PublicationJournal Article Balancing renewable energy and river resources by moving from individual assessments of hydropower projects to energy system planning

January 9, 2023
  • Carvallo Bodelon, Juan Pablo
  • Kammen, Daniel
  • Jeffrey J. Opperman,
  • Rafael Kelman,
  • Rafael J. P. Schmitt4,
  • Rafael Almeida,
  • Emily Chapin,
  • Alexander Flecker,
  • Marc Goichot,
  • Guenther Grill,
  • Julien J. Harou,
  • Joerg Hartmann,
  • Jonathan Higgins,
  • Erik Martin,
  • Taina Martins,
  • Amy Newsock,
  • Carlos Rogéliz,
  • Justus Raepple,
  • Rajesh Sada,
  • Michele L. Thieme,
  • David Harrison
Publication Type:
Journal Article

As gov­ern­ments and non-​​state actors strive to min­i­mize global warm­ing, a pri­mary strat­egy is the decar­boniza­tion of power sys­tems which will require a mas­sive increase in renew­able elec­tric­ity gen­er­a­tion. Lead­ing energy agen­cies fore­cast a dou­bling of global hydropower capac­ity as part of that nec­es­sary expan­sion of renew­ables. While hydropower pro­vides gen­er­ally low-​​carbon gen­er­a­tion and can inte­grate vari­able renew­ables, such as wind and solar, into elec­tri­cal grids, hydropower dams are one of the pri­mary rea­sons that only one-​​third of the world’s major rivers remain free-​​flowing. This loss of free-​​flowing rivers has con­tributed to dra­matic declines of migra­tory fish and sed­i­ment deliv­ery to agri­cul­tur­ally pro­duc­tive deltas. Fur­ther, the reser­voirs behind dams have dis­placed tens of mil­lions of peo­ple. Thus, hydropower chal­lenges the world’s efforts to meet cli­mate tar­gets while simul­ta­ne­ously achiev­ing other Sus­tain­able Devel­op­ment Goals. In this paper, we explore strate­gies to achieve the needed renew­able energy expan­sion while sus­tain­ing the diverse social and envi­ron­men­tal ben­e­fits of rivers. These strate­gies can be imple­mented at scales rang­ing from the indi­vid­ual project (envi­ron­men­tal flows, fish pas­sage and other site-​​level mit­i­ga­tion) to hydropower cas­cades to river basins and regional elec­tri­cal power sys­tems. While we review evi­dence that project-​​level man­age­ment and mit­i­ga­tion can reduce envi­ron­men­tal and social costs, we posit that the most effec­tive scale for find­ing bal­anced solu­tions occurs at the scale of power sys­tems. We fur­ther hypoth­e­size that the pur­suit of solu­tions at the sys­tem scale can also pro­vide ben­e­fits for investors, devel­op­ers and gov­ern­ments; evi­dence of ben­e­fits to these actors will be nec­es­sary for achiev­ing broad uptake of the approaches described in this paper. We test this hypoth­e­sis through cases from Chile and Uganda that demon­strate the poten­tial for system-​​scale power plan­ning to allow coun­tries to meet low-​​carbon energy tar­gets with power sys­tems that avoid damming high pri­or­ity rivers (e.g., those that would cause con­flicts with other social and envi­ron­men­tal ben­e­fits) for a sim­i­lar sys­tem cost as sta­tus quo approaches. We also show that, through reduc­tion of risk and poten­tial con­flict, strate­gic plan­ning of hydropower site selec­tion can improve finan­cial per­for­mance for investors and devel­op­ers, with a case study from Colombia.

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