By Irina Slav - Oct 31, 2024
Drought has been one big reason for hydro’s smaller contribution to dispatchable electricity this year.
Greater water use by industry and households has diminished water availability.
Ember: hydropower output this year has fallen to a record low of 5.2% of total generation, while nuclear has gone up by 1.3% to 17.6%.
Hydropower is, along with nuclear, the best of both worlds in terms of electricity. It is a zero-emission source of energy, and its output can be adjusted in response to demand—a dispatchable source. The problem? It depends on the weather, and because of this dependence, hydropower managed to drag the total share of low-emission power generation down this year, and boosted gas. Dispatchability matters.
Back in April, the Energy Information Administration forecast that hydropower output this year would jump by 6% over 2023, when it dipped to the lowest since 2001. “We expect hydropower to increase in nearly every part of the country, with notable increases in the Southeast and in the Northwest and Rockies,” the EIA wrote. “We expect other regions with significant hydropower generation to either increase slightly, such as in New York, or remain about the same, such as in California.”
None of this happened, however. Instead of growing, hydropower output this year has remained essentially unchanged from last year’s 23-year low, reducing the total share of dispatchable low-emission electricity generation in the total U.S. mix. Geothermal has not been able to help because it has not reached a massive enough scale of utilization. Wind and solar could not help, even with the substantial additions in capacity because of their weather dependence. So, generators turned to gas yet again to respond to growing electricity demand. Dispatchability matters.
The EIA did not seem to think so earlier this year. In May, a month after its forecast about hydropower generation, the agency forecast that wind, solar, and hydro would grow to account for a total 22% of U.S. power generation this year. Indeed, in an October 29 data highlight, the EIA said that wind and solar alone accounted for 22.6% of total generation. There is just one problem with that data highlight. It says nothing about demand.
Wind and solar together could eventually come to generate a third of U.S. electricity—on clear, windy days. Yet what’s important is the balance between supply and demand. With electricity, there’s no space for a shortage because a shortage means blackouts, so the grid needs to be perfectly balanced at all times.
Hydropower has been great at doing this because output at hydropower stations can be adjusted in the same way that output at gas and coal power plants can be adjusted, and at nuclear plants, too. Where output cannot be adjusted, save for so-called curtailment, which means dumping excess electricity, is wind and solar. Hydro, therefore, has been excellent at “covering” for these two. But only if there’s enough water in the dams.
For context, China experienced an extended drought in the last two years. It significantly reduced the amount of hydropower the country generated. This year, however, the weather changed and brought abundant rainfall to China. As a result, hydropower output surged, raising the total share of low-carbon energy in the country to elevated levels. Apparently, the opposite happened in the U.S. And, unlike the EIA predicted earlier in the year, low-carbon sources will not be able to meet rising demand.
Drought has been one big reason for hydro’s smaller contribution to dispatchable electricity this year. Another issue has been greater water use by industry and households, Reuters’ Gavin Maguire noted in a report on the latest data from the EIA. In it, Maguire also cited data from climate outlet Ember showing that hydropower output this year has fallen to a record low of 5.2% of total generation, while nuclear has gone up by 1.3% to 17.6%.
At the same time, demand for electricity has risen a lot faster, Maguire also noted, prompting generators to turn to the only dispatchable and weather-independent source of electricity available besides anathematized coal: natural gas. The rising share of natural gas in the U.S. energy mix this year has become yet another stark reminder of just how important it is for electricity supply to be available on demand.
By Irina Slav for Oilprice.com
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