What Would it Take to Build a Global Supergrid?


Let’s Build a Global Power Grid

IEEE Spectrum, July 28, 2015. Image credit: Funkenschlag / Power Grid

Reports abound of homeowners and businesses unplugging from the power grid and opting instead to generate and store their own electricity. Such grid defections may make sense in places where electricity rates are sky-high or service is spotty. But for just about everywhere else, it’s far more sensible to do the very opposite: interconnect regional electricity networks to form a globe-spanning supergrid.

What makes this idea so compelling are the major strains on today’s power grids: soaring energy demand in fast-growing megacities; rapid expansion of carbon-free but intermittent wind and solar power; and the ever-increasing need to secure grids against electronic and physical attacks. The smaller and more isolated a power network is, the more difficult it is to maintain the nearly instantaneous balance between electricity supply and demand.

But the technology now exists to transmit massive amounts of electricity over long distances without significant losses, thereby allowing operators to balance consumption and generation across an entire continent—or, potentially, the globe. If an outage occurs in one country, the sudden change in line voltage and frequency could trigger a generator thousands of kilometers away to compensate for the shortfall. Similarly, if the wind in a normally wind-dependent area dies, electricity from its neighbors could quickly fill in. Or if one region is experiencing heavy rainfall, hydroelectric dams there could capture the energy, to send elsewhere as needed. A supergrid would ensure that all or nearly all the electricity that’s generated would get consumed, thus avoiding such wasteful practices as paying wind-farm operators to curtail production or dumping energy that’s not immediately needed. (To be sure, storing excess energy would also help avoid such problems, but large-scale economical energy storage is still not widely available.)

So what would it take to build a global supergrid? Technologically, it would hinge on a globe-encircling network of high-voltage direct-current (HVDC) transmission systems, most of the components of which already exist. Beyond that, regional grid operators would need to agree on how to pay for such a network, establish rules for trading the electricity, and specify the technical codes and standards that will allow the supergrid to operate safely, reliably, and securely.

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