Under the Green Options Plan, SaskPower’ll undertake a competitive process to procure up to 175 MW of wind power from one or more independent power producers.
The Green Options Partners Program will introduce a standing offer program to purchase up to 50 MW of renewable power from private sector developers, with up to 25 MW of the total coming from wind power. The remainder will be generated through proven clean technologies such as biomass, heat recovery or low impact hydro generation.
The expansion of wind power will reduce our carbon dioxide emissions by approximately 225,000 tonnes a year. Wind [intermittent] — large 6 to 10¢/kWh (150 MW or more); small 12 to 22¢/kWh (1 MW to 10 MW); micro 27 to 57¢/kWh (10 kW or less).
Wind is a clean but intermittent source of energy. In most areas of the world, wind speeds vary both daily and seasonally. As wind speed varies, so does the amount of energy that can be captured by a wind turbine. If a wind power site can generate electricity 30% to 40% of the time (based on fluctuating wind conditions), it is considered to be a high performing facility.
The high variability in energy production from wind is the major disadvantage. For large turbines, the wind velocity has to be greater than 3.5 metres/second. Conversely, at extremely high wind speeds in the range of 25 metres/second, the wind turbines must shut down for safety reasons.
Wind speeds outside of the optimal range for a particular wind turbine means that the output is less than rated maximum production. Also, if the temperature is below -30 C, wind turbines will automatically shut down due to generator and other equipment limitations.
Because of the intermittent nature of wind, it requires support from other power plants to ensure that electricity can be available on the grid when wind generating facilities are producing little or no electricity. In addition, there are difficulties associated with predicting the amount of energy that a wind farm will be able to produce at any given time. Utilities are working to improve wind forecasting techniques in order to better dispatch wind.
Energy storage options could help stabilize wind power, although the concept is still in the developmental stage. SaskPower is currently in the midst of working with an external consultant to obtain quantitative and qualitative analysis of a range of energy storage technologies that could work on the Saskatchewan grid.
Large scale wind farms are optimized to maximize electrical energy production using tower heights (50 metres or greater) and meteorological wind site studies. In Saskatchewan, these wind farms reach annual capacity factors in the range of 35% to 40%.
Micro wind systems are normally sited near the load being served rather than at the optimum wind sites. These units have lower tower heights. Annual capacity factors for micro wind turbines in Saskatchewan seldom exceed 20% and on average are about 10%.
Why not more wind?: Wind power has many benefits but it also has limitations. Simply put, we cannot count on the wind to blow all day, every day. Since the technology to store electricity generated by this renewable source does not exist in a large-scale, utility-grade format, if there was no wind on any particular day, this approach would leave us without electricity.
For this reason, wind will likely never be able to provide all of the electricity required by our customers. Wind generation must always be backed up by other forms of generation to provide a seamless transition of power to your home or business.
What kinds of power do we have in Saskatchewan? Currently wind makes up about 5 per cent of our generating capacity. That’s the highest percentage in all of Canada.
Coal provides base-load power generation and approximately half of our overall generation capacity. Natural gas and hydroelectric generation stations provide peaking capacity, another 16 per cent and 24 per cent respectively, when demand for electricity from our customers is very high. The balance of our power needs are met by power purchased from independent power producers.
Can we add more wind power to the mix? As we gain knowledge into how to best incorporate fluctuating wind generation into the provincial electrical system, we will be able to make decisions on how much more wind generation can be added.
Estimates indicate we could potentially use wind power to meet between 10 and 20 per cent of our total generating capacity. Only a few places in the world are able to incorporate those high levels of wind generation into their systems, and usually only by relying on interconnections with electrical grids in neighbouring jurisdictions to keep the system stable and ensure adequate capacity.
We remain enthusiastic about the future of wind generation in Saskatchewan and continue to follow emerging developments world-wide.
How good is our wind resource? Saskatchewan’s three major wind power facilities all calculate their annual generation based on formulas developed for their particular location, specifications and expected maintenance schedules. Saskatchewan’s rich wind resources allow for an expected annual generating capacity of around 40 per cent. This is considered very good – in many other areas of the world, wind turbine average capacity is 20 to 30 per cent.
SaskPower plans to issue a formal Request for Qualifications (RFQ) on December 1, 2009 to identify qualified bidders for the upcoming solicitation for up to 175 megawatts of wind power from Independent Power Producers in Saskatchewan. Additional information on the process for submitting wind power proposals will be made available at that time.