Plant Upgrade Options. You may undertake one upgrade option per year at a given plant, with a
maximum of two upgrade options throughout the life of the plant. The cost of a plant upgrade is
treated as additional investment; the upgrade equipment that is installed has a 20-year service life and is
depreciated on a straight-line basis at the rate of 5% annually. Upgrade options take effect the year
after being ordered. Payments to the suppliers of upgrade options are made the year the option is
ordered. An upgrade option can be ordered for a new plant the first year the new plant is on line or any
year thereafter; upgrades for a new plant cannot be ordered in the same year a new plant is under
construction.