# Extremely Efficient Energy Storage Based On Three-Level Silicon Carbide Power Module

SiC makes the difference – both consumers and energy providers benefit from high-efficiency energy conversion between decentralized energy storage and the main power grid. The attraction for cost-effective and environmentally sustainable energy storage peaker plants is unlimited.

Decentralized battery energy storage systems (BESS) reduce the reliance on fossil fuels and allow a wide range of other powerful benefits. Power grids need sufficient extra capacity to work properly during peak demand periods and to satisfy reliability requirements. This disadvantage is strengthened by the fact that the energy sources the energy providers prefer to use are only available with different time lags. In order to counteract large immediate peak demands, energy providers implemented pricing structures that led to a common use of combustion turbines (CT) in the past providing instantaneous energy. The benefit-side of the overall cost-benefit analysis will make energy storage more attractive to customers. If a proper analysis is done, not only acquisition costs, but also operating costs must be taken into consideration. The price for battery cells plus peripherals and the inverter competes against the acquisition and operating costs of CT plants.

## Flexibility of CTs versus energy storage

The well-known output characteristics, acquisition and operating costs of CTs led to high acceptance in the world for adding peak power capacity to the main power grid. Furthermore, they were historically proven to be very reliable. However, when discussing the good points of CTs, the benefit of meeting shorter-duration peaking capacity requirements compared to coal or nuclear plants needs to be moved from the benefits of CTs to the ones of energy storage: Compared to energy storage, CTs are turtles in start and ramp-up phases. In addition, distributed energy storage facilitates the integration of variable wind and solar resources. The California Public Utilities Commission (CPUC) reported the negative impacts on grid stability occurred primarily due to solar PV. The potential of energy storage has been discussed in “Guide to procurement of flexible peaking capacity: Energy storage or combustion turbines” (by Chet Lyons, Energy Strategy Group, 2014): Flattening system load with energy storage synergistically reduces the need for all major categories of utility asset investment, including generation, transmission and distribution.

Table 1: Projected costs (price) for a 1-MW, 4-hour redox flow battery (Source: ViZn Energy, used by Chet Lyons)