The Grid: Electricity Transmission, Industry, and Markets

Highest Transmission Losses

Togo 71% 🇹🇬
Libya 70% 🇱🇾
of electricity output is lost in transmission, distribution, and pilferage

Lowest Transmission Losses

5 countries* < 3% 
of electricity output is lost in transmission, distribution, and pilferages

*Singapore, Trinidad and Tobago, Slovak Republic, Iceland, and Israel

Largest Electricity Consumers

China 32% 🇨🇳
U.S. 16% 🇺🇸

Electricity Demand

Increase:
⬆14%
(2017-2022)

Largest Electricity Consumer

Texas 13%

Electricity Demand

Increase:
⬆5%
(2017-2022)

Most Expensive

Hawaii 39 cents/kWh

National Average

12 cents/kWh

Least Expensive

Idaho 8.0 cents/kWh
North Dakota 8.1 cents/kWh
Wyoming 8.4 cents/kWh

Blackouts/Black System Events

All consumers on a network lose power, typically for hours to days. This type of event is usually caused by equipment failure or weather events. Because blackouts are often unexpected, the impacts can be wide ranging and severe. This is the most common type of power interruption in the U.S.

Example: In 2017, 80% of Puerto Rico’s electricity grid was knocked out by Hurricanes Irma and Maria. The storms caused nearly the entire system in Puerto Rico to collapse, with loss of power lasting up to 11 months for some consumers.

Load Shedding via Rolling Blackouts and Brownouts

When demand exceeds supply, system operators must reduce demand by disconnecting power from parts of the system. It is a last resort measure after using all available capacity, importing electricity, and implementing demand response measures to prevent a blackout. Loss of power lasts only minutes to hours. This type of interruption is often implemented as “rolling blackouts” where loss of power is spread to many groups of customers for short periods of time. Operators can also achieve load shedding by implementing “brownouts.” During a brownout, power is not completely shut off but the voltage to homes and businesses is reduced. Many appliances and electricity-dependent systems will still work but may flicker/turn on and off repeatedly.

Example: Rolling brownouts and blackouts are common in California summers due to heat waves and wildfire risk. Heat waves increase demand for air conditioning, sometimes above supply. In areas with high fire risk, system operators sometimes shut down transmission lines to prevent power lines from sparking and igniting nearby dry vegetation.

Long Rationing Periods

When regions have chronic deficits in supply, system operators may implement planned outages. These periods of planned outages can last for months with consumers losing power for hours at a time. Due to the long term nature of this type of interruption, the impacts are severe including loss of economic output and lower quality of life.

Example: South Africa has had long periods of load rationing since 2017 due to heavy reliance on coal, aging infrastructure, and centralization of generation capacity under one utility. These periods last for months and customers typically lose power for 2-4 hours in rolling blackouts. In 2021, South Africa experienced 1,165 hours with loss of power, totaling 1.8 TWh of unserved energy, equivalent to the amount of energy used in 167,000 U.S. homes in a year.

Unreliable Grids

An estimated 1.5 - 2.75 billion* people have unreliable access to electricity (not including the 756 million people with no access). Regions with unreliable access are concentrated in the Global South, primarily in Sub-Saharan Africa and South Asia.

Reliable Grids

Developed nations tend to have the most reliable grids, including countries in North America, Europe and East Asia.

Least Reliable Grids

Maine 3 days/year
with electric interruptions (average duration of 7 hours per interruption)

Most Reliable Grid

Washington, D.C. <1 day/year
with electric interruptions (average duration of ~3 hours per interruption)

Drivers

• High-quality energy currency; flexible and relatively efficient for end uses
• Important for modern quality of life, reduced indoor air pollution, and human health
• Increase in electricity access worldwide allows for improved education and economic activity
• Growing demand from economic and population growth
• Increase in electrification due to demand for decarbonization
• As electricity demand increases there is a need to invest in modernization of old, outdated grid infrastructure
• Integration of intermittent renewable energy sources like wind and solar and accelerating coal and nuclear retirements requires improvements in grid management
• Growth in distributed generation (e.g., residential rooftop solar panels) can reduce the need for grid updates by co-locating supply and demand

Barriers

• Electricity is difficult and expensive to store; must match supply and demand in real time
• Expansion and upgrading of the grid is capital intensive and expensive
• Grid management requires coordination among grid operators, utilities, and policymakers
• Opposition due to land use impacts from transmission and distribution (NIMBY/BANANA*)
• Fire risk from transmission lines, especially in remote areas
• Extreme weather events such as hurricanes, storms, and wildfires cause more grid disruptions as they become more frequent due to climate change

^{Updated November 2024}