Hydro-Electric Evolution: Page 3 of 4

An Interview with Hydro Expert Chris Soler
Intermediate
Chris Soler purging the lines
Chris Soler purging the lines
Chris Soler prepares for a job digging a penstock ditch
Chris “The Human Backhoe” Soler prepares for a job digging a penstock ditch. Chris has spent many days and weeks of his life scoping out hydro sites; mapping out the best locations for intakes and turbines and the best routes for penstocks and transmission lines; and digging thousands of feet of ditches to protect and secure pipelines.
Early homebrew systems used car alternators
Chris’ early homebrew systems used car alternators matched with homemade or cast runners, with a square plastic bucket lid sandwiched between. The bucket (with tailrace channel or pipeline) was dug into the ground, and the manifold lines terminated in simple nozzles in the bucket’s sides. Snapping the lid on the bucket aligned the runner with the nozzles and set up the system for production.
One of Chris’ early homemade runners
One of Chris’ early homemade runners. As his understanding of hydro and his customers’ budgets increased, Chris switched to manufactured runners with much higher efficiencies, capturing more energy from the same head and flow.
A modern Harris hydro turbine
A modern Harris hydro turbine in one of Chris’ upgraded systems. The square bucket lid was supplanted by a manufactured housing and the used alternator replaced with a permanent-magnet alternator that was custom-designed for hydro systems.
Hydro intake screen
Chris learned early on that poorly designed and installed hydro intake screens can cause a lot of trouble, requiring frequent cleaning.
Self-cleaning screen
When self-cleaning screens became available, Chris found ways to use natural spots in the stream and a dab of concrete to set up durable, maintenance-free intakes.
Chris prepares low-pressure PVC pipe
Chris prepares low-pressure PVC pipe for the top end of a penstock.
High-density polyethylene pipe is heat-welded
High-density polyethylene pipe is heat-welded for a high-pressure portion of a penstock.
Battery Bank
As Chris’ customers’ energy needs became larger, the systems grew and improved. Upgrading from early 12 VDC systems to standard 48 VDC battery/inverter systems increased efficiency and energy possibilities.
Modern solar controllers in smaller and simpler configuration
Modern solar controllers—with some protection and electronic wizardry—have allowed significantly better production from hydro systems. They can sometimes be used in smaller and simpler configurations.
Modern solar controllers in larger, multiple-inverter systems
Modern solar controllers—with some protection and electronic wizardry—have allowed significantly better production from hydro systems. They can also be used in larger, multiple-inverter systems with higher production and loads.
Using manufactured components
Upgrades like this one use manufactured components, while still keeping the budget low.
Underside of the turbine
The underside of the turbine is exposed as Chris inspects the runner and nozzles. The turbine bolts on a bucket that is cemented into the ground. Note the large tailrace pipe that returns the tailwater to the stream.
Chris Soler and Don Harris
Chris, along with many other hydro contractors and users, owes a large debt to retired hydro pioneer Don Harris, who helped a whole generation of people with his excellent equipment and generous technical support.
Chris Soler purging the lines
Chris Soler prepares for a job digging a penstock ditch
Early homebrew systems used car alternators
One of Chris’ early homemade runners
A modern Harris hydro turbine
Hydro intake screen
Self-cleaning screen
Chris prepares low-pressure PVC pipe
High-density polyethylene pipe is heat-welded
Battery Bank
Modern solar controllers in smaller and simpler configuration
Modern solar controllers in larger, multiple-inverter systems
Using manufactured components
Underside of the turbine
Chris Soler and Don Harris

The problem with using these units is they are designed for solar-electric arrays that put out a defined high-voltage limit that isn’t too much higher than the system’s running voltage. However, in a DC hydro turbine, the open-circuit voltage is twice the running voltage. So using an MPPT controller directly with a hydro turbine is limited to low-voltage systems.

One “bleeding edge” method is to connect the hydro in parallel with a solar-electric array at about the desired voltage, and the array will “clip” the peak voltage at about 10% above its rated open-circuit voltage. The modules act like giant zener diodes protecting the MPPT controller in high-voltage conditions. Many small hydro systems are on seasonal creeks that dry up in the summer, so a PV array is already a part of the off-grid hybrid system. The MPPT controller gets the maximum output from both components of the renewable energy system.

If you could wave a magic wand to make some changes for hydro turbines and the industry, what would they be?

I would love to see some real numbers comparing the efficiency between the different manufacturers’ turbines. If independent testing showed their efficiency under specific conditions, it would aid in deciding which turbine to install. There are newer products available, but I hesitate to invest in lower-cost turbines if the savings is negated by lower output.

All I have is my own tests of Harris units that back up the claims of up to 70% efficiency. I always use these turbines except for low-head sites where the Turgo wheel on the ESD turbines can handle higher flow and faster rpm. With their simpler, nonadjustable magnets, the APM turbines might be a lower-cost alternative if the efficiency is still high. PowerSpout turbines have some interesting features, including a built-in voltage clamp that works with MPPT without other electronic tricks, or with higher voltage grid-tied systems.

What is your key advice for people who are thinking about using hydro electricity?

Educate yourself as much as possible before getting expert help. The more you know, the better questions you can ask. Read older articles in Home Power and online. I find the best level of expertise is on the fieldlines.com forum. I try to answer questions about hydro posted on that site.

There are a limited number of people with experience with multiple hydro systems, so you will have to choose someone who can see all the possibilities of your site and create a system that does what you need. Any RE dealer can provide the batteries and inverters, but you may have to search harder for someone local to design and install the hydro system.

What does your home system look like today?

My personal off-grid system includes two Harris hydro turbines. One is producing about 200 W at 24 VDC from 35 feet of head. The other is currently putting out about 1,000 W at 70 VDC from 110 feet of head into an OutBack Power Systems FLEXmax 80 MPPT charge controller.

During times of higher flows, the larger magnets in the second Harris turbine boost the energy output. The old configuration topped out at 920 W, and it’s now more than 1,000 W. I haven’t completed testing this arrangement to find its maximum output.

Comments (3)

jhd's picture

hi - i am very new to hydro power. me and my husband have bought a site with an old mill ruin - two leads and a weir. we want to develop the mill site into a small self sufficient house. it makes sense to use the power we already have in the stream. i can't seem to find turbines small enough to fit in the lead though. We have very little budget and are based in the uk..any hints on where to start? many thanks jo

Ian Woofenden's picture

Hi jo,

Hugh Piggott in Scoraig Scotland does a fair amount of hydro, and may be able to help you or refer you to someone closer. You'll easily find his contact info online by searching his name and location.

Regards,

Ian Woofenden
Home Power senior editor

Andrew Romaniuk's picture

very good

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