Green Energy, Meet Blue Energy: Using Osmosis to Generate Clean Power
In the late 1950’s, two scientists working at UCLA came up with a process in which fresh water can be made from seawater. It’s a little thing called reverse osmosis. One of those UCLA guys, while working at Ben-Gurion in Israel, had an idea to use the same kind of process to create energy.
It’s quite simple. The way that osmosis works with fresh versus seawater, water will naturally move from a less-concentrated solution (fresh water) to a more-concentrated solution, i.e. the salty water, and once something moves, it creates kinetic energy, and energy is energy, people. You just have to figure out a way to optimize and harness it.
And that is what this Sidney Loeb fellow wanted to do. He patented it anyway in 1973, and named the process Pressure Retarded Osmosis (gee, I wonder if you could get away with naming it that today). But with osmosis, you need a membrane that is permeable to something like water and not to something else, say salt. The water moves from fresh to salty, creating a flow, if enough pressure is present. The amount of pressure is key, and if you doubt me, think of a shower with really low water pressure. Yeah, exactly.
With enough pressure, you can move turbines, and turbines run generators, and yep, you got power. A group in Norway is working on new and improved membranes that can actually produce the pressure (about 12 atmospheres) needed to create power, which was the sticky point since 1973. The Norwegians are looking at plans to build a prototype power plant in a fjord near Oslo, a great location in terms of ample supplies of both fresh and seawater.
The Dutch group working on similar plans for their own prototype and they have come up with the term Blue Energy. The Dutch plans also include a series of batteries, powered by the salt water. Blue Energy uses the movement of the ions present in salt water, the + Na and the - Cl. It makes me think of how a solar panel works, using ions to create an electron flow which creates electricity.
So far, it seems that a fifth of the power that the little pressure retarded osmosis systems produce are needed to pump the water, so obviously, things are going to have to become a lot more efficient before we start replacing all the coal plants with osmosis plants. So designing the shape of the membrane “tubes” will become important, to maximize surface area, but also be as compact as possible. And then there is maintenance and cleaning of said membranes…and a limited number of suitable locations…constructing in hard-to-reach places that will require new roads…
Besides that, it’s brilliant. Clean, non-obtrusive, safe for the environment and wildlife…The Europeans are obviously getting creative.
reverse osmosis, osmosis, UCLA, desalinization, fresh water, seawater, salt water, pressure retarded osmosis, PRO, membrane, electron flow, ions, electricity, power, kinetic energy, energy, green energy, Blue Energy, Oslo, Norway, Netherlands
