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Hydropower

Chi-Jen Yang, at AGCI's 2016 Getting Near Zero workshop, discusses the potential of pumped hydroelectric storage.

Hydropower is regarded as a mature and cost-competitive renewable energy source and plays a significant role in today’s electricity mix. Hydropower accounts for more than 16% of global electricity from over 1,200 GW of installed capacity, and about 85% of global renewable electricity [IEA, 2018]. In 2017, 21.9 GW of hydropower capacity was added world over [IHA 2018].

Leading hydropower markets such as China and Brazil are expected to slow down aggressive capacity additions in the next few years. That said, cumulative installed capacity is expected to go up by as much as 125 GW by 2023. China in spite of a slower growth rate is expected to contribute to 40% of the net capacity additions by 2023 [IEA, 2018].

As such, hydropower is expected to be the leading renewable energy source in terms of capacity and attention is expected in pumped hydro storage to increase power sector flexibility as a means to further decarbonize the economy [IEA, 2018].

The top countries for hydropower capacity accounted for about 63% of global installed capacity at the end of 2017; these countries include China, Brazil, Canada, the United States, the Russian Federation, India and Norway [REN21, 2018].

Imminent Breakthroughs

  • Modern hydro turbines can convert 90% of available energy into electricity, which is an advantage over fossil fuels, which average only about 50% efficiency [Bilgili et al., 2015].
  • Small hydropower plants (SHPs), with less than 10 MW installed capacity, are becoming increasingly significant with over 82000 SHPs currently functioning or under construction, collectively in 150 countries. The scope for expansion for SHPs is almost thrice the current number if all resource availability is exploited. China leads the pack globally with over 47000 SHPs currently in operation [Couto et al., 2018].
  • Large-scale Hydropower stood just behind solar and wind in global investments. Through 2017 saw a reduction in SHP, asset financing reaching financial go-ahead in 2017 stood at USD 45 billion, more than doubling from 2016 values. [REN21, 2018].
  • Advancement of hydrokinetic energy conversion (HEC) technology is being applied to harness hydro energy from slow-moving rivers [Laws & Epps, 2016].

Obstacles to TW-Scale Integration

  • Sediment management is a key aspect of ensuring continued high hydropower energy production efficiencies. Sediment management can happen at the reservoir, the catchment or at the dam. While technical solutions are being created, the lack of an explicit policy signal focused on sediment quality and quantity is absent at the moment. Other policy directives sometimes have an indirect effect on sediment management [Hauer et al., 2018].
  • Socially important activities such as agriculture upstream of the reservoir is seen to pose a major technological threat due to increased sedimentation. Orientation of farmers to sustainable practices such as avoiding over irrigation to reduce nutrient runoff becomes necessary [Mdee et al., 2018]
  • Technical challenges related to power generation, such as hydro-kinetic turbines, include relatively low efficiency, cavitation, high installation costs, and maintenance difficulties [Zhou & Deng, 2017].
  • Modernization and rehabilitation of existing plants become a key consideration and also a trend in purposes of reducing maintenance cost, increasing maintenance intervals during the industry operations, increasing operation efficiency, and providing grid support [REN21, 2018].
  • Hydropower plants can take long periods of time to construct. In remote locations, project costs become quite high owing to the economic burden of transporting manpower and machinery to the site. Isolated hydro-power plants would also require extensive transmission investments, which further shoot up the project costs [Hussain, et al.]
  • Hydropower is challenged from a life-cycle sustainability perspective especially because of the sheer pace at which they are being constructed. Countries are being encouraged to view the reservoir construction overheads when discussing emission savings from hydropower [MIT Technology Review, 2016].
  • Obstacles restricting hydropower development in China include: 1) shortage of small hydropower development funds; 2) Excessive dependence on bank credit; 3) government investment management issues; and 4) lag of national policies [Ximei et al., 2015].

