Solar system prices dropped 90 percent over the last nine years, but the decline was tempered by American trade tariffs, leaving U.S. prices 45 percent above those in Europe and Australia, according to new research from Wood Mackenzie Power & Renewables. Solar products shipped from China to the U.S. face Section 201 and 301 tariffs, plus anti-dumping and countervailing duties. Those policies have helped shift solar manufacturing into Southeast Asia, while constraining the amount of lower-cost product available to U.S. developers. The Trump administration is currently undertaking a midterm review of the Section 201 tariffs and has wide latitude to determine whether and how tariffs will continue.