The Energy Storage Technologies in Generation-Integrated Systems (GIES) and Non-GIES
Authors: Yeserah Gefayehu Tameru 
Published: December 2024

Energy storage technologies can be categorized into generation-integrated systems (GIES) and non-GIES. The effectiveness of an increasing number of non-dispatchable sources of electricity from low-carbon power generators is being provided via the economic and financial evaluation of innovative large-scale energy storage technologies for future generations. Energy storage offers flexibility to the power system by storing excess electricity generated. One type of energy storage that stores energy at some point during the conversion from the primary energy form to electricity is called a Generation Integrated Energy Storage System, or GIES. Given that GIES and novel energy storage systems are still in their infancy and that there are many opportunities and uncertainties in the fields of technology, economics, and finance, it is pertinent to investigate these systems' financial and economic benefits.

This increase causes several power grid issues related to stability and balancing energy supplies and demands. Increased energy storage capacity is required to improve grid resilience and flexibility to address these problems. Batteries are currently the "business as usual" or standard method of storing electricity (i.e. non-GIES). Lithium-ion batteries, for example, have excellent response times and efficiency rates, but their lifespans are comparatively short, and their initial costs are high. Batteries also influence the environment during manufacture and disassembly. Without the need for batteries, a novel class of energy storage devices called GIES stores energy as it is converted from the primary energy form and electricity. The primary energy form is where the energy is kept.

From an economic and financial perspective, this work has shown that GIES is a feasible method to store large scales of grid energy. Considering energy policy, there is a need for enhanced planning mechanisms for co-locating low-carbon power generation with energy storage systems; governments need to examine the type and number of optimal incentives for low-carbon power generation and not forestall the need for storage. The most influential factors for GIES are the specific generator overnight cost and the specific Balance of the System for generator cost. The wind power generator cost is more prominent than the pumped-heat energy storage in Wind-TP. The low transmission efficiency is also important for GIES as the energy losses can increase the LCOE. For non-GIES, the operating lifetime is one of the most important factors considering the LCOE. This is due to the relatively short lifespan of batteries. With a relatively high capital cost, the specific energy storage overnight cost is one of the most influential inputs for non-GIES.

The main objective of this study is a state-of-the-art effective model to compare the economics and financial merits of GIES (with pumped-heat energy storage) and non-GIES (with a Lithium-ion battery) systems coupled with wind generation all over the world. The deterministic, risk, and sensitivity analyses show that, for GIES’s economics, the key driver is the generator capital cost; for non-GIES, the energy storage capital cost is the most important factor nowadays in the world.

Government Bank

Equity Tax Debt repayment

DCF model (for GIES and earnings before Free cash free cash flow to

Debt non-GIES system) Interest and taxes flow to firm equity (investors)

Schem 1. Schematic of the financial model for GIES and non-GIES studies. This DCF model considers three outputs.