Adoption Pathways for DC Power Distribution in Buildings

Driven by the proliferation of DC energy sources and DC end-use devices (e.g., photovoltaics, battery storage, solid-state lighting, and consumer electronics), DC power distribution in buildings has recently emerged as a path to improved efficiency, resilience, and cost savings in the transitioning building sector. Despite these important benefits, there are several technological and market barriers impeding the development of DC distribution, which have kept this technology at the demonstration phase. This paper identifies specific end-use cases for which DC distribution in buildings is viable today. We evaluate their technology and market readiness, as well as their efficiency, cost, and resiliency benefits while addressing implementation barriers. The paper starts with a technology review, followed by a comprehensive market assessment, in which we analyze DC distribution field deployments and their end-use characteristics. We also conduct a survey of DC power and building professionals through on-site visits and phone interviews and summarize lessons learned and recommendations. In addition, the paper includes a novel efficiency analysis, in which we quantify energy savings from DC distribution for different end-use categories. Based on our findings, we present specific adoption pathways for DC in buildings that can be implemented today, and for each pathway we identify challenges and offer recommendations for the research and building community.

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Analyses of efficiency/energy-savings of DC power distribution systems/microgrids: Past, present and future

International Journal of Electrical Power & Energy Systems ◽

10.1016/j.ijepes.2018.06.057 ◽

2019 ◽

Vol 104 ◽

pp. 89-100 ◽

Cited By ~ 12

Author(s):

Faizan Dastgeer ◽

Hassan Erteza Gelani ◽

Hafiz Muhammad Anees ◽

Zahir Javed Paracha ◽

Akhtar Kalam

Keyword(s):

Power Distribution ◽

Distribution Systems ◽

Energy Savings ◽

Power Distribution Systems ◽

Dc Power

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Robust Stability Control for Electric Vehicles Connected to DC Distribution Systems

Frontiers in Energy Research ◽

10.3389/fenrg.2021.740698 ◽

2021 ◽

Vol 9 ◽

Author(s):

Wei Teng ◽

Yuejiao Wang ◽

Shumin Sun ◽

Yan Cheng ◽

Peng Yu ◽

...

Keyword(s):

Electric Vehicles ◽

Power Distribution ◽

Distribution System ◽

Distribution Systems ◽

Voltage Stability ◽

Stability Control ◽

Power Distribution Systems ◽

Power Distribution System ◽

Dc Power ◽

Dc Distribution

DC power distribution systems will play an important role in the future urban power distribution system, while the charging and discharging requirements of electric vehicles have a great impact on the voltage stability of the DC power distribution systems. A robust control method based on H∞ loop shaping method is proposed to suppress the effect of uncertain integration on voltage stability of DC distribution system. The results of frequency domain analysis and time domain simulation show that the proposed robust controller can effectively suppress the DC bus voltage oscillation caused by the uncertain integration of electric vehicle, and the robustness is strong.

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AC vs. DC Distribution Efficiency: Are We on the Right Path?

Energies ◽

10.3390/en14134039 ◽

2021 ◽

Vol 14 (13) ◽

pp. 4039

Author(s):

Hasan Erteza Gelani ◽

Faizan Dastgeer ◽

Mashood Nasir ◽

Sidra Khan ◽

Josep M. Guerrero

Keyword(s):

Power Distribution ◽

Distribution System ◽

System Modeling ◽

Comparative Efficiency ◽

System A ◽

Dc Power ◽

Dc Distribution ◽

Ac Networks ◽

The Right ◽

Made In

The concept of DC power distribution has gained interest within the research community in the past years, especially due to the rapid prevalence of solar PVs as a tool for distributed generation in DC microgrids. Various efficiency analyses have been presented for the DC distribution paradigm, in comparison to the AC counterpart, considering a variety of scenarios. However, even after a number of such comparative efficiency studies, there seems to be a disparity in the results of research efforts, wherein a definite verdict is still unavailable. Is DC distribution a more efficient choice as compared to the conventional AC system? A final verdict is absent primarily due to conflicting results. In this regard, system modeling and the assumptions made in different studies play a significant role in affecting the results of the study. The current paper is an attempt to critically observe the modeling and assumptions used in the efficiency studies related to the DC distribution system. Several research efforts are analyzed for their approach toward the system upon which they have performed efficiency studies. Subsequently, the paper proposes a model that may alleviate the shortcomings in earlier research efforts and be able to give a definite verdict regarding the comparative efficiency of DC and AC networks for residential power distribution.

