India has an installed capacity of about 17000 MW of wind, which is about 10% of the total grid electricity installed capacity. While the wind penetration is as high as 40% of the installed capacity in some of the states such as tamilandu and i think over 25% penetration has already taken place in most of the southern wind states hence the grid integration is the urgent need.
There are earlier references in terms of wind integration studies in Europe and USA which highlights the significant changes requirements in terms of the system operation as we’ll in the utility planning process to accommodate the variable capacity of the wind farms.
Indian experience show that there are variation in the wind power outputs from 15 MW to 1500 MW in a single day (data available for TN).
As wind is considered as an energy source rather than a capacity source, the wind penetration affects the mix and dispatch pattern of the other generation sources. The balancing power requirement for wind power may vary with reference to the local conditions. For example in case of Tamilnadu the wind power is available in the mansion season where there is a system demand of only 30% as per my own understanding and the wind power is delivering about 80% of their output in these four months.
The studies conducted for Minnesota in united states evaluate the physical impact of wind power penetration levels (Different level % of penetration of wind power) and the requirements of the balancing resources which can be brought in terms of increamental system cost with any wind source in the system ( a base case scenario) and the system balancing cost with the different levels of wind penetrations. for example in case of TN if the installed capacity is about 16000 MW and the wind capacity is about 6000 MW. In this scenario there is a balancing power source requirements to the system even without wind capacity which will become the base case and then different levels of penetration will estimate the balancing reserves requirements The balancing reserves apart from the gas or pump hydro can also be proposed in the form of some of the DSM options such as demand response options.
Balancing reserve requirement is also the function of the wind fore case accuracy levels in terms of day ahead forecast, or hour ahead forecast capability of the wind farm. First green consulting has adequate competancies to conduct the wind resource forecasting and scheduling.
The another important cost factor apart from the balancing reserves is the transmission cost which will remain unutilised for significant period of year. This additional transmission cost burden estimation also needs to be estimated.
There are issues in terms of the concentrated wind resources vis a vis dispersed wind resources. There variability of the dispersed wind resource over a large geographic area is less as compared to a concentrated wind resources having maximum generation in lone location. This will also affect the transmission system cost burden as well.
The cost of increased variability and uncertainty can also be controlled by installing some of the technological solutions such installing the ramp up controller at the wind farm level which will avoid some of the spikes in the system.
While power evacuation from wind power projects has become a major concern to the investors in wind power, the addition of solar power in the grid at a large scale is going to create problems worse in near future. There is an urgent need to assess the grid and its absorbing capacity before adding additional RE sources.