The first Generation plant on the island of Grenada was owned and commissioned by the Grenada Electricity Services Limited (GRENLEC) on February 14th, 1928, and was located at Burn’s Point, St. George’s where the Grenada Postal Corporation is now situated.
In the year 1960 the total installed capacity was 1700 kW. At this point the company decided to expand its generating capacity, and in 1961 two 600 kW Ruston-Hornsby Gensets were installed at Queen’s Park, St. George’s. The lone generating facility remains at the Queens Park location even to this day. Later in 1961, the 375 kW Lister Blackstone and the 375 Ruston-Hornsby units were moved from the Burn’s Point Plant to the Queen’s Park Power Station. After this move, the Queen’s Park Power Station increased installed capacity totaled 1950 kW.
The company’s largest single generating unit up to 1962 was added in the form of a 1000kW Ruston-Hornsby unit. In 1968, a completely new type of unit, which was different from the existing fleet, an English Electric unit, was added to the generation fleet. This unit was a 16 Cylinder, 1.425 MW Diesel generating set. In 1971 another 16-cylinder unit 1.450 MW Genset was installed. The next major Generation addition was completed in 1984 when two 1.82 MW, 12RKC Ruston units were added to the system. These are currently the #8 and #9 units. In 1986 another 12RKC, 1.82 MW Diesel Prime Mover was installed; this was coupled to an old alternator and was de-rated to 1.425 MW.
In 1987 unit #10 was installed. This is an EMD645 (General Motors), rated at 2.04 MW. From 1980 smaller, containerized, standby units were installed as backup with black-start capabilities. The first of these, installed in 1980, had a Caterpillar Engine, although the Genset carried the name Woodlands.
The Mirlees Blackstone unit (#11), which is now decommissioned, was installed in 1991. This unit had an alternator that was rated just over 4MW and an engine rated at over 5MW. Subsequent to this addition another relatively large unit in the form of the Vaasa32, Wartsila generating set was installed. This set is rated at 5.2 MW.
The latest plant expansion, which was commissioned on July 23rd, 2002, includes a new building named “Plant B” and the installation of two Caterpillar MaK units each rated at 5.5 MW. The present total installed capacity stands at 33MW.
We generate power to feed the entire island from this location. At present we have a total of 17 generating units ranging in size from 1280KW to 5500KW. To distribute the power generated here we have 7 feeders that take power to the consumers.
These feeders are named Gouyave (Cherry Hill to La Mode), Grenville (Mt. Gay to La. Mode on one end and Soubise on the other end), Industrial (Mt. Gay to Soubise on one end and Red Gate on the other end), Belmont (Lucas Street to Red Gate, and parts of the Grand Anse area), Grand Anse (Mt. Gay to Grand Anse), St. George’s West (Queen’s Park to Sendall Tunnel, including the hospital, CID and many of the businesses in and around the Market area), St. George’s East (Queen’s Park to Sendall Tunnel, and incorporating River Road, Tempe, Lowthers Lane and the Carenage).
At the plant the generators use diesel fuel to run the engines. Diesel is pumped from a tanker at sea to the three bulk fuel tanks located on the North end of the compound. With all the tanks filled we have 1.5 million gallons of fuel on site, which can last approximately 6 weeks. Fuel is then gravity fed from these to smaller tanks, which feed the plant. Each engine has its own day service tank. Oil is also stored on site and pumped to the engines as required.
Here’s how we generate electricity:
We use fuel to heat water, which creates steam.
The steam spins a turbine in the generator.
The spinning turbine causes a large magnet to rotate around a piece of wire. This motion creates a magnetic field, which in turn electrifies the wire.
The electric current flows through the wire, and is then pushed out by high- voltage transformers.
By design the generators are sized differently, both in terms of their rated voltages and output power. For example we have sets rated at 1280KW @ 400V and 5500KW @ 3300V. In each case a step-up transformer is used to transform the voltage to 11000V (11kV). 11kV is the Distribution Voltage and the Bus as well as the main circuit. Canadian pharmacy breakers are rated at 11kV. As a result of this many differently rated units can be paralleled together onto the common Bus. A Power Plant is unique to other installations on the island in that we have to parallel a number of generating sets to meet our demand. In order to parallel two or more gensets three conditions have to be met. The frequency/speed of the generators must be equal, the voltages must be equal, and the phases must match. Only after all these conditions are met can the two units be paralleled.
System Demand is 20MW and highest peak recorded was 22.7 MW. We have an installed capacity of 33MW. This power is then distributed via the seven feeders to all areas around the island. Near to your homes or villages the voltage is stepped-down to 400V for commercial applications and 230V for domestic applications. The main reason for stepping up the voltage to 11kV is that at that high voltage the current is very small and as a result smaller cables can be used to transfer the power. Additionally there are fewer losses as a result of using the smaller cables; therefore most of the power we produce reaches the consumer. Smaller support structures and longer distances between poles can be achieved by using smaller cables.
How do we operate?
We have on site Power Plant Operators, Maintenance Personnel, and System Control Operators.
The Power Plant Operators monitor and control the generators. They start, stop, load and unload the units as required to maintain the system frequency, voltage, and to meet the demand. The operators monitor the engines and the alternators as well as the auxiliary equipment needed to run the gensets. They look at temperatures and pressures of the oil, air, water, and fuel systems of the mechanical components, and also the voltage, current, and system frequency of the electrical components. To aid in their monitoring they have specialized equipment as well as tools we are all familiar with. Thermometers, manometers, voltmeters and ammeters are some of the basic instruments.
Our maintenance personnel are mechanics and technicians, who ensure that the equipment is kept to manufacturers’ specifications.
System Control Operators work from the Planning and Engineering Department in Queen’s Park, and they cover the entire network. They are responsible for answering trouble calls and dealing with fault reports. They also direct service crews to the areas where faults have been reported.