The ocean energy sector is still at an early stage of development. Despite the fact that the ocean is permanently in motion, extracting energy from that motion on a major scale continues to be a challenge. But the potential benefits of ocean technologies are compelling enough that many approaches continue to be pursued.
A recent study by Harvard University researchers published in two papers looked at the environmental impact of installing sufficient wind power to meet all the energy needs of the US. While doing so would be far better for the environment than burning coal, it would not have negligible impacts.