It’s high summer in Texas and a heatwave is pushing already sweltering temperatures beyond 100 Fahrenheit. In homes and offices across the lone-star state, people are ramping up the air conditioning – and the resulting surge in energy demand is straining power stations to breaking point.

It was the same sort of scenario that in August 2011 resulted in a supply emergency that very nearly saw the lights go out across Texas. According to the Energy Information Administration (EIA), the heatwave pushed demand to record levels and way beyond the maximum forecast by energy suppliers.

Five years later, the EIA has developed an interactive map to monitor energy supplies in real time.

 US electricity demmand
Image: Energy Information Administration

Hour by hour, the system constantly compares actual energy production with forecasts for maximum predicted consumption.

Areas on the map producing more electricity than required are coloured orange. Regions where production is falling behind predicted usage appear in blue. By clicking on the production-centre icon, staff can see how many extra megawatts are required to get an under-supplied region back on track.

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An interconnected grid

As the map shows, the US electricity grid has a number of interconnected supply areas. This means reserve capacity can be diverted from an over-supplied area to one hit by shortages. As the EIA explains, “these diversions happen automatically. Electric system disturbances occur too quickly to rely on human intervention to detect losses and manually bring on new generating capacity.”

Earthquake disrupts supplies

Just a few days after the 2011 heatwave crisis in Texas, an earthquake struck the Washington DC area.

The safety systems at two nuclear power stations in Virginia took them offline for 12 seconds. It doesn’t sound like a long time, but this video animation shows the plunge in the energy available to the region while the reactors were off the grid.

With supplies under serious threat, generating systems across the affected area automatically detected the fall-off in capacity and upped their output slightly to claw back the missing output and restore stability to the system.

Safeguarding supplies

Before the EIA’s new real-time monitoring system came online, forecasts were made a day in advance. When freak weather and technical problems affected the grid, the power supply to huge parts of the United States could be jeopardized.

The new real-time system should make sure that the lights stay on under anything but the most extreme of circumstances.