Closing the California Clean Energy Divide: Reducing Electric Bills in Affordable Multifamily Rental Housing with Solar+storage

This economic analysis indicates that pairing solar PV with battery storage systems can deliver significant electricity bill savings for California affordable housing residents and property owners.Battery storage is emerging as an effective new strategy for reducing electricity costs for affordable multifamily rental housing in California. Battery storage systems not only provide economic returns today, they can also preserve the value of solar in an evolving policy and regulatory environment. Because batteries empower owners of solar photovoltaic (PV) systems to take control of the energy they produce and when they consume it, storage can deliver deeper cost reductions that can be shared among affordable housing owners, developers, and tenants.California has installed numerous integrated solar and battery storage projects; however, few have served lowincome tenants or owners of affordable rental housing. This disparity is due to many factors, including a lack of information about the economics of these systems in multifamily housing. To provide that needed information, Clean Energy Group, California Housing Partnership, and Center for Sustainable Energy, with analytical support from Geli, are embarking on a series of reports on solar and storage in California affordable multifamily rental housing.This first report examines the utility bill impacts of adding battery storage to stand-alone solar in affordable rental housing facilities in California's three investor-owned utility service territories, each with different rate structures. It is the first such report ever completed on these technologies in this sector in California.The report reaches several key conclusions:Under current utility rate tariffs, the combination of solar and storage technologies could virtually eliminate electric bills for many owners of affordable housing properties. Unlike stand-alone solar, which reduces energy consumption expenses but does little to offset demand related charges, a properly sized solar and battery storage system can eliminate nearly all electricity expenses, resulting in an annual electric utility bill of less than a few hundred dollars in some cases.It makes good economic sense today for solar and battery storage to be installed in affordable multifamily rental housing in California. The addition of battery storage to solar improves the economics of each property analyzed across all utility territories, reducing project payback by over three years in some cases.The addition of storage technologies has the potential to nearly double stand-alone solar electricity bill savings at about a third of the cost of solar. For example, the addition of a $112,100 battery storage system to a$385,000 solar installation increased savings from $15,000 per year to$27,900, an 85 percent increase in savings for only a 29 percent increase in cost

Technical and economic feasibility of a microgrid for a fire station in Humboldt County, California.

Microgrids are emerging as a promising solution to unreliable grid energy. Today, California is not only witnessing grid resiliency challenges from natural disasters such as wildfires, earthquakes, floods and heatwaves, but it is also seeking to green the grid and bring more renewables online. For example, Humboldt County, where this project is focused, has recently experienced an earthquake of 6.4M (on December 22nd, 2022), which shut down the regional grid for ~20 hours. Microgrid adoption enables critical facilities to operate seamlessly. The Humboldt Bay Fire Station (HBFS) No.1 is one such example, where first responders work to protect citizens against emergencies, be it emergency medical services (EMS) operations or fire rescue or even helping in restoration of power lines. This study involves a techno-economic analysis of a microgrid design that could support efficient and seamless operations for the fire station as it serves the people of Humboldt County during emergencies. A clean energy microgrid for the station aligns with the Humboldt County GHG emission target to reach net zero by 2030, and could provide resilient power to their general and critical loads during regular operations and emergencies. The recommended microgrid for the HBFS No. 1 facility includes a 70-kW photovoltaic (PV) array and a 90 kW/360 kWh battery energy storage system (BESS). The project cost ranges from $300k to$600k (depending upon the level of investment tax credits (ITC) the microgrid project would get). It provides 51-day resiliency in the best case and 28-hour resiliency in the worst case depending upon the weather condition. The system would also reduce greenhouse gas emissions from electricity use at the station by over 98% annually. Considering the potential availability of incentives and the value of resiliency (VoR), the microgrid project for HBFS No.1 demonstrates promising economic feasibility results. The next steps involve further evaluation of the project\u27s financial viability, engaging with relevant stakeholders to secure funding, and proceeding with the detailed design and implementation phases of the microgrid

Integrating climate, health, resilience, and bill savings into the cost-optimal deployment of solar plus storage on public buildings

