In today's competitive environment, the need for greater detail in system planning analyses has become increasingly important. The computational requirements of PowrSym3 are satisfied by new efficient algorithms coupled with faster computing hardware--making the use of this full chronological model for short, medium, and long-term planning analyses possible. With PowrSym3 the ability to compare alternatives under real system operating conditions is available now.

PowrSym3 represents the cumulative algorithmic expertise of over thirtyt-five years of production cost modeling. PowrSym3 is the latest in a series of models which began with PowrSym in 1969 and continued with new developments and spin-off versions which are in use throughout the industry.

PowrSym3 combines the best of previous PowrSym algorithms with a new unit commit and economic dispatch algorithm that simultaneously solves all hours in each weekly horizon. This novel algorithm retains the same chronological detail of previous versions while allowing optimal allocation of fixed energy constraints such as energy limited fuels and emission caps. While previous chronological models could consider a small number of fixed weekly energy constraints by using an iterative method, PowrSym3 can directly solve multi-fuel, multi-station contracts. Each fuel may have hourly, daily, and weekly minimum and maximum requirements, all of which may vary with time. PowrSym3 achieves this solution with a network model directly integrated into the unit commit and dispatch algorithm.

PowrSym3 is a multi-area, chronological, Monte Carlo production costing simulation model capable of detailed, short-term studies with high levels of optimization. It can also perform long-term system planning studies representing chronological system operating conditions. Multi-year system operation is simulated over sequential weekly optimization horizons with a time step of one hour.

Accurate simulation of chronological operating conditions, unit commitment optimization, energy storage optimization, multiple fuel allocation, Monte Carlo outage method, and a multi-area transport model allow PowrSym3 to be used for short term optimization and operational planning studies. The same algorithms, optionally with lower optimization levels, are used to include dynamic system operating effects in long term system planning studies. PowrSym3 allows system planners to evaluate future system configurations from an operations viewpoint not possible with most planning models.

The computational requirements of a chronological Monte Carlo model are satisfied by new efficient algorithms, faster computing hardware, and the possibility of parallel processing over local area networks. It is no longer necessary for system planners to give up operational detail in long range studies.

In addition to the ability to represent forced outages by either of two derating methods, PowrSym3 has three Monte Carlo outage options. The classic random draw option allows multiple draw numeric convergence on a weekly horizon. The "smart" Monte Carlo option chooses a small set of statistically balanced draws for faster convergence. The semi-guided method achieves converged annual results in a single pass and is used for long range planning studies.

PowrSym3 algorithm features include:

• Preservation of the chronological sequence of events
• Accurate unit dispatch
• Realistic unit commitment with dynamic optimization
• Pumped hydro simulation with reservoir constraints
• Hourly marginal and average cost calculations
• Monte Carlo/derating options for forced outage simulation
• Emission influenced commit/dispatch
• Complex fuel contract model with fuel blending
• Multi-area power transport model
• Energy limited fuel optimization
• Integrated reliability model
• Maintenance schedule optimization
• Combined heat and power simulation

PowrSym3 report categories include:

• System reliability
• Reserve margin
• Capacity factors
• Energy generation
• Fuel consumption
• Number of unit starts
• Startup costs
• Fuel costs
• Power plant emissions
• Purchased power
• Total costs
• Inter-area transfers and wheeling charges
• Marginal costs
• Cogeneration heat reports
• Operation and maintenance costs

PowrSym3 applications include:

• Generation expansion studies
• Optimization of pumped hydro design parameters
• Time-of-day pricing studies
• Revenue requirement studies
• Benchmarking of less detailed models
• Evaluation of demand side management options
• Hydro power evaluations
• Real time power exchange evaluation
• Power exchange contracting strategies
• Maintenance scheduling options
• Plant retirement studies
• Integrated resource planning
• Near term operational studies
• Real time resource scheduling
• Hourly marginal cost evaluations
• Fuel burn, fuel budgeting, and fuel contract evaluation