Texas escaped rolling blackouts: Data centers and the power grid interdependency

In Texas, a state with data centers of several notable IT companies, including WordPress.Com, Cisco, Rackspace and Host Gator, the power grid company ERCOT have been working around the clock to keep the electricity flowing, and to avoid rolling blackouts as power demand reaches record levels.

According to The Wallstreet Journal for the second year in a row, ERCOT, underestimated summer demand in its forecasts. ERCOT’s forecasts are based on an average of the past 10 summers, but the past two years have been unusually hot, and this is pushing up energy use. With almost 40 consecutive days of temperatures of more than 37 Celsius (100 degrees F) it was the hottest start to August in Texas history. The drought in the southern U.S. is exceptional as can be seen in the map below, see also the 12-week animation of the U.S. drought monitor.

Drought monitoring

Texas has its own power grid, regulated and managed by  Electric Reliability Council of Texas (ERCOT). The Texas Interconnect supplies its own energy and is completely independent of the Eastern and Western Interconnects, which means that Texas can’t get help from other places when it runs short of power.

On the second of august  ERCOT even put out a notice  saying the state’s reserve levels dropped below 2,300 megawatts, putting into effect an Energy Emergency Alert level 1.“We are requesting that consumers and businesses reduce their electricity use during peak electricity hours from 3 to 7 p.m. today, particularly between 4 and 5 p.m. when we expect to hit another peak demand record,” said Kent Saathoff, vice president of system planning and operations. “We do not know at this time if additional emergency steps will be needed.” ERCOT only has peak capacity of 73,000 megawatts this time of year, and about 3,000 megawatts is offline for repairs at any given time. ERCOT recorded an all-time peak demand for electricity: 68,296 megawatts. ERCOT thus narrowly avoided instituting rolling blackouts.

Texas energy demand

According to an Aug. 2 blog article by Elizabeth Souder of the Dallas Morning News, “The high temperatures also caused about 20 power plants to stop working, including at least one coal-fired plant and natural gas plants.” Souder noted that a spokesman for ERCOT, “said such outages aren’t unusual in the hot summer…”

The demand for energy sent prices sky high, topping out at $2,500 per megawatt-hour on Friday afternoon, more than 50 times the on-peak wholesale average, according to the U.S. Energy Information Administration.

ERCOT energy prices

The power plants are also in a different way under siege. The drought shows a structural problem with the U.S. energy sector: it needs a lot of water to operate. Power plants account for 49 percent of the nation’s water withdrawals (according to the U.S. Geological Survey). Levels of “extreme” and “exceptional” drought grew to 94.27 percent of the state of Texas. The drought and triple-digit temperatures (F) have broken numerous records and already left the southern Plains and Mississippi Valley struggling to meet demand for power and water. A prolonged drought such as in Texas can force power plants to shut down because their supply of circulating cooling water runs out or the cooling water is not cool enough (which happens in  2007 when several power plants had to shut down or run at a lower capacity because there was not enough water. As showed in a study from the University of Texas at Austin alternative cooling technologies, such as cooling towers and hybrid wet–dry or dry cooling, present opportunities to reduce water diversions.

Although we didn’t hear much from the data center operators about the current threat to the power grid, the Texas case shows very clearly the interdependency between data centers as huge energy consumers and the power grid, the water distribution systems and the weather and climate conditions.

Data centers are part of a complex electrical power value chain. People are mostly not aware of this value chain and the energy losses in this value chain. As a customer of cloud computing and/or data center services but also a data center provider you must have a good understanding of the power grid to appreciate the risks that are at stake in terms of resiliency and business continuity.  The power grid, and water distribution systems are struggling to survive a record breaking drought across the southern United States. That is also a wake up call for data center users and providers to rethink the energy efficiency and the energy consumption of their data centers.

Saving a kiloWatt at the end of this power value chain saves a lot of energy. This can offer some relief to the current power grid. It can be shown that by saving 1 unit power consumption in information processing saves us about 98 units in the upstream of the power value chain. See the blog entry Following the data center energy track 

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