Climate change, public health, and resilience to power outages are of critical concern to local governments and are increasingly motivating investments in on-site solar and storage. However, designing a solar plus storage system to co-optimize for climate, health, resilience, and energy bill benefits requires complex trade-offs that are not captured in current analyses. To fill this gap, we integrate climate and health benefits into the REopt Lite optimization model using forward-looking, location-specific marginal emissions factors and health costs. Using this novel framework, we quantify the impact of including energy bill, climate, health, and/or resilience benefits on the cost-optimal sizing, battery dispatch, and economic returns of solar plus storage on three public building types across fourteen U.S. cities. We find that monetizing and optimizing for climate and health benefits, as compared to only energy bill savings and resilience, increases the net present value of the modeled solar plus storage systems by $0.2 million to$5 million. Due to changes in the cost-optimal battery dispatch, our expanded optimization results in additional climate and health benefits of $0.50 per dollar invested, as compared to optimizing for only energy bill savings and resilience. Our results illustrate significant differences across geographies and building types, highlighting the need for sitespecific analyses of the costs and benefits of solar plus storage.Master of ScienceSchool for Environment and SustainabilityUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/167262/3/Farthing_Amanda_MastersThesis.pd

Solar-plus-storage benefits for end-users placed at radial and meshed grids: An economic and resiliency analysis

[EN] A resilient photovoltaic system, which comprises from the joint use of photovoltaic solar panels and electrochemical storage that is able to operate both with and without grid connection, is capable of providing an added service both during normal grid-connected operation and when a blackout occurs (as opposed to a traditional solar system). When the conventional power grid is in normal operation, resilient photovoltaic systems are able to generate revenue and/or reduce the electricity bill. During blackouts, resilient photovoltaic systems are capable of providing critical emergency power to help backup diesel generator systems. The research presented here evaluates the technical and economic feasibility of systems based on photovoltaic solar energy and electrochemical storage in three critical infrastructures which have to account with a typical backup diesel generator. To this end, the research presented here assigns a monetary value to the cost of avoiding a blackout. Thus, the REopt Lite software has been used to optimally select and dimension different resilient schemes. For each of the cases evaluated the resilient systems were able to obtain benefits associated with the substitution of the energy use of the electricity grid, the reduction of charges for the use of energy during peak energy periods, and the modification of energy purchase periods from periods of high cost to periods of low cost. For all cases the model found the optimal combination of technologies capable of minimizing the cost of energy throughout the life cycle of the project. The obtained results show that assigning a value to the cost of blackouts can have a major impact on the economic viability of a resilient solution. For all cases the net present value of a system was always higher when a value was assigned to resilience. The values assigned to resilience were higher for users plugged to radial networks, which are more prone to blackouts, and lower for users connected to meshed grids, usually more reliable. Despite the fact that for the investigation presented here only three types of infrastructures were assessed, similar results could be expected for other critical infrastructures with similar loads and electricity tariffs. Resilient systems using photovoltaic solar installations that are limited in size could provide both economic savings during normal grid-connected operation and limited emergency power during blackouts. When these systems based on photovoltaic solar energy and electrochemical storage are used in conjunction with an emergency diesel generator, these resilient “hybrid” systems are capable of satisfying critical loads during short- and long-term blackouts.[ES] Un sistema fotovoltaico resiliente, que comprende el uso conjunto de paneles solares fotovoltaicos y un almacenamiento electroquímico que sea capaz de funcionar tanto con conexión a red como sin ella, es capaz de dar un servicio añadido tanto durante el funcionamiento normal conectado a red como cuando se produce un apagón ( a diferencia de un sistema solar tradicional). Cuando la red eléctrica convencional está en funcionamiento normal, los sistemas fotovoltaicos resilientes pueden generar ingresos y/o reducir la factura eléctrica. Durante los apagones, los sistemas fotovoltaicos resistentes son capaces de proporcionar energía de emergencia crítica para ayudar a respaldar los sistemas de generadores diésel. La investigación aquí presentada evalúa la viabilidad técnica y económica de sistemas basados en energía solar fotovoltaica y almacenamiento electroquímico en tres infraestructuras críticas que deben contar con un típico generador diésel de respaldo. Para ello, la investigación aquí presentada asigna un valor monetario al costo de evitar un apagón. Por lo tanto, el software REopt Lite se ha utilizado para seleccionar y dimensionar de manera óptima diferentes esquemas resilientes. Para cada uno de los casos evaluados los sistemas resilientes lograron obtener beneficios asociados a la sustitución del uso energético de la red eléctrica, la reducción de cargos por el uso de energía durante los períodos pico de energía y la modificación de los períodos de compra de energía de los períodos de alto costo a periodos de bajo costo. Para todos los casos el modelo encontró la combinación óptima de tecnologías capaces de minimizar el coste de la energía durante todo el ciclo de vida del proyecto. Los resultados obtenidos muestran que asignar un valor al costo de los apagones puede tener un impacto importante en la viabilidad económica de una solución resiliente. En todos los casos, el valor actual neto de un sistema siempre fue mayor cuando se asignó un valor a la resiliencia. Los valores asignados a la resiliencia fueron mayores para los usuarios conectados a redes radiales, que son más propensos a sufrir apagones, y menores para los usuarios conectados a redes malladas, generalmente más confiables. A pesar de que para la investigación aquí presentada sólo se evaluaron tres tipos de infraestructuras, se podrían esperar resultados similares para otras infraestructuras críticas con cargas y tarifas eléctricas similares. Los sistemas resilientes que utilizan instalaciones solares fotovoltaicas de tamaño limitado podrían proporcionar ahorros económicos durante el funcionamiento normal conectado a la red y energía de emergencia limitada durante los apagones. Cuando estos sistemas basados en energía solar fotovoltaica y almacenamiento electroquímico se utilizan junto con un generador diésel de emergencia, estos resistentes sistemas “híbridos” son capaces de satisfacer cargas críticas durante apagones de corto y largo plazo.S

