Periodic Reporting for period 1 - POSYTYF (POwering SYstem flexibiliTY in the Future through RES)
Reporting period: 2020-06-01 to 2022-05-31
POSYTYF intends to develop output methodologies to increase the performance of an integrated portfolio of dispatchable and non-dispatchable RES to be operated together as a Dynamic Virtual Power Plant, capable of providing flexibility and ancillary services to the energy system.
1. Context
The context of POSYTYF project is :
• System stability is the main bottleneck to the further integration of Renewable Energy Sources (RES) into the power system.
• Distributed RES, if aggregated and technically/economically optimized, have the potential to provide flexibility to the grid and contribute to system stability.
• Dispatchable RES can beneficially complement non-dispatchable RES for such optimization; alternative to electrochemical storage
2. Project objectives
The main objectives of POSYTYF project are :
• Determine optimality criteria to define the DVPP perimeter for long term and real-time application
• Develop new controllers to allow RES to contribute to ancillary services
• Test the developed solutions by simulation and Hardware in the Loop (HiL) on realistic scenarios
• Define new business cases for the optimal operation and configuration of DVPP
• Propose regulatory recommendations to support the DVPP deployment
• Assess economic competitiveness of the DVPP compared with solutions combining variable renewable energy with electrochemical storage
• Propose new stability definitions and methodologies for stability analysis and assessment
1. Context
The context of POSYTYF project is :
• System stability is the main bottleneck to the further integration of Renewable Energy Sources (RES) into the power system.
• Distributed RES, if aggregated and technically/economically optimized, have the potential to provide flexibility to the grid and contribute to system stability.
• Dispatchable RES can beneficially complement non-dispatchable RES for such optimization; alternative to electrochemical storage
2. Project objectives
The main objectives of POSYTYF project are :
• Determine optimality criteria to define the DVPP perimeter for long term and real-time application
• Develop new controllers to allow RES to contribute to ancillary services
• Test the developed solutions by simulation and Hardware in the Loop (HiL) on realistic scenarios
• Define new business cases for the optimal operation and configuration of DVPP
• Propose regulatory recommendations to support the DVPP deployment
• Assess economic competitiveness of the DVPP compared with solutions combining variable renewable energy with electrochemical storage
• Propose new stability definitions and methodologies for stability analysis and assessment
The work performed for an initial 24-month period post launch of the project are:
In WP1, selected scenarios for the project were described, including technology definition for the Dynamic Virtual Power Plant-DVPP and the rest of the system. The proposed scenarios were used to prepare simulation models for the whole project. Next, the requirements and services for existing and future power systems were addressed. Finally, a new methodology for VSC role assignment in modern power systems was developed.
In WP2, the underlying renewable-energy power plant (RPP) models of the overall DVPP systems have been developed so far. A general physical description of each RPP type is used for high flexibility and practical applicability. In detail, PV and wind power plants, biogas plants, solar thermal plants (with the support of the industrial partner CIEMAT), and hydropower plants were modeled. The DVPP power plant is composed of this mix of generators. The developed models were tested on several scenarios including changing the reference variables active and reactive power, disturbance variables (solar irradiation, wind speed…).
In WP3, advancement has been achieved in three main directions. First, centralized vs centralized with distributed implementation of the control of the DVPP generators for ancillary service, robustness and resilience was studied. For this, the control of renewable generators connected to the grid via power electronics has been revisited by abondonating several hypothesis and proposing new robust controls based and fuzzy control for local (generator level) control with coordination between the DVPP generators. Next, controls for both secondary voltage and frequency controls were developed. Finally, a study of the interaction of the DVPP generator with other neighbor dynamic elements of the grid was proposed.
In WP4, the problem of developing decentralized control methodologies for DVPPs was addressed. To do so, a decentralized control design method composed of two steps was proposed: i) disaggregating the desired dynamic behavior among the individual devices, and (ii) local model matching for each individual device. In addition, extensions of the initial control design method towards a grid-forming signal causality was developed, as well as spatially distributed device arrangements. The problem of redefining stability and proposing methodologies for analysis was also investigated. The concept of “complex-frequency synchronization” was defined to analyze the stability of power systems when considering P/θ and Q/V coupling on the power networks.
In WP5, a novel DVPP planning model, composed of exclusively Renewable Energy Sources-RESs (including hydro, wind, solar PV, solar thermal and biomass), and flexible demands, was developed. The model considers the optimal configuration and operation of the DVPP for different business cases. It was demonstrated that, by appropriately combining the features and efforts from RESs of different nature that are currently installed and operating in a power system, one can achieve higher economical and operational benefits than other solutions that imply the installation of large electrochemical (battery) energy storage systems (BESSs).
In WP1, selected scenarios for the project were described, including technology definition for the Dynamic Virtual Power Plant-DVPP and the rest of the system. The proposed scenarios were used to prepare simulation models for the whole project. Next, the requirements and services for existing and future power systems were addressed. Finally, a new methodology for VSC role assignment in modern power systems was developed.
