Anatomy of the Amaila Falls Hydro Power Project ‒ Geo-technical dimensions)

guyana and the wider worldIntroduction
There has been, surprisingly, very little consistent and sustained official information flows to the public aimed at improving their awareness and understanding of the Amaila Falls Hydropower Project (AFHP). My belief is that this is linked, in part, to the non-availability of up-to-date economic evaluations of the project available for public review.

Much of the publicly available economic information has come from two main sources. One is information, which readers have managed to ferret out independently from their searches of the print media and the Internet.

And, the other comes, regrettably, as the incidental or collateral by-product of contentious public debates, thereby casting much doubt on its authenticity.

This is unacceptable, given the premier place this project presently commands in the country’s public investment strategy.

For these reasons alone, if no other, I am focusing this week’s column on providing readers with a synopsis of the AFHP’s major dimensions and specifications. I believe every citizen ought to have this minimal information at his or her command in order to form a reasoned judgement about the project.

All the ‘official’ descriptions of the project, which I have come across (Government of Guyana; Sithe Global; Amaila Falls Hydropower Inc, the special purpose company created to develop the project; IDB; IMF; and World Bank), identify three major components. These are 1) The hydropower facility; 2) the electrical interconnection between the facility and its main intended consumer (GPL); and 3) the access roads, which are required to facilitate the operationalisation of the project. These three components have been brought together under a single project financing model, which I shall discuss beginning next week. For now, the geo-physical and operational dimensions of the three components are separately addressed below.

The hydropower facility
The hydropower facility is to be located at the confluence of the Kuribrong and Amaila Rivers in west-central Guyana, about 250 kilometres southwest of Georgetown. Its main components are a reservoir; power generating turbines/generators; and related ancillary works and operational structures for efficiently collecting, controlling, and utilizing the available water.

The planned reservoir is about 23.3 square kilometres. This is to be constructed within two rock-filled dams. One of these is on the Kuribrong River (19 metres high) and the other on the Amaila River (36 metres high). On average this reservoir is projected to hold 23 days active supply of water, to cater for any variations in the flow of the rivers that might occur. The power generation is presently targeted at about 154 megawatts (MW). This will be based on four 38.5 MW Francis generators/turbines.

Three observations are noteworthy at this stage. The first is that the adequacy of the reservoir capacity indicated above had been challenged at a recent seminar presentation at the University of Guyana (UG) (M Veecock, Presentation on Amaila Hydroelectric Reservoir Capacity, University of Guyana, 2010). Second, over the years there have been several iterations as regards the expected generating capacity at Amaila Falls.

Indeed in the early 2000s engineering estimates had put it between 85 and 100 MW, as these planned to utilize 4 or 5 turbines/generators with capacities ranging from 20-25 MW each. Third, recent engineering estimates clearly envisage that GPL will continue to supply its own independent electricity as a back-up for the AFHP, in order to deal with any emergencies. The most commonly cited minimum estimate I have seen is 25 per cent of GPL’s present generating capacity.

Sithe Global
The project is being developed by Amaila Falls Hydro Inc a special purpose vehicle, which is a member of the Sithe Global Group. This subsidiary is constructing the AFHP under a ‘build, own, operate, and transfer arrangement (BOOT).’ Amaila Falls Hydro has entered into an Enhanced Procurement Construction (EPC) contract with China Railway First Group Co.

The latter will be responsible for the hydropower facility and the transmission lines discussed below.  Under the project arrangement the company is also contracted to supply electricity to GPL on a ‘take or pay’ basis for a period of 20 years after the facility is completed, under the agreed terms of a Power Purchase Agreement (PPA).

After 20 years of operation, the facility reverts to GPL at no cost. The government and Sithe Global are the lead arrangers for the project financing. This topic will be discussed in my next column.

After several changes, the most recently cited date posted on Sithe Global’s Website for project completion is 2017.

Electrical interconnection
Given the different locations of the hydropower facility and its main electricity consumption centre, the electrical interconnection between these is a substantial component of the AFHP.

As planned, the intentions are 1) to lay an approximately 270 kilometre long high voltage (230 – KV) transmission line; 2) to construct two electrical power sub-stations; one at Linden (on its outskirts) and the other one in Georgetown (Sophia); 3) to make the transmission lines double-circuit in order to minimize outages (and other emergencies), as well as to control line losses, which are presently projected to range between 2-5 per cent of the electricity transmitted.

This information reinforces the observation that GPL would retain some of its current generating capacity (about 25 per cent!) in order to smooth fluctuating flows of electricity from the AFHP.

Access roads
Again, because of the different locations of the hydropower facility and the main electricity consumption centres, access roads also form a substantial component of the AFHP. Based on the published technical specifications as regards width, gradients, road coverings, drainage, culverts, trailings, drainage facilities, feeder roads, connecting bridges, and so on about 88 kilometres of new roads and 22 kilometres of upgraded roads are to be constructed.

This component of the project is left to the government, which is responsible for the financing, construction, and maintenance of the access roads.

Next week’s column, and the following, will provide a synopsis of the project’s financing.