Enabling Technologies

  • Recent technologies, such as tunnel boring machines and the drill-and-blast method, have facilitated tunneling construction, and have reduced excavation costs by 25% (0.8% per year) in the last three decades [Kumar et al., 2011].
  • Hydropower plants can be generally classified, according to their functions in three categories: run-of-river, reservoir, or storage and pumped storage plants [Bilgili et al., 2015].
  • Digitalization of hydropower facilities is one of the enabling technologies for modernization on existing plants. This technology enables advanced simulation, monitoring, and control; more flexible integration, greater plant reliability, as well as efficiency improvement in operation and maintenance [REN21, 2018]. For example, the virtual reality application for remote analysis on plants condition, introduced by Vioth Hydro (Germany); computer-generated digital simulations of plant components for timely recommendation provision, implemented by GE (U.S.); digital solutions that facilitate to decision-making on enhancing operation and maintenance, offered by Andritz (Austria) [REN21, 2018]
  • Hydro-kinetic turbines can convert energy in flowing water to electricity, and power generation could be increased by wind farms. They are usually applied in rivers, rides, ocean currents, artificial waterways, and other sites with sufficient water velocities [Zhou & Deng, 2017].
  • Run-of-river hydropower plants (Figure 1) generate electricity production by harnessing energy contained in river flow. Usually, short-term storage facilities (or “pondage”) exist for temporary energy storage [IEA, 2017].

Figure 1. Run-of-the-river systems. From Chief Joseph Dam, 2015.

  • Reservoir hydropower plants harness the energy of stored water in a reservoir. They provide the flexibility to generate electricity on demand, and reduce dependence on the variability of inflows [IEA, 2017].

Figure 2. Reservoir hydropower plant. From http://www.whyhydropower.com/HydroTour2b.html

  • Pumped storage plants (PSPs) work when electricity supply exceeds demand or can be generated at low cost. PSPs currently represent 99% of on-grid electricity storage [IEA, 2017].

Figure 3. How do pumped storage hydro plants work. From Duke Energy

  • Pico Hydro Power (PHPs) with installed capacities in the kilo-Watt (kW) scale are becoming increasingly popular as a conceivable alternative energy provider for remote or rural locations. Owing to their scale, they also require very less capital expense and virtually no operational expenses, making them a very attractive choice [Kadier et al., 2018].

Political Considerations

  • Many countries regard hydropower as a strategic clean energy. For example, in Norway, a large proportion of electricity is derived from hydropower, and more than 50% of production capacity is provided from storage reservoirs [Bilgili et al., 2015].
  • Some countries put great emphasis on the exploration of hydropower. For example, China is pursuing both large-scale projects and smaller projects in more remote regions, including a 10.2 GW Wudongde plant to be completed in 2020, and small hydropower plants in Tibet [REN21, 2016].
  • Hydropower has a role in international carbon markets. Carbon credits are awarded to hydropower projects through the Clean Development Mechanism (CDM), and the credits bring additional funding to the project, accruing investment capital for the host countries. Registered hydropower projects in the CDM avoided 50 Mt of carbon dioxide by 2012 [Kumar et al., 2011].
  • From the political ecology perspective, people need to consider the cross-sectoral and cumulative impacts of development initiatives, especially the relationship between large hydropower dams and large tree plantations [Baird & Barney, 2017].
  • Financing is difficult for hydropower projects because of high upfront costs that often deter investment [Kumar et al., 2011].
  • Research show that hydropower has significant influences on a country's governance [Sovacool & Walter, 2018].

Social Considerations

  • Hydropower has acted as a catalyst for economic and social development because it provides energy and water management services, allowing for power production as well as many job opportunities [Kumar et al., 2011; Okot, 2013].
  • On the other hand, the social costs of dam construction are often underestimated. Hydropower constructions are prone to delays and cost overshoots, with one in every 10 mega project surpassing earmarked budget. Time overshoots of construction also interrupt local fishing and transport economies. Some 40-80 million people have been displaced to date, as a result of large-scale hydropower construction [Moran et al., 2018].
  • The integration of environmental and social risks at the early stages of project planning is imperative for sustainability and allows for broad economic benefits beyond energy generation alone [REN21, 2018]
  • Research show that both hydropower constructing and producing countries had a higher poverty gap than non-hydro countries [Sovacool & Walter, 2018].
  • Hydropower dams can be used for flood and drought mitigation, to store water for irrigation, to facilitate navigation, to promote fishing, tourism, and leisure activities, and to augment the supply of water for domestic, municipal, and industrial uses [Kumar et al., 2011].
  • Several dams built during the construction boom in the US (the 1930-1950 period) are reaching ages well past 50 years. Strategies to safely retrofit or retire dams is vital to avoid human fatalities due to possible dam breaches [Moran et al, 2018].
  • Other social considerations include insufficient hydrological data, unexpected geological conditions, lack of watershed-based planning, insufficient project financing, shortage of local and skilled human resources, and an absence of regional cooperation [Kumar et al., 2011].

