Watershed analysis20 September 2010
Brian Yanity and Brian Hirsch present an analysis of conventional and in-stream hydro power in the Yukon River watershed
The Yukon River is 3700km long, draining a watershed with an area of 832,700km² (Figure 1). It is the fourth largest river system in North America, and a significant contributor to the Bering Sea ecosystem. Spanning the east-west length of the US state of Alaska and much of Canada’s Yukon Territory, the Yukon River supports the longest inland run of Pacific salmon in the world, with over 70 different indigenous Tribes and First Nations dependent on the fish and other natural resources.
The majority of the river’s length, and over 60% of the watershed drainage (508,900km²), is in the US state of Alaska, with the rest (321,800km²) in Canada’s Yukon Territory and a small part of the headwaters located in British Columbia. By comparison, the watershed’s total area is more than 25% larger than the nations of France or Ukraine. With an average flow volume of 6430m³/sec at its mouth, the river empties into the Bering Sea at the Yukon-Kuskokwim Delta, one of the largest coastal alluvial plains in the world.
As a bi-national resource, the Yukon River is managed by and subject to international treaties, e.g., the Pacific Salmon Treaty and the Jay Treaty, as well as US and Canadian federal, state, provincial, territorial, tribal, land claims and municipal laws and practices. These complementary and at times competing mandates result in a patchwork of management regimes and potentially conflicting priorities. Calls for a watershed-wide approach to resource management, including for hydro power development, are becoming more common (Indian Law Resource Center, 2003).
History of hydropower in the Yukon River watershed
Historically, the mining and smelting industries have been the largest factor influencing hydropower development in the Yukon River watershed. Many of the early hydropower installations in the region provided mechanical energy for mining equipment, as opposed to hydroelectric power generation. Placer gold mines throughout the Yukon River watershed relied on hydraulic extraction methods. In the early 20th century, two hydroelectric plants were developed in the Dawson City area, Twelve Mile and North Fork, to serve local mining operations. The 1.2MW Twelve Mile plant operated between 1907 and 1920, on the Twelve Mile (now Chandinau) River, and the 5.4MW North Fork plant (later expanded to 8.1MW) operated between 1911 and 1966, on the Klondike River.
Not long after, some hydropower facilities were developed in interior Alaska for gold mining operations in the Yukon River watershed.
Soon after the Fairbanks gold rush of 1902, several hydropower installations for Tanana Valley gold mines were constructed, operating seasonally. Early mining operations also harnessed energy from the Yukon River’s headwaters in northwestern BC. In the mid-1920s, the Wann River hydroelectric plant was built to power the nearby Engineer gold mine, near the southern end of the Taku Arm of Tagish Lake.
Between the 1940s and the 1970s, several large-scale hydroelectric projects were proposed for the Yukon River watershed, yet never built. In addition to Rampart – the largest prospect of all and further discussed later – other large dams were proposed for the Yukon River in interior Alaska, and four different Upper Yukon headwater diversions were proposed through the coastal mountains. Three of the proposed tunnel routes were diversions to the Taiya River in Alaska, while one was to divert waters to the Taku River in British Columbia.
As described in “The economics of an Upper Yukon basin power development scheme” (Schramm, 1968): “The overall development scheme of all four plans is essentially the same. It is based on the use of existing lakes, plus, in some cases, additional storage and diversions of lakes and rivers adjacent to the primary storage area, the drilling of one or more tunnels through the coastal mountains and the construction of one or more power plants in the valleys below. The main differences lie in the number of additional storage lakes created and the routing of the main tunnel or tunnels.”
As lake-tap projects, Yukon-Taiya and Yukon-Taku would have had far less potential environmental impacts than the Rampart or other large dam proposals for the Yukon River described below. Therefore, these large-scale proposals to divert water from the Yukon’s headwaters may be resurrected in the future.
R.C. Johnson, an engineer with US Bureau of Reclamation, first proposed in 1946 what was initially called the Tagish-Lynn project. The proposal’s name was soon changed to Yukon-Taiya, after the Taiya Inlet, in northern Lynn Canal. A joint US-Canada effort, the Yukon-Taiya project would have consisted of an underground tunnel (ranging between 23km and 27km in length) underneath the Chilkoot Pass area, going from Bennett Lake in British Columbia, to a powerhouse site in the Taiya River Valley near Skagway, Alaska. The plant would intake water from a series of connected lakes in the Yukon and British Columbia.
