New method for soft restrictions
Researchers at HydroCen have developed a new method to treat such soft reservoir restrictions. In this way, with ProdRisk, production can be better planned for reservoirs where the maximum tapping capacity depends on the degree of reservoir filling.
The solution consists in linearizing the non-convex relationship between reservoir condition and maximum permitted tapping capacity which is described by a soft reservoir restriction. As a supplement, an artificial lower reservoir limit is calculated during the restriction period. This is based on incoming inflow statistics and is calculated as the minimum accumulated inflow from the start of the restriction period. Even with zero reservoir filling at the start of the restriction period, one will therefore be able to meet this artificial minimum requirement with certainty. The linearization is based on the artificial lower reservoir limit.
Tested and ready for implementation
A prototype of the method has been tested on the hydropower systems in Bergsdalen and Rjukan in Norway, and parts of the functionality have been tested in a prototype by ProdRisk.
Based on good results from the tests, the method is considered suitable for implementation in operational versions of the program ProdRisk.
The new method defines what we know as best practice for modeling soft restrictions in production planning models for water value calculation. By adopting the new method, producers will be able to represent soft reservoir restrictions in the water value calculation with higher precision without compromising calculation time.