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Energy & Grid Management
Vishwas Powar
Vishwas Powar
·Posted in Energy & Grid Management
Mon, Apr 10

The Urgency to Take Bold Steps to Transform the Electricity Infrastructure

Co-Authored By: Rajendra Singh 1,2 and Vishwas Powar 1
1Holcombe Department of Electrical and Computer Engineering, Clemson University, Clemson, SC, 29634
2)Department of Automotive Engineering, Clemson University, Greenville, SC 29607

It is quite common to read headings like “Get Ready: More Blackouts are Coming” [1]. The U.S. electric system is generally leaning on customers to avoid blackouts [2]. As the number one global economy, there is an urgency to solve this problem. Other than climate emergency, the continuous use of fossil fuel as an energy source is already creating havoc on the global economy [3] and disrupting world peace [4]. Based on abundance, nearly free-fuel, minimum greenhouse gases emissions, minimum use of water in power generation, highest safety, access to all, and ultra-low-cost, photovoltaics (PV) and wind turbines are proving to be the source of generating sustainable, green, and equitable electric power for all [5]. The cost of PV-generated electricity has reached the sub $0.02/kWh range at the utility-scale in a number of countries. It will play the same role in the energy field as that is being played by complementary metal-oxide semiconductor technology (CMOS) in electronics. In the future, improvements such as glass manufacturing co-located with PV manufacturing and larger wafer size can provide a cost of PV energy production of $0.01/kWh or less, as recently demonstrated in Saudi Arabia [6]. Due to advancements in technology and ultra-large-scale manufacturing, lithium-ion batteries are emerging as a cost-effective solution for electric power storage. Combined with lithium-ion battery (LiB) storage, PV and Wind energy have led to a disruptive transformation of the global energy sector. However, the maximum utilization of these free-fuel sources is throttled due to traditional centralized alternating current (AC) grid policies and lossy infrastructure limits imposed on these ultralow cost newer generation sources. Traditional approaches of injecting active and reactive power into the transmission and distribution corridors for balancing harmonics in frequency, phase, and voltages must be phased out to ensure reliable ultra-low-cost electric power. The re-evaluation of the 21st-century power grid is necessary rather than implementing the same practices established almost 150 years ago in generating, transmitting, and distributing electricity. It is imperative to return to the drawing board and rethink the grid infrastructure necessary for optimizing the power flows for modern generations and diverse evolving loads. The major drivers of the modern power grid comprise the six D’s, as illustrated in Figure 1.

 

Figure 1. The Six D’s as Drivers of The Modern Electric Power Grid

Today, most of the loads can operate on direct current power. PV generates DC power, and LiB store DC power. Wind turbines generate erratic AC power, which is sometimes converted to DC and back to AC power to match the frequency and phase of the legacy AC grid. Thus, from an energy efficiency (directly related to the cost of electricity) viewpoint, the current AC grids are highly inefficient and waste a large amount of energy.

In this short article, we propose the utilization of an end-to-end DC network grid in tandem with the existing AC grid to integrate clean DC power generation, and DC loads smoothly. Data-driven digitization of the new DC grid will be implemented to mitigate faults better and reduce the severity of outages in near real time. Integrating cyber-physical communication with the Internet of Things (IoTs) will also be the key disruptive force to achieve better visibility across various components in new DC grid operations.

 

Proposed End-to-End DC Power Networks

The existing AC grid has several looming challenges and pitfalls. Aging grid infrastructure, lossy conversion techniques, slow ramping rates of inertial generators, lack of flexibility, lack of transmission corridors, increased frequency of negative wholesale prices, curtailment of PV and Wind generation, ever-growing interconnection queues, and lack of real-time preventive and prescriptive decision making, are some challenges of today’s grid to name a few. As compared to high-voltage AC transmission (HVAC), high-voltage DC (HVDC) transmission is preferred for long–haul transmission of power due to lower losses and lower overall life cycle costs. Due to the fundamental nature of DC transmission, higher power can be transmitted over the same AC lines if converted for DC operation. As compared to HVAC, a lower right of way is required in the case of HVDC transmission. HVDC technologies also have significant advantages over AC options for connecting remote, large-scale offshore wind from both economic and technical perspectives. Without affecting the existing grid, an innovative concept of the end-to-end DC power-based architecture for existing and new loads is shown in Figure 2. As compared to existing HVDC, which involves multiple AC-to-DC and DC-to-AC conversion stages to connect solar and wind farms to the load, our proposed architecture demonstrated for EV charging loads in our recent publication [7] will save more than 25% energy as compared to existing HVDC that serves AC infrastructure. Figure 3 shows EV Charging Architecture utilizing the proposed end-to-end DC power architecture.

