In the United States, in addition to favorable natural conditions in certain regions, policies to support energy storage funds, and pressure from high electricity bills, some other factors are also stimulating the combined application of optical storage systems.
Initially, Investment Tax Reduction (ITC) was a tax reduction policy introduced by the government to encourage green energy investment. Photovoltaic projects could deduct 30% of the investment amount from their taxable income. The cost accelerated depreciation method is a tax guideline issued by the United States Tax Administration, which stipulates that photovoltaic systems constructed after December 31, 2005 can adopt the cost accelerated depreciation method, which means that the depreciation amount of fixed assets gradually decreases according to the age of the equipment.
In 2016, the American Energy Storage Association submitted the ITC bill to the United States Senate, clarifying that advanced energy storage technologies can apply for investment tax exemptions and can operate independently or through integration into microgrids and renewable energy power generation systems.
To promote the coordinated development of energy storage and renewable energy, policies also require that 75% of the electricity stored in energy storage systems must come from renewable energy in order to enjoy ITC support. This support ratio is 30% of the system investment, and by 2022, this support ratio will decrease to 10%. When the energy storage system stores renewable energy for power generation between 75% and 99%, it can enjoy partial ITC support. Only when the energy storage system is fully charged by renewable energy can it fully enjoy ITC support.
At the same time, energy storage systems without supporting renewable energy can use a 7-year cost accelerated depreciation, which is equivalent to a 25% reduction in capital costs. Energy storage systems that use renewable energy to charge less than 50% may not meet the ITC support standards, but they can still enjoy the same cost accelerated depreciation support. Energy storage systems with a ratio higher than 50% can use a 5-year accelerated depreciation, equivalent to a 27% reduction in capital costs.