New Study: Energy Choices Today Affect Water Availability Tomorrow

Today, the Energy and Water in a Warming World initiative (EW3), a collaborative effort between the Union of Concerned Scientists and a team of independent experts, released their second major report, Water-Smart Power: Strengthening the U.S. Electricity System in a Warming World. This study examined various pathways by which the power industry could choose to generate electricity over the coming decades and what the subsequent effects are on watersheds – both in terms of water quality and quantity. Despite recent industry shifts in generation, ongoing water requirements could still adversely affect water-strained areas, and do little to lower power generation-related carbon emissions.

In the Southeast, the study focused on the Apalachicola-Chattahoochee-Flint (ACF) and the Alabama-Coosa-Tallapoosa (ACT) water basins in Georgia, Alabama, and the Florida Panhandle, which are already significantly stressed and are lined with multiple water-thirsty coal and nuclear plants. For years, those states have fought over water from the two basins, particularly in times of water stress such as the devastating drought of 2007. Power generation accounts for more than 40 percent of the nation’s freshwater withdrawals. In parts of the Southeast like Georgia and Alabama, power plants are by far the largest water users with withdrawals ranging from over 50 percent to upwards of 80 percent (respectively).

The South is experiencing unprecedented population growth compared to the rest of the nation. Estimates of 40 percent growth by 2030 will increase demand for electricity. Conservative estimates show that conventional power plant capacity is projected to rise almost 20 percent by 2030 in order to meet that demand. As the effects of climate change mount, including rising temperatures and declining water availability, these factors combined will contribute to greater strain on our limited water supplies. The competing demands for energy and water are colliding, putting both at risk.

Utility companies across the Southeast are at a moment of great change as the economic viability of coal and nuclear plants declines, natural gas prices remain low, and global awareness of the seriousness of climate change drives new policy measures. It is clear that the choices utilities make today will seal the fate of how much strain their energy portfolios will place on the region’s dwindling water supplies and contribute to the effects of climate change in the decades to come.

If the “business-as-usual” (BAU) path continues in the Southeast, scientists expect the net water supply to decline by 2060 while population and demand rise, worsening water stress and affecting wildlife in some of the nation’s most sensitive and biologically diverse rivers.

STUDY FINDINGS

The study authors analyzed four primary scenarios. These included “business-as-usual” (BAU) and three scenarios based on a strict carbon budget to address the power sector’s contributions to global warming. Two of those three scenarios assumed the use of specific technologies to make significant cuts in carbon emissions. The most impactful scenario in terms of reducing carbon emissions and water withdrawals modeled utilities investing heavily in renewable energy, such as wind and solar, and energy efficiency to meet energy needs instead of conventional power plants.

High renewables and efficiency Scenario 3 (blue line) shows significant water consumption and withdrawal improvements over the years.

The study found that under the industry’s current, or business-as-usual (BAU), path, carbon emissions would stay within 5 percent of current levels despite some reduction in coal plant usage. Water withdrawal and consumption would improve only slightly before 2030, but would drop more than 80 and 40 percent, respectively, by 2050. Given today’s water constraints, a twenty year delay in water savings leaves utilities unnecessarily vulnerable to drought and other water users in unnecessary competition.

In the Southeast, this status quo path would eventually reduce water consumption and withdrawals, but would also decrease water quality as the heated water released by power plants increases the temperature of nearby waterways [click here for image]. On the Coosa River above Weiss Lake on the Alabama-Georgia border, water temperatures in 2040-2049 would exceed 90°F eighteen days per year on average, three times what the study projects would happen under BAU for 2010-2019 because of increasing temperatures and lower water availability. Such high water temperatures from thermal pollution can severely stress and even kill aquatic life and ecosystems.

The report authors also analyzed a final pathway (Scenario 3 – graphs on the right) in which energy efficiency would more than meet the projected 2050 growth in electricity demand and renewable energy would produce 80 percent of the remaining energy needs, thereby greatly reducing power generation’s water use. That approach would also cut carbon emissions 90 percent from current levels, chiefly in the first 20 years.

Under that projected pathway, water withdrawals would drop by 97 percent from current levels by 2050—much greater than under the business-as-usual pathway. Such withdrawals would also drop much faster, with 2030 withdrawals only half as much as under BAU. Water consumption under the renewables and energy efficiency scenario would drop by 85 percent from current levels by 2050.

CONCLUSIONS

The study concluded that many near-term options exist to reduce current risks and develop a resilient electricity system. Options include prioritizing low-carbon, water-smart energy options such as renewable energy and energy efficiency, upgrading power plant cooling with systems that ease local water stress, matching thermoelectric cooling needs with more appropriate water sources, and instituting state-level integrated resource planning that connects energy and water decision makers.

Peter Frumhoff, UCS’ Director of Science and Policy, lead author of the new report, and head of the EW3 Scientific Advisory Committee concludes:

Making low-carbon, water-smart choices is a high-stakes effort—the choices we make in the near term to define the power sector of the 21st century will in turn shape changes to our water resources directly, to our climate and long-term hydrology, and to the power sector’s long-term resilience. We set electricity and water on a collision course years ago. Now we must build a power system hard-wired not for risk, but for resilience.

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