Solar and wind power costs globally have dropped rapidly during the past decade. Renewable project tender prices and feed-in tariffs are also dropping across the world. Many believe aggressive cost declines are still possible and will likely allow renewables to reach parity with conventional power very soon. How will technological development, scale of manufacturing, and local development experience build-up continue to affect costs for wind and solar? When should we expect renewable costs to become competitive with thermal generation costs? Will storage cost fall fast enough to allow system-wide costs of firm renewable power also reach parity with conventional power?