Dominica Micro-hydro Work Spring 2004

By Alvin Chan and Kacey Campbell

 

 

Status of Hydro and Micro-Hydro in Dominica:

            DOMLEC, the utility monopoly power company, runs a 5MW hydro plant which supplies 40% of the electricity for the island. The source comes from a small dammed freshwater lake. There are three separate generating stations found at Trafalger, Laudat and Padu. In terms of micro-hydro, there was a system producing about 60 watts of electricity, which supplied the lighting for a small house for several years until it was stolen. The location is unknown, somewhere on the island.

            The Springfield Guesthouse has a small stream running through the property with a flow rate of approximately 80 gallons per minute during normal precipitation conditions. One very beneficial aspect of Dominica is the large amount of rainfall. Another measurement was taken after a period of rain and the flow rate was about 118 gallons per minute. Given the 140-240 foot head on the source, the potential electricity is about 1.12 KW (based on average flow rate and 140ft of head), which would be about 27 KWH/day. The Springfield Guesthouse uses about 68 KWH/day, therefore the electricity could be reduced by nearly one third. As can be seen, a micro hydro system is an extremely valuable renewable resource that should not be wasted.

 

Significance of the Installation of a System:

            In the land of 365 rivers, there are amazingly no running micro-hydro units. A two day micro-hydro training workshop (http://www.uvm.edu/giee/ateliers/dominica/hydro_workshop/ ) was held last year. Several attendees expressed interest in installing one after the workshop, but have not. We strongly believe that once there is a running micro-hydro system, only then this will create a domino effect on the actual implementation of micro-hydro systems and making it widespread in Dominica.

 

 

 

 

SES-P175F T Hydro Unit:

            This unit is best fit for the stream. It was also proposed and recommended by Gary Flo's friend, Deepak Malghan, the owner of the company that makes the unit which is based in India who we've been consulting constantly about our project. He has put countless hours of work in advising with equipment selection and dedicated to work with underdeveloped areas. He is also willing to train the people on installation and maintenance of the system even though this unit requires minimal maintenance. He will provide technical support as required for troubleshooting any future issues.

 

Specs on the Stream across the road:

 

            Flow Rate:                             80-100 gallons/minute

            Head:                                       140 feet

            Power:                                     1 -1.5 kW

                                                            Based on head*flow/10

            Power/Day                              24 -36 kWh

 

            Intake:

 

 

Springfield's current power usage, 60 -100 kWh/day:

 

            Daily average:                         68 kWh

            Monthly average:                    2040 kWh

            Monthly Bill (.80 EC/kWh):  $653 (US)                   $1632 (EC)

                        EC = 2.5*US$

                        Range:                         $576 - $960 (US, monthly)

 

                        Savings Range: $230 - $346 (US, monthly)

                        After Savings:             $346 - $614 (US, monthly)

                                    Savings based on subtracting the minimum KWh to the maximum

kWH produced per month and then figuring out the new prices.

Breakdown of Prices:

 

(a) Hydro Unit (attached):                                                                             $1250

            Shipping:                                                                                             $ 500

            (Also attached the dimensions for the base plate/powerhouse)

 

(b) 600' of Sched. 40 PVC Pipe:                                                                   $2111

 

For the rest of these parts (c-n), we're waiting for the prices from Deepak.

The expected cost of everything is $5-6000, but until we get the rest of these prices then we can be sure of exact total price.

 

(c) the complete turbine assembly with the casing and mounting for
generator.                                                                                                 

(d) belts for belt drive

(e) alternator

(f) oil filled pressure guage at the inlet to the turbine to measure
water pressure

(g) voltmeter, ammeter for measuring voltage and current at the powerhouse.

(h) the electronic load controller for synchronous generator

(i) gate valve

(j) flange joint for turbine input

(k) electrical wires to the junction box

(l) Auxiliary breaker for hydro loads

(m) Transfer switch for grid back-up to hydro loads

(n) Wiring for hydro breaker

 

Total:                                     $5-6000

 

 

 

 

 

 

 

Funding Outlook:

 

            We will be able to provide $1000 from our funding left over from our Spring Break trip. Gary has applied for a $1000 grant for Alvin to return in the Fall to help facilitate with installation in which about $750 would be used for airafare and $250 to cover parts. That still leaves $4-5000 to be funded. The desired completion date was September, but anytime next Fall would be great.

 

Future Consideration, grid-tie inverter:   $2000

 

            Since the micro-hydro operates 24/7, this grid-tie would be nice to feed back excess power to the grid to be used later when needed. However, issues with this are still being worked out and once it is definite that this can be installed then it should be installed for maximum efficiency. Batteries can be used too, but this would be the easiest solution. For now, the excess power should be fed to a shunt load like 2 hot water heaters in parallel would do it.

 

Flow Calculations:

 

Stream across the road:

 

 

Which method should be used to calculate flow?

 

 

 

 

 

 

 

 

 

Flow Calculations cont'd:

 

Check Hall River: How about this one? Check out the last picture.

 

 

 

Power Calculation:

 

Power = (Head*Flow)/10