Through channel dredging, six existing lakes in Canada – Marsh, Tagish, Atlin, Little Atlin, Bennet and Lindeman lakes – would be merged into one interconnected reservoir of over 1200km2 in size, with a surface elevation about 670m above sea level (Bureau of Reclamation, 1955).
The minimum diverted flow of the three different Yukon-Taiya proposals ranged between 79m³/sec and 524m³/sec, or between 1% and 8% of the total Yukon River average flow volume. The proposed power plant would have ranged between 320MW and 4000 MW of estimated generation capacity, representing 2.8 to 25 TWh in annual firm energy (Wardle, 1957). As originally proposed, the powerhouse would be located in what is now Klondike Gold Rush National Park, near the historic Dyea town site.
In the late 1940s, the joint US/Canada Yukon-Taiya Commission studied the project, but it was halted in 1951 at the request of the Canadian government. During the 1950s, the Aluminum Company of America (Alcoa) expressed serious interest in developing Yukon-Taiya to power a smelter to be built at Dyea, near Skagway. Alcoa dropped all plans for Yukon-Taiya in 1957, after the Canadian and BC governments decided against cooperating on the project. There were several reasons, mostly relating to unresolved international waters issues that made the Yukon-Taiya proposal unpopular in Canada.
In particular, the Alcoa aluminium smelter proposed for Skagway was seen as direct competition to the Alcan smelter at Kitimat, BC, which was under construction during in the early 1950s. However, despite the Canadian opposition, business interests in Alaska continued to advocate for Yukon-Taiya for the entire decade of the 1960s. To advance the project, the Alaska Legislature created the Yukon-Taiya Commission in 1967. However, its work stopped in 1972 after being unable to gather meaningful support for the project in either the US or Canada (Norris, 1996).
The massive Yukon-Taku scheme would have consisted of three separate tunnels with a combined length of about 31km. All of the facilities would be completely located within Canada, and would have required multiple dams, with far greater artificial reservoirs compared to Yukon-Taiya. Yukon-Taku would have had three powerhouses in different locations, with a total of 3600MW of total generation capacity, and a firm annual energy output of 31.2 TWh (Wardle, 1957). The minimum flow diverted was to be 793m³/sec, representing about 12% of the total Yukon River average flow volume. However, in addition to the Yukon River watershed, some water was to be diverted into the Upper Yukon from the Alsek River watershed. As part of the Yukon-Taku project, a large aluminium smelter was proposed for Tulseqah, BC, on the Taku River.
Rampart dam and other large dam proposals in Alaska
The US Army Corps of Engineers first proposed the 5040MW Rampart Dam project in the early 1950s. The plan was to dam the Yukon at Rampart Canyon, near the town of Rampart about 160km from Fairbanks, creating a reservoir over 28,000km² in area (US Department of the Interior, 1965 and 1967). The project was designed to produce about 34TWh annually, or about five times the amount of electricity the entire state of Alaska consumes today. The resulting “Lake Kennedy” would have required almost 30 years to fill up completely, and would been the largest artificial reservoir in the world. The proposed dam would have been 162m high and 1430m long.
More than a quarter million salmon pass through Rampart Canyon each year, and millions of ducks make their homes in the wetlands of the Yukon Flats, which would have been flooded under the reservoir. About 1500 people would have been directly displaced by the huge reservoir, and the lives of thousands more would have been negatively impacted by the loss of fish and animal life. Conservationists, indigenous peoples in the region, and poor project economics combined to eventually quash the proposal (Nash, 2001; O’Neill, 1995). USACE formally decided against proceeding with the Rampart project in 1971.
In 1980, the Yukon Flats National Wildlife Refuge was created, protecting most of the proposed reservoir area from development. Other large dam proposals in the watershed discussed during the 1950s and 60s included Woodchopper (3200MW), Holy Cross (2800MW), Ruby (460MW) on the main stream of the Yukon River, and a 530MW project on the Porcupine River, a major tributary of the Yukon (Alaska Power Administration, 1980).
