According to an article in the New York Times, interest payments on bank loans make up more than half the costs of the typical solar panel manufacturer. The owner of a firm that imports solar panels made this observation about solar panel manufacturers: "So as long as companies can cover their variable costs and earn at least some revenue to put toward interest payments, they will continue to operate even at a loss." Source: Diane Cardwell, "Solar Tariffs Upheld, but May Not Help in U.S.," New York Times, November 7, 2012. Part 2 The interest payments these firms make are a fixed cost since they do not vary with output. fixed cost since they vary with output. variable cost since they vary with output. variable cost since they do not vary with output