Figure 2. Proposed End-to-End DC Power Architecture

 

Reliability and Resiliency of PV and Battery Microgrids

The reliability of well-designed DC power microgrids is directly related to the efficiency of power electronic converters, PV panels, Battery storage components, and modified DC power lines. Solar PV panels retain about 90% of the power after 25 years [8]. Battery systems with advanced sensing and thermal management have proven reliability for more than 15-20 years [9]. Sustainable, green, and equitable power generation systems must be resilient against manmade and natural threats. PV-based local Direct Current (DC) power networks provide an effective yet simple and cost-effective solution to mitigate the threats from space weather-related events. Well-designed PV systems are resilient against floods and hurricanes. As an example, in October 2022, a 100% solar community in the United States endured hurricane Ian with no loss of power and minimal damage [10]. A similar resiliency in PV farms was observed in immense flooding environments in Queensland and New South Wales [11]. A direct hindrance to the reliability of PV and Wind power usually stems from the reluctance to utilize renewables as baseload power plants. The majority of the PV and Wind generation today is only utilized to balance the peak loads while maintaining the baseload with nuclear and coal power. This practice needs to change as loads and generations evolve. Grid flexibility, oversized PV farms, and real-time control updates are necessary to phase out baseload power constraints [12-13]. Co-located battery storage with complementary PV and Wind can reliably manage 100% of the grid demand [14]. The MW-level future EV charging loads can completely be met with grid-independent PV and LiBs with 25% savings, as shown in our recent publication [7] in Figure 3.

 

Figure 3. EV Charging Architecture utilizing the proposed end-to-end DC power architecture [7].

 

In conclusion, we propose establishing a national commission consisting of all stockholders with two goals.  The first objective is to provide the details of the necessary and sufficient technology that is required to implement the proposed end-to-end DC architecture. The second objective is to provide a roadmap that can be implemented to phase out AC infrastructure, and eventually, we will have DC power-based electricity infrastructure. The roadmap will assist key players and policymakers in developing new standards for prompt implementation. The replacement of incandescent light bulbs with LEDs is an example of an enabling technology for phasing out AC infrastructure. Similar strides will be observed in futuristic power grids where DC power networks will emerge as the only option for sustainable, low-loss, cost-efficient techniques to provide affordable power to all.

References:

  1. T. Dorrell, Get ready: More blackouts are coming. Available online: https://www.businessinsider.com/blackouts-power-outages-more-common-climate-change-electric-grid-infrastructure-2023-3 (accessed on 26 March 2023).
  2. J. Hiller, The U.S. Electric System Is Leaning on Customers to Avoid Blackouts, The Wall Street Journal, Available online:https://www.wsj.com/articles/the-u-s-electric-system-is-leaning-on-customers-to-avoid-blackouts-11668205522 (accessed on 26 March 2023).
  3. D. Vetter, Fossil Fuels Are ‘Weapons of Mass Destruction’ Preventing Economic Development, New Report Finds. Available online: https://www.forbes.com/sites/davidrvetter/2022/06/01/fossil-fuels-are-weapons-of-mass-destruction-preventing-economic-development-new-report-finds/ (accessed on 26 March 2023).
  4. M. Lavelle, Whatever His Motives, Putin’s War in Ukraine Is Fueled by Oil and Gas. Available online: https://insideclimatenews.org/news/06032022/putin-russia-ukraine-oil-gas-petrostate/ (accessed on 26 March 2023).
  5. P. Paniyil et al., Batteries and Free Fuel based Photovoltaics and Complimentary Wind Energy based DC Power Networks as 100% Source of Electric Power around the Globe, 2021 IEEE 48th Photovoltaic Specialists Conference (PVSC), 2021, pp. 1821-1828, doi: 10.1109/PVSC43889.2021.9518729
  6. E. Bellini, Saudi Arabia’s second PV Tender Draws World Record Low Bid of $0.0104/kWh” pv-magazine.com. Available online: https://www.pv-magazine.com/2021/04/08/ saudi-arabias-second-pv-tender-draws-world-record-low-bid-of-0104-kwh/ (accessed on 26 March 2023).
  7. V. Powar and R. Singh, End-to-End Direct-Current-Based Extreme Fast Electric Vehicle Charging Infrastructure Using Lithium-Ion Battery Storage, Batteries, vol. 9, no. 3, p. 169, Mar. 2023, doi: 10.3390/batteries9030169.
  8. SunPower. Available online: https://us.sunpower.com/sites/default/files/media-library/white-papers/wp-sunpower-module-40-year-useful-life.pdf (accessed on 26 March 2023).
  9. Tesla Megapack Datasheet. Available online: https://docs.planning.org.uk/20210319/202/QPV6H7SOJ8900/zisuxgvois9byi3q.pdf (accessed on 26 March 2023).
  10. R. Ramirez, This 100% solar community endured Hurricane Ian with no loss of power and minimal damage. Available online: https://amp.cnn.com/cnn/2022/10/02/us/solar-babcock-ranch-florida-hurricane-ian-climate/index.html (accessed on 26 March 2023).
  11. S. Vorrath, What happens when a solar farm is flooded? Sunshine Coast project lives to tell the tale, Available online: https://onestepoffthegrid.com.au/what-happens-when-a-solar-farm-is-flooded-sunshine-coast-project-lives-to-tell-the-tale/ (accessed on 26 March 2023).
  12. J. Harvey, We don’t need Baseload Power. Available online: https://cleantechnica.com/2022/06/28/we-dont-need-base-load-power/ (accessed on 26 March 2023).
  13. IRENA, From baseload  to peak: Renewables provide  a Reliable solution, Available online: https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2015/IRENA_Baseload_to_Peak_2015.pdf (accessed on 26 March 2023).
  14. J. D. Rhodes, A. Choukulkar, B. Cote et al., Baseload power potential from optimally configured wind, solar and storage power plants across the United States, 06 October 2020, PREPRINT (Version 1). Available online at Research Square https://doi.org/10.21203/rs.3.rs-86826/v1