Conventional hydropower generation
Despite all of the failed attempts at mega-projects reviewed above, several conventional, utility-scale hydroelectric facilities in the watershed were built in the Yukon Territory, the largest being the 40MW Whitehorse Rapids Dam. Today, there is nearly 76MW of conventional hydro power generation capacity in the Yukon Territory. It should be noted that 30MW of this capacity, the Aishihik development, is located outside of the Yukon River watershed in the headwaters of the adjacent Alsek River watershed. Not counting micro-scale installations on private property, there are no conventional hydroelectric facilities in the Yukon River watershed installed in Alaska.
In addition to the hydro power capacity, the Yukon Territory also has about 52MW of installed diesel generation capacity, and 0.8MW of wind, for a total installed capacity of 130MW. The vast majority of this capacity is owned by the Yukon Energy Corporation, and the remainder by the Yukon Electrical Company Ltd. (and several private installations with one contained in the table), as shown in Table 1.
The three largest hydroelectric plants are owned by Yukon Energy, while Fish Lake is owned by the Yukon Electrical Company Limited. The three larger plants were originally developed by the Northern Canada Power Commission, which turned over these assets to the Yukon Energy Corp. in 1987. Also note that six turbines totalling 17.9MW, over 23% of installed capacity, are over 50 years old.
Micro-hydroelectric development, both in the Yukon Territory and northwestern BC, started attracting more interest in the 1980s and 1990s. A 250kW hydroelectric plant in Fraser, BC (south of Haines Junction in the Yukon Territory) powers the Canadian border station, and was completed in 1990. It is owned and operated by a small private corporation and sells power to the Federal and provincial consumers of power at Fraser. The Rancheria 155kW microhydro plant in the Yukon Territory was also installed in 1990, and is also privately owned (by the operator of the Rancheria Lodge and RV Park). The 2MW Pine Creek hydropower plant in Atlin, BC, came online in April 2009.
Yukon Energy’s 20-year resource plan (Yukon Energy Corporation, 2006) states that the two industrial sectors of mining and gas pipeline development will drive future electricity demand. In the mid-1990s, the report Yukon Energy Resources: Hydro (Yukon Economic Development, 1997) listed eleven undeveloped small hydroelectric sites (each under 10MW of potential) that were considered feasible, shown in Table 2, partly due to their proximity to existing transmission lines. Note that the total installed capacity of all these undeveloped hydroelectric sites, 43.9MW, would still not equal the current diesel installed capacity of 52MW, but the additional hydropower would go a long way toward displacing almost all diesel electric generation in the Yukon Territory.
Other hydro projects were also considered in the past such as Chutla Creek and Tank Creek near Carcross (on the Whitehorse-Aishihik-Faro, or WAF, power grid); and Copper Joe Creek, Nines Creek and the Donjek River, all near the (diesel-electric) communities of Burwash Landing and Destruction Bay (about 30km apart and sharing the same diesel plant). Currently Yukon Energy is planning the “Mayo B” project which will more than double the output of the Mayo hydro plant (at Wareham dam) by building a new powerhouse 3km downstream of the existing powerhouse ( http://www.yukonenergy.ca/about/projects/mayob/ ). Another option currently being considered is called the Southern Lakes Enhancement, which would utilize Atlin Lake as a reservoir for the Marsh Lake/Yukon River system that supplies the Whitehorse Rapids hydro facility in Whitehorse (http://www.yukonenergy.ca/about/projects/slenhancement/).
Both Atlin Lake and Marsh Lake would be used for greater seasonal storage to supply more hydro and for the peak demand months of December and January. The environmental impacts of such altered hydrology would require substantial study for better understanding.
In Alaska, there are several small-scale conventional hydropower proposals presently being pursued within the Yukon River watershed. Contrary to previous trends noted above, these projects have been driven primarily not by industrial demand, but by a need for clean and affordable power to displace diesel generation in remote communities. In 2008, as the Alaska state government was reaping the windfall of high oil prices which produced significant tax revenues, the state legislature established the Alaska Renewable Energy Fund (AREF) with a $100M investment, followed by $25M in 2009.
