Between 2010 and 2016, U.S. imports of solar photovoltaic modules rose 550% to 13 gigawatts of direct current, and two-thirds of the 2016 imports came from Malaysia, China and South Korea, according to the U.S. Energy Information Administration.
The EIA reports import capacity in direct current because it reflects the capacity of the solar panels. Operating capacity is reported as the panels deliver energy to the grid in alternating current. Capacity values reported in alternating current are between 10% and 30% lower than for direct current because of the amount of energy lost when converting direct current to alternating current.
In 2016, the United States installed 8 gigawatts of alternating current utility-scale solar capacity and 3 gigawatts of alternating current small-scale solar capacity. The installed amount was about equal to 14 gigawatts of direct current capacity, and many of the solar photovoltaic systems installed in 2016 likely used imported panels, according to the EIA.
The United States established tariffs on imported silicon solar cells and modules in January 2017. Solar cells are the individual units or wafers that convert sunlight into electricity. A group of interconnected cells in a sealed package comprises of a module or panel. Solar panels are installed in arrays, or a row of panels, and include hardware, such as an inverter, for a complete installation.
The tariffs will last over the next four years, starting at 30% of the cell or module price and decline annually by 5 percentage points until reaching 15% in the fourth year. Up to 2.5 gigawatts of direct current capacity for unassembled solar cells will be exempt from the tariff each year, but this comprises of a small fraction of the U.S. imports. The tariff doesn’t apply to panels including thin film and concentrator types, but the majority of systems installed in the United States are crystalline silicon, for which the tariff applies.
Between 2012 and 2016, the price of solar panels fell 40% to 72 cents per watt of direct current, according to the EIA. Between January and December 2017, the spot price for solar panels fell 37.5% to 45 cents per watt of direct current.