Retrofits of power plants to meet EPA regulations are very expensive. There are more than 1,000 power plants that are more than 40 years old still in service. Most of these are obsolete, and would require very expensive retrofits to remain in service. Consumer advocates and regulators should make sure that the full range of potential compliance expenses are known before any retrofits are approved. This could include SOx, NOx, mercury and toxics, coal combustion residuals, effluent, and ultimately CO2 regulation. It may not be cost-effective to retrofit many plants, and it would be a serious mistake to approve intermediate retrofits if the full cost of all required retrofits exceeds the value that would be received. It may be cheaper to acquire demand response, energy efficiency, or new generating resources instead.