Renewable-energy-based Single and Community Microgrids Integrated with Electricity Markets
Narayanan, Arun (2019-11-22)
Väitöskirja
22.11.2019
Lappeenranta-Lahti University of Technology LUT
Acta Universitatis Lappeenrantaensis
School of Energy Systems
School of Energy Systems, Konetekniikka
Kaikki oikeudet pidätetään.
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In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of Lappeenranta-Lahti University of Technology LUT's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to http://www.ieee.org/publications_ standards/publications/rights/rights_ link.html to learn how to obtain a License from RightsLink.
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-335-441-8
https://urn.fi/URN:ISBN:978-952-335-441-8
Tiivistelmä
The deployment of renewable-energy-based microgrids in the electrical power system is a wellknown pathway to realize sustainable energy goals. Further, community microgrids incentivize residential houses to exchange renewable electricity production with each other. Community microgrids can also be interconnected to form microgrid clusters to improve their operations and economics. Community microgrids and microgrid clusters reduce interactions with the external grid, promote grid independence, optimize renewable energy usage, and enhance grid resilience and reliability.
Today, many electricity markets across the world have, completely or partially, transitioned from regulated monopolies to open electricity markets. Hence, it is important to interconnect microgrids with the electricity markets, keeping in mind the roles of all the stakeholders of an electricity network—the DSO, retailers, customers, society, etc. The broad aim of this dissertation is to develop concepts and solution methodologies for implementing community microgrids and microgrid clusters with the objective of economically and fairly allocating their economic resources to residential customers, retailers, and the distribution system operator (DSO), considering local electricity market designs and external electricity market connections.
This dissertation first examines single microgrids. Novel linear optimization-based methodologies are presented to cost-effectively dimension the distributed energy resources (DERs) in a single microgrid for full loads, partial loads (i.e., load fractions), and flexible loads (i.e., shiftable loads). These methodologies are also used to investigate whether a microgrid’s electrical loads can be cost-effectively met by using 100% renewable energy sources (RES) supported by battery energy storage systems (BESS). A small city in Belgium, Kortrijk, is used as a case study to illustrate the methodology. From a purely economic viewpoint, RES–BESS systems are not cost-effective even with flexible loads when reference RES and non-RES costs from 2014 are used. This is because in 2014, NRES were significantly cheaper than RES–BESS systems.
The dimensioning methodologies are then used to investigate the long-term economic benefits obtained by Finnish residential customers who install photovoltaic (PV)–BESS microgrid systems and participate in the Nordic electric power market. We found that even when a BESS of 6:4 kWh is included to support the PV production, the reference levelized cost of electricity (LCOE) for PV (in 2015) of 0:20 C/kWh is expensive. However, at half the LCOE of 0:10 C/kWh, electricity from PV panels is preferable over electricity from the grid. In addition, we demonstrate that Finnish residential customers have significant long-term benefits from using PV and PV–BESS systems.
The economic potential for DSOs to utilize BESS for decreasing outages in low-voltage (LV) single microgrids is also examined. A mixed binary linear programming (MBLP) model is applied to a typical Finnish rural electricity network where a BESS is assumed to be installed at the substation to reduce outages. This MBLP model makes it possible to determine the minimum capacity and optimal schedule of the installed BESS. The tradeoff between improvements in reliability and the costs of BESS can also be determined, including the situation wherein the BESS is used for peak shaving when there are no outages. We found that Li-ion-based BESS can be cost-effectively used for interruption management only if their decrease to one-third of their costs in 2016.
We extend our analysis to community microgrids and microgrid clusters. We present a general mathematical formulation of the microgrid cluster problem, taking into consideration the requirements, costs, and profitabilities of different stakeholders. Subsequently, we present a novel methodology to enable fair allocation of the profits that are obtained by the co-operation between the customers of a community microgrid. In a test case with a Finnish LV microgrid, our methodology saved ~ 8% when the customers collaborated as compared to no collaboration, whereas the methodology saved ~ 25% in a microgrid test case in Austin, Texas. Prosumers benefited more from our methodology than a conventional auction-based trading mechanism, whereas consumers benefited less, especially in the Finnish environment. The methodology promotes fair allocation of the cost resources of a microgrid and encourages RES proliferation. Finally, the impacts of another recently proposed electricity tariff design—power–based tariffs (PBTs)—on p2p electricity exchange between residential customers in a community microgrids are also investigated.
