Firming solar power

The high variability of solar power due to intrinsic diurnal variabil-ity, as well as additional stochastic variations due to cloud cover, have made it difficult for solar farms to participate in electricity markets that require pre-committed constant power generation. We study the use of battery storage to ‘firm ’ solar power, that is, to remove variability so that such a pre-commitment can be made. Due to the high cost of storage, it is necessary to size the battery parsimoniously, choosing the minimum size to meet a certain re-liability guarantee. Inspired by recent work that identifies an iso-morphism between batteries and network buffers, we introduce a new model for solar power generation that models it as a stochastic traffic source. This permits us to use techniques from the stochastic network calculus to both size storage and to maximize the revenue that a solar farm owner can make from the day-ahead power mar-ket. Using a 10-year of recorded solar irradiance, we show that our approach attains 93 % of the maximum revenue in a summer day that would have been achieved in daily market had the entire solar irradiance trace been known ahead of time