Demand Flexibility Management for Buildings-to-Grid Integration with Uncertain Generation

Round 1

Reviewer 1 Report

In this paper, authors have presented two new developments for the BtG integration framework. Authors extended the existing models to integrate the wind farm generation by explicitly formulating the interactions between TSO, DSOs, and buildings and in next phase they have developed a unified BtG framework to handle uncertain generation. In this article authors provided explicit expressions to determine the available amount of buildings demand-side flexibility from HVAC and electrical storage units. Using the unified BtG model, they have formulated a finite-horizon stochastic control problem and provided a tractable robust reformulation with probabilistic feasibility certificates. Output of this research is that the demand-side flexibility can substitute the traditional reserve scheduling services in power systems in the presence of wind power generation. This will be possible by application of the presented method without losing stability properties of the power grid and violating the buildings thermal comfort of occupants.

Author Response

We thank the reviewer so much for his/her positive assessments.

Reviewer 2 Report

The paper presents a model for capturing and acting on transmission and distribution system interactions with load flexibility, specifically, building end use. This is a timely subject given the increasing need for system operation at the distribution level and given the increased complexity in dynamics between transmission and distribution. Generally the paper is well written and has incorporated a number of well chosen prior works to set the contribution in context. I have minor concerns about the accessibility of section 4, which I feel may be too abstract for some readers and therefore could benefit from supporting narrative to ensure they don’t lose the paper. To expand:

Section 4 presents the reader with a bit of a challenge unless they are well versed in optimisation:

Equation 19a-i – the narrative needs expanded here to support the reader. There is quite a lot to take in. State what each of these mean in the application context and the reader will be in a better position to understand (and ideally, adopt) your contribution.

Likewise, with equations 20 & 21 explain W (bounded) and W (unbounded). A ‘set with minimum volume’ – need to cast this in power systems terms otherwise it could lose the core audience of the journal.

Notation at the start of the manuscript might be helpful?

Relatively minor points:

• Figure 5 – plot DSO and TSO on the same y-axis scales; also stack these plots vertically. This will permit a better comparison. The DSO frequency excursions look much worse otherwise.
• In equation 1 – what is ‘b’ – can you expand on this? Line susceptance is mentioned in passing.
• Two lines below line 139 – elaborate on the special case and how/why it arises
• ‘probabilistic feasibility certificates’ – mentioned 3 times but never explicitly defined despite its potential importance; highlight this concept and its meaning to DSO/TSO in section 5
• Fig4 –stacked bars are a bit confusing in terms of colour contrasts. What are the two black lines? Wind forecast is the lower one but what is the upper one?
• Line 197 – prediction horizon – don’t understand how Nh is 12
• Missing interaction – no generation on distribution? Surely this is a key DSO feature? I’m not necessarily asking for this here as it could be quite a bit of work (or already covered by discharge of storage) but could note in the conclusion how this might be expanded upon.
• What are the load profiles at distribution? It would be good to display these.
• Expand on IEEE 5 bus network – what are voltage levels, line lengths, underground or overhead cabling? This is a useful bit of context – could have a line diagram to demonstrate.

Author Response

We thank the reviewer very much for his positive and constructive feedback. We have carefully addressed all the comments. Please find the detailed responses for each comment attached.

Author Response File: Author Response.pdf

Reviewer 3 Report

  Editing corrections:   - Figure 8 should not end the document. The document should end with a text.
- Figures 1,2,5,7 are illegible. You need to enlarge and increase readability. - In the content of the document, first there must be a reference to the figure and only then the figure can be inserted (Figure 4,6)

Other comments: - What the author means by "current net" (line 243). Necessary to add description.
- The paradigm of the TSO's operation is already changing. Flexibility-based services are available in many countries (Poland, UK). It is worthwhile for the authors to refer to specific actions of TSO in this regard and present the characteristics of these mechanisms for selected cases.
- Have the authors investigated how and where that 40% of energy consumption occurs in buildings? (line 27)
- In addition to the Monte-Carlo simulation, have the authors performed analyzes on real network data? (line 198) Are the conclusions for such data the same as for the simulation?

Author Response

We thank the reviewer very much for his positive and constructive feedback. We have carefully addressed all the comments. Please find the detailed responses for each comment attached.

Author Response File: Author Response.pdf