Challenges. There are many engineering challenges to making ocean energy more efficient. ocean energy can produce 10-20% of the energy needs of smaller countries that border major oceans. The Netherlands is one good example. Presently, most wave-energy technologies are in their formative years. Critics argue that the amount of energy produced by even 100,000 wave machines is too small. It can barely provide enough power for a large city. The further inland the electricity has to go, the more power it uses. To send electricity from a wave-generator to the shore would be highly inefficient. It would have to go from the Atlantic Ocean to the shore, then over 1,000 km to cities like Chicago.