Coal Unit Retirements
The costs associated with decommissioning the coal units, retrofitting or refueling of other units, purchasing power, or developing future generation or transmission resources will have significant rate impacts for customers. In addition, the loss of significant base load generation creates greater electric grid reliability risks that must be mitigated by strengthening and expanding the current transmission system. These drivers require us to continue to plan, design and implement cost-effective and sustainable strategies for managing our generation and transmission resources.
Compliance with environmental regulations has dominated our capital investment strategy for more than two decades. More than $7 billion was spent on compliance from 1990 through 2011 to reduce emissions from coal-fueled plants. We estimate that the cost of complying with new regulations will be an additional $2.8 billion to $3.3 billion between 2013 through 2020. These amounts include investments to refuel some of our coal units to natural gas. In addition, cost estimates will change depending on the to-be-determined scope of requirements, implementation timeline and compliance flexibility of future regulatory programs.