Halifax Water uses excess pressure on turbine

waynefromnscanada

Well here's something different! The city of Halifax, in East Coast Canada is trying something new. Instead of blowing off excess water pressure in their system, they're directing it through a turbine in a first for Canada, and generating electricity in the process!

http://globalnews.ca/news/1669332/halifax-waters-new-in-pipe-hydro-power-turbine-a-first-for-canada/

westbranch

Re: Halifax Water uses excess pressure on turbine

Wayne somethign doesnt add up :
First they say the are re-routing excess water to the turbine and;
Next, they re sending the water to houses Then, it continues its usual path to thousands of homes.

I like it, but a bit of poor reporting?

BB.

Re: Halifax Water uses excess pressure on turbine

They have done this in our area too for years (as I understand/remember).

Basically, we put our water tanks on the top of the local hills, and then let the water "fall" to the point of use.

However, we have ~800-1,000 foot hills and sea level cities too. To get ~60 PSI, the water only needs to be ~120 feet above the point of use.

So, there is a large "head" of hundreds of feet that you could simply put through a pressure regulator--However, all of the energy that was used to pump the water to the hill top tank is wasted.

Instead, they direct the water through a turbine (or even possibly a "bi-directional" pump) and program it to "drop" XYZ PSI of pressure to the next group of users farther down the hill (or even fill lower water tanks if needed). In our area, they "sell" the excess electricity back to the utility.

More or less, "free" energy from what was a 100% loss of pressure regulation through a "micro" hydro system.

-Bill

waynefromnscanada

Re: Halifax Water uses excess pressure on turbine

westbranch wrote: »

Wayne somethign doesnt add up :
First they say the are re-routing excess water to the turbine and;
Next, they re sending the water to houses Then, it continues its usual path to thousands of homes.

I like it, but a bit of poor reporting?

Yes. I agree a bit of poor reporting, confusion. Actually, from what I understand, one of their main water supplies comes with a 500 foot head, and it appears that may be what they're using to power the turbine. I suppose it's possible they COULD, under some circumstances add (divert) excess pumping pressure to the incoming water line with the 500 foot head to recoup some of the otherwise lost energy, but that's not clear. At least it's not clear to me. But all the confusion aside, it's great they're generating energy with the excess pressure.
And thanks "BB" for your interesting post. Nice to see at least some water utilities have employees using their heads.

peakbagger

Re: Halifax Water uses excess pressure on turbine

There is a water utility in Lenox mass that has done this for years. Its pretty simple, basically a centrifugal pump that runs backwards. A local utility recently installed one.

When I worked in the pulp and paper industry we had to be careful as many pumps had impellers that screwed onto the end of the shaft. If they ran backwards, the impeller would spin off causing damage. If this might happen, we could key the impellers or even locktite them.