East River Turbines Face Upstream Battle

From the Gothamist, following up a story about which, for some reason, I never heard (my wife emailed this story to me). I did not know there were turbines hanging about in New York’s East River. Possibly not for long, though:

The alternative energy company that has plans to install hundreds of turbines in the East River to harness tidal energy and generate zero-emission electrical power is running into trouble due to the massive amount of energy they are dealing with. The small number of turbines already placed in the East River by Verdant Power have been temporarily removed as the strong currents continue to overwhelm the physical construction of the underwater “windmills.” The six turbines that were placed in the water last December and were capable of supplying 1,000 daily kilowatt hours of power and serving the Gristedes supermarket on Roosevelt Island could not withstand currents.

The East River is not actually a river; it’s a tidal strait, and one can easily observe the current moving in opposite directions with the tides. Verdant Power’s plan is to install a field of turbines anchored to the bottom of the East River and use the currents to generate pollution-free electricity for the city. The currents have proven so strong, however, that the turbine propellers have been sheared off a third of the way down, and stronger replacements were hampered by insufficiently strong bolt connections to the turbine hubs.

Well, that’s …promising? Hydro-electric has a couple of basic forms: tidal, meaning windmills underwater, and non-tidal(?), meaning the Three Gorges Dam or Niagara Falls. In the case of the former, the river is dammed, such that water that is allowed through comes through with sufficient pressure to spin the turbines. In the case of Niagara, some of the water (about 80%, I’ve been told) is piped off to the turbines, using simple speed and gravity (rather than placing the turbines on the falls themselves), and piped back to the river afterwards.

The environmental impact of dams hardly needs to be discussed. As I understand the mechanics of the hydro-electric engines at Niagara, environmental disruption is minimal-to-nil.

Here, though? For a start, the scattered pieces of broken turbine probably ought to be swept out of the river. But allowing for the eventuality of turbines strong enough (with strong enough bolts) being stuck in the mud, ready to go. How much tide do they stop? Oddly enough, this testing phase of the East River project was, in part, designed to figure that out, so I guess we still don’t know.

I do know of studies on on-shore or basin tidal energy projects, where the consensus is that wave heights, though not tide heights, are affected. Suggesting that the water would still go up and down the East River, but the current will dissipate, possible significantly. Sadly, I just don’t know enough about the river to say what that means. As long as the river still actually runs, it should be fine. If it slows down too much, it will most likely just start dumping crap at the end and not taking it back out – it will also demonstrate that turbines in rivers defeat their own purpose.

I imagine, also, that the true impact will depend on the river, how fast it goes and what is at either end. According to Eco-Geek:

Preliminary site approvals for in-stream turbine farms have already been given for 25 sites along the Atlantic and Pacific coasts of the US, and a further 31 sites are under consideration. Other companies are developing other forms of tidal turbines, some with as much as 1 megawatt capacity.

I don’t know what that suggests. I don’t much like the idea of all that commercial pressure building up on one side of an as-yet undetermined environmental impact debate, though.

Finally of interest – I noticed that the turbines in this story:

match the conventional windmill-type, but not others, such as the ones seen in this 2001 article on tidal energy:

I believe that is the Gorlov Helical Turbine (designed by the author of the article). It’s an adaptation of another type again, the Darrieus Turbine:

I wonder if replacing the tide-mills (no, that doesn’t work at all) with the Helical Turbine would make a difference to the problem of being over-powered? Amongst other things, the Gorlov adaptation can be moored-and-floating, which would help protect against being sheared off at the bottom by the current.

The Whole House-Off Switch

Brought to you by someone brighter than a brain pie (with apologies to Rowan Atkinson):

The ‘House-off’ Switch is a switch that allows a user to turn off all non-essential electronic items in their home from a central switch. Push the button to turn your house on when you get home; push it again to turn it off when you leave. Aiming to make the ‘green’ way the most convenient way, the ‘House-off’ Switch was part of a larger project to encourage ‘green’ action among the environmentally disenfranchised.

…

a more expensive version of the same concept has a central switch that also allows the inhabitant to leave some items plugged into ‘safe’ sockets around the house which can be left on for security of peace of mind when everything else has been turned off at the central switch.

Originally spotted at – unsurprisingly – the blog Inhabitat.

What a wonderful idea. I’ve thought this often: that it is all well and good to talk about how much power our ‘devices’ use when merely on standby, but we have a lot of them, and it’s a pain in the ass to go turning things on and off at the wall – particularly given the nature of the modern entertainment system (I’m using those of my parents and brother: we do not have one, just laptops), where it’s deliberately made difficult to get at those sockets (Americans: outlets).