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AC vs DC Distribution Efficiency: Are we on the Right Path?

10.20944/preprints202105.0578.v1 ◽

2021 ◽

Author(s):

HASAN ERTEZA GELANI ◽

FAIZAN DASTGEER ◽

Mashood Nasir ◽

sidra khan ◽

Josep M. Guerrero

Keyword(s):

Power Distribution ◽

Distribution System ◽

System Modeling ◽

Comparative Efficiency ◽

System A ◽

Dc Power ◽

Dc Distribution ◽

Ac Networks ◽

The Right ◽

Made In

The concept of DC power distribution has gained interest within the research community in the past years; especially due to rapid prevalence of solar PVs as a tool for distributed generation in DC microgrids. Various efficiency analyses have been presented for the DC distribution paradigm, in comparison to the AC counterpart, considering a variety of scenarios. However, even after a number of such comparative efficiency studies, there seems to be a disparity in the results of research efforts - wherein a definite verdict is still unavailable: 'Is DC distribution a more efficient choice as compared to the conventional AC system?' A final verdict is absent primarily due to conflicting results. In this regard, system modeling and the assumptions made in different studies play a significant role in affecting the results of the study. The current paper is an attempt to critically observe the modeling and assumptions used in the efficiency studies related to the DC distribution system. Several research efforts will be analyzed for their approach towards the system upon which they have performed efficiency studies. Subsequently, the paper aims to propose a model that may alleviate the shortcomings in earlier research efforts and be able to give a definite verdict regarding the comparative efficiency of DC and AC networks for residential power distribution.

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A basic mathematical testbed for energy efficiency analyses of DC power distribution systems/microgrids

Bulletin of Electrical Engineering and Informatics ◽

10.11591/eei.v10i3.2775 ◽

2021 ◽

Vol 10 (3) ◽

Author(s):

Faizan Dastgeer ◽

Hafiz Muhammad Anees ◽

Hasan Erteza Gelani ◽

Kashif Amjad ◽

Muhammad Rameez Javeed

Keyword(s):

Power Distribution ◽

Distribution System ◽

Distribution Systems ◽

Research Effort ◽

Strong Dependence ◽

Efficiency Analysis ◽

System Efficiency ◽

Current Effort ◽

Dc Power ◽

Dc Distribution

DC power distribution has become a topic of interest in the recent past, despite being given up a long time. A number of research efforts have been carried out in this field; especially the idea of DC distribution for microgrids has witnessed a significant amount of time and attention. System efficiency is one of the under-research areas of this field that has witnessed a lot of research efforts which were generally simulation based studies. Detailed mathematical efficiency analysis is missing in the present body of knowledge. In this regard, the current research effort aims to present a foundation level mathematical efficiency analysis set-up that may be used as an analytical testbed for different efficiency studies especially those related to the comparative evaluation of DC and AC systems. The current effort highlights the strong dependence of AC and DC distribution system efficiency on the factor of time. The efficiency advantage of DC over AC or vice versa within a specified duration depends on the ratio of DC and AC grid powers summed over the duration.

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Research on Access Mode of the Flexible DC Power Distribution System into AC System

Energies ◽

10.3390/en12204002 ◽

2019 ◽

Vol 12 (20) ◽

pp. 4002

Author(s):

Yao ◽

Jianfu ◽

Lu ◽

Zhanqing ◽

Zipan ◽

...

