I large investment will be required to just maintain existing capacity.
Most nuclear reactors in the province will need to be refurbished or relaced between 2010 and 2025. Pickering A has already been refurbished to extend its life marginally (10-15 years), same thing for Bruce A. The province will have to Refurbish Pickering B and Bruce B (6 reactors total, two have been done, two are being refurbished now - at least $1.5 billion a piece) or replace them. (Several billion dollars each) It's not like there's much time to make a choice since it takes 10+ years to build a plant, and that's if everything is on time and on budget. (Nuclear is rarely on time and on budget
) Darlington is the newest station and will probably have to be shut down and refurbished any time between 2020-2025. (It came online in the late 80s/early 90s)
The province has capped nuclear at 14,000 MW; at least two more reactors will have to be built at the Darlington sight to achieve that goal, if all of the others can be refurbished. Bruce power (private company) has also proposed to build at least two reactors on the existing (Bruce) sight.
I really hope that they replace Pickering B when the station reaches the end of it's lifespan ; it's been the second most problematic station after pickering A. (High capital costs, low capacity factor, poor performance, too close to Toronto)
As for the coal plants, the decision to shut them down and replace them with gas plants is incredibly short cited to say the least. Coal is an abundant and cheap fuel; the cost of natural gas has skyrocketed and Canadian (natural gas) production peaked in 2001. (Production is declining now) Switching to gas will increase Ontario's usage by 25% in a time when there's no room for growth; to top it off, using the fuel directly for heat can be 90%+ efficient, while the best combined cycle power plants are only 55-60% efficient.
Yes, conventional coal fired plants are very dirty and polluting; however, new technologies (Synthetic gas from coal, scrubbers, etc.) can enable the fuel to be used in a environmentally responsible manner. (Plus clean coal research and development will create more jobs than building gas fired plants)
Yes, reducing demand must come first; the OPA has grossly underestimated the potential impact of extensive energy efficiency upgrade programs.