Master's Thesis Michael Theo Sentis

 

Analysis of the potential for grid-supportive behavior by heat pumps and CHP plants in city districts

The expansion of renewable energies steadily affects the electricity market.Non-controllable energy
sources cause fluctuations in the electricity grid. Those fluctuations have to be balanced to ensure
power supply.
The task of this thesis is to analyse the potential of heat pumps and CHP plants in terms of mitigating
fluctuations within the grid. While CHP plants generate electricity and produce heat, heat
pumps need current to provide heat. This can be used to level both excess power and high loads.
The integration of renewable energy sources requires a certain amount of operational flexibility.Within
this framework, operational flexibility is defined as the ability of a plant to generate or to use
electric power in a controllable way.
With regard to the analysis, characteristic values are used to describe operational flexibility. In order
to determine the demand of operational flexibility, the residual load of a district is considered.
In a first approach, the potential of compensating fluctuations is estimated by comparing both required
and available flexibility.
In a second step, the exchange of energy with the upper grid is minimized. This is achieved by using
a minimization algorithm which can choose the amount of plants that are installed to the grid.
To increase the potential of the plants to balance electrical fluctuations, an adjustment of operation
profiles is executed.
In a final step, an optimization throughout several years is performed. The output represents a possible
scenario of the electrical energy market.
Results show that reduction of energy import can be gained by applying CHPs to a PV-dominated
district whereas heat pumps optain less benefit in such districts.
Districtswith awind energy dominated supply can effectively be equipped with bothCHPs and heat
pumps. In this case, import and export of energy can be decreased significantly.