Design of a Resilient and Eco-friendly Microgrid for a Commercial Building

Recent natural disasters such as hurricanes Harvey and Maria have caused great disruption to the electric grid system. Additionally, government authorities have set ambitious goals to reduce greenhouse gas emissions. Thus, there is a growing interest in making the electric power systems more resilient while reducing their carbon footprint. In this work, a methodology to design a resilient and eco-friendly microgrid is presented. First, the input parameters of the model are defined; second, simulation of different microgrid configurations are performed in HOMER Grid software; third, the outputs of the model are analyzed; and finally, a microgrid configuration is selected based on economic, environmental, and resilience criteria. The considered microgrids consist of PV, battery, natural gas generator, and the electric load of an office building that consumes an average of 2 MWh per day. Different component sizes were used to determine the configuration with the lowest generator size to provide power during a two-day outage in the summer peak load. Environmental and economic analysis were performed to show the tradeoffs between different system design goals. The results indicate that installing a microgrid in an office building with a 600 kW PV array and 2.8 MWh lithium-ion battery can avoid the release of up to 287 tons of CO2 per year. The same microgrid configuration can endure a two-day blackout during the highest electric demand in the hurricane season without the need of a polluting backup generator. From this study, it was concluded that the optimal microgrid configuration depends on specific needs. Additionally, based on current technology costs, large PV systems with small batteries are economically more attractive than the base case configuration.Los desastres naturales recientes, como los huracanes Harvey y María, han causado una gran interrupción en la red eléctrica. Por otra parte, las autoridades gubernamentales se han fijado metas ambiciosas para reducir las emisiones de gases de efecto invernadero. Por lo tanto, existe un interés creciente en hacer que los sistemas de energía eléctrica sean más resilientes y con un impacto mínimo al medio ambiente. En este trabajo, se utilizó el software HOMER Grid para modelar microrredes que se contienen sistemas fotovoltaicos, baterías de ión-litio, generadores de gas natural y la carga eléctrica de un edificio de oficinas que consume un promedio de 2 MWh por día. Se modificaron los tamaños de los componentes para determinar la configuración con el generador más pequeño que pudiera suministrar energía durante un corte de energía de dos días en verano. Se realizaron análisis ambientales y económicos para mostrar las diferencias entre los diferentes objetivos de diseño del sistema. Los resultados indican que la instalación de una microrred en un edificio de oficinas con un arreglo fotovoltaico de 600 kW y una batería de ión-litio de 2.8 MWh puede evitar la emisión de hasta 287 toneladas de CO2 por año. La misma configuración de microrred puede soportar un apagón de dos días durante la mayor demanda eléctrica en la temporada de huracanes sin la necesidad de un generador de respaldo. Las microrredes jugarán un papel importante en la transición a una red inteligente porque proporcionan energía confiable, hacen que el sistema sea más tolerante a fallas de la red y permiten una alta penetración de energía renovable en la red eléctrica, lo que en consecuencia reduce el impacto ambiental

A screening tool for the implementation of electric and thermal energy storage systems at commercial and industrial facilities