This dissertation presents and discusses methodologies, results, and analyses that form building blocks for the broader research community to solve bigger problems. In essence, they represent small steps toward a larger goal—to promote electrification using RES to transform not only the environment but also people’s lives.
Today, many electricity markets across the world have, completely or partially, transitioned from regulated monopolies to open electricity markets. Hence, it is important to interconnect microgrids with the electricity markets, keeping in mind the roles of all the stakeholders of an electricity network—the DSO, retailers, customers, society, etc. The broad aim of this dissertation is to develop concepts and solution methodologies for implementing community microgrids and microgrid clusters with the objective of economically and fairly allocating their economic resources to residential customers, retailers, and the distribution system operator (DSO), considering local electricity market designs and external electricity market connections.
This dissertation first examines single microgrids. Novel linear optimization-based methodologies are presented to cost-effectively dimension the distributed energy resources (DERs) in a single microgrid for full loads, partial loads (i.e., load fractions), and flexible loads (i.e., shiftable loads). These methodologies are also used to investigate whether a microgrid’s electrical loads can be cost-effectively met by using 100% renewable energy sources (RES) supported by battery energy storage systems (BESS). A small city in Belgium, Kortrijk, is used as a case study to illustrate the methodology. From a purely economic viewpoint, RES–BESS systems are not cost-effective even with flexible loads when reference RES and non-RES costs from 2014 are used. This is because in 2014, NRES were significantly cheaper than RES–BESS systems.
The dimensioning methodologies are then used to investigate the long-term economic benefits obtained by Finnish residential customers who install photovoltaic (PV)–BESS microgrid systems and participate in the Nordic electric power market. We found that even when a BESS of 6:4 kWh is included to support the PV production, the reference levelized cost of electricity (LCOE) for PV (in 2015) of 0:20 C/kWh is expensive. However, at half the LCOE of 0:10 C/kWh, electricity from PV panels is preferable over electricity from the grid. In addition, we demonstrate that Finnish residential customers have significant long-term benefits from using PV and PV–BESS systems.
The economic potential for DSOs to utilize BESS for decreasing outages in low-voltage (LV) single microgrids is also examined. A mixed binary linear programming (MBLP) model is applied to a typical Finnish rural electricity network where a BESS is assumed to be installed at the substation to reduce outages. This MBLP model makes it possible to determine the minimum capacity and optimal schedule of the installed BESS. The tradeoff between improvements in reliability and the costs of BESS can also be determined, including the situation wherein the BESS is used for peak shaving when there are no outages. We found that Li-ion-based BESS can be cost-effectively used for interruption management only if their decrease to one-third of their costs in 2016.
We extend our analysis to community microgrids and microgrid clusters. We present a general mathematical formulation of the microgrid cluster problem, taking into consideration the requirements, costs, and profitabilities of different stakeholders. Subsequently, we present a novel methodology to enable fair allocation of the profits that are obtained by the co-operation between the customers of a community microgrid. In a test case with a Finnish LV microgrid, our methodology saved ~ 8% when the customers collaborated as compared to no collaboration, whereas the methodology saved ~ 25% in a microgrid test case in Austin, Texas. Prosumers benefited more from our methodology than a conventional auction-based trading mechanism, whereas consumers benefited less, especially in the Finnish environment. The methodology promotes fair allocation of the cost resources of a microgrid and encourages RES proliferation. Finally, the impacts of another recently proposed electricity tariff design—power–based tariffs (PBTs)—on p2p electricity exchange between residential customers in a community microgrids are also investigated.
This dissertation presents and discusses methodologies, results, and analyses that form building blocks for the broader research community to solve bigger problems. In essence, they represent small steps toward a larger goal—to promote electrification using RES to transform not only the environment but also people’s lives.
Kokoelmat
- Väitöskirjat [1060]