The Alaska Center for Energy and Power (ACEP) has put together an insightful analysis of stranded non-renewable energy in Alaska. Their report suggests high voltage, direct current (HVDC) transmission as a way to bring more renewable energy sources into use.
The ACEP summarizes Alaska’s immense non renewable resource potential, including:
The Alaska renewable energy sources are typically located far away from populated centres. The ACEP reports suggests that:a) HVDC offers a lower-cost alternative to AC transmission in many applications; b) HVDC transmission can achieve lower costs than AC transmission HVDC systems can have lower losses than comparable AC systems; c) HVDC systems can have smaller right-of-way requirements than AC systems; and, d) HVDC provides an asynchronous transmission link, which can be advantageous in some power transmission grids.
ACEP noted a study (Freitas, S., “Alaska Electric Line,” 2008) that found that exporting electricity over an HVDC line to Alberta would likely be more profitable than constructing a natural gas pipeline and associated infrastructure to export the gas to market. Interestingly, the cost per mile suggested by the Freitas study is $2.5 million /mile.
The report states that a primary barrier to utilizing HVDC for stranded renewables, despite the potential capital and construction cost savings of the HVDC transmission system, has been the tremendous cost of the DC conversion equipment when considered for medium- and small-scale applications. The converter technology is changing, with costs being reduced. As well, costs of materials and construction methods used for transmission infrastructure can be reduced though the use of fiberglass poles, nesting poles, long spans, and innovative foundations all have the potential of reducing the installed cost of transmission lines.
Manitoba Hydro has established an HVDC research centre. This crown corporation has led a number of HVDC projects in Canada and the US.
The report concludes that small-scale HVDC transmission is of particular interest, and if implemented, could provide a source of critical lessons learned for Alaska. Monitoring the development of relevant HVDC infrastructure, and perhaps pursuing the demonstration of this technology here in Alaska, are also important activities. Finally, detailed economic assessments of proposed and potential HVDC solutions is critical.
A small-scale export project might be just the ticket for greater deployment of HVDC and getting more renewables developed. For example, HVDC could be for a transmission line from the West Creek hydro development in Alaska to grid connection at Carcross, Yukon. The distance is about 50 miles, using the Freitas study figure of $2.5 M per mile, suggests a line could be built for $125 M. Skagway does not need energy in the winter and Yukon does.