Photovoltaics’ Innovative Forces

By Karl-Heinz Remmers, CEO of Solarpraxis AG

Dear Readers, If a British company in the automotive industry builds a five megawatt (MW) solar plant on its factory roofs in the North West of England, as happened recently, a large amount of solar power no longer flows into the grid. The plant capacity covers up to 40 percent of the company’s energy needs. This way, that 40 percent can be used at a stable price regardless of market prices for electricity because it is produced and consumed on site.

Another example of how energy-intensive production facilities have made major headway when it comes to energy self-sufficiency can be found on the other side of the globe. In Tennessee, USA, a PV plant produces 9.5 MW of rated output on the premises of an automobile factory. When the manufacturing facility operates at full capacity, the solar power plant provides 12.5 percent of the electricity required. It can even meet the entire energy needs if production is ground to a halt.

These two projects show that more and more energy-intensive companies are now turning to the on-site production of solar power in the megawatt range to, at least in part, meet their energy needs. However, what happens if the electricity is to be consumed off site and several megawatts of power are to be integrated into the public grid as usual? After all, the continued success of renewable energy increases the risk of overloading the power grid because sun and wind provide fluctuating energy that does not follow consumption.

Storage systems are the solution. They are both an opportunity and a necessity. On one hand, they allow for a time gap between power production and consumption (which of course is also good for direct consumption); on the other hand, the energy revolution can only be successful if renewable energy storage systems can ease the burden on the public power grid in the long term.

However, large-scale storage for PV plants is not yet competitive, with the exception of pumped storage. Specific geographical conditions are needed for pumped storage, which can therefore only be implemented in a limited number of places and, even then, this significantly impacts the environment – decentralization is a different matter.

Although the technological tug of war has only just begun and it remains to be seen if we will combine mechanical, electrochemical or electrical storage with large-scale PV plants in the future, storage systems will no doubt transform the centralized grid structure into a decentralized one. Together with an intelligent energy management system, they pave the way for large-scale grid integration of photovoltaic power. Technology that is used in various applications from load balancing to cloud mitigation will play an important role in the near future. The inverter will become a flexible interface which takes over associated system management tasks.

Experts are still engaged in a zealous debate when it comes to weighing up the costs and benefits of storage technologies. Most concepts for large-scale PV plants have not yet emerged from the experimental stage. Small, privately-owned PV systems will be the first to see storage take hold, in favor of increased direct consumption. A look at current projects shows that storage for large-scale plants is still a marginal topic and a major challenge. That said, the industry is already waiting in the wings – and photovoltaics will once again prove how it is driving the energy revolution forward thanks to its innovative force.

Best regards,

Karl-Heinz Remmers