Renewable Energy Systems & Technologies, LLC


Micro-Hydro Systems

Today’s micro-hydro Run-of-River system designs are dependable, economical, efficient, and environmentally friendly.

Harnessing the power of water to generate electricity allows us to gain some sense of responsibility for meeting our own needs and for reducing our impact on the environment.

Micro-hydro turbines are typically 4-5 times more cost effective than other renewable technologies. Modern micro-hydro turbines have come a long way from the clunky metal turbines seen in the past.

Advancements in turbine wheel (turgo or pelton) construction and generator design allow today’s turbines to operate reliably in a wide variety of water conditions

Other forms of renewable energy require much higher subsidies and regulation to come even close to the value of small and micro-hydropower systems. Whether your needs are large or small, grid-connected or off-grid, the professional staff of RES-TEC micro-hydro experts will be able to design a system to meet your needs and to your complete satisfaction.

Can I make hydro power at my site?

If you are lucky enough to have a stream running down your hillside, micro-hydro is the resource to visit first

Before deciding on a micro-hydro system, it is important to know the potential of your site.

Ample, year-round water is a prerequisite for successfully siting a micro-hydro turbine, and generally speaking, the more the better.

The power that can be generated is directly related to the “head” or height of the water in feet and the flow of the stream in gallons per minute.

Typical "high-head" micro-hydro installations involve the placement of sufficient water pipe (PVC or polyethylene) to move water stored (pond) or harvested from a high point adjacent to a stream to a lower point where the turbine is located. The minimal useful head for most micro-hydro systems is around 20-30 feet, which corresponds to an outlet pressure of about 10 psi (2.3 ft = 1 psi). The design challenge is to size the pipe and its outlet nozzle(s) appropriately for seasonally changing conditions. The minimal useful flow for most micro-hydro turbines can be as small as 2 gallons per minute (gpm) depending on the available head pressure.

"Low head" micro-hydro generators can operate on as little as 6 feet of fall, but require a lot of flow to make useful power - typically 100's of gallons per minute.

It is also important in the Northeast part of the country to design the catchment, distribution and generating system for freeze protection. Finally, the generator must be connected to a suitable energy storage system (batteries).

Other factors include proper pipe sizing and installation, system voltages, wire length and sizing.  The professionals at RES-TEC will perform a preliminary evaluation of your site at no charge.

How Much Power Can I Make?

This is the most frequent question we are asked, and very easy to answer.

As indicated above, the amount of power available is affected primarily by head and flow rates.

Simply stated:

Power (watts) = Head (feet)  x  Flow (gal/min) x  0.09 (turbine efficiency, pipe losses, conversions, etc.).

For example, a stream with a 100ft head or drop and an average flow rate of 50 gal/min would be able to make the following amount of power:

Power (watts) =  100 ft x 50 gal/min x 0.09 ~= 450 watts

And remember, your system is always working!

How Does a Micro-Hydro System Work?

RES-TEC offers micro-hydro systems that are grid-connected electrical power generation or off-grid stand-alone battery charging systems.

The simplest and most cost effective system is the grid-tied system.  In the grid tied system, seen below, water from a stream or pond is diverted to the turbine through a penstock (usually 2-3” PVC pipe).

The turbine sends electricity to a charge controller to charge a bank of batteries.

An inverter conditions the DC power of the battery bank to AC to match the electrical grid power.

The power is then sent to the grid and/or home via your existing load center.

Off-grid systems are similar, but require no connection to the grid.

The grid-tied micro-hydro system is connected through an agreement with your local power company and the energy is net-metered.

In the net-metered energy system, your electric meter will spin backward whenever you are generating more power than you are using and forward when you are using more power than you are generating.

The result is that your electrical usage is billed at the net difference between what you make and what you use.

Battery charging applications are normally used for our customers living in remote areas with no electrical grid connection available.

The RES-TEC professionals can install a micro-hydro turbine to supplement your existing off-grid electrical system as well as design a complete turn-key stand alone off-grid electrical system powered with wind, solar, micro-hydro, or a combination of these power generating systems.

How Do I Get Started?

Simply give us a call or contact us by email.

RES-TEC will provide you with a detailed explanation of the various micro-hydro systems available, examine flow rates and head availability, generate performance estimates, and answer any questions you may have.

Note that grid-tied micro-hydro systems have significant environmental permitting requirements at both the Federal and State level. We will consult with the customer in acquiring these permits, however the process is the responsibility of the customer. Off-grid systems require no permits. Generally, RES-TEC will only install micro-hydro systems in conjunction with Solar PV systems for off-grid applications for optimization of your energy storage. Additionally, due to the considerable site work requirements for micro-hydro in installation of the intake, penstock, and turbine mounting, this effort is also, left to the customer.

We will provide a preliminary proposal showing you the estimated system cost, system payback period, and carbon footprint reduction associated with the proposed system.

We will apply for all rebates or incentives available and assist you with the permitting process.

We look forward to hearing from you and working together with you to bring more green energy to the Green Mountains! Contact Us.

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