Ranking system results

The following results presented (Appendix III) are based on the previous FCR step response test results of the Fortum owned Kaplan turbine powered TG systems located in Finland.

The results do not take in account the absolute time delay values of end components or the relative effect of the PID -controller parameter settings.

The ranking system defining values are composed of valuation coefficient and stability co-efficient presented in chapter 6.2.1. The ranking coco-efficient, RC is acquired from equation presented below. (Eq. 53)

𝑅𝐶 =𝑉𝐶 𝑆𝐶

(53)

The complete ranking table is presented as an appendix (Appendix III). The colour scales of the cells indicate whether the value is desirable or not, green being the most desirable and red the least desirable.

From the ranking result table presented in the appendix (Appendix III) it can be seen that Aittokoski TG 1 has the most desirable overall performance, while Tainionkoski TG 2 has the least desirable overall performance. With the ranking results the TG systems can now be divided to three groups as mentioned in chapter 6.2.1 (Appendix IV)

It is crucial to remember to always use also external information or data when comparing power plants inside the groups, as the ranking does not take every variable in to account.

From the ranking table (Appendix IV) it can be seen that the most desirable performance is delivered by far the Aittokoski hydropower plant. Aittokoski features however an older ver-sion of used controller systems so the ranking value of Aittokoski TG 1 is not at that level in reality.

The light yellow sector from Pyhäkoski TG 1 to Nuojua TG 3 illustrates the group of TG systems that performed as well as or better than Nuojua TG 3 in the old FCR tests. This indicates that the TG systems coloured on light yellow or light green should be able to per-form desirably in the upcoming FCR tests. From this ranking, it can be seen that only 5 TG systems out of 26 TG systems, Pyhäkoski TG 3 is not included as it had no FCR test data, should be able to pass the upcoming FCR tests without any modification, using just control-ler tuning.

The amount of tuning and modification needed for the remaining TG systems to perform desirably on the upcoming FCR tests is unclear, and needs further research. Some of the remaining TG systems should be capable of fulfilling the upcoming demands with just dif-ferent type of controller setup, but some with lowest ranking scores might not fulfil the de-mands without major modifications.

7 CONCLUSIONS

The main research subjects in this thesis were the upcoming FCR requirements and model-ling the affect the FCR requirements cast on the Fortum hydropower fleet. As answer to first research question; How does the new TSO requirements compare to old ones? it can be said that the upcoming FCR requirements are going to set higher demands on hydropower plant optimization and controller tuning. The time delay factor of power output capacity has a significant role in the upcoming requirements, whereas it has little or none impact in the current requirements.

The time delay factor has a high affect on the FCR test results, and thus should be more thoroughly researched. The time delay mechanisms are not yet fully researched, and the formation of total time delay is still unclear. These factors have to be researched to exploit the full potential of the hydropower fleet. The upcoming requirements also poses good op-portunities for those who have prepared for the change. The new version of FCR require-ments will hopefully increase the frequency quality and thus eliminate the unnecessary stress posed to hydropower plants. The upcoming FCR requirements are also going to clear the field and set every producer on the same line, reducing the amount of free loaders thus re-warding the producers with properly optimized power production.

The answer to the second research question; how does the new requirements affect Fortum hydropower? is a bit more convolute. The main goal of this thesis was to create a ranking system for the Fortum Finnish Kaplan powered hydropower fleet, from which it can be seen that a minority of the hydropower plants are capable of fulfilling the upcoming requirements according to the research done. The ranking list was created using current hydropower plant test data, which does not correspond the actual upcoming FCR testing. The controller tuning and structure was found to be a crucial factor on the success in the upcoming test set. Some of the assumptions made in the early stages of this research was partly proven to be faulty, such as that the usage of Kaplan turbine provides undesirable result as a standard. The prob-lem was discovered to be more in the control systems than in the turbine itself.

However, the affects of this result are yet to be researched completely. In the following chapter 7.1, future research subjects are listed, which may provide the complete answer to the question of “what are the affects of this result and what actions are needed”.

There are two possibilities for actions needed. First one is that the FCR production is seen to have such economic value that further research is funded to fine tune the hydropower plant controllers using modelling and mathematical optimization. The second option is that the wear and tear of hydro turbines due to FCR production is researched thoroughly. This alternative may lead to a result that the FCR production is not economically feasible, in which case the action needed is to terminate the FCR production using hydropower.

This thesis does not provide the solution to this two way dilemma. The base for further re-search is however established and the possible outcomes are recognized.