The United States’ continued build out of renewable energy, is giving rise to tensions between competing environmental interests. One such conflict is between constructing more renewable energy infrastructure and the ecological damage that comes with it.
Renewable energy is needed more now than ever as the U.S. continues to rely heavily on fossil fuels. Most domestic greenhouse gas emissions are still caused by burning coal, natural gas, and hydrocarbons. Despite a seven percent drop in global carbon dioxide emissions in 2020 due primarily to the COVID-19 pandemic limiting transportation emissions, these numbers figure to rise again as pandemic restrictions are lifted and travel resumes. Switching from fossil fuels to renewable energy will mitigate water and air pollution, excessive water and land use, ecological loss, public health concerns, and climate change.
However, each type of renewable energy has its own environmental concerns. One of the most controversial sources of renewable energy is hydroelectric power due to both its ability to create large amounts of electricity but also its potential to create massive ecological damage. 
Hydroelectric power includes both large dams and small riverside plants. Massive hydroelectric dams require a significant amount of land, specifically near a body of water that can support the dam at all times. Hydroelectric power sources also can only be located in places with a sufficient amount of precipitation. Approximately fifty percent of hydroelectric power sources are concentrated in Washington, California, and Oregon. Since hydroelectric power requires valuable and limited space to operate, most ideal locations in the United States have already been utilized.
The challenges and ecological costs of hydroelectric power in the U.S. are often due to its advantages, such as the ability to pair with other forms of renewable energy. However, it is important to recognize the disadvantages of hydroelectric power to properly evaluate what renewable energy sources are appropriate for communities in the future.
Hydroelectric power not only requires significant land use, but also large reservoirs that often flood and can destroy natural habitats, agricultural lands, and even local communities. In addition, hydroelectric power facilities can significantly impact aquatic ecosystems by disturbing fish migration, killing fish with facilities’ turbine blades, and interfering with aquatic reproduction by changing water patterns downstream.
Furthermore, large scale hydroelectric powerplants produce short- and long-term carbon emissions. Short term emissions occur during facility construction, while long-term emissions result from flooding, as after an area is flooded from the reservoir, soil and other vegetation decomposes and releases carbon dioxide and methane. Reservoir water also has less oxygen and higher amounts of nutrients, which can cause eutrophication, damaging other aquatic ecosystems connected to the local ecosystem. And as the U.S. experiences more draughts each year, these water-dependent systems may deplete other necessary resources like drinking water.
Conflict of Interests in Maine
New England Clean Energy Connect (NECEC) is a $1 Billion project to build a transmission line from Quebec through Maine to bring hydropower to Maine and Massachusetts. The NECEC would be the largest source of renewable energy in New England.
The power would come from Hydro-Quebec’s massive network of large dams and sixty-three hydropower stations, and then through the proposed 145-mile transmission pipeline to Maine and Massachusetts. NECEC is New England’s solution to responding to climate change, with all six states in the region aiming to cut greenhouse gas emissions by 2050.
The project has been met with both regulatory challenges and concern from activist groups. Massachusetts Governor Charlie Baker has made the project a priority, saying it would help reduce the region’s reliance on natural gas, which accounts for 50 percent of New England’s electricity generation and can lead to high heating bills during the worst stages of New England’s winters.
Democratic lawmakers in Maine disagree and are concerned that the project will have a significant environmental toll on scenic landscapes, wildlife, and potential disruption of current electricity sources. Environmental groups such as the Sierra Club and Natural Resources Council of Maine (NRCM) are also concerned that Hydro-Quebec will lead to increased emissions, since the company has financial incentives to sell as much electricity to New England, where electricity rates are high.
One of the largest points of contention is actually understanding how much this new source of power would reduce greenhouse gases, if at all. New Hampshire rejected a similar project that would have built an underground transmission line to import Quebec hydroelectric power to the state.
In addition to concerns regarding the transmission line’s potential to disturb the state’s wildlife, the state’s evaluation committee found that Eversource Energy, the company that proposed the line, failed to demonstrate that the project would not unduly interfere with the future goals of development of the region. The state also found issues with the proposed reduction of greenhouse gas emissions, and the New Hampshire Supreme Court upheld the committee’s decision.
The challenges with adequately calculating the carbon footprint of hydropower comes from several variables that affect what and how much a hydropower reservoir emits, including include climate, geographic location, area of flooded land, the kind of vegetation flooded, and land management practices previous to the reservoir. As Bradford H. Hager, an earth sciences professor at MIT, said on behalf of NRCM:
“The amount of power Hydro-Quebec produces per acre flooded is among the lowest of any hydropower in the world. The trees, bogs and soils Hydro-Quebec floods have been storing carbon since the last Ice Age. When flooded, this stored carbon decomposes, releasing CO2 and methane. To make things worse, drowned trees are gone forever and cannot grow back to remove CO2 in the future.”
Environmental groups and Indigenous communities have concerns beyond the project’s potential greenhouse gas emissions. Other disadvantages of hydropower plants include widespread harm to forests and wetlands, and environmental justice issues. First Nations communities, for example, have been displaced before with by hydroelectric dams—36 percent of Hydro-Quebec’s power is located on Innu, Atikamekw, and Anishnabeg land—which also exposes local indigenous communities to the neurotoxin methylmercury.
