Solar cells and photovoltaic modules are only one part of a solar energy system and other aspects need to be considered when heading towards a high penetration of PV in our electricity network. This tutorial discusses the fundamentals of PV systems and their integration into the grid. One challenge is the fluctuating nature of solar energy which is not always matched to consumption and therefore requires storage solutions. This tutorial discusses options for short-term and seasonal storage solutions and requirements to reach a stable grid with high amount of wind and solar power.

Speakers / Authors:
Dr. Sarah Kurtz / UCMerced
Prof. Arno Smets/TU Delft

This tutorial will be presented in two parts with the PV Systems part covered by Dr. Smets and the Storage Solutions covered by Dr. Kurtz.
In the first part of this tutorial we will cover the design of photovoltaic systems, such as utility scale solar farms or residential scale systems (both on and off the grid). You will learn about the function and operation of various components including inverters, batteries, DC-DC converters and their interaction with both the photovoltaic modules and the grid. The different types of inverters, methods of maximal power point tracking and the overall efficiency of energy conversion of the system will be discussed. The design principle of PV systems for different applications, A wide variety of applications of PV systems, such as off-grid, grid-connected, microgrids, will be discussed.

We will then discuss the storage solutions needed to facilitate high penetration of solar including: peaking power (< 4 hours), diurnal storage (generally 4-12 hours), cross-day storage (generally 12 – 30 hours), and seasonal storage (may be 30 – 1000 hours, including cross sector storage). The number of specified hours is the ratio of the rated energy to the rated power for the storage. Then, we will review the storage technologies available commercially and under development, including pumped hydro (the largest today), lithium-ion batteries (fastest growing today), other forms of gravity storage, compressed air storage, flow batteries, liquid air or carbon dioxide, zinc batteries, and more. Prices for lithium-ion batteries are coming down rapidly and efficiencies are high, but lifetimes and scalability are poor. The tutorial will emphasize how a collection of solutions is likely to be most effective at supporting solar- and wind-driven grids.