Customer Environment
The Nova Scotia Power system modeled within the AUTO Vista environment includes more than 33 hydroelectric plants on several rivers within the province.

Also included in the modeling environment are the other non-hydro generating systems:

• Existing wind
• Biomass
• Coal
• Natural gas plants

Challenge
The Department of Energy retained Hatch to identify the impacts of incremental wind generation on the Nova Scotia electrical system, on system reliability, overall system costs, green house gases and other air emissions reductions and to provide support in the development of renewable-to-retail market design.

Solution
To evaluate the impacts of different wind penetration levels on the Nova Scotia system, AUTO Vista, (the hourly
optimization/simulation model which can model hydro, the external energy sources (e.g. wind, thermal) and the reserve requirement for the external energy sources, in combination, for up to a full year on an hourly basis), was used to perform the wind integration study.

AUTO Vista is the long-term planning and analysis component of the Vista DSSTM suite of programs. AUTO Vista optimizes the long-term operation of the hydraulic system using detailed operational procedures analogous to those used in actual practice. To do this, AUTO Vista uses LT Vista (long-term) to guide long-term water management decisions and ST Vista (short-term) to dispatch generating units on an hourly basis. AUTO Vista automatically invokes LT Vista and ST Vista multiple times over the analytical horizon. This approach (that is, using both long-term and short-term analyses) yields a realistic hourly time series of water levels, discharges and power generation. AUTO Vista considers the physical constraints, operating conditions, and operating constraints.

The tasks for the Nova Scotia study included evaluation of:

• The generation coordination between hydro and wind and its effects on reservoir operations
• The different levels of wind generation penetration in combination with high, median and low hydrologies and
• The reserve requirement that is necessary to support the wind energy supply and its impact on operations

Client Benefits
At the end of the study, the Department of Energy was equipped with the knowledge of:

• System reliability, system costs and greenhouse gas emissions reduction impacts as incremental wind generation is added to the Nova Scotia electrical system
• The impact of incremental wind energy additions on Nova Scotia Power’s ability and the associated costs