The AREF has funded both feasibility studies and preliminary construction of small hydropower throughout Alaska, including some projects in the Yukon River watershed. Golden Valley Electric Association received AREF funding to study the Little Gerstle site on the Tanana River, and a run-of-river site on the Nenana River. The Alaska Power and Telephone Company (AP&T) also received AREF funding for design and construction costs of the Yerrick Creek hydro development near Tok. AP&T has previously developed village-scale (2-10MW), high head, low impact hydropower in other parts of Alaska, namely the Southeast, as well as projects in Central America, and are now bringing this expertise to the Yukon River watershed. As of the time of writing, the state of Alaska’s 2010 investment in the AREF has not yet been determined.
In-stream (Hydrokinetic) power projects
Because many isolated small communities in the watershed still rely on costly diesel power as well as local resources such as fish, a variety of small-scale, low impact hydroelectric technologies are attracting great interest, including in-stream, or hydrokinetic turbines that do not require dams or diversions of water. In the summer of 2008, a 5kW hydrokinetic turbine was installed in the Yukon River village of Ruby, Alaska – one of the first in-stream turbines successfully installed in the US. Other Yukon watershed-based hydrokinetic projects in Alaska include planned installations in the communities of Nenana, Eagle, Tanana, and Whitestone, and at least one project slated for the Canadian side of the watershed. All of these projects are in various stages of planning, permitting, design, and/or installation.
The Ruby project has provided valuable information regarding “proof of concept” for the viability of in-stream hydrokinetic power generation and has also identified challenges that will need to be overcome before widespread deployment occurs. Specifically, the 5kW turbine installed at Ruby by the Yukon River Inter-Tribal Watershed Council (www.yritwc.org) and designed and manufactured by New Energy Corporation (www.newenergycorp.ca) based in Calgary, Alberta, incorporated an inverter that was originally used for wind energy projects.
The inverter software was successfully adapted for expected power parameters more typical of a slow moving river than rapidly changing wind currents. This system properly integrated into the village’s diesel electric grid, thus demonstrating the technical feasibility of the technology. Alternatively, mechanical diversion of stream debris without obstructing river flow and cost-effective anchoring of the turbine and support structure in the fastest moving part of the river still present challenges to this particular installation and all in-stream hydrokinetic projects on the Yukon River. Impacts to migrating and resident fish populations are another ongoing area of investigation.
The hydrokinetic project proposed in Eagle, Alaska, by AP&T is in final design stages and will also use a New Energy Corporation in-stream turbine, but instead of a 5kW version like in Ruby, this will be a 25kW turbine. Both of these turbines employ a unique design that incorporates a robust, slow moving, vertical axis turbine housed on a pontoon boat that aims for minimal impact to fish and durability from the elements.
Both the Ruby and Eagle projects, if successful, would eventually include a series of turbines that could meet a large portion of the community’s electrical load during the ice-free summer months, thus allowing diesel generators to be completely turned off much of the time and only starting up when high demand exceeds the power production of the hydrokinetic turbines. This would require sophisticated switchgear to integrate the diesel generators and hydrokinetic turbines, but such technology is already available and in use in Alaska villages integrating wind turbines and diesel generators. Because the Yukon River freezes in the winter, hydrokinetic turbines such as these, set in pontoon boats anchored to the bottom of the river, would need to be removed from approximately October through mid-May. Maintaining anchors over the winter such that they would not need to be re-set each spring is another area of current investigation.
The hydrokinetic project planned for Nenana, Alaska, is a collaboration among numerous entities, including the University of Alaska, Ocean Renewable Power Company, Yukon River Inter-Tribal Watershed Council, and the municipal and Tribal governments co-located in Nenana. As envisioned, this will be a full-blown research project with a test bed for various turbine technologies and anchoring systems. Currently, the research has focused on site characterization, effective means of mechanical debris diversion, anchoring systems, and fish impacts. The first turbine that is slated for installation in the summer of 2011 or 2012 is a helical, cross flow design with an estimated output of 50kW manufactured by Ocean Renewable Power Company (www.oceanrenewablepower.com).
