Hydropower

When drought reduces hydropower, carbon emissions and costs escalate

When drought reduces hydropower, carbon emissions and costs escalate

The need to switch from hydropower to fossil fuels during droughts has led to higher carbon emissions and cost 11 Western U.S. states tens of billions of dollars over the past two decades, Stanford University research finds.

When drought-stricken rivers and reservoirs run low, utilities fire up power plants that burn coal, oil or natural gas to keep up with the demand for electricity. In states that rely heavily on hydropower for electricity generation, emissions caused by drought-induced shifts in the energy supply could account for up to 40% of all greenhouse gas emissions from electricity in future drought years.

The study finds these overlooked consequences of drought dramatically increase carbon emissions, methane leakage, local air pollution and deaths caused by poor air quality.

The social and economic cost of these impacts have cost 11 Western states tens of billions of dollars over the past two decades, according to the study. In California alone, the increase in fossil generation caused by drought between 2012 and 2016 led to more than $5 billion in damages, 2.5 times the direct economic cost of switching from cheap hydropower to pricey fossil fuels.

Because climate change is making droughts in the American West more frequent and severe, the results indicate failure to account for these effects leads governments to underestimate the social and economic costs of global warming – and the worth of investments to combat it.

“Our research suggests the impact on greenhouse gas emissions, air pollution, and human health could represent a large and unaccounted-for cost of climate change,” said lead study author Minghao Qiu, a postdoctoral scholar in the Stanford Doerr School of Sustainability and Stanford Center for Innovation in Global Health.

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Qiu and co-authors estimate the total health and economic damages from drought-induced fossil electricity generation between 2001 and 2021 in western states amounted to $20 billion, with the cost of carbon emissions accounting for $14 billion of that damage. Deaths associated with additional air pollution account for $5.1 billion, and methane leakage accounts for just under $1 billion.

Like many climate impacts, these damages often bleed across borders. When hydropower runs low in Northwestern states that export electricity to regional neighbors, for example, communities in California and the southwest feel the effects. “This is not a local story. A climate shock in one place can have serious ramifications for a totally different geographic area due to the interconnected nature of many energy systems,” said Qiu, who works with senior study author Marshall Burke as part of the university’s Environmental Change and Human Outcomes Lab.

While the study focused on the American West, the researchers stress that many countries relying on hydropower are facing greater drought risk due to climate change. In places where coal-fired power plants are the most likely replacement for lost hydropower, the authors said the economic and health damages from deteriorated air quality and GHG emissions will be higher than in U.S. western states, which more often turn to natural gas.

“Our findings have implications for many other parts of the world that depend on hydropower but could face increasing drought,” said Burke, an associate professor in the global environmental policy area of the Stanford Doerr School of Sustainability’s social sciences division. “In these regions, drought’s interaction with the energy system can have a cascading series of negative impacts on emissions and health.”

In states that rely heavily on hydropower for electricity generation — such as Washington, California and Oregon — planet-warming emissions caused by drought-induced shifts in the energy supply could account for up to 40% of all GHG emissions from electricity in future drought years, the research shows. Increasingly frequent droughts will make it more challenging for the electricity sector to fully decarbonize, and hydro-reliant states will need to pursue extra initiatives to achieve net-zero emission goals.

In the coming decades, even as renewable energy and energy storage cover more of the overall average demand for electricity in the American West, fossil fuel-based power plants are projected to remain the dominant energy source for these marginal energy needs.

“If we want to solve this issue, we need an even greater expansion of renewable energy alongside better energy storage, so we don’t need to tap into fossil fuels as much,” said Qiu. “Ultimately, to limit future warming and the drought risks that come with it, we need to reduce our emissions.”

This research was supported by a planetary health fellowship from Stanford’s Center for Innovation in Global Health.

Originally published by Hydro Review