November 1, 2017 Read More →

Wind Booms, Coal Suffers in Oversupplied Texas Grid

S&P Global Market Intelligence:

When Vistra Energy Corp. subsidiary Luminant Generation Co. LLC announced on Oct. 13 that it would retire two large coal plants in Texas next year, the company stated that “these two plants are economically challenged in the competitive ERCOT market” because of “sustained low wholesale power prices, an oversupplied renewable generation market, and low natural gas prices, along with other factors.”

That statement echoed what has become a truism among merchant generators operating in the Electric Reliability Council of Texas region: the rapid spread of cheap wind power is creating an oversupply of electricity in the Texas market. ERCOT oversees the grid that supplies most of Texas with its electricity.

“ERCOT is currently oversupplied,” found a December 2016 report prepared for the Texas Clean Energy Coalition by the Brattle Group, Inc. that looked at grid reliability in the face of rising penetration of renewable energy sources and accelerating retirements of coal-fired plants, “and the forecasted additions of natural gas, solar, and wind generation should provide a cushion to absorb many of the retirements that may occur.”

A market that appears oversupplied to an owner of coal-fired plants, however, may not appear so to a grid operator charged with maintaining adequate resources for summertime peak loads. What’s clear is that as the penetration levels of wind and solar generation climb toward and past the 20% threshold, the issues around supply and demand, grid stability and market functioning become more complex. And Texas, a pioneer in wind power, could serve as a glimpse into the future of the U.S. power grid as renewables become cheaper and more widespread.

Even as peak loads have remained relatively flat in the region in the last few years, total operating capacity from all sources combined has continued to climb.

And much of that new capacity comes from wind, which grew from just over 11,000 MW in 2013 to nearly 16,260 MW in 2016 — a 48% increase in just three years — despite a renewable energy mandate that was met years ago.

Following a construction boom fueled by the federal tax credits and the state’s $8 billion investment in long-distance transmission lines, Texas has nearly 20,000 MW of wind power capacity. The state supplied 25% of U.S. wind power in 2016, and wind capacity in the state is expected to reach 25,500 MW by 2019. Along with abundant supplies of low-priced natural gas, all that wind has helped depress energy prices in Texas. Despite having, by far, the highest energy usage per capita in the nation, Texas enjoys energy prices per MWh among the lowest of any state.

As the Luminant retirements indicated, low wholesale power prices are driving coal generators out of the market. Exacerbating that trend, the wind boom is expected to be followed by a solar boom in the Lone Star state; in its most recent long-term scenario, ERCOT said between 14,500 MW and 28,100 MW of solar capacity could be added to the system by 2031. Through September, Texas had generated about 17% of its electricity from wind in 2017. Developers have already signed interconnection agreements for another 8,655 MW of new wind, plus 2,050 MW of new solar installations, in ERCOT.

For coal plant owners, low natural gas prices and high wind penetration “have been like a one-two punch,” says Chen-Hao Tsai, senior energy economist with the Jackson School of Geosciences at the University of Texas, Austin. “If solar really takes off as ERCOT predicts, that will replace a good amount of generation from conventional generators during the daytime. I would consider that the third punch.”

Adding to the blows against coal, natural gas plant construction is proceeding as well: “more than 14 GW [of] gas-fired generation capacity are also in the pipeline, with 7.6 GW scheduled to come online in 2018,” according to a July 2017 report by Tsai and his colleague Gürcan Gülen for the International Association of Energy Economics.

What goes for Texas today could soon apply to the U.S. as a whole. According to the American Wind Energy Association, nearly 26,000 MW of wind capacity is now in development nationwide, with more than 14,000 MW under construction. New installed wind capacity reached 2,357 MW in the first half of this year, the American Wind Energy Assocation says, pushing total installed capacity to 84,405 MW. According to the U.S. Energy Information Administration, electricity generation from wind will reach about 526 billion KWh by 2040, nearly 11% of total U.S. generation.

The Department of Energy’s more ambitious Wind Vision program aims to boost wind to 35% of U.S. generation by 2050.

In Texas, meanwhile, wind power’s position is being strengthened by new farms built not in West Texas, home to the majority of the capacity built to date, but along the Gulf Coast. While West Texas still accounts for the majority of the state’s wind capacity, wind power along the Gulf Coast has increased sixfold in the last five years, reaching 2,385 MW, or nearly 12% of the state’s total wind capacity. That’s important because Gulf winds blow more consistently than those in West Texas, and better match with the peak daytime hours for electricity consumption, overcoming the variability that of generation from farms in West Texas, where the wind is highest at night.

That will likely crowd out more fossil fuel generation, especially from coal plants, which are less flexible than plants that burn natural gas and are thus less able to ramp up quickly when the sun’s not shining and the wind’s not blowing. According to a May 2016 report from the Brattle Group — also prepared for TCEC — coal generators face a sharp decline in Texas: Coal’s share of generation in the state will fall from 34% in 2013 to 6% in 2035.

Coal’s dethronement in Texas has implications for coal producers in Wyoming’s Powder River Basin, as well. Texas, which consumed some 86 million tons of coal in 2015, much of it from Powder River mines, is by far the largest coal market in the U.S. Accelerating retirements in Texas will have a dramatic effect on Powder River Basin mines: Luminant’s Monticello and Big Brown plants, for instance, both of which are now slated for early retirement, bought up 54% of production from Peabody Energy’s Rawhide mine through the first seven months of 2017, according to the Institute for Energy Economics and Financial Analysis.

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