One rate does not fit all: An empirical analysis of electricity tariffs for residential microgrids

Increasingly, residential customers are deploying PV units to lower electricity bills and contribute to a more sustainable use of resources. This selective decentralization of power generation, however, creates significant challenges, because current transmission and distribution grids were designed for centralized power generation and unidirectional flows. Restructuring residential neighborhoods as residential microgrids might solve these problems to an extent, but energy retailers and system operators have yet to identify ways of fitting residential microgrids into the energy value chain. One promising way of doing so is the tailoring of residential microgrid tariffs, as this encourages grid-stabilizing behavior and fairly re-distributes the associated costs. We thus identify a set of twelve tariff candidates and estimate their probable effects on energy bills as well as load and generation profiles. Specifically, we model 100 residential microgrids and simulate how these microgrids might respond to each of the twelve tariffs. Our analyses reveal three important insights. Number one: volumetric tariffs would not only inflate electricity bills but also encourage sharp load and generation peaks, while failing to reliably allocate system costs. Number two: under tariffs with capacity charges, time-varying rates would have little impact on both electricity bills and load and generation peaks. Number three: tariffs that bill system and energy retailer costs via capacity and customer charges respectively would lower electricity bills, foster peak shaving, and facilitate stable cost allocation

Solar+ microgrid costs at gas station and convenience stores in the state of California

This project estimates the capital costs for Solar+ microgrids for the year 2018 and forecasted out to 2030. Solar+ systems include the use of battery energy storage, solar energy, electric vehicle chargers and control systems to manage energy consumption and generation for a single building and provide islanded “microgrid” features. The capital cost includes estimates for the components: DER technologies (battery, solar PV and EV charging stations), controls (programming and hardware), and integration costs (switchgear, engineering, permitting and site work). Methods used to estimate each cost included assessing historical and projected costs for each of the components. Five Solar+ scenarios are evaluated to forecast the estimated total project cost, the separate component costs, and the variability of these estimates. The scenarios considered constructing Solar+ systems to fit gas station and convenience stores with varied sizes (small, medium, and large) and goals (resilient scenarios). The average capital cost projections for each scenario show that costs are expected to decrease by 50-60% by 2030, with today’s unit cost at $4.8/W for a medium Solar+ microgrid. Changes in cost for each scenario show dependence on the system specification, including size of the battery system and solar PV. EV charging infrastructure has the greatest impact on the total cost and is reported as the largest cost contributor for all scenarios in the future. Additional results from this project suggest that medium to large Solar+ systems have the lowest unit cost currently (in 2018), but smaller Solar+ systems will have comparable costs by 2030 at roughly$2.0/W

MOVEABLE, DEPLOYABLE MICROGRID ANALYSIS

This report focuses on the assessment of the feasibility of Moveable, Deployable Microgrids (MODEMs) from an interoperability and sustainment perspective as an alternative solution to traditional backup power methods aimed at bringing critical loads back online after installation microgrid failures or operational energy needs. Prior research into microgrid solutions by MAJ Daniel Varley in his paper “Feasibility Analysis of a Mobile Microgrid Design to Support Department of Defense (DOD) Energy Resilience Goals” identified MODEM as a potential solution. This report utilized the work done by MAJ Varley and further assesses system feasibility. Base and operational energy managers will benefit from MODEMs by having access to multi-energy source systems that are both easily moveable and relatively simplistic in design. As concerns surrounding energy resiliency of defense critical infrastructure by both the DOD and Department of Energy (DOE) mount, as expressed in a March 2022 report by the Electricity Advisory Committee (EAC) titled “Strengthening the Resilience of Defense Critical Infrastructure”, there is a push to identify cost-effective solutions that utilize alternative energy sources in order to improve the overall resiliency of this infrastructure. The MODEM system has the potential to be a viable solution to the resiliency problem.Outstanding ThesisCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyApproved for public release. Distribution is unlimited