This document discusses the investment case for solar power, outlining long term bullish factors such as projected spending of $3.7 trillion on new solar installs through 2040. It notes solar costs are falling due to improved technology and economies of scale, and grid parity is being reached in more markets. Advantages of solar include being clean, having fixed upfront costs with no fuel costs, and falling installation costs. The document recommends investing in the MAC Solar Index ETF to gain diversified exposure to the growing global solar sector.