4. TVA's electrical generation portfolio is 39% nuclear, 19% coal, 26% natural gas, 11% hydro, 3% wind and solar, and 1% energy efficiency programs for a total of approximately 33,727 megawatts. If TVA's coal-based electrical generation capacity is replaced with copper-indium-gallium-diselenide photovoltaic cells requiring 50 kg of indium and 10 kg of gallium per megawatt of power generat (a). calculate the total amount of Ga and In required, (b) compare these quantities from part a with total worldwide production of Ga and In of 207 and 1345 metric tons per year. 4. TVA's electrical generation portfolio is 39% nuclear, 19% coal, 26% natural gas, 11% hydro, 3% wind and solar, and 1% energy efficiency programs for a total of approximately 33,727 megawatts. If TVA's coal-based electrical generation capacity is replaced with copper-indium-gallium-diselenide photovoltaic cells requiring 50 kg of indium and 10 kg of gallium per megawatt of power generat (a). calculate the total amount of Ga and In required, (b) compare these quantities from part a with total worldwide production of Ga and In of 207 and 1345 metric tons per year