Microhydroelectric power is making a comeback in electricity generation for homes, farms, and small businesses. This trend is fueled by factors including favorable regulation, rising energy prices, and advances in automation. And do-it-yourselfers worldwide are diving in.
The only requirement to generate electricity is access to a stream with a two-foot drop in water level and two gallons of flow per minute. A hydroelectric system isn’t overly complicated, isn’t difficult to operate and maintain, has longevity, and is often more cost-effective than any other form of renewable power.
Although we’d never built such a system before, we did so by using low-cost components and free technical support, both supplied by AutomationDirect.
In 1980, my father, Arno Froese, began investigating the potential for generating hydroelectricity on his property. The land is situated near the dam of a 64-acre communal lake, allowing access to the 10-foot height differential between the lake and the tailwater on the other side of the dam.
My dad measured the water flowing over the spillway and determined that an average of 40 cubic feet per second flowed through the pond, making it a marginally feasible hydroelectric project. In 2004, my brother Simon discovered our dad’s research and decided to move forward.
This microhydroelectric power plant generates 20kW of power, controlled by equipment from AutomationDirect.
In March 2004, Simon began excavation. For two years, the project was a challenging and sometimes disappointing excavation site, requiring us to dig 17 feet below lake level for the foundation while groundwater and mud continuously seeped into the hole. By the end of 2006, the underwater portions of the plant had been built, a four-foot aluminum pipe through the back of the dam was in place, and a temporary cofferdam was removed. We then installed a refurbished 50hp Francis turbine. Testing determined that the turbine’s optimal speed would be 150rpm.
The hydroelectric system is powered by water draining from the lake that flows through a turbine, which drives three generators via a belt and pulley system. The generators are three Baldor Electric model L1177T 15hp single-phase induction motors.
Driving an induction motor at higher than normal speed generates electricity. Output from the three motors was tied into the local electric grid via the same transformer that formerly only provided power to the property. The utility’s meter now turns backward when our plant supplies more power than we consume.
...try again with the watts to horsies...as one horse is 746 watts...so a 15 horse motor would be around 10 KW....
Article says 3 of the 15 horse motors...so yes...about 20KW...if all goes well.
Then, to get the buy-back...I'm assuming the generator must be exactly 60 Hz...?
I've worked at a couple small (30-40) Mega-watt Bio-Mass plants...the on-line syncro is extremely important...and...I'd assume this set-up here in the article has at least a transfer switch of some kind...? That is one of the first things any hydro or PV set-up requires. Otherwise I would think you could end up with utility power running your motors and pumping the water backwards...but then, I could be wrong....
My admiration for all the hard work and ingenuity!
Here in Michigan (and in most states I would think) the DNR would be all over this. Also FERC (Federal Energy Regulatory Commission) claims jurisdiction and requires that a hydro have a license even with the tiniest stream generated electricity if it is grid interconnected. These two entities would easily double the cost of the project even at this small scale. I would like to know how you avoided these burdens.
A lot of people have trouble conceptualizing the induction aspect of a motor/generator. An induction machine delivers the nameplate rated hp as a motor at the nameplate rated amount of slip below synchronous rpm and, in turn, will generate the rated equivalent electricity as a generator at the same amount of slip above synchronous rpm. An electric motor is not "synchronized" at start up - that is just the condition under which it delivers maximum torque because it is at maximum slip. The line sets the voltage, frequency and phase relation. The induction machine simply uses those properties to operate without need for complex controls, regulation and phasing.
Thank you, renuengineer for that explanation of how induction generation works; I couldn't have done it better!
Re: FERC, they don't involve themselves with individual installations this small. In South Carolina, our department of Health and Environmental Control does regulate dams & reservoirs, but our lake had already been in existence for over 100 years. The utility company was satisfied with some cursory drawings and assurance that we were entirely induction-based. The only official inspection was that of the county building department.
You're numbers look spot on. At that scale, standard induction motors might achieve 70%-80% efficiency, and the turbine/penstock losses are in that range as well.
I have yet to connect our Micro Hydro to the grid. Except for a few hours of testing, when I discovered what 'absolute value' metering meant, we have been running autonomously since commissioning 2006. I used pumps as turbines and 3 phase motors as single phase generators to cut costs. I don't think I gave up any efficiency at all since I'm getting a bit more than my initial calculations indicated. NY just passed the net-metering law for under 25kW hydro, so we'll be hooking up soon.
Syncing induction generators of a few tens of KW to each other or the power-line is not a problem as long as they are within a few RPM or Hz of each other.
This is a very good work! I wonder if this is affordable for developing countries like Mexico or Latin America where there is good potential for micro hydroelectric generation, how expensive is the system and where can I purchase one? Thanks
You are absolutely correct. There's little more than .001 hp available from water @ 2 GPM dropping 2 feet. If this was able to produce 20 Kw we'd have ourselves a nice perpetual motion machine! I think that the heading of the article is misleading. The article itself is worthy.
Design News asked for people to moderate and presumably add comments to their web site. You had to make a certain number of posts to remain in the system and to receive a stipend or whatever it was called. I get the feeling that this thread is more about maintaining a posting record than making real comments about an idea that is impractical in almost every state.
The idea may or may not be impractical, but the comments are entusiastic. Those who comment on the Design News site are passionate about their views. I think that's very clear in this thread as well as the other comment threads.
I applaud this project from a technical and ingenuity standpoint.
However, I tend to agree with the pessimism on the regulatory stuff. Here in NY, the environmental hurdles as well as the federal & state energy commisions/authorities and utilities would make it nearly impossible. The thousands you would have to spend on attorneys, permits, fees, and political contributions to make it happen legally could buy you electric power from the utility for a hundred years or better. I think in this state the only thing attempting such a project would get you is legal trouble and the related fines and attorney fees.
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