Environmental Considerations

  • Hydropower produces no atmospheric pollutant and only very few GHG emissions [Okot, 2013]. A mini hydro plant can reduce about 950 tons of CO2, 12 tons of SOx and 5 tons of NOx, compared with an equivalent thermal power plant [Laghari et al., 2013].
  • Hydropower can have both potentially positive and negative impacts on freshwater ecosystems. On the one hand, hydropower infrastructure can create new freshwater ecosystems with increased productivity [Okot, 2013]; on the other hand, hydropower causes fragmentation of free-flowing rivers and habitat changes that can threaten freshwater biodiversity [Zarfl et al., 2015, Kumar et al., 2011]. Hydropower plants create barriers for fish migration and fish entrainment, modification of aquatic habitats, as well as the change in water quality [Okot, 2013, Kumar et al., 2011].
  • Large dams may have adverse effects on the ecosystem due to the delay and attenuate seasonal flood pulses, hindering fish from getting access to floodplain habitats for nursery and feeding activities [Winemiller et al., 2016].
  • As for flow regime, reservoirs can significantly alter stream flow, subsequently impacting water temperature. These changes may affect fish, birds, and other animals in the ecosystem [Kumar et al., 2011].
  • Dams that are used for hydropower impound about 14% of all global water runoff and fragment 60% of the world's 227 largest rivers [Sovacool & Walter, 2018].
  • Hydropower, though a clean energy source, is dependent on natural resource availability for its functioning. Climate change is greatly disrupting precipitation patterns and affecting the power output of existing hydropower projects. Developed countries are revisiting hydropower plans or are retrofitting existing projects with more efficient turbine technology in preparation for resource interruptions [Moran et al., 2018].
  • South American countries have extensive hydropower generation capacities and most generation comes from the Amazon basin. It is vital to reconsider future hydro plans to account for resource disruptions [Moran et al., 2018].
  • Hydropower construction brings forth land use change patterns. Large footprints of forest cover are cleared to allow for dam construction in the case of many large-scale projects. This forest cover change can cause local precipitation pattern variations affecting the output of hydropower plants. In addition, the clearing of forests rids trees which are important carbon sinks [Moran et al., 2018].

References:

Baird, I. G., & Barney, K. (2017). The political ecology of cross-sectoral cumulative impacts: modern landscapes, large hydropower dams and industrial tree plantations in Laos and Cambodia. The Journal of Peasant Studies, 44(4), 769-795.

Bilgili, M., Ozbek, A., Sahin, B., & Kahraman, A. (2015). An overview of renewable electric power capacity and progress in new technologies in the world. Renewable and Sustainable Energy Reviews, 49, 323-334.

Choudhury, N. (2014). Towards responsible hydropower development through contentious multi-stakeholder negotiations: The case of India. In Evolution of Dam Policies (pp. 95-129). Springer Berlin Heidelberg.

Couto, Thiago BA, and Julian D. Olden. "Global proliferation of small hydropower plants–science and policy." Frontiers in Ecology and the Environment 16.2 (2018): 91-100.

Harris, M. 2018. Project Drawdown comes to Europe, includes hydro amongst solutions for sustainable greenhouse gas reduction. Retrieved from: https://www.hydroworld.com/articles/2018/04/project-drawdown-comes-to-europe-includes-hydro-amongst-solutions-for-sustainable-greenhouse-gas-reduction.html

Hauer, C., et al. "State of the art, shortcomings and future challenges for a sustainable sediment management in hydropower: A review." Renewable and Sustainable Energy Reviews 98 (2018): 40-55.

