Demand response and distributed solar generation in the Swedish residential sector - A techno-economic evaluation
Licentiate thesis, 2015
There is an urgent need to transform the electricity system so as to reduce greenhouse gas emissions. Among the possible pathways for such a transformation, the demand side of the electricity system is likely to take a more active role than it has historically. As part of this, consumers will take on the role of electricity producers, through distributed generation, as well as being more active in the management of their loads through demand-side management measures. Therefore, there is a need to investigate what this more active consumer might entail. The overall aim of the work of this thesis is to investigate the potential for demand response (DR), i.e., the shifting of loads in time, and the interplay between DR and distributed solar photovoltaic electricity (PV) generation in a Swedish context.
To assess the potential for DR in Swedish single-family dwellings (SFDs), a building-stock model that employs an hourly energy balance is used to calculate the net energy heating demand for a set of sample buildings, which are taken as representative of all Swedish SFDs with electrical heating. Actual measured load profiles are used for the analysis of the interplay between DR and solar PV. For the modeling of solar technologies, a modeling framework based on empirical models is used.
There is a considerable technical potential for the DR of electric space heating in Swedish SFDs, with 7.3 GW of load. Shifting limits of up to 12 hours are observed during summer, although the maximum number of consecutive hours with a considerable reduction in load during winter is approximately 3 hours. Given the current Swedish electricity prices, up to 5.5 GW of decreased load and 4.4 GW of increased load are observed. The modeling shows that DR shifts up to 1.46 TWh of electric heating, corresponding to 1% of the total Swedish electricity demand.
The synergic effects of DR and solar PV are significant for the DR of hydronic loads, showing an ability to reduce yearly electricity cost by up to 5% depending on the size of the installation. However, due to the seasonal mismatch between the hydronic load and PV electricity generation, the impact is diminished as PV installations increase capacity to more than 4.2 kWp for the average household. The DR of appliance loads shows weak potential for improving the value of a PV investment, despite generous shifting time-frames.
Overall, it can be said that the economic incentives for DR are low given current electricity prices. However, DR might be valuable in a future electricity system in which more flexibility is required. The largest share of the potential of DR lies in managing the hot water and space heating loads, which may entail the least burdensome behavioral changes for consumers.
Distributed solar generation