(703d) Techno-Economic Modeling and Analysis of Energy Storage Options for a Self-Sustained Solar PV Array

Renewable energies, such as solar and wind, are an ever-growing part of energy consumption world-wide. The primary push to grow renewable energy production is two-fold: reducing carbon dioxide emissions, thus moderating the effects of increased atmospheric levels of the gas, and reducing dependence on a diminishing fossil fuel supply. However, renewable energies certainly have issues, chiefly their intermittent and non-dispatchable nature. This is to say that solar power is only available when the sun shines, and wind is only available when the wind blows. This makes supplying electricity to a given demand load impossible for stand-alone renewable energy sources, limiting the financial incentive to invest in renewable energies. Intermittency also causes frequency and voltage instability for the grid when renewables are integrated into it. Energy storage is integral to the viability of renewable energy as it allows for load-smoothing and frequency regulation. Currently, no one or two obvious energy storage technologies exist to economically meet the requirements of meeting demand with renewable energy.

There are numerous ways in which energy can be stored: chemically, electrochemically, mechanically, and electrostatically. A model is proposed to study the economic feasibility of several energy storage options available today for a self-sustained solar PV array. Hourly demand data and hourly solar generation were used to determine constraints on the studied energy storage component. Factors including system capital cost, system operating cost, various replacement cost, and energy storage replacement times were used to calculate a net present value of the energy storage options for different demand curves. The model was used to examine the full lifetime of the PV array, typically 25 years. The most promising energy storage technologies for financial feasibility of a generalized solar PV array are sulfur-sodium batteries and carbon-enhanced lead acid batteries, depending on the scale, timeframe, and location of the energy storage.