While potentially using different technology, all of these projects in Alaska employ a low environmental impact, robust technology approach to meeting community energy needs based on similar imperatives and design criteria, including: relatively slow moving, high volume water; high conventional energy costs; protection of fish and other water resources; significant debris in the water column; integration with existing diesel generators and mini-grids; Maximum displacement of diesel fuel; and severe seasonal icing and extremely energetic spring break-up
Some “lessons learned” from these early deployments are already influencing next generation technologies. For example, New Energy Corporation is re-designing its turbine to produce more power at lower current speeds based on initial performance of the turbine installed at Ruby. Similarly, the Nenana project is incorporating information about river debris learned at Ruby in designing a filter, or “trash rack,” to divert incoming material before it reaches the turbine in Nenana.
Numerous fish impact studies are now underway that will provide essential data to help resolve this concern, possibly streamlining future development efforts. The Alaska Energy Authority has also created a “Hydrokinetic Working Group” that includes state and federal permitting and resource agencies, developers, communities with potential project sites, and others to identify concerns and possible bottlenecks before they become costly obstacles. As this is a new process for most agencies, they are also identifying studies that will be necessary for developers to comply with permitting requirements.
While these technologies are also being deployed throughout North America and the world, the combination of the Yukon River resource potential, community and government initiative throughout the watershed, and availability of funding through the AREF seems to have created a burgeoning development cluster within the region.
Within Canada, at Fort Selkirk, Yukon, the Ampair micro-scale hydrokinetic turbine was tested in 2000 on the Yukon River, near the mouth of the Pelly River. This was a project sponsored by the Heritage Branch of the Yukon government (Yukon Energy Corp., 2001). The turbine is now out of the water. Also, New Energy Corporation has donated a 5kW turbine identical to the turbine in Ruby, Alaska, for installation on the Yukon Territory side of the watershed, to the Yukon River Inter-Tribal Watershed Council, but this project is not yet deployed.
Other resource opportunities and challenges within the region
Both traditional drivers of hydropower development in the watershed, i.e., mining and other industrial activity, and new imperatives such as high fossil energy costs and preference for cleaner energy, are now providing impetus to develop not just hydropower but other renewable energy resources found in the watershed. Because hydropower is the most apparent, seemingly abundant, and historically used renewable resource in the region, it has received the most attention to date.
However, as efforts to develop locally available wind, tidal, solar, biomass, and geothermal resources advance, new technical, economic, and institutional solutions will be necessary to optimize the mix among hydropower (conventional and in-stream), other renewables, and fossil fuel. Entities such as the Yukon River Inter-Tribal Watershed Council, a coalition of 70 Tribes and First Nations in Alaska and Canada and lead developers in the Ruby hydrokinetic project, are now looking beyond just hydropower and are involved in community-based solar, wind, and biomass projects along with “green collar” workforce training for indigenous peoples and net-zero energy efficient residential construction.
Successful past projects and ongoing investigation and dissemination of “lessons learned” from new hydropower technology in the region can accelerate and facilitate future renewable energy development within the watershed and beyond. The AREF, as described above, has also played an important role over the past two years in accelerating renewable energy deployment and an expectation that if technology is properly developed, there will be funding for its deployment. This is an example of how targeted programs can be used to achieve policy ends – in this case, reducing the use of diesel fuel and cost of energy throughout Alaska, especially the rural areas.
As more renewable energy resources are used to produce electricity within the Yukon River watershed and elsewhere, concerns with “grid instability” can be expected to emerge. For example, as wind or solar energy becomes a higher proportion of the total amount of electricity generated at any moment in time, uncontrolled fluctuations can make the overall electric grid unstable, compromising power quality and sensitive electronic equipment. Especially with diesel mini-grids such as those in remote Alaska villages, this can quickly become a problem as diesel generators are the primary means of regulating voltage and frequency control for acceptable power quality and a stable grid.
Hydropower, more than any other renewable energy resource except geothermal, has an important advantage as a “grid stabilizer” that, when properly configured, can allow for higher penetration rates of renewables and maximize diesel displacement. Even with run-of-river or in-stream hydrokinetic power, because rivers vary in speed and hence power production much less and slower than wind or sun, hydro power is a uniquely valuable renewable energy resource.
While the Yukon River and tributaries present numerous hydropower opportunities, the watershed also holds substantial mineral and fossil energy reserves and lies between some of the largest natural gas deposits on the continent just north of the watershed and large markets to the south. Thus, it is likely that the watershed will see increased development in the future once again driven by industrial opportunities and distant demand. Given the remote nature of the region and ongoing dependence, especially among the indigenous peoples, on locally available natural resources, any future hydropower development will need to carefully consider impacts to the people and environment and recognize trade-offs that such development will require.
