Study: “Flexible Coal” is the Future

(Wyoming Business Report, December 19) – A new report from the National Renewable Energy Laboratory indicates that coal generation could and should become more flexible in the future, though conversions would be pricey.

Currently, coal is used widely as baseload generation because it can’t cycle on or off quickly, among other concerns. Other generation can react more quickly to demand so operators can more easily stay within their target generation as demand requires. However, NREL’s shows that coal can also supply for peak demand if outfitted correctly.

The results, one of the study’s author stated, are that coal could be more tightly integrated with renewable energy, which is usually at the mercy of mother nature to supply power.

“Coal plants can be modified to respond to the changing output of renewable energy and run at low levels when renewable electricity generation is high but demand is low, such as at night,” said NREL’s Jaquelin Cochran, a lead author of the report. “There is a cost to this flexibility, but these costs can be minimized with strategic modifications and maintenance.”

Physical modifications to make it possible include, but are not limited to, a retooled condenser that would cost $6-$8 million per unit; a converted water deluge system that would cost $2-3 million; “modified buckstays” that would cost $1-$1.5 million per unit; and replaced “dissimilar metal welds” that would also cost $1-$1.5 million for a major header.

But, NREL noted, with the changing “economic and political circumstances,” this may be necessary to keep coal generation as part of a “cleaner energy system.”

Many experts, because of stringent regulation on new coal plants, have said that it is essentially illegal to build new coal-fired power plants. But the study’s authors say such technology is vital to coal’s future.

“Older coal units can still serve a purpose if they are operated flexibly,” Cochran said.

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