Theoretical optimization of solar electricity using a DC-microgrid
Sammanfattning: This master thesis contributed to a project financed by the Swedish Energy Agency and managed by the housing company Eksta AB in collaboration with the consulting Company WSP. The main aim of this master thesis was to perform a theoretical optimization on the usage of own used solar electricity by transferring the surplus PV between buildings in a demonstration area in a DC-microgrid. To achieve this objective, the Swedish regulatory framework for concession was analyzed in order to find exceptions that allow the transfer of solar electricity surplus between buildings in the same real state. A demonstration area belonging to Eksta and located in Fj¨ar˚as, Kungsbacka, was used in order to simulate the transfer of solar electricity surplus. The area consisted of four new residential buildings, one substation, a preschool, a community living, a retirement home and Eksta’s expedi- tion building. The regulation 2007:215 presents the exceptions for the Swedish electricity law (1997:857). The exceptions 22A and 30 from the regulatory framework for concession stated that an internal power line, allowing the transmission of electricity between facilities, could be built when connecting to electrical production facilities. These exceptions were inter- preted as valid for the demonstration area although not all buildings generated solar electricity. The electricity usage and solar electricity generation for each building varied dependent on the building’s purpose and PV system design. When combining all Buildings in a DC-microgrid the electricity usage and PV generation were summarized leading to a more homogeneously distributed consumption and higher solar electricity generation. As a consequence, the own usage rate and self-sufficiency rate were increased by 32 and 6 percentage points compared to the current individual system. In a DC-microgrid the solar electricity surplus accounted for 9% of the total PV generation compared to 41% if not interconnected. The difference was calculated to an optimization of 27 000 kWh/year which represented the demonstration area’s total electricity usage that could come from solar electricity instead of delivered from the grid. Further optimization of the own-used solar electricity could be achieved by maximizing profitable PV roof areas, increasing the electricity efficiency and connecting the solar electricity surplus to a common energy storage system.
HÄR KAN DU HÄMTA UPPSATSEN I FULLTEXT. (följ länken till nästa sida)