Chalillo onstream but BECOL wants another dam at Vaca Falls

January 27 2006

By William Ysaguirre - Staff Reporter

The much bally-hooed Chalillo hydroelectric facility added another 7.3 megawatts to the nation’s generating capacity when it came onstream last November, but the Belize Electric Company Limited (BECOL) is already suggesting another 18 megawatt hydro facility be built upstream from Vaca Falls in the Cayo district.

This was the word from BECOL’s Chief Engineer, Stephen Usher, when the Reporter joined a media tour on a visit to the Chalillo site at BECOL’s invitation on Friday last, January 20.

With Belize’s energy demand growing, Belize Electricity Limited (BEL) is presently involved in renegotiating a power purchase agreement with the Comision Federal de Electricidad (C.F.E.) of Mexico since the existing agreement is due to expire in August 2006. But C.F.E. is asking 30%, more, because the new prices will be linked to oil prices, which continue to rise. BEL’s CEO Lynn Young said CFE’s new rates are only slightly less than what it would cost BEL to build and operate a diesel generating plant.

BEL has been seeking other options, from both domestic generators or other foreign suppliers. So when BEL invited bids from other power suppliers to supply power to the national grid, BECOL submitted a bid to supply power from the proposed facility in the Vaca Falls area.

Usher said BECOL is presently preparing an Environmental Impact Assessment which when completed will be submitted to the Department of Environment for approval. The precise site has not been set since that will be depend on the mitigation measures that the DOE may require and what site the DOE designates as having the least environmental impact.

Since the site has not been fixed and that will determine the cost, based on the width of the river channel at that point, Usher said the cost cannot yet be estimated. Other factors affecting the cost would be the cost of concrete at the time that construction actually begins.

Another factor that would affect cost, he said, would be the method of construction. The company has proposed two designs, a concrete dam with an underground tunnel to the powerhouse, like at Mollejon, or a rock-fill dam with the powerhouse built right near the outlet valve at the base of the dam. The choice of the final design will also be determined by the E.I.A.

What has been set is the type of dam - a “run of the river” facility just like Mollejon. The dam itself would be 40 metres high, taller than the dam at Mollejon, but lower than the Chalillo dam.

There is as yet also no indication which contractor will build the dam. If and when the E.I.A. is approved, Usher said, BECOL will invite bids to build the dam according to the approved design. These factors will determine the cost, which will probably be financed by Fortis Limited of Canada, which wholly owns BECOL.

Fortis is also the majority shareholder in BEL, which will continue to seek to buy its power domestically where possible.

It has already contracted to buy power from the BELCOGEN Cogeneration Project at Tower Hill when it comes onstream in 2008 and Hydro Maya in Toledo when it becomes available, hopefully in 2007.

With 25 Megawatts from Mollejon and 7.5 megawatts and another 18 Mw from Vaca falls, Belize’s hydro capacity would be a little over 50 Megawatts. Even if BELCOGEN were on line with 13 Megawatts more and Hydro Maya with another 3 megawatts, Belize would be barely self-sufficient in power, since the peak power demand on the national grid is 68 megawatts at present.

With demand expected to rise as the tourism industry builds more hotels to accommodate the tourist from European flights, demand will still exceed domestic generating capacity by the time Hydro Maya and BELCOGEN come online.

The Chalillo dam

Designed as an upstream storage facility, it’s intended to double the energy output from the Mollejon Hydroelectric facility from an average of 80 GWh per year to 160 GWh per year.

The “run of the river” dam at Mollejon can generate 25 megawatts of electricity, but because the Macal River does not have enough water during the dry season, the Mollejon is only used to supply power during the peak hours 6:00 - 9:00 P.M., when Mexican electricity is prohibitively expensive. Before Chalillo, during the rainy season Mollejon was unable to take advantage of excess flood water which spills over the top of the dam. Now Mollejon can generate 24-hour power using water which Chalillo releases as it generates 7.5 Megawatts.

When Mollejon was first proposed back in 1992, it was envisaged it would generate 163 Gigawatt hours of energy per year, but when it finally came onstream in 1995, it was found that the engineers had overestimated the average flow of the river and the facility was only able to generate half of that power output, an average of 80 GWh per year.It was also touted that Challilo would bring down the cost of power to consumers. Not so it was later said in fact electricity rates has increased twice in six months. The latest increase came in like a thief in the night on New Year’s Day.

The Chalillo dam stands 46 metres high and when filled to its maximum level of 41 metres can hold approximately 120 million cubic metres of water, covering some 8 square kilometres of land.

Because the dam was not completed until last September, the company was not able to take advantage of the entire rainy season to fill the reservoir, where the water level presently stands at a level of 32 meters from the bottom.

The building contractors, Sinohydro of Beijing, China began building the dam in May 2003 at the Chalillo site, which is located some 12 km downstream from the confluence of the Macal and Raspaculo rivers.

Over 350 Belizean workers were employed in the building of the dam, working beside the contractor’s experienced technicians.

The Chalillo dam has displaced the natural habitats of hundreds of birds, animals along with flora and fauna.

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