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Dynamic Net Metering for Energy Communities

Ahmed S. Alahmed, Lang Tong

TL;DR

Dynamic NEM (D-NEM) tackles the challenge of pricing electricity within self-organized energy communities by ex-ante, threshold-based pricing that depends on the community's aggregate renewable generation $g_{\mathcal N}$. Framed as a Stackelberg bi-level problem, D-NEM couples decentralized member consumption decisions with a centralized pricing rule that maximizes social welfare while satisfying the cost-causation principle and group rationality. The mechanism is extended to include a central BESS with multi-interval co-optimization (generalized D-NEM), proving efficiency, individual rationality, and stability under storage-enabled operation. Numerical results with real data demonstrate welfare gains over DSO NEM and benchmark community pricing, particularly when BESS is employed, and highlight robust performance under varying NEM rate structures. The work provides a tractable, ex-ante, welfare-maximizing framework for transactive energy in communities, preserving privacy and scalability while offering strong theoretical guarantees and practical insights for deployment.

Abstract

We propose a social welfare maximizing market mechanism for an energy community that aggregates individual and community-shared energy resources under a general net energy metering (NEM) policy. Referred to as Dynamic NEM (D-NEM), the proposed mechanism dynamically sets the community NEM prices based on aggregated community resources, including flexible consumption, storage, and renewable generation. D-NEM guarantees a higher benefit to each community member than possible outside the community, and no sub-communities would be better off departing from its parent community. D-NEM aligns each member's incentive with that of the community such that each member maximizing individual surplus under D-NEM results in maximum community social welfare. Empirical studies compare the proposed mechanism with existing benchmarks, demonstrating its welfare benefits, operational characteristics, and responsiveness to NEM rates.

Dynamic Net Metering for Energy Communities

TL;DR

Dynamic NEM (D-NEM) tackles the challenge of pricing electricity within self-organized energy communities by ex-ante, threshold-based pricing that depends on the community's aggregate renewable generation . Framed as a Stackelberg bi-level problem, D-NEM couples decentralized member consumption decisions with a centralized pricing rule that maximizes social welfare while satisfying the cost-causation principle and group rationality. The mechanism is extended to include a central BESS with multi-interval co-optimization (generalized D-NEM), proving efficiency, individual rationality, and stability under storage-enabled operation. Numerical results with real data demonstrate welfare gains over DSO NEM and benchmark community pricing, particularly when BESS is employed, and highlight robust performance under varying NEM rate structures. The work provides a tractable, ex-ante, welfare-maximizing framework for transactive energy in communities, preserving privacy and scalability while offering strong theoretical guarantees and practical insights for deployment.

Abstract

We propose a social welfare maximizing market mechanism for an energy community that aggregates individual and community-shared energy resources under a general net energy metering (NEM) policy. Referred to as Dynamic NEM (D-NEM), the proposed mechanism dynamically sets the community NEM prices based on aggregated community resources, including flexible consumption, storage, and renewable generation. D-NEM guarantees a higher benefit to each community member than possible outside the community, and no sub-communities would be better off departing from its parent community. D-NEM aligns each member's incentive with that of the community such that each member maximizing individual surplus under D-NEM results in maximum community social welfare. Empirical studies compare the proposed mechanism with existing benchmarks, demonstrating its welfare benefits, operational characteristics, and responsiveness to NEM rates.
Paper Structure (37 sections, 5 theorems, 78 equations, 7 figures, 2 tables)

This paper contains 37 sections, 5 theorems, 78 equations, 7 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Related Work
  3. Summary of Results and Contributions
  4. Notations and Nomenclature
  5. Energy Community Model
  6. Member Resources
  7. Community Pricing and Member Surplus
  8. Standalone Prosumer Under DSO Pricing
  9. Axiomatic Community Pricing
  10. Decentralized Welfare Maximization
  11. Members' Optimal Consumption Policy $\psi_\chi^\sharp$
  12. Operator's Optimal Pricing Policy $\chi_\psi^\sharp$
  13. Stackelberg Equilibrium
  14. Stackelberg Equilibrium Policy and Properties
  15. Dynamic NEM: Optimal Community Pricing
  16. ...and 22 more sections

Key Result

Proposition 1

When $g_{\cal N} \in [f_{\cal N}(\pi^+),f_{\cal N}(\pi^-)]$, $\pi^\ast(g_{\cal N}) =\pi^z(g_{\cal N}) \in [\pi^-, \pi^+]$ and the price $\pi^z(g_{\cal N})$ monotonically decreases with increasing $g_{\cal N}$.

Figures (7)

  • Figure 1: Energy community framework. The decentralized DERs include flexible consumption, renewables DG, and net consumption denoted by $d_i, g_i \in \mathbb{R}_+, z_i \in \mathbb{R}$, respectively. The centralized resources include solar PV $\tilde{g} \in \mathbb{R}_+$ and a BESS $b_{{\cal N}} \in \mathbb{R}$.
  • Figure 2: Depiction of community prices and optimal operation under D-NEM.
  • Figure 3: Community price under D-NEM (blue) and generalized D-NEM with BESS (green).
  • Figure 4: Community monthly welfare gain with and without storage.
  • Figure 5: Community price with and without storage (dark blue is $\pi^+$, white is $\pi^-$ and light blue is $\pi^z(g_\mathcal{N}) \in (\pi^-,\pi^+)$).
  • ...and 2 more figures

Theorems & Definitions (6)

  • Definition 1: Cost-causation principle
  • Proposition 1: Net-zero zone price $\pi^z(g_{\cal N})$
  • Theorem 1: Equilibrium of the bi-level optimization and welfare optimality
  • Theorem 2: Group rationality under D-NEM
  • Lemma 1: Cost-causation conformity of D-NEM
  • Lemma 2: Centralized community welfare maximization