When one thinks of photovoltaic (PV) energy, one cannot help but think about the Sun as the ubiquitous, renewable source of the energy. However, I also like to think about the Mississippi River.  What do I mean by that?  The energy network with its utility grid is very similar to a water system with its reservoirs, dams and rivers.  PV energy is becoming an increasing important contributor to this energy network.                                                                                                                                                                                                  

Managing the Flow

Electricity flows from the higher voltage point to the lower voltage point like water in a river. And as the water pressure decreases as users on the river consume the water, so does electricity voltage as users consume it. Moreover, like the myriad of dams, levees, bunds, and reservoirs used to control the level of water in the river, electrical equipment is used in similar fashions to manage the voltage level within certain ranges throughout its journey from the source to its consumers.  Situations like overvoltage and undervoltage can lead to serious problems with electronic machinery and consumer appliances.

So what does this mean for PV energy?  Well, energy companies have more than 130 years experience managing the centralized energy generation at coal, nuclear, natural gas, hydroelectric and petroleum power plants. And they are reasonably successful at transmitting this electricity from the centralized source to the distributed consumption albeit with substantial energy loss.  In fact, most initial deployments of alternative energy power plants are similarly placed on the grid.

However, PV energy has the potential to be generated where the consumption occurs, even in densely populated urban areas.  Given the amount of energy lost during its transmission, this is very appealing and critical to the return-on-investment of PV solutions.  To maximize the PV systems efficiency at these distributed locations, they need to be intelligently monitored to understand the impact of shadows, contaminants and positioning of the solar panels. Environmental conditions can change, pollution can settle and trees will grow; all of these can affect the amount of sunlight hitting the panel and its subsequent effectiveness.

Unpredictability is Bad

As mentioned before, overvoltage or undervoltage is definitely not a good thing and can limit the urban adoption of PV energy. Overvoltage can shorten the lifetime of equipment like transformers that supply the power and undervoltage limits the normal operation of electrical equipment and consumer appliances.  With multiple PV systems providing energy onto the grid, the challenge to properly manage the voltage levels becomes paramount.

Also, there are other situations that need proper management.  For example, if multiple PV systems are simultaneously brought off the grid at the same time, it could lead to a precipitous voltage drop if not adequately compensated for by the main grid.  What about the opposite? If PV systems in a network are cut off from the main grid but yet delivering energy, safety issues could exist for maintenance personnel coming to fix the problem. Finally, there is a lot of conditioning of the electricity that needs to be done to maintain a solid network.

Consequently, PV systems must have sufficient intelligence to monitor itself, identify issues, act on those issues and notify a centralized location.  These features and the associated equipment require the capabilities of Spansion^® NOR flash as part of the solution.  Cost-effectiveness, ability to operate in extreme conditions and long lifespan (10+ years) are critical to the profitable success of the PV solutions. Spansion Flash solutions are designed specifically to address the needs of these mission-critical embedded environments.