Keyword(s):

Power Distribution ◽

Distribution System ◽

System Control ◽

Power Distribution Network ◽

Power Distribution System ◽

Protection Strategy ◽

Dc Power ◽

Dc Distribution ◽

Access Mode ◽

The Cost

The connection mode of the direct current (DC) power distribution system and the alternating current (AC) system is the foundation of system design, and it is also one of key technologies of the DC power distribution network. Based on the topology structure, grounding method, main equipment parameters, load parameters and system control protection strategy of the DC power distribution system, this paper establishes the system simulation model in the case of configuring the connection transformer and not configuring the connection transformer. Simulation results show that, when no connecting transformer is installed, the interaction between AC and DC systems will be great when faults occur, and the cost of converter valves and DC reactors will be increased. When connecting transformers are installed, the interaction between AC and DC systems can be effectively isolated, and the operation reliability of the system will be greatly improved while the cost is saved. Therefore, it is recommended to configure an independent connection transformer in the DC distribution system.

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Interoperable IoT system that could adapt local context of the built environment

Impact ◽

10.21820/23987073.2020.6.52 ◽

2020 ◽

Vol 2020 (6) ◽

pp. 52-54

Author(s):

Tomonari Yashiro

Keyword(s):

Energy Efficiency ◽

Built Environment ◽

Energy Use ◽

Energy Savings ◽

Cost Savings ◽

Local Context ◽

Smart Lighting ◽

Efficiency Cost ◽

Operational Energy ◽

Iot Devices

IoT technology has great potential to transform the built environment and, in doing so, create energy savings. With operational energy use in buildings causing around 30 per cent of CO2 gas emissions, and demand for energy use in buildings on the rise, it is necessary to develop measures to reduce consumption, and IoT could hold the key to this. Just a few examples of ways that this can be achieved are: real-time energy monitoring, with IoT smart sensors measuring the power consumption of a building to show how and where energy is used; smart lighting, whereby unnecessary lighting is switched off and energy saved; and smart metering systems, leading to higher energy efficiency, cost savings and new data sources. Indeed, IoT devices in buildings can collect important data, which has a number of important applications, and the long-term value of IoT devices in buildings comes from mining the data collected by sensors and devices as this can be used to enhance building performance and efficiency. Professor Tomonari Yashiro, based at the Institute of Industrial Science, The University of Tokyo, is exploring how ICT and the IoT could help improve the sustainability and energy efficiency of buildings.

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Laboratory Validation of Integrated Lighting Systems Retrofit Performance and Energy Savings

Energies ◽

10.3390/en13133329 ◽

2020 ◽

Vol 13 (13) ◽

pp. 3329 ◽

Cited By ~ 1

Author(s):

Jordan Shackelford ◽

Paul Mathew ◽

Cynthia Regnier ◽

Travis Walter

Keyword(s):

Energy Savings ◽

Cost Benefit Analysis ◽

Cost Benefit ◽

Lessons Learned ◽

Benefit Analysis ◽

Light Emitting ◽

Occupant Comfort ◽

Advanced Controls ◽

Lighting Systems ◽

End Use

Light-emitting diodes (LED) fixtures and lamps have emerged as leading technologies for general illumination and are a well-established energy efficiency retrofit measure in commercial buildings (from around 2% of installed fixtures and lamps in 2013 to 28% by 2020). Retrofit approaches that integrate elements, such as networked controls, daylight dimming, and advanced shade technologies lag in comparison. Integrated retrofits have been shown to increase savings over single end-use retrofits, but are perceived as higher complexity and risk. More validation of integrated lighting system performance is needed. This study presents results from laboratory testing of three packages combining fixtures, networked controls, task tuning, and daylight dimming, advanced shades, and lighting layout changes. We characterize performance in perimeter open-office zones, finding energy savings from 20% for daylight dimming and automated shades (no LED retrofit) to over 70% for LED retrofits with advanced controls and shades or lighting layout changes. We present some implementation details, including lessons learned from installation and commissioning in the laboratory setting. We also discuss cost-benefit analysis approaches for the types of packages presented, including the need to quantify and incorporate energy and non-energy benefits for advanced shades packages, which enhance occupant comfort but add significant cost.

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