The integration of on-site renewable systems with energy storage devices is an important topic in improving energy management for commercial buildings and industrial facilities. Energy storage technologies have the ability to impact the end user’s power reliability while creating measurable energy and cost savings. However, the potential yet remains to increase the application of these systems. To determine the feasibility of renewables and energy storage in commercial and industrial applications, a pre-screening software tool is developed using data-driven algorithms to complete an energy, cost, and carbon savings analysis of storage implementation. A case study of a standalone retail building is also modeled using a comprehensive building energy modeling software program, EnergyPlus, to simulate the energy and cost savings of a solar PV with battery energy storage systems. The work in this project collectively analyzes the future impacts of renewables integrated with energy storage for small-and-medium industrial facilities and commercial buildings

Microgrid Energy Management

In IEEE Standards, a Microgrid is defined as a group of interconnected loads and distributed energy resources with clearly defined electrical boundaries, which acts as a single controllable entity with respect to the grid and can connect and disconnect from the grid to enable it to operate in both grid-connected or island modes. This Special Issue focuses on innovative strategies for the management of the Microgrids and, in response to the call for papers, six high-quality papers were accepted for publication. Consistent with the instructions in the call for papers and with the feedback received from the reviewers, four papers dealt with different types of supervisory energy management systems of Microgrids (i.e., adaptive neuro-fuzzy wavelet-based controls, cost-efficient power-sharing techniques, and two-level hierarchical energy management systems); the proposed energy management systems are of quite general purpose and aim to reduce energy usages and monetary costs. In the last two papers, the authors concentrate their research efforts on the management of specific cases, i.e., Microgrids with electric vehicle charging stations and for all-electric ships

Stand-Alone Direct Current Power Network Based on Photovoltaics and Lithium-Ion Batteries for Reverse Osmosis Desalination Plant

Plummeting reserves and increasing demand of freshwater resources have culminated into a global water crisis. Desalination is a potential solution to mitigate the freshwater shortage. However, the process of desalination is expensive and energy-intensive. Due to the water-energy-climate nexus, there is an urgent need to provide sustainable low-cost electrical power for desalination that has the lowest impact on climate and related ecosystem challenges. For a large-scale reverse osmosis desalination plant, we have proposed the design and analysis of a photovoltaics and battery-based stand-alone direct current power network. The design methodology focusses on appropriate sizing, optimum tilt and temperature compensation techniques based on 10 years of irradiation data for the Carlsbad Desalination Plant in California, USA. A decision-tree approach is employed for ensuring hourly load-generation balance. The power flow analysis evaluates self-sufficient generation even during cloud cover contingencies. The primary goal of the proposed system is to maximize the utilization of generated photovoltaic power and battery energy storage with minimal conversions and transmission losses. The direct current based topology includes high-voltage transmission, on-the-spot local inversion, situational awareness and cyber security features. Lastly, economic feasibility of the proposed system is carried out for a plant lifetime of 30 years. The variable effect of utility-scale battery storage costs for 16–18 h of operation is studied. Our results show that the proposed design will provide low electricity costs ranging from 3.79 to 6.43 ¢/kWh depending on the debt rate. Without employing the concept of baseload electric power, photovoltaics and battery-based direct current power networks for large-scale desalination plants can achieve tremendous energy savings and cost reduction with negligible carbon footprint, thereby providing affordable water for all

Dynamic Modeling and Optimal Design for Net Zero Energy Houses Including Hybrid Electric and Thermal Energy Storage

Net zero energy (NZE) houses purchase zero net metered electricity from the grid over a year. Technical challenges brought forth by NZE homes are related to the intermittent nature of solar generation, and are due to the fact that peak solar generation and load are not coincident. This leads to a large rate of change of load, and in case of high PV penetration communities, often requires the installation of gas power plants to service this variability. This article proposes a hybrid energy storage system including batteries and a variable power electric water heater which enables the NZE homes to behave like dispatchable generators or loads, thereby reducing the rate of change of the net power flow from the house. A co-simulation framework, INSPIRE+D, which enables the dynamic simulation of electricity usage in a community of NZE homes, and their connection to the grid is enabled. The calculated instantaneous electricity usage is validated through experimental data from a field demonstrator in southern Kentucky. It is demonstrated that when the operation of the proposed hybrid energy storage system is coordinated with solar PV generation, the required size and ratings of the battery would be substantially reduced while still maintaining the same functionality. Methodologies for sizing the battery and solar panels are developed