Hess, C. E. E., & Fenrich, E. (2017). Socio-environmental conflicts on hydropower: The São Luiz do Tapajós project in Brazil. Environmental Science & Policy, 73, 20-28.

Hussain, Abid, et al. "Hydropower development in the Hindu Kush Himalayan region: Issues, policies and opportunities." Renewable and Sustainable Energy Reviews 107 (2019): 446-461.

IEA. (2017). https://www.iea.org/fuels-and-technologies/hydropower

IEA. (2018). Hydropower. Retrieved from: https://www.iea.org/topics/renewables/hydropower/

IHA, (2018). Hydropower preparation facility gains support at finance workshop. Retrieved from: https://www.hydropower.org/news/hydropower-preparation-facility-gains-support-at-finance-workshop.

IHA, (2018-19). World Hydropower Activity and Strategy Report. Available at: https://www.hydropower.org/sites/default/files/publications-docs/iha_activity_and_strategy_report_2018-2019_0.pdf

Kadier, Abudukeremu, et al. "Pico hydropower (PHP) development in Malaysia: Potential, present status, barriers and future perspectives." Renewable and Sustainable Energy Reviews 81 (2018): 2796-2805.

Kumar, A., T. Schei, A. Ahenkorah, R. Caceres Rodriguez, J.-M. Devernay, M. Freitas, D. Hall, Å. Killingtveit, Z. Liu, 2011: Hydropower. In IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)], Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Laws, N. D., & Epps, B. P. (2016). Hydrokinetic energy conversion: Technology, research, and outlook. Renewable and Sustainable Energy Reviews, 57, 1245-1259.

Mdee, Ombeni J., et al. "Assessment of hydropower resources in Tanzania. A review article." Renewable Energy and Environmental Sustainability 3 (2018): 4.

MIT Technology Review, 2016. Available at: https://www.technologyreview.com/s/602508/hydroelectric-power-isnt-as-green-as-we-thought/

Moran, Emilio F., et al. "Sustainable hydropower in the 21st century." Proceedings of the National Academy of Sciences115.47 (2018): 11891-11898.

Okot, D. K. (2013). Review of small hydropower technology. Renewable and Sustainable Energy Reviews, 26, 515-520.

Renewable Energy Policy Network for the 21st Century (REN21). (2016). Renewables 2016 global status report. https://www.ren21.net/wp-content/uploads/2019/05/REN21_GSR2016_FullReport_en_11.pdf

Sovacool, B. K., & Walter, G. (2018). Major hydropower states, sustainable development, and energy security: Insights from a preliminary cross-comparative assessment. Energy, 142, 1074-1082.

Supriyasilp, T., Pinitjitsamut, M., Pongput, K., Wanaset, A., Boonyanupong, S., Rakthai, S., & Boonyasirikul, T. (2017). A Challenge of Incentive for Small Hydropower Commercial Investment in Thailand. Renewable Energy.

The Renewable Energy Policy Network for the 21st Century (REN21). 2018. Renewables 2018 Global Status Report. Retrieved from: http://www.ren21.net/status-of-renewables/global-status-report/

Wikimedia Commons. (August 24, 2015). Chief Joseph Dam [Online]. Available: https://upload.wikimedia.org/wikipedia/commons/6/6c/Chief_Joseph_Dam.jpg

Winemiller, K. O., McIntyre, P. B., Castello, L., Fluet-Chouinard, E., Giarrizzo, T., Nam, S., ... & Stiassny, M. L. J. (2016). Balancing hydropower and biodiversity in the Amazon, Congo, and Mekong. Science, 351(6269), 128-129.

Ximei, L., Ming, Z., Xu, H., Lilin, P., & JunRong, D. (2015). Small hydropower financing in China: External environment analyses, financing modes and problems with solutions. Renewable and Sustainable Energy Reviews, 48, 813-824.

Zarfl, C., Lumsdon, A. E., Berlekamp, J., Tydecks, L., & Tockner, K. (2015). A global boom in hydropower dam construction. Aquatic Sciences, 77(1), 161-170.

Zhou, D., & Deng, Z. D. (2017). Ultra-low-head hydroelectric technology: A review. Renewable and Sustainable Energy Reviews, 78, 23-30.

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