I saw this little gem this morning:
Now, I am NOT against things that make electricity. The pitch here is that it is generated by free flowing water in water mains. Well, I guess the water is free flowing.
Let’s discuss what is really happening. In order for there to be water pressure in the water mains, one of two things must happen; the water must be pumped into a water tower or higher elevation reservoir to provide hydrostatic pressure, or there must be a large pump driving the water under pressure.
I am sorry to burst the bubble here, but this is not actually “free flowing” water. In both of the above scenarios, water is either lifted or kept under pressure by massive pumps, and this is not “free”. It requires oodles of electrical power to lift water 24/7 or to keep it under constant pressure.
I am sure there are some isolated cases where water is naturally higher and flows downstream to drive these mini-generators. But for most places on the planet, the water is first lifted to a higher reservoir by massive pumps. In other places with less change in elevation, the pumps simply run constantly to provide pressure.
So what we have here is a sort of ‘recapture’ of the energy expended to provide water pressure in the first place – it is not free at all. This might offset the cost of the original lifting or pumping of water, but it certainly is not “free”. In the case of water reservoirs being initially higher in elevation than the customers supplied, this still is not ‘free’.
This tech-savvy idea is a bunch of mini-hydropower stations along the water main. Each of these stations requires monitoring and maintenance (lubrication and overspeed governors, etc.) remotely, and then a crew to fix and lube them regularly.
They may require additional access tunnels to install and maintain. If one fails, then there must be a bypass loop installed on the main line so the generator can be removed and replaced without interrupting water service. This is standard practice when installing anything with moving parts in a pipeline, which will require replacement or service. I don’t think the bypass loop is free at all, nor is the excavated and cement lined tunnel access required to install these generators and bypass loops. Each must be tied to the electrical grid via waterproof conduit and an electric run to the nearest power pole, along with the associated backfeed equipment.
It is cool though – look at the whiz-bang tekkies go!! See them making ‘free’ electricity from a dumb water main…
This is a very great example of how hypercomplex technology is sold. It will require more money to install, more people to monitor, adds more failure points and requires a maintenance crew. At best, these generators will recapture some of the energy lost in the original lifting or pumping that makes the pressure for the water main.
What this ‘new technology’ will do, in the end, is raise the cost of water for everyone in the supply system.