[The Case for “Hybrid” Renewable Energy Systems]


There is a growing need for energy throughout the world. This insatiable demand is being driven from an ever expanding growth from the middle class of people in emerging economies looking to avail themselves of conveniences and tools that are normally taken for granted. Additionally, the worldwide explosion of technologies of all types, including personal electronics, mobile devices, and “quality of life” conveniences, place a greater demand or strain on traditional grid or utility supplied energy sources.

Where will this additional power come from, how will we fill the “gap”?

WindStream believes that this gap will be addressed with the aggressive deployment of clean, renewable energy devices, designed to provide the needed energy at the origin of its generation – Distributed Energy. But single source renewable energy solutions, while clean and efficient, only work when the resource is there to be harnessed. Therefore, to maximize the available resources and provide consistent and stable energy generation, WindStream believes that a mix of technologies is the only viable answer and has created the first of its kind, fully integrated Hybrid energy solution, the SolarMill®.

Why Hybrid Systems?

WindStream’s engineers have developed a product to overcome the “inconsistent” nature of renewable energy resources. By integrating wind and solar technologies in a single unit a customer can for the first time reliably depend on a renewable energy generation device. Not only does the system overcome the fluctuations of resources in a 24-hour period, but, over the course of a year as well. A hybrid energy solution smoothes out the highs and lows of energy generation periods due to seasonality as solar irradiation and wind speeds change throughout the course of the year.


A truly hybrid solution will compensate for seasonal losses of power generation not solely depending on one type of renewable energy system. It is easy to see that the combination of wind and solar is a natural one, and one which is complementary on a seasonal basis:

 As seen above, winter months with typical reductions in solar irradiance (shorter days) bring an increased power in potential wind energy. This relationship extends to the daily cycle as well. During the mid-day, wind speeds are typically lower, but the solar potential is high. Conversely, at night winds are more typical, but there is no power available to the P.V. elements in the system. P.V. is operational only during daylight hours, which limits the overall production of a system. Wind has the potential to produce 24 hours a day, given the right conditions, but most importantly throughout evening hours when solar is not available. A hybrid approach provides a more secure and even supply of energy, and provides an energy floor in the event that a location has seasonal weaknesses in the wind resources available. There are locations that, because of seasonal variations in wind resources, do not support a wind only solution. If the production of energy during extended periods is not guaranteed, energy storage requirements to bridge the lean times are extremely expensive, and the return on investment will be excessively long. Where both wind and solar are in abundance, the products make even more sense, especially in space constrained installations.

 WindStream has determined the renewable resources available in 90% of the world can easily justify a hybrid energy system, not just to balance annual energy output, but to capture the available resources at the lowest cost per watt in the market for a renewable energy platform.