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State of US’ Electricity Grid: Country’s grid faces various challenges and changes [free access]

April 10, 2017

The electricity sector of the United States (US) is currently facing a complex set of changes and challenges, as per the second Quadrennial Energy Review (QER 1.2) of the Department of Energy (DoE), and the latest Infrastructure Report Card of the American Engineering Standards Committee (AESC). These include aging infrastructure; changing generation mix; growing penetration of variable generation; low or negative (in some cases) load growth; climate change; increased physical and cybersecurity risks; and widespread adoption of distributed energy resources (DERs) in some regions. Effective and efficient management of these changes are required to transform the electricity system’s structure, operations, customer base and jurisdictional framework.

 

With the rising share of renewable energy sources and demand management systems (DMS), the US energy system is likely to meet power demand in the short- and medium-term. However, the increasing share of renewable energy in the grid, which is significantly aged and congested, is likely to affect the long-term sustainability of the country’s power sector.

 

The majority of the operational transmission and distribution (T&D) lines in the US were constructed in the 1950s and 1960s with a 50-year life expectancy, and were not originally engineered to meet either current demand, or severe weather events. Presently, more than 640,000 miles (1,030,400 km) of high voltage transmission lines across the three interconnected electric transmission grids—the Eastern Interconnection, Western Interconnection and Texas Interconnection—are operational at their full capacity, with many other lines operating well beyond their designed capacity. The resulting congestion raises concerns regarding the reliability of the T&D network, cost of services, and the systems’ ability to deliver power from remote generation sites, specifically from renewable sources, to consumers. Often, a single line cannot be taken out of service to perform maintenance as doing so will overload other interconnected lines in operation. Grids operating in Alaska and Hawaii are similarly congested and physically islanded from the other states. As a result of aging infrastructure, severe weather events, and physical and cyber attacks and vandalism, the US experienced about 3,570 outages, with an average duration of 49 minutes, in 2015.

 

To resolve these issues, QER 1.2 and the Infrastructure Report Card have made several recommendations. Both reports have attempted to identify the threats, risks and opportunities associated with the country’s T&D network (under an energy and climate security study), and to provide guidelines to enable the federal government to translate policy goals into a set of integrated actions.

 

The recommendations of the Infrastructure Report Card (some of which are similar to those mentioned in the QER 1.2 report) include adopting a single federal energy policy; streamlining the permitting processes; developing a national storm hardening plan to consider investments in T&D, refinery and generation systems; improving the designs of new and existing lines to bear extreme weather conditions; promoting the use of remote sensing and inspection technologies; implementing performance-based regulations; and promoting the use of accepted engineering standards for all overhead T&D lines, pipelines and support structures to help ensure safety and reliability. The QER 1.2 analysed trends and issues confronting the nation’s electricity sector and built its analysis and recommendations on the basis of the first QER report.

 

In this article, Global Transmission Research provides a snapshot of the key trends facing the US grid, and the key findings and recommendations of the QER 1.2 for modernising the power grid.

 

Trends in the US electricity sector

Since the 1950s, growth in US electricity consumption has gradually slowed down every decade due to several factors, including moderating population growth, improvements in the energy efficiency of buildings and industry, market saturation of certain major appliances, and a shift in the broader economy to less energy-intensive industries. Looking forward to 2040, electricity use is projected to continue its slow growth rate.

 

The national generation mix has realigned over the past few decades and is likely to continue to change. The US generation fleet is transitioning from one dominated by centralised generators with high inertia and dispatchability to one that is more hybrid, relying on a mixture of traditional, centralised generation, and variable utility-scale and distributed renewable generation. Though new generation plants are coming up, the T&D network continues to age. The continual maintenance and replacement of electricity system infrastructure components and the development of new generation plans provide opportunities to modernise the electricity system, to develop adequate power storage capacity, and to shift to smart grid systems.

 

The US government has adopted various initiatives to establish a smart grid. During 2007-15, the US federal government invested about USD9 billion in smart grid initiatives. The majority of these initiatives have resulted in the widespread adoption of smart meters. By the end of 2015, the number of installed advanced (smart) metering infrastructure (AMI) meters reached 64.7 million, 88 per cent of which were residential customer installations. These meters enable the two-way flow of electricity data through digitisation, thereby increasing flexibility, system efficiency and consumers’ interaction with the grid, and reducing energy consumption.

