Growing up on the west coast, I spent a lot of my time on the beach and in the cold waters of the Pacific. I vividly recall the first time I truly got a taste of the power the ocean can deliver. It was a stormy day, nothing intense, but enough cold wind coming off the water to make a noticeable difference. You could feel a front coming through that day, but it was still nice enough to stand on the shore and enjoy the day. I may be one of few here, but I have always enjoyed a windy, stormy day coupled with choppy seas. As I wandered back and forth, glancing at the where the ocean meets the sky periodically, I noticed that the waves were getting bigger and stronger, but I wasn’t concerned. Nothing looked menacing, and I had only done this same exact thing a hundred times before. I continued to walk and wade, watching the water hit my legs, and scoping the shells and rocks as they tumbled back and forth. I bent down to get a closer look at something and before I knew it a brick wall hit me. In less than a second I was one of the tumbling rocks. No doubt I only spent a fraction of a second under the water, but in that moment, I had no idea which way was up or down, and when I resurfaced, I was much further out into the water than where I had started. The force of a relatively small wave did a whole lot that day, and that broad idea is translating into the green energy revolution.
Our oceans provide us with oxygen, food, and serve as home to the majority of life on Earth. Covering over 70% of the world, ocean power is currently rarely used, but holds promising potential for the future. There are four main ways that clean, renewable energy can be harnessed from the ocean: thermal energy conversion, tidal energy, wave energy, and salinity gradient energy. Salinity gradient energy uses osmotic pressure differences between salt water and fresh water. Fresh water is able to flow through a semipermeable membrane and increase pressure in the salt water tank. Thermal energy conversion relies on temperature differences between varying depths. In this form, there are closed-cycle using a low boiling liquid and warm seawater to rotate turbines, open-cycle systems using tropical ocean water in low pressure containers causing it to boil and rotate turbines to create energy, and hybrid systems combining both methods. Tidal energy is technically a form of hydropower, since it relies on the movement of water through reservoirs and dams as sea tides rise and fall. Wave energy is generally used towards the surface of the water, a wave enters a chamber, which forces air within the chamber to spin turbines and turn a generator. There is a large power potential for wave energy, but not all areas of the world have are created equally when it comes to waves. Where other options of harnessing this energy are relatively equal throughout the world, waves change with location, Alaska garners the highest recoverable energy, 620 TWh per year, the West Coast is a far second at 250 TWh per year.
While ocean energy is green, renewable, reliable, and incredible powerful, it is really often times only efficient depending upon location. It can also have an adverse affect on sea life and conflict with tourism. The cost of build out is 4x more expensive than the more popular solar and wind options, but the idea is relatively in it’s infancy. As will all, advancement in technology will steer the way.