Further, these proposed industrial activities will likely influence the demand and specific economics for any future hydropower projects.
No hydropower discussion in remote, far northern reaches of the globe would be complete without some consideration of climate change. Both Alaska and the Yukon Territory are widely recognized as global “hot spots” already experiencing significant temperature escalation much higher than the global average, wide ranging shifts in precipitation, melting permafrost, shoreline erosion, and increased intensity and frequency of fire events (IPCC, 2007).
Hydropower production projections based on historic precipitation patterns may not accurately predict future energy output, and in extreme cases, infrastructure such as dams, penstocks, and transmission lines may be compromised as well under conditions of melting permafrost and increase shoreline erosion.
Additional challenges to hydropower development in the Yukon River watershed include:
• Short construction and study season.
• Greater expense for everything due to cost of shipping.
• Limited access to many areas.
• Limited human capacity (technical experts, maintenance specialists, operators, etc.).
• Isolated grids.
• Unpredictable energy demand (from industries such as mining).
• Diesel-electric communities receive subsidies that reduce economic drivers to find alternatives to diesel generation in those communities.
• The Yukon River watershed is a large region with a small population and limited revenue from natural resources. This limits the capacity of communities, utilities and governments to invest in capital-intensive renewable energy solutions.
As one of the greatest watersheds of North America and the world, over the past century the Yukon River system has inspired a wide array of hydropower development proposals, ranging in capacity from several hundred to several billion watts. Only a small fraction of the watershed’s technically and environmentally feasible hydropower potential has been tapped, and the 21st century is certain to see pressure for additional hydropower development. A huge amount of environmental and technical information must be disseminated in the process of planning, policy development and implementation, and coordination across jurisdictions. Properly informing the public is necessary for the democratic, pro-active process of creating the future that the Yukon River watershed’s citizens and other stakeholders desire, and to protect publicly owned natural resources.
It appears that the Alaska portion of the watershed has trended from proposed – but never completed – mega-projects from the middle of the last century to more recent environmentally sensitive and community-driven small-scale projects, some of which are employing new technologies. High diesel fuel prices, environmental concerns, and ongoing local dependency on harvesting natural resources such as fish are driving this transition to a clean energy economy in which village-scale conventional and hydrokinetic in-stream developments are uniquely suited to reduce diesel use and minimize fisheries impacts. Other renewable energy options are also being actively explored. As communities throughout the watershed benefit from improved regional cooperation and resource management, such technologies and approaches – if successful – can be expected to rapidly expand. Government support such as the Alaska Renewable Energy Fund appears to be creating a development cluster that could benefit the watershed and far beyond.
Organizations such as the Yukon River Inter-Tribal Watershed Council and cooperative structures such as the Yukon River Salmon Agreement are improving watershed-wide communication and opportunities for regional resource management and coordination. Successfully balancing the competing needs and desires of the various watershed stakeholders will require, among other things, good information, long term planning, cross-jurisdictional coordination, resource protection, and enlightened policy, and could provide important lessons and role models for all of us.
Brian Yanity, EIT, is an electrical engineer with WHPacific, Inc. in Anchorage, Alaska, and an adjunct faculty member at the University of Alaska Anchorage (UAA) School of Engineering. His work focuses on village-scale renewable energy projects and energy planning for rural Alaska. Mr. Yanity received his B.S. degree in electrical engineering from Columbia University, and his M.S. in arctic engineering from UAA, with a focus on small-scale hydropower systems for cold-climate applications. Email: [email protected]
Brian Hirsch, PhD, is the Senior Project Leader for the National Renewable Energy Laboratory’s (NREL) Alaska initiative, a part of the US Department of Energy Office of Energy Efficiency and Renewable Energy. Dr. Hirsch received his doctorate in Land Resources from the University of Wisconsin-Madison, with a focus on energy issues and indigenous communities in northern regions of the world. Email: [email protected]
Special thanks to following reviewers: Sean MacKinnon of the Yukon Energy Solutions Centre (Yukon Department of Energy, Mines and Resources), and Neil McMahon of the Alaska Energy Authority.
TablesTable 1 Table 2