Comprehensive Assessment of Grid Services Capabilities of XFLEX HYDRO Demonstrators

Core Concepts

The XFLEX HYDRO project has systematically evaluated the ability of its demonstrators to provide a range of ancillary services to the power grid, including synchronous inertia, synthetic inertia, fast frequency response, frequency containment reserve, automatic frequency restoration reserve, manual frequency restoration reserve, replacement reserve, voltage/reactive power control, and black start capability.

Abstract

The XFLEX HYDRO project aimed to develop and demonstrate new technological solutions for hydropower plants to improve their efficiency and performance in providing various electric power system services. The project conducted a detailed assessment of current and emerging flexibility services and their associated market frameworks, focusing on the countries where the project's demonstrations are taking place (Portugal, France, and Switzerland).
The key activities included:

Developing 1D SIMSEN simulation models for each of the 6 XFLEX HYDRO demonstrators, including fixed speed, variable speed, smart power plant supervisor, hydraulic short circuit, and hydro-battery-hybrid technologies.
Performing systematic 1D numerical simulations to quantify the magnitude of active power response that each demonstrator and technology can provide for different ancillary services.
Scoring the results on a scale of 0 to 5 to populate an Ancillary Services Matrix, summarizing the capabilities in a graphical and synthetic way.
Analyzing the Ancillary Services Matrix to draw key conclusions about the benefits unlocked by the implementation of these technologies.
The analysis showed that variable speed technology enables significant improvements in the provision of fast frequency response, frequency containment reserve, automatic frequency restoration reserve, and black start capability compared to fixed speed technology. Hydraulic short circuit operation allows fixed speed plants to provide frequency containment reserve and automatic frequency restoration reserve services. The smart power plant supervisor extends the operating range for automatic, manual, and replacement reserves. The hydro-battery-hybrid solution helps overcome adverse power responses and enables frequency containment reserve provision.

Stats

The maximum FCR capacity of the Frades 2 pumped storage plant in hydraulic short circuit mode is 231.4 MW.
The maximum FFR capacity of each Frades 2 variable speed unit in turbine mode is 110 MW delivered in 1.3 s.
The maximum black start capacity of the Frades 2 variable speed units is 124 MW.

Quotes

"Variable speed enables the FFR ancillary service, which is not adapted for the case of fixed speed as a very fast dynamic is necessary to be able to provide the requested power within the service timeframe."
"With variable speed, the FCR and aFRR ancillary services are enabled over the full operating range in pump mode whereas with fixed speed, the input power is fixed by the rotational speed for a given head, so that provision of the ancillary service is not possible."
"Large improvement of Black-Start capacity can be achieved with variable speed. Especially by choosing a strategy which fully exploits the flywheel effect such as setting the initial rotational speed at nmax."

Key Insights Distilled From

XFLEX HYDRO demonstrators grid services assessment and Ancillary Services Matrix elaboration

by Chri... at arxiv.org 04-10-2024

https://arxiv.org/pdf/2404.06275.pdf

Deeper Inquiries

How can the insights from the Ancillary Services Matrix be used to inform policy and market design to better incentivize the provision of grid services by hydropower plants?

The insights from the Ancillary Services Matrix can play a crucial role in informing policy and market design to incentivize the provision of grid services by hydropower plants. By understanding the capabilities of different technologies in providing ancillary services such as FCR, FFR, aFRR, and Black-Start, policymakers can tailor regulations and market mechanisms to encourage the adoption of technologies that enhance grid flexibility. For example, if the matrix shows that variable speed technology enables higher contributions to FCR and FFR compared to fixed speed technology, policymakers can introduce incentives or mandates that promote the adoption of variable speed solutions in hydropower plants. This could include financial incentives, capacity payments, or preferential treatment in grid service markets for plants equipped with advanced technologies that enhance grid stability and reliability. Additionally, the matrix can guide the development of specific requirements in grid codes or market rules that recognize and reward the provision of ancillary services by hydropower plants, thereby creating a more conducive environment for investments in flexible technologies.

What are the potential barriers or challenges in implementing the technologies evaluated in the XFLEX HYDRO project, and how can they be addressed?

Implementing the technologies evaluated in the XFLEX HYDRO project may face several barriers and challenges. One key challenge is the high upfront costs associated with upgrading or retrofitting existing hydropower plants with advanced technologies like variable speed units or Smart Power Plant Supervisors (SPPS). These costs can be a significant barrier for plant operators, especially if the economic benefits or revenue streams from providing ancillary services are not clearly defined or guaranteed. To address this, financial mechanisms such as grants, subsidies, or low-interest loans could be provided to support the adoption of these technologies. Additionally, capacity-building programs and technical assistance can help plant operators understand the technical requirements and benefits of the new technologies, facilitating their implementation.
Another challenge is the regulatory and market framework, which may not always be conducive to the provision of ancillary services by hydropower plants. Grid codes, market rules, and operational practices may need to be updated to accommodate the unique characteristics and capabilities of advanced hydropower technologies. Collaboration between policymakers, regulators, grid operators, and industry stakeholders is essential to identify and address regulatory barriers and ensure a level playing field for all technologies to participate in grid service markets.

What other emerging technologies or hybrid solutions could be explored to further enhance the grid services capabilities of hydropower plants?

In addition to the technologies evaluated in the XFLEX HYDRO project, several emerging technologies and hybrid solutions could further enhance the grid services capabilities of hydropower plants. One promising technology is Energy Storage Systems (ESS), such as batteries or pumped hydro storage, which can complement hydropower plants by providing additional flexibility and fast response capabilities. By integrating ESS with hydropower plants, operators can optimize energy storage, ramping, and frequency regulation, enhancing the overall grid services provided.
Furthermore, advanced control systems, machine learning algorithms, and predictive analytics can be leveraged to optimize the operation of hydropower plants and maximize their contribution to grid services. These technologies can enable real-time monitoring, predictive maintenance, and adaptive control strategies, improving the efficiency and reliability of hydropower plants while enhancing their grid support capabilities.
Hybrid solutions like Hydro-Battery-Hybrid (HBH) systems, combining hydropower with battery energy storage, offer a flexible and reliable way to provide grid services. By integrating different technologies and energy sources, hybrid solutions can optimize the utilization of renewable resources, improve grid stability, and enhance the overall resilience of the power system. Exploring these emerging technologies and hybrid solutions can unlock new opportunities for hydropower plants to play a more dynamic and integral role in the future energy landscape.