HOT SPRINGS ETERNAL

I had the pleasure of visiting Dominica recently. En route from the airport to the capital Roseau, the signs of geothermal energy potential were everywhere – from the smell of sulphur on the rainforest air, to the sight of people bathing in hot springs along the way.

Hot spring at Wotten Waven area, Dominica
Photo: H Samuel

I’m told that the sparsely-populated, mountainous island, popularly known as “The Nature Isle” has at least 9 active volcanic areas and too many hot springs to keep track of. So it should seem to be a natural for the exploitation of geothermal energy.

Geothermal is the most important prospect for renewable energy in the Caribbean, for two reasons: First, it represents baseload power – power that is constantly available at large scale, as opposed to solar and wind, which are intermittent resources and second, it is apparently widespread throughout the Caribbean.

The various studies that have been done of the geothermal potential of the Eastern Caribbean over the past two decades all basically say the same thing – that there appears to be significant geothermal potential in the region – and, crucially: that it appears to be far greater than present demand for electricity.

So if large geothermal resources are proven to be available on a few strategically-located islands (say Nevis in the north, Dominica in the middle and Grenada or St Vincent in the south), power can be made available via undersea transmission lines to the others, thereby creating an interconnected, renewable and sustainable electricity network spanning the Eastern Caribbean.

So (the inevitable question): why isn’t there more geothermal being used in the Caribbean? The region's only geothermal plant is in Guadeloupe, with an installed capacity of 15.5 MW, which is reported to provide close to 10% of Guadeloupe’s electricity demand.

As is the case with many RE technologies, a major issue is the up-front cost. Geothermal energy in particular is affected by this because, notwithstanding sulphurous valleys and hot springs: in order for a geothermal power plant to be built, specific explorations (geological, geochemical and geophysical studies, drilling a few holes through rock to depths of several thousand feet, etc.) must be carried out – and they are very expensive. For example; the recently-concluded exploration that established Nevis’ geothermal potential is reported by the developer to have cost US$8 million. The power plant construction is estimated at US$45 million, to install 11.6 MegaWatts of power, which can supply Nevis’ existing electricity demand (currently about 9 MW).

These costs sound high, but they actually represent an economic and environmental bargain (in a subsequent post, we’ll dig deeper into some details of the economics of geothermal vs diesel power on these islands).

The Nevis power plant construction is reported to be going ahead, so it looks as though Nevis will indeed become the Caribbean’s first green island. Meanwhile, Dominica is not far behind; there are two separate geothermal explorations proceeding on the island. One is funded by the European Union; the other is being carried out by the Nevis project developer. One or both of them could bear fruit; this would create the central point for geothermal electricity generation in the Eastern Caribbean. Then all we would need is another in the south and the foundation for the creation of an entire string of green islands would be in place.

Dominica’s geothermal explorations could be concluded by mid 2010, but significant hurdles exist. If her geothermal resources are proven, Dominica’s mountainous terrain will challenge the builders and increase the cost of building a power plant and the transmission lines required to get the power to end users. Then there are the technical, economic, business and political challenges of designing and building an interconnected Eastern Caribbean power grid.

But these challenges will pale in comparison to the legacy of failure we will leave if we continue a business-as-usual-with-a-few-incremental-improvements approach.

That time has passed.

More information on geothermal energy can be found here

.