Challenges

Since conversion of the plant to a solid fuel, such as biomass or municipal solid, would be a logistical nightmare, and the use of coal as a feedstock was out of the question, 4 SKIES quickly concluded that a natural gas plant was the only logical option worth considering that would be able to make use of some of the power equipment already installed.

This equipment includes substation, transformers, high-voltage transmission lines, and possibly even the power block equipment (turbines, generators and heat exchangers associated with the plant’s 4 CANDU reactors (A1 – A4), two of which are already shut down (A2 and A3) and two (A1 and A4) are scheduled to be shut down in by 2020. Access to natural gas should be relatively easy, since a network of gas pipelines already exists close by. 

Basic Assumptions: Single Turbine and Generator
 Power Capacity per Turbine 540 MW/h
 Parasitic Power Demand 25 MW/h
 Net Power Capacity to Grid 515 MW/h
 Plant Availability 350 days/year
 Plant Capacity (Availability) 95.8 %
 Steam Volume 4613 t/h
 Steam Pressure 100 Bar
 Steam Inlet Temperature 540 °C 
 Steam Outlet Temperature 320 °C
 Turbine Efficiency 33 % 
 Turbine Stages – HP 1 stage
 Turbine Stages – LP (reheated) 3 stages
 Shaft Speed 1800 RPM
 Generator Type – 3 phase, 4 pole, 60 hz, 24,000 volt 540 MW/h 

Integration with Existing Power Block 

If it is determined that the integration of a natural gas boiler with the Pickering Nuclear Power Plant’s existing power block is possible, and the best option for repurposing the plant, then the steam conditions would need to match closely the steam conditions currently being supplied to the plant’s turbines. 

Given that the plant was purpose-built to be a nuclear power plant using CANDU reactor technology, it may not be a simple task to merely decouple the reactors from their power block and insert a steam connection to a natural gas boiler. It may be easier and more cost effective to custom build a complete gas plant on the property and connect it to the grid using the existing substation. Regardless, 4 SKIES understands that a complete engineering study and feasibility study would need to be done to determine what if any of the existing plant’s power block can be used, or refitted, or if an entirely new plant would make more sense.

Rather than focusing on the design and integration of a gas plant with the existing Pickering Power Plant, which would no doubt be subject to a future engineering study, 4 SKIES has focused the purpose of this concept document primarily on the idea of environmental sustainability by combining cogeneration with green house production (trigeneration) to take advantage of waste heat and CO2 from a natural gas plant.

The following schematic illustrates in general terms how a trigeneration gas plant and green house concept will work.

schematic 2.jpg