context: Renewable energy technologies are getting cheaper, through technological change and through the benefits of mass production and market competition. A 2011 IEA report said: "A portfolio of renewable energy technologies is becoming cost-competitive in an increasingly broad range of circumstances, in some cases providing investment opportunities without the need for specific economic support," and added that "cost reductions in critical technologies, such as wind and solar, are set to continue." As of 2011[update], there have been substantial reductions in the cost of solar and wind technologies:
question: సౌర, పవన సాంకేతిక పరిజ్ఞానాల వ్యయాలు ఏ సంవత్సరంలో గణనీయంగా తగ్గాయి?
answers: 2011