Ancillary Services from Smart Thermostatic Loads in Power Grids

Project Information

SmarTher Grid

Grant agreement ID: 891101

DOI

10.3030/891101

Project closed

EC signature date 21 April 2020

Start date 1 September 2020

End date 31 August 2022

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 157 941,12

EU contribution

€ 157 941,12

Coordinated by

UNIVERSITY OF CYPRUS
Cyprus

Periodic Reporting for period 1 - SmarTher Grid (Ancillary Services from Smart Thermostatic Loads in Power Grids)

Reporting period: 2020-09-01 to 2022-08-31

Summary of the context and overall objectives of the project

The penetration of renewable sources of energy in power networks is expected to grow over the next years, motivated by environmental concerns. However, renewable generation is in general intermittent and a large penetration may cause frequent generation/demand imbalances that may compromise power quality and even result in blackouts. Demand side participation can offer a solution to this problem, due to loads ability to provide a fast response when required. However, a large portion of the total demand corresponds to thermostatic loads (TLs), which are characterized by a cyclic thermostatic behavior. Such effects need to be taken into account in the design of control schemes for TLs, if those are to provide support to the power grid.

The primary technical research objective of this project were the design of control schemes for TLs such those provide effective, efficient and reliable ancillary support to the power network.
In particular, the major research objectives of the project are to:
(i) Enable suitable control designs that enable ancillary support to the power grid and an optimal power allocation.
(ii) Provide analytic stability guarantees for power networks when the proposed control designs are implemented.
(iii) Validate the proposed control designs with realistic simulations and provide tools that enable further research on controllable demand.

The SmarTher Grid project outcomes will enable improved reliability and resilience in power networks. The enhanced resilience of power grids will allow a larger penetration of renewable energy sources and contribute towards the transition to a sustainable energy sector, having a significant environmental impact. Moreover, the increased reliability of the power network will reduce the frequency of failures, and hence the resulting hardship and discomfort experienced by the public. In addition, the SmarTher Grid project outcomes allow enhanced economic operation, which yields a strong economic impact. Hence, the SmarTher Grid project has the potential for strong socio-economic and environmental impact.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

The main results of the SmarTher grid project are synopsized below:
(i) We have designed a decentralized scheme for controllable thermostatic loads that enables ancillary support in the power grid. The proposed scheme is deterministic, which allows a fast response at urgencies. In addition, we provided conditions on the proposed scheme that ensure than no synchronization phenomena will occur.
(ii) We proposed a scalable hierarchical control scheme for on-off loads which enables a near optimal power allocation and can be combined with ancillary support schemes. In addition, the proposed scheme ensures that the secondary frequency regulation objectives are satisfied. For the proposed scheme, we provide analytic stability guarantees in power networks.
(iii) We proposed a distributed scheme for generation and controllable demand that simultaneously: (i) enables an optimal power allocation, (ii) ensures the privacy of prosumption and (iii) satisfies the secondary frequency regulation objectives. For the proposed scheme we provide analytic privacy, stability and optimality guarantees.
(iv) We designed an intraday blocking pricing scheme that aims to minimize the peak to average demand in the power system, and hence improve its resilience. The proposed scheme delivers improved performance and robustness to uncertainty than existing schemes in the literature.
(v) We studied the stability properties of power networks at the presence of controllable virtual inertia. This study developed sufficient decentralized stability conditions that enabled stability guarantees. In addition, it demonstrates how unregulated virtual inertia may destabilize the power gird.


The dissemination of these results was done through a series of means, such as scientific publications, conference presentations and other activities.
In particular, the SmarTher Grid project has resulted in two journal and two conference publications, with one more conference publication to appear later this year.
In addition, two more journal papers are currently in revision and three more papers (two journal, one conference) are in preparation.
The project outcomes have also been presented at two conferences and will also be presented later this year at one more.
For enhanced dissemination, the Fellow created and maintained a project website and posted regularly on social media about the project outcomes.
In addition, the KIOS CoE aided in the dissemination of the project results with posts through its website and press releases.
Finally, the Fellow has given three seminars and participated in two dissemination events, to promote the SmarTher Grid project outcomes.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The SmarTher Grid project has extended the current state of the art in the following ways:
(i) We proposed a decentralized scheme for controllable thermostatic loads that enables ancillary support in the power grid. The proposed scheme is deterministic, enabling a fast response at urgencies and simultaneously guarantees the prevention of synchronization phenomena. This is the first study that shows the lack of synchronization in the power grid using a deterministic approach. The methodology to do so is novel, combining tools from hybrid systems analysis and Lyapunov theory.

(ii) We proposed a scalable hierarchical control scheme for on-off loads which enables a near optimal power allocation and simultaneously ensures that the secondary frequency regulation objectives are satisfied.
This study extends the state of the art by providing analytic equilibrium conditions that enable a close to optimal power allocation and designing a scalable control schemes that ensures that those are satisfied.

(iii) We developed the first distributed control scheme for generation and controllable demand that simultaneously achieves the following important targets: (i) enables an optimal power allocation, (ii) ensures the privacy of prosumption and (iii) satisfies the secondary frequency regulation objectives.

(iv) We developed a pricing scheme that minimizes the peak to average demand in power systems using intraday blocks. The proposed scheme extends the state of the art by proposing a novel pricing approach and demonstrating its robustness against uncertainty.

(v) We provided decentralized analytic conditions that enable stability guarantees in power networks under varying inertia. In addition, we analytically show that single bus inertia variations may destabilize the power network.

The potential impact of optimized demand management in power grids is high and important for the society. Controllable loads may enable a larger penetration of renewable generation and support the effort to reduce our reliance on carbon fuels. The design of suitable schemes that enable an optimal power allocation allows to save power and reduce the energy related economic costs. The provision of power network stability guarantees under these schemes allows their widespread adoption without compromising the operation of the power grid. Additionally, the fact that the suggested designs are distributed, enables their plug and play operation, without requiring excessive or centralized communication requirements, which might result in high implementation costs. This project is a step forward towards the transition to a smart and green energy sector.

smarther-grid-logo.png