Natural gas-fired generation and storage in Wyoming and California could play a key role if Wyoming is to fulfill a long-term strategy of making itself a major exporter of wind-generated electricity, according to a second phase study released Monday by the state Energy Office and Wyoming Infrastructure Authority (WIA). The cost of a 12 GW wind collector system and integration system for wind and natural gas would total tens of billions of dollars, the report said.

The study, adding to an initial analysis completed a year earlier, was funded by a stimulus grant from the U.S. Department of Energy and completed for the state by Fairfax, VA-based ICF International. Overall, the cost of transporting 12 GW of wind-generated power from Wyoming to California could be $49-58 billion, according to the report, with the firming costs representing 5-19%, or $2.5-11 billion.

In addition to six high-voltage transmission power lines, Wyoming is examining the structure and development of a large collector system that would be required for export of large quantities of wind power with natural gas-fired generation and storage to account for the time when the wind is not blowing.

ICF's Phase 2 study "furthers the notion that our superb wind resources partner well with natural gas-fired generation to address the variability of wind," said Wyoming Gov. Matt Mead. "WIA has been tasked to support the responsible development of such new transmission and corresponding generation."

The report outlines several possible next steps, including work to optimize plans for integration of the backup assets for firming of the intermittent wind power. It suggests that scenarios developed for possible gas-fired generation and storage be detailed in various models to "optimize the type and quantity of the backup assets." Such factors as the differences in elevation between California-based gas-fired generation and similar plants in Wyoming would be taken into consideration, according to the report's recommendation.

While the study assumes that no new gas-fired generation plants would be required, it does suggest in some of the scenarios studied that new gas storage would be required in California. In other scenarios electric storage would replace the gas storage, but the cost analysis indicated that the gas option would be considerably less costly.

For a hypothetical 12 GW nameplate wind system, ICF determined that backup power from natural gas and storage sources would have to equal a little more than 25% of the wind capacity. "Wyoming has high-quality wind, and most other state would require more backup capacity to achieve a firming level of 99%," the report concluded.

In the 10 scenarios developed by ICF, the capital costs of creating the firming power range widely from $207/kW to $920/kW, and natural gas combustion turbines generation turned out to have lower capital costs compared to electricity storage. "The lowest ($207/kW) scenario assumed that existing natural gas turbines can be used for backup (no new infrastructure would be required)," the report said.

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