Preliminary Analysis of Generating Resources

An important element in developing the Seventh Power Plan is a review of the characteristics of generating resources that could be used to meet the region's future electricity needs. The Council assesses the operation and costs of power plants currently in service and forecasts future trends.

At the Council's power committee meeting in February, Council staff presented their preliminary findings for the draft Seventh Power Plan and provided a comparison with the assumptions made in the Sixth Power Plan. The types of resources most likely to be built over the plan's 20-year planning horizon are natural gas combined-cycle plants, gas peakers (single-cycle turbines and reciprocating engines), wind, and solar photovoltaic (PV). Other commercially available resources, including geothermal, hydropower, biomass, and energy storage technologies, could play an important, though more limited role.

Natural gas combined-cycle plants are expected to continue playing a significant role as a dispatchable baseload power supply thanks to a robust infrastructure tapping into gas sources in the U.S. and Canada.

Gas peaking plants, both single-cycle and reciprocating engine, are likely to be built to help meet peak loads and keep the system in balance. With growing wind and solar development, gas peakers are becoming more important to help integrate variable generation into the power system.

Since 2000, the Northwest has installed about 7,500 megawatts (capacity) of wind energy. Although development slowed down after 2012 because of uncertainty over the availability of federal incentives and utilities reaching their near-term renewable portfolio standard goals, it's expected to ramp up as utilities focus on their 2020 goals.

Montana is becoming more attractive as a high wind resource state because its generation is winter peaking compared to the spring/fall peaking in the Columbia Gorge. Montana wind also receives a higher capacity factor for its wind production, so upgrading and building transmission to the west continues to be under discussion.

The biggest surprise is the decreasing cost of utility-scale solar PV. While it has a limited presence here, activity has picked up in southern Idaho, which may be the best location for solar in the Northwest. Although its output varies seasonally, if costs continue to decline, it could become an important renewable resource for the region.

The preliminary staff analysis also includes a comparison of the levelized cost of energy across the candidate resources. Surprisingly, utility solar PV moved up considerably from the Sixth Plan's analysis to second place behind natural gas combined-cycle plants. Montana wind, using the existing limited transmission capacity, was next, followed by Columbia Basin wind. The most expensive first tier resources were gas peaking plants.