Without access to a stable source of electrical power, the effects of the coronavirus pandemic to our society would be far more devastating. Imagine the loss of electronics from lifesaving medical devices to communication networks and even entertainment systems for tens of millions of stay-at-home individuals. But is our power grid as stable and safe as we think?
|Caption: US Energy Information Administration (EIA)|
The U.S. power grid is made up of over 7,300 power plants, nearly 160,000 miles of high-voltage power lines, and millions of miles of low-voltage power lines and distribution transformers, according to the U.S. Energy Information Administration. A variety of resources and technologies are used to generated electricity including the conventional sources of natural gas, oil, coal and nuclear. Still, one of the fastest growing sources come from renewable technologies like wind, solar and etc.
Renewables are a critical element to the future of the U.S. power grid as sun, wind and other renewable resources are inexhaustible and clean. They are also cheaper since they generate electricity closer to home, which means fewer long power transmission lines and other expensive grid infrastructure. Further, some renewable sources like wind may be less affected by earth currents, solar flares and EM pulses.
Understanding how and where Earth currents are generated naturally in the ground may be at the heart of dealing with other phenomena – like solar flares and EM pulses - that might affect the power grid. This is why the work by Oregon State University to map the electrical structure of the Earth’s crust and upper mantle is so important. This project, first began about 15 years ago with funding from the National Science Foundation’s EarthScope Program, was to collect information about the structure and evolution of the North American continent. Initially, the project was managed by the Incorporated Research Institutions for Seismology and carried out by an OSU research group headed by Adam Schultz, a professor in OSU’s College of Earth, Ocean, and Atmospheric Sciences.
“The current national emergency around the COVID-19 pandemic and its impact on the health care system reminds us how vitally important critical infrastructures like the power grid is to be able to respond to and recover from natural disasters,” said Schultz.
Earth or telluric current is an electric current that moves underground or through the sea. Currents arise naturally in the earth from the chemical composition of certain minerals as well as temperature differences such as those near volcanoes. Electric currents are generated when a portion of the earth interacts perpendicular to the Earth’s magnetic field.
As far back as the 1840s, telegraph systems used Earth batteries to access low voltage current from telluric sources. An Earth battery is a pair of electrodes made of two dissimilar metals, such as iron and copper, which are buried in the soil or immersed in the sea at a sufficient distance. Such batteries were sometimes referred to as telluric power sources and telluric generators.
Today, Earth currents are often measured with a Narod Intelligent Magnetotelluric Systems (NIMS). The NIMS is a 1 Hz sample rate long-period magnetotelluric instrument. It includes a triaxial ring-core magnetometer gel-type electrodes and a receiver unit which contains its data acquisition system.
Narod Intelligent Magnetotelluric Systems or NIMS (Courtesy Oregon State Univ.)