## 2 Related Works
Recently, a new concept called virtual net metering (VNM) emerged as an alternative to NEM. VNM is a billing arrangement that allows multiple electricity consumers to share the benefits of a renewable energy system, such as solar panels, even if they are not physically connected to the same generation source. In a VNM setup, the electricity generated via a renewable energy system installed at one location can be credited against the electricity consumption of one or more separate accounts elsewhere [23]. VNM allows for greater flexibility and access to the benefits of renewable energy, particularly in scenarios where physical connections between the generation source and the consumers are not feasible or practical. On the other hand, net billing schemes offer several benefits to the grid. The primary purpose behind most DER incentive mechanisms is to encourage end-users to maximize their self-consumption thus reducing their demand from the grid. Additionally, since energy is generated where it is needed, the grid's technical losses are reciprocally lowered, and in most cases, they contribute to a lower levelized cost of energy [24]. However, under schemes like NEM and FiT, energy retailers are at risk of induced \"death spiral\" phenomenon [25]. This happens when overcompensation for distributed renewable generation leads to oversupply, distorted price signals, and grid-integration challenges, resulting in revenue losses for retailers. The \"electricity death spiral\" is a term used to describe a potential scenario in which the traditional utility business model becomes economically unsustainable due to disruptive changes in the energy landscape, particularly the increasing adoption of DERs and renewable energy technologies. The concept of the electricity death spiral typically involves declining revenues, rising costs, and customer defection. As more customers install rooftop solar panels, battery storage systems, energy-efficient appliances, and other DERs, they may reduce their reliance on grid-supplied electricity. This can lead to decreased electricity sales for traditional utilities, resulting in declining revenue. Moreover, utilities usually incur fixed costs on end-user bills associated with maintaining the grid infrastructure, such as transmission lines, substations, and distribution networks. As electricity sales decline, these fixed costs per unit of electricity sold increase, putting upward pressure on electricity rates for remaining customers. Thus, to compensate for lost revenue and cover fixed costs, utilities may raise electricity rates for customers who remain connected to the grid. However, higher rates can further incentivize customers to invest in DERs or pursue energy efficiency measures, exacerbating the decline in electricity sales and perpetuating the cycle. Additionally, faced with higher electricity rates and the availability of cost-effective alternatives like rooftop solar and battery storage, more customers may choose to disconnect from the grid entirely or significantly reduce their reliance on utility-provided electricity. This further accelerates the decline in utility revenues and increases the financial strain on the remaining customers. The electricity death spiral poses significant challenges for utilities and regulators tasked with ensuring the electricity system's reliability, affordability, and sustainability. Regulators may need to reassess utility business models, rate structures, and regulatory frameworks to address the evolving energy landscape and mitigate the risks associated with declining grid revenues. However, it is important to note that the electricity death spiral is not an inevitable outcome but rather a potential scenario driven by market dynamics, technological advancements, policy decisions, and consumer behavior.