I operate a photovoltaic system with a large battery and source my electricity from a provider with dynamic pricing (in Germany, prices are notoriously high). During winter, the house battery remains largely unused due to limited sunlight, with only up to 20% of capacity being charged by the sun.
Through a workaround, I am able to purposefully draw power from the grid to charge the house battery. The system is claimed to have an efficiency of 98%, but, taking a cautious approach, I assume a worst-case scenario of 90%. Charging the storage becomes economically viable when the electricity price exceeds 6 cents, and price fluctuations throughout the day are significant.
I've automated this process to occur during the most cost-effective time window. Now, I just need to optimize the charging amount. Fully charging the battery at all times doesn't make sense, as I essentially give away excess electricity when the sun is shining. Therefore, I need information on the regional expectations for sun hours.
Simultaneously, it would be helpful to know the forecasted wind conditions on a broader scale in the upcoming days. A high wind forecast serves as an indicator that electricity will become very cheap two days from now, before the announcement of spot market prices. In this scenario, it would be wise to keep the house battery minimally charged the day before.
Hence, the question is: Which API provides reliable data for regional sun hours and overreaching wind forecasts?
It's crucial that sun hours are reflected on a regional level and wind predictions are available on a broader, overreaching scale.