Tidal power is amazing from a grid-cost perspective. Unlike other forms of renewable energy, you can literally set your clock to the tides, making it much easier to schedule into the grid. I am so happy to see these advances, and look forward to other forms of oceanic renewable energy, like wave, thermal, and offshore wind!
Building electricity generators underwater is challenging. If a big storm comes through, the storm surge will destroy almost everything in its path. You design a hydropower station so that it will have resistance when the water passes over it, if you don't have the ability to disengage (wind turbines have locks and newer ones have adjustable blades) it will get destroyed when large waves come in (sometimes, all that power is a bad thing).
It's great that we're still attempting these though, the power of the sea is too tempting to stay away from. Whether or not it works, it will give us another data point on what to try, or what not to try.
As a Mainer I am very proud of this. It has been talked about for a long time in Maine and tidal power is not exactly a new idea. But it's good to see ORPC finally executing on this idea.
The blades of the turbine, shaped like the helical strands of a DNA molecule, turn as the underwater current passes through them.
Has anyone proposed using these instead of hydroelectric dams? How much will it affect wildlife? Can fish swim among the turbines?
Edit: video shows these are arranged like lawnmower blades, so the fish would probably be chewed up. I wonder, if they were turned sideways, so the water flowed through the center -- would they turn at all?
They wouldn't turn, (sort of) like an aircraft wing flying sideways, it is not designed to create lift in that direction. These blades have big paddles that catch the force of the water and push it (like a waterwheel).
Dammit, Jim, I'm a programmer, not a power engineer! So I'm just wondering whether harnessing tidal power will diminish that power over time, with results that might make global warming look like a church picnic by comparison. Conservation of matter and energy and what-not, right?
Of course, if we won't see any knock-on effects till well after the sun has expanded to incinerate the planet, then shoot, full speed ahead!
I can't seem to find a solid reference, but I recall reading that on a global scale it's negligible, similar to wind power: the amount of power extracted in even a deployment much larger-scale than anything we currently envision is a rounding error compared to the total power in the earth's tidal movements.
There is some research on local environmental effects, however, since the amount of energy extracted from a particular bay's tidal flows might actually be noticeable. There's a review of that literature in Section 2 of this paper: http://www-civil.eng.ox.ac.uk/research/tidal/EWTEC2009_tidal...
