Heat Pumps as Flexible Resources for a Resilient Electrical Grid

The increasing need to introduce more and more energy from renewable energy sources into the energy mix has brought with it numerous challenges to be solved within today’s electricity grid. A prominent challenge is that these new technologies, such as wind and solar photovoltaic power generation, connect to the grid mainly through power electronic converters. This has led to a growing concern about grid stability, particularly regarding the decrease in system iner- tia and the increase in the rate of change of frequency (RoCoF) following contingencies. As a result, there is an urgent need to find ways to maintain stability in compliance with the regula- tions in force in various countries. The problems can be addressed through demand response programs, which are designed to adapt the demand side in order to balance and synchronize the power system. These methods decouple renewable energy generation from demand, enabling the demand side to support the grid when needed. Going to the extremes of the previous idea, one can introduce grid-forming loads, i.e. loads connected with special converters to the electricity grid and able to fully manage and support the grid services for frequency adaptation and voltage control. This paradoxical change of vision could produce an electricity grid in which renewable ener- gies could proliferate, always operating at nominal points and at maximum power, and in which grid control would fall entirely on the demand side. The loads that could be used for this purpose are numerous, but the common factors are that they must be able to have a flexible demand, and so a certain type of inertia, without affect- ing the end user too much. In this thesis, we go on to analyse the behaviour of a heat pump, at a domestic level, used for cooling the air in a house and how it is able to support the net- work for providing grid services. To do this, various models are used and implemented on Matlab/Simulink and case study applications are presented also based on experimental results.