[7] Council Finds Coal Cutbacks Vital To Lower CO₂ Emissions

Retiring some existing coal-fired plants and replacing their output with cleaner resources is the key to maintaining or lowering carbon dioxide emissions from the regional electric sector, according to a new Northwest Power and Conservation Council paper.

State renewables portfolio standards, substantial energy conservation and summer-spill elimination are insufficient to significantly slow or reverse the rising trajectory of regional power-related CO₂ emissions, according to "Carbon Dioxide Footprint of the Northwest Power System," released Sept. 13.

"CO₂ production from electricity generation is dominated by existing coal-fired generating plants," the paper said. "To stabilize CO₂ production at 2005 levels or to reduce CO₂ production to 1990 levels would require substituting low CO₂-producing resources or additional conservation for some of these existing coal-fired power plants.

"In addition, the scenario analysis shows that policy choices that are made for purposes other than CO₂ reduction (in this case fish and wildlife policy) can also have significant effects on CO₂ production; enough effect to negate policies such as renewables portfolio standards," it said.

The council analysis estimated that regional CO₂ emissions from the Northwest electric system have risen from about 44 million tons in 1990--a popular baseline year for climate-change policies--to 67 million tons in 2005. Economic growth, added fossil-fueled generators, diminished hydro capabilities and closure of the Trojan nuclear plant near Portland all contributed to this trend, the council said.

The study also noted that had 2005 been a normal water year as was 1990, CO₂ emissions in 2005 would have been about 59 millions tons, a 34-percent increase over 1990.

Looking ahead, the council projected that if regional resource development follows its 2004 plan emphasizing renewables, conservation and some natural gas, CO₂ production by 2024 would amount to 71 million tons, representing a 20-percent gain over 2005, assuming normal water conditions in 2024.

"It's really easy to go up [with CO₂ emissions] and it's really difficult to go down . . . is what appears to be happening," said council senior resource analyst Jeff King, at the Aug. 14 meeting of the council's Power Committee.

To return to 1990 CO₂ levels or below, "you have to address the existing stock of coal-fired resources to achieve that kind of objective," he said. From 2015-2024, under the council's recommended resource portfolio, coal would account for 81 percent of Northwest power system CO₂ production.

The Northwest, whose total capacity is close to two-thirds hydropower, fares well in CO₂ emissions, relative to the greater West. Under normal water conditions in 2005, the region's power system would have emitted about 540 pounds of CO₂ per megawatt-hour generated, compared to about 990 pounds/MWh for the Western Electricity Coordinating Council area, the council figured.

However, it noted, all regions possess "essentially the same set of future resource options," and consequently, "it will be difficult for the Northwest to maintain or reduce its CO₂ emissions rate."

If state renewables portfolio standards were met in Washington, Oregon and Montana, and all summer spill were eliminated to enable more hydro generation, the growth rate of CO₂ emissions would only be lowered an estimated 60 percent, the council found. The effect of their removal on regional CO₂ emissions depends on the replacement resources.

"Failure to achieve the conservation targets in the Fifth Power Plan, or removing the lower Snake River dams and replacing the power in a manner consistent with the Fifth Power Plan, could more than offset the potential savings from the scenarios that reduce CO₂ production," the paper said.

The four federal dams on the lower Snake River generate about 1020 aMW of energy under current river operations, and provide 2650 MW of sustained-peaking capacity, according to the council.

The effect of their removal on regional CO₂ emissions depends on the replacement resources, taken in the study to be 810 aMW from new and existing gas plants, and 170 aMW from existing coal units. This would raise average annual CO₂ production 4.6 millions tons over the council plan's resource scenario from 2015-2024.

Making up the loss of the hydro generation from the lower Snake dams with a market-purchase scenario was considered but not reported. The council said this approach "would compromise system adequacy and reliability by reducing the amount of resource available to meet load."

Another potential scenario involves conservation and renewables as the main substitute resources, a notion promoted by the Northwest Energy Coalition, among others, in support of dam breaching as a salmon-recovery measure.

This approach could delay some CO₂ increases, but not stop or reverse it, the council paper said.

Tying the increased development of conservation and renewables to dam breaching is "misleading," it said, because this means discarding more than 1000 MW of "emission-free generation" that must eventually be replaced, "unless the supplies of renewables and conservation are considered unlimited."

However, given the difficulty of reducing CO₂ emissions, discarding existing CO₂-free power sources has to be considered "unproductive," it concluded.

Steve Weiss, policy analyst with NWEC, told the council's Power Committee last week that conservation and renewables as dam resource-replacements would not all be cost-effective, but added that he expected Congress to "make the region whole" and not increase costs specifically to Northwest electric ratepayers if it does authorize dam removal.

Weiss also said keeping the dams, in various spill scenarios, "doesn't change the CO₂ problem very much."

The paper estimated that no summer spill at Snake and lower Columbia dams would decrease CO₂ emissions by 1.4 million tons a year in the Northwest from 2015-24. Court-ordered spill has added another 700,000 tons of CO₂ per year, compared to the base case 2004 BiOp.

The overall effect of court-ordered spill to no spill within the Northwest from 2015-24 was estimated to increase average annual CO₂ production in the Northwest by 2.1 million tons. West-wide, the paper estimated the court-ordered spill to increase average annual CO₂ production by 5.2 million tons compared to no summer spill operations.

The council asked its staff to forecast CO₂ production using an assortment of future resource scenarios. The base case corresponded to the council's latest plan, while other scenarios were based on low conservation gains, high renewables development, or utility integrated resource plans.

Under all these scenarios, regional CO₂ emissions rose in 2024 from the 59 million tons emitted in 2005, an average water year. The lowest level was the high-renewables scenario, at 66 million tons in 2024, while the highest was the utility IRPs, at 77 million tons.

"The purpose of these alternative scenarios is to quantify the sensitivity of results to plausible changes in the power system and some related policies that have received attention," said the paper. "No new council position on any of these policies is intended by this analysis, nor should any be inferred."

Comments on the paper are due Oct. 19. -Mark Ohrenschall

The following links were mentioned in this story:

New Northwest Power and Conservation Council paper

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