The NECEC transmission line began construction in February in East Moxie Township despite these points of concern. In November 2020, Maine voters had a ballot referendum to vote on the project, but the Maine Supreme Court ruled the referendum unconstitutional. Another ballot initiative is being considered after a petition with 100,000 signatures opposing the project was delivered to the Main Secretary of State’s Office; a decision on whether the measure will be put on the ballot is pending. And though construction is underway, each permit issued for the project is being challenged due to concerns about a lack of environmental protection.
 Environmental Impacts of Renewable Energy Technologies, Union of Concerned Scientists, (Mar. 5, 2013), https://www.ucsusa.org/resources/environmental-impacts-renewable-energy-technologies (Last Visited Mar. 7, 2021).
 Energy and the environmental explained, U.S. Energy Information Administration, https://www.eia.gov/energyexplained/energy-and-the-environment/where-greenhouse-gases-come-from.php (Last Visited Mar. 7, 2021).
 COVID lockdown causes record drop in carbon emissions for 2020, Stanford University School of Earth, Energy, and Environmental Sciences, (Dec. 10, 2020), https://earth.stanford.edu/news/covid-lockdown-causes-record-drop-carbon-emissions-2020#gs.v8ut71 (Last Visited Mar. 7, 2021).
 See Union of Concerned Scientists, supra note 1.
 Environmental Impacts of Hydroelectric Power, Union of Concerned Scientists, (Ma. 5, 2013), https://www.ucsusa.org/resources/environmental-impacts-hydroelectric-power (Last Visited Mar. 7, 2021).
 Hydropower Explained, U.S. Energy Information Administration, https://www.eia.gov/energyexplained/hydropower/where-hydropower-is-generated.php (Last Visited Mar. 7, 2021).
 Hydroelectric Power Water Use, USGS, https://www.usgs.gov/special-topic/water-science-school/science/hydroelectric-power-water-use?qt-science_center_objects=0#qt-science_center_objects (Last Visited Mar. 7, 2021).
 Peter H. Gleick, Impacts of California’s Ongoing Drought: Hydroelectricity Generation 2015 Update, Pacific Institute (Feb. 2016), https://pacinst.org/wp-content/uploads/2016/02/Impacts-Californias-Ongoing-Drought-Hydroelectricity-Generation-2015-Update.pdf.
 Generating stations, Hydro Quebec (Jan. 1, 2020), https://www.hydroquebec.com/generation/generating-stations.html (Last Visited Mar. 7, 2021).
 Benjamin Storrow, Effort to Trade Gas for Hydropower in Northeast Meets Resistance, Scientific American (May 22, 2019), https://www.scientificamerican.com/article/effort-to-trade-gas-for-hydropower-in-northeast-meets-resistance/ (Last Visited Mar. 7, 2021).
 David Brooks, N.H. Supreme Court agrees with state’s rejection of Northern Pass transmission line, Concord Monitor (Aug. 19, 2019), https://www.concordmonitor.com/northern-pass-electricity-eversource-grid-energy-power-27118513 (Last Visited Mar. 7, 2021).
 State of New Hampshire Site Evaluation Committee, Doc. No. 2015-06 at 6 (2018).
 Yves Prairie, et. al, Greenhouse Gas Emissions from Freshwater Reservoirs: What Does the Atmosphere See? NCBI (Jan. 1, 2019), https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6309167/ (Last Visited Mar. 7, 2021).
 Bradford Hager, Hydro Quebec Offers Misleading Claims about Power’s Climate Impact, Natural Resources Council of Maine (Jan. 5, 2019), https://www.nrcm.org/news/hydro-quebec-offers-misleading-claims-powers-climate-impact/ (Last Visited Mar. 7, 2021).
 See Innu First Nation of Pessamit, Quebec Export of Electricity to the United States- The moment of truth for Pessamit and Wemotaci First Nations, Cision (Aug. 5, 2020), https://www.prnewswire.com/news-releases/quebec-export-of-electricity-to-the-united-states—the-moment-of-truth-for-pessamit-and-wemotaci-first-nations-301106759.html (Last Visited Mar. 7, 2021); but see Leah Burrows, Human Health Risks from Hydroelectric Projects, Harvard John Paulson School of Engineering and Applied Sciences (Nov. 9, 2016), https://www.seas.harvard.edu/news/2016/11/human-health-risks-hydroelectric-projects, (Last Visited Mar. 7, 2021).
 Don Carrigan, Despite court and petition challenges, first pole goes up for NECEC, News Center Maine (Feb. 9, 2021), https://www.newscentermaine.com/article/life/despite-court-and-petition-challenges-first-pole-goes-up-for-necec/97-bdcca7ae-a0dc-43f5-8350-922b80fe0aef (Last Visited Mar. 7, 2021).
 Steve Mistler, Maine Supreme Court Says Ballot Initiative Aimed at Stopping CMP Project is Unconstitutional, Maine Public Radio (Aug. 13, 2020), https://www.mainepublic.org/post/maine-supreme-court-says-ballot-initiative-aimed-stopping-cmp-project-unconstitutional (Last Visited Mar. 7, 2021).
 Tux Turkel, Controversial power line caught up in high-stakes power struggle, Portland Press Herald (Feb. 8, 2021) https://www.pressherald.com/2021/02/07/controversial-power-line-caught-up-in-high-stakes-power-struggle/# (Last Visited Mar. 7, 2021).