In this short period, significantly more old plants have been decommissioned and some new power plants have come on stream compared with lignite. The average efficiency has increased noticeably, with corresponding positive effects on CO2 emissions and primary energy consumption in this power plant segment. This development is a glimmer of hope.

However, there will be no getting around the need to create further incentives for the sake of the environment, so that investments are made in new, highly efficient fossil-fired power plants of whatever type in the foreseeable future. The high electrical efficiencies that can be achieved, if possible coupled with heat extraction, centralized and decentralized, are indispensable in the mix with renewables.