As Sweden switches to increasing renewable electricity production the demand on the energy grid and energy market will become higher. Since a bigger part of the electricity consumption will come from flowing energy sources the production will become less stable and harder to plan with the consumption. The inertia of the electrical system will also decrease since solar and wind power are not synchronously connected to the electrical system which will make the system more sensitive to interference. In order to keep the short-term balance so that the frequency remains at 50 ๐ป๐ง, Svenska kraftnรคt has several reserves at their disposal. As of summer 2020, Svenska kraftnรคt will launch a new reserve called Fast frequency reserve (FFR) with the purpose to deal with rapid imbalances. By supplementing a wind farm with a battery energy store system (BESS), it becomes possible to even out the wind farm's intermittent electricity production by applying peak shaving and lower the grid costs for the wind farm. Because a BESS can provide power within a fraction of a second and is therefore is suitable to provide FFR. To study the profitability and determine what capacity and power a BESS needs for peak shaving and FFR with a wind farm, an optimization model was built in MATLAB to study the profitability of a BESS with multiple power and capacity combination. In addition, the cycling of the BESS and the limitation of peak shaving was also studied to get deeper knowledge about the limitations. The optimization model is using hourly generation data from a wind farm in northern Sweden. Besides the BESS optimization, a separate optimization model was built in order regulate the output power to minimize the generation cost by prolonging the service life of a wind turbine (WTG). The purpose of this optimization was to study if regulating the output power could lower the generation cost, more for the WTG. In addition of the net income the loss of electricity was also studied. The optimization used hourly data during one time period every season during of 2019. The optimization for the BESS showed that the levelized cost of storage (๐ฟ๐ถ๐๐๐ธ) is currently too high for a BESS to be used for only peak shaving with a wind farm. For a BESS to be feasible together with a wind farm the ๐ฟ๐ถ๐๐๐ธ needs to decrease towards ๐ฟ๐ถ๐๐๐ธ<6 ๐ธ๐๐ /๐๐โ, and when the BESS also supplied FFR the income increased between 1.5 โ 8% depending on the power output for the BESS. The capacity was the limiting factor for the BESS when preforming peak shaving while FFR was limited by the power because of the low energy demand in FFR. Lowering the power output for a WTG resulted in an increased net income for every month between 10 โ 90% although this increased income will become more apparent when the operation and maintenance cost starts to drop over a couple of year but this open up a discussion of how an owner should operate there WTG.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:umu-172786 |
| Date | January 2020 |
| Creators | Sundgren, Robert |
| Publisher | Umeรฅ universitet, Institutionen fรถr tillรคmpad fysik och elektronik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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