The biggest story in renewable energy this past year was the incredible performance of SolarCity (SCTY.DL). The solar leasing company is up 385% since its IPO, growth that would not be possible without the plummeting costs of solar power systems. In fact, the cost of solar panels have dropped over 60% in the past 2 years. Will SolarCity continue its march higher in 2014 and meet its projections of 80% annual growth in installations?