In WP2, the underlying renewable-energy power plant (RPP) models of the overall DVPP systems have been developed so far. A general physical description of each RPP type is used for high flexibility and practical applicability. In detail, PV and wind power plants, biogas plants, solar thermal plants (with the support of the industrial partner CIEMAT), and hydropower plants were modeled. The DVPP power plant is composed of this mix of generators. The developed models were tested on several scenarios including changing the reference variables active and reactive power, disturbance variables (solar irradiation, wind speed…).
In WP3, advancement has been achieved in three main directions. First, centralized vs centralized with distributed implementation of the control of the DVPP generators for ancillary service, robustness and resilience was studied. For this, the control of renewable generators connected to the grid via power electronics has been revisited by abondonating several hypothesis and proposing new robust controls based and fuzzy control for local (generator level) control with coordination between the DVPP generators. Next, controls for both secondary voltage and frequency controls were developed. Finally, a study of the interaction of the DVPP generator with other neighbor dynamic elements of the grid was proposed.
In WP4, the problem of developing decentralized control methodologies for DVPPs was addressed. To do so, a decentralized control design method composed of two steps was proposed: i) disaggregating the desired dynamic behavior among the individual devices, and (ii) local model matching for each individual device. In addition, extensions of the initial control design method towards a grid-forming signal causality was developed, as well as spatially distributed device arrangements. The problem of redefining stability and proposing methodologies for analysis was also investigated. The concept of “complex-frequency synchronization” was defined to analyze the stability of power systems when considering P/θ and Q/V coupling on the power networks.
In WP5, a novel DVPP planning model, composed of exclusively Renewable Energy Sources-RESs (including hydro, wind, solar PV, solar thermal and biomass), and flexible demands, was developed. The model considers the optimal configuration and operation of the DVPP for different business cases. It was demonstrated that, by appropriately combining the features and efforts from RESs of different nature that are currently installed and operating in a power system, one can achieve higher economical and operational benefits than other solutions that imply the installation of large electrochemical (battery) energy storage systems (BESSs).
The DVPP is a promising solution to improve the high penetration of both dispatchabe and nondispatchable renewable energy sources with a minimization of the BESSs. The new concept integrates and studies all power system aspects (static (load-flow), optimal (perimeter definition for short/medium and long term run), and dynamic (all levelscontrol for local- machine- and global grid objectives)).
• The expected results until the end of project are:
– Define structure and controls for DVPP to fully participate to grid ancillary services.
– Develop new methodologies for analysis and assessment of DVPP’s stability.
– Develop a strategy that aggregates the DVPP objectives and actions in accordance with the split of the grid into transmission and distribution levels.
– Propose models that are adequate to the multi-scale and coupling dynamics of the new grid.
– Define the perimeter of DVPP (to ensure economic efficiency). DVPP resources portfolio should be optimized in function of availability of DVPP sources, grid conditions and market prices.
– Provide business cases and regulatory solutions to allow DVPP development. DVPP concept should be flexible enough to allow implementation in several stages (transmission TSOs, Distribution DSOs, and generators).
• The potential impacts of the POSYTYF project are:
– reduce the use of conventional power sources, therefore, minimize the carbon emission,
– make the energy generation more environment-friendly,
– improve energy equity and supply security,
– reduce reliance on capital investment in large-scale energy infrastructure,
– reduce the expensive peak power and balancing energy,
– reduce the maintenance and the expansion costs for the electrical grid,
– reduce the integration of electrochemical energy storage system in order to avoid the following disadvantages:
∗ high installation cost,
∗ short life,
∗ intrinsic self-discharge,
∗ limited materials availability,
∗ negative environmental impact at the time of their disposal
• The expected results until the end of project are:
– Define structure and controls for DVPP to fully participate to grid ancillary services.
– Develop new methodologies for analysis and assessment of DVPP’s stability.
– Develop a strategy that aggregates the DVPP objectives and actions in accordance with the split of the grid into transmission and distribution levels.
– Propose models that are adequate to the multi-scale and coupling dynamics of the new grid.
– Define the perimeter of DVPP (to ensure economic efficiency). DVPP resources portfolio should be optimized in function of availability of DVPP sources, grid conditions and market prices.
– Provide business cases and regulatory solutions to allow DVPP development. DVPP concept should be flexible enough to allow implementation in several stages (transmission TSOs, Distribution DSOs, and generators).
• The potential impacts of the POSYTYF project are:
– reduce the use of conventional power sources, therefore, minimize the carbon emission,
– make the energy generation more environment-friendly,
– improve energy equity and supply security,
– reduce reliance on capital investment in large-scale energy infrastructure,
– reduce the expensive peak power and balancing energy,
– reduce the maintenance and the expansion costs for the electrical grid,
– reduce the integration of electrochemical energy storage system in order to avoid the following disadvantages:
∗ high installation cost,
∗ short life,
∗ intrinsic self-discharge,
∗ limited materials availability,
∗ negative environmental impact at the time of their disposal