 

However, the shift to using a smart grid is also putting the physical and cyber security of the power network at risk. Thus the government is also focusing on setting up cyber security standards and their enforcement.

 

QER reports

In June 2013, in response to a 2011 recommendation by the President’s Council of Advisors on Science and Technology, the central government began a quadrennial cycle of energy reviews to provide a multi-year roadmap for US energy policy. In January 2014, the White House Task Force was established to develop the QER and DoE was directed to provide analytical support to prepare QER reports.  

 

The first QER was published in April 2015, with a focus on infrastructure challenges, and the threats, risks and opportunities facing US energy and climate security. It also aimed to help enable the federal government to translate policy goals into a set of clearly articulated, sequenced and integrated actions, and proposed investments.

 

The report highlights the fact that the power and energy infrastructure in the US is outdated and perhaps more vulnerable than ever to the effects of climate change, terrorist attacks and other threats, and will require billions of dollars in repairs and modernisation to keep pace with the 21st century. It paints a grim picture of the country’s electrical grid, power transmission lines, natural gas and oil pipelines, ports, railways and other critical pieces of national infrastructure. The report points out that the country’s power transmission network is becoming congested and aged. The rising share of renewable energy is further affecting the reliability of the power grid. Thus, to maintain the reliability of the power network, it is important to build new infrastructure while utilising smart technologies. In this regard, the first QER report recommends providing state financial assistance to promote and integrate various T&D infrastructure investment plans, promote grid modernisation, and improve grid communication through standards and interoperability.

 

The second report of the QER focuses on the electricity system and its role as the enabler for accomplishing three key national goals that address the needs and challenges of the present electricity sector. These objectives include maximising economic value and consumer equity; building a clean electricity future; and ensuring electricity system reliability, security and resilience. In addition to these objectives, QER 1.2 also explores other issues mainly related to workforce and electricity system integration.

 

While considering the roles of various state, regional and tribal prerogatives, QER 1.2 supports the development of a consistent federal strategy that accounts for the complex electricity sector.

 

Recommendations of QER 1.2

 

A snapshot of the key recommendations of the report is given below:

 

In addition to these, the report also recommends improving the energy management and demand response (DR) systems; encouraging public-private partnerships (PPP) to underwrite and support clean energy access for low- and moderate-income households; increasing electricity access and improving electricity-related economic development on tribal lands; and strengthening rural electricity and broadband infrastructure to maximise economic value and consumer equity.

 

For grid operations and planning for electricity system reliability, security and resilience, QER 1.2 suggests developing uniform methods for cost-benefit analysis of security and resilience investments for the electricity system; offering incentives for energy storage; supporting grants for small utilities facing cyber, physical and climate threats; supporting mutual assistance for recovering from disruptions caused by cyber threats; supporting the timely development of standards for grid-connected devices; enhancing coordination between energy sector information-sharing and analysis centres and the intelligence communities to synthesise threat analysis and disseminate it to industry in a timely and useful manner; and promoting the deployment of advanced technologies for new and existing transmission.

 

The report also emphasises the importance of increasing North American cooperation on electric grid and clean energy issues. To this end, it recommends increasing US and Mexican cooperation on reliability, advancing North American grid security and modernising international cross-border transmission permitting processes.

 

Conclusion

The US electricity sector is experiencing various changes and challenges, which policymakers are working to identify in order to take actions accordingly. Several transmission projects are at various stages of development in the country, however, the majority of them are not able to meet scheduled completion deadlines due to lengthy and tedious approval processes, and opposition from local residents or authorities. The majority of these transmission projects have been proposed for upcoming renewable energy projects. As these take less time to construct as compared to a T&D network, delays in completing the latter are further increasing the gap between the generation and T&D networks. Thus serious efforts are required to upgrade the country’s grid. The recommendations of the QER 1.2 report will help in strengthening the power network of the US.