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Supply & Demand

Juneau Hydropower Electrical Supply and Demand

(From CBJ-Community Development Department-Planning Commission Document)

As the simple set of projections shown in the figure below, Juneau Hydro Supply and Demand, shows, conversions of heating and transportation energy sources from oil and gas to electric have the potential to raise the community’s demand for electricity beyond what is available. In this Figure, the Demand with Conversions (Projected) line shows what would happen if all existing and new heating and vehicles were converted to electric systems, using current technologies.

The cost of generating additional electricity with diesel would raise the cost of electricity so as to eliminate much of the financial justification for conversion; however, the increased cost of additional energy generated by diesel would be diluted with existing lower-rate hydropower, and could still yield economic ratepayer advantages for conversions. The take-away from this graph is that Juneau’s potential hydroelectric supply can easily be outstripped by Juneau’s demand for energy, and that conservation of existing supply and reduction of demand will be necessary to avoid reliance on expensive diesel-generated electricity in the future.

Figure 1: Juneau Hydro Supply and Demand

(Source: CBJ Community Development)

Juneau’s hydropower resources are not limitless.  In years with low rainfall, hydropower production must be supplemented with standby diesel generation. Permitting and Licensing new hydropower facilities, which is regulated the Federal Energy Regulatory Commission is a time consuming process. Permitting and licensing on a national average can take three to five years with one to two years for construction. Therefore, the lead times required to place additional hydropower facilities on line take long planning horizons.

Juneau has a hydropower project currently under development at the Sweetheart Lake Hydroelectric Project and a planned future hydropower project at Lake Dorothy Phase II.