NYISO schedules and controls the bulk power flow of more than 335 power plants on about 17,340 kilometres of transmission lines in the state and balances the supply and demand for as much as 34,000 MW of peak load on a minute-by-minute basis. Wind makes up less than 1% of total generation on the system, with 425 MW operating by the end of 2007. But over 7000 MW of wind project proposals are in the NYISO interconnection queue and there are "very concrete plans" to go to as much as 2500 MW wind by the end of next year, says Robb Pike, NYISO's Manager of Energy Markets Products.
NYISO management believes integrating thousands megawatt of wind is best done with the co-ordination of a real-time centralised wind forecasting system and a balancing approach where wind generation is allowed to perform at maximum capacity, with other generation being shifted to make room for it. "We want to accommodate wind the best we can," says Pike. "And to the extent that we can, we'll let them generate output and put power on the grid and we'll manage around them. So we needed to have the best forecast in place to manage the grid." It is more a reliability item than a market aspect, but it will grow the market beyond what had earlier been expected, he says.
A 2005 study conducted for NYISO by General Electric concluded that 3300 MW, or roughly 10% of average New York state load, could be reliably integrated. But it became a de facto cap, annoying wind project developers collectively who had greater overall ambitions. Although nowhere near that level, the wind industry felt 3300 MW was an arbitrarily chosen number and pushed NYISO to consider higher levels. So along with the forecasting plan, NYISO will conduct a second version of the study to explore higher penetrations, which it believes are very possible.
NYISO also plans to increase the volume of wind generation exempted from penalties for failing to generate promised electricity and provide full compensation for electricity generated in excess of the scheduled amount. The approach must be approved by the Federal Energy Regulatory Commission (FERC).
New York-based wind forecasting company AWS Truewind has been selected to provide the centralised forecasting. It will gather its data largely from operating wind projects in New York, which will be required to provide a variety of weather metrics. Wind generators already typically have most of the required meteorological equipment to provide the data, but what will be new is establishing a way for the data to be transmitted in real time to the central forecaster and NYISO grid operators.
Penalties will be established for wind generators that fail to deliver forecast data to the operator. The cost for the central forecasting plan will be shouldered by wind companies who will pay an up front fee along with a proportional fee based on project capacity. All these items will also have to be approved by FERC, but expectations are high the regulator will do so. It has always had a history of embracing rule changes that improve grid stability and in recent history has looked favourably on ways to integrated more wind into electric systems.
Growing grid trend
The New York contract is not the first time AWS Truewind has provided centralised forecasting for a grid operator. It has been doing so for California's central grid operator since 2003 and has recently started providing forecasts for the grid operator in Texas, the Electricity Reliability Council of Texas (ERCOT). Those forecasts will soon become "operational," says AWS Truewind's Noah Francis, meaning they will be actively integrated in real time for use in grid operation. The Texas forecasting plan has been speeded along following an unusual circumstance earlier in the year when a major weather event caused wind generation to drop by around 1200 MW in three hours with little warning to ERCOT (Windpower Monthly, April 2008).
Most of the time, it is up to a generator to provide some sort of power schedule to a grid operator for expected day ahead, monthly and annual production expectations. But these requirements differ between grid operators or are dictated by the power purchase agreement signed between a wind generator and a utility. "They are not real demanding," says Francis. More demanding and high quality wind data transferred in real time to grid operators will have a positive effect on the smooth integration of wind on systems throughout the US, he says.
This side of the forecasting business is growing fast as grid operators like NYISO and ERCOT (with rumours that the Midwest System Operator is joining in) become more interested in centralised, co-ordinated forecasting. "The work we do on wind project pre-development is still larger but the forecasting is growing very quickly," says Francis.