Zambian geothermal explorer Kalahari GeoEnergy’s ongoing feasibility study has modelled an initial power capacity of between 5 MW and 7 MW on the shallow outflow reservoir within the Bwanda section of the Bweengwa river geothermal resource area.

The feasibility study is expected to be completed in the fourth quarter of this year.

Further capacity in the order of between 10 MW and 12 MW can conceivably be expected from ongoing exploration work at other selected targets, the company says.

Gas sampling and subsequent analysis have also detected high levels of helium in the geothermal fluids. Concentrations of up to 2.3% helium have been identified in gasses released by the geothermal fluid, as assayed by Oxford University Earth Sciences Department in the UK.

The Bwanda system comprises a shallow reservoir at a depth of between 200 m and 500 m with a temperature of between 108 °C and 110 °C. This is fed by deeper upflow of between 130 °C and 150 °C from faults within the basement rock.

Project work so far includes geology, geophysics, hydrochemistry, light detection and ranging, and the drilling and testing of 21 temperature-gradient holes and slim wells totalling 6 156 m.

Further drilling and testing is to be undertaken to de-risk the reservoir boundaries.

Direct application of thermal energy for aquiculture, horticulture, dairy and crop processing, to generate social uplift and food security for the communities in and around Monze town are integral to the project, the company says.

Kalahari GeoEnergy CE Peter Vivian-Neal notes that the preliminary figures and current model within the project are “hugely exciting” and represent a significant step towards the company’s objective of producing geothermal power through binary technology.

“Ultimately, geothermal power may provide a valuable component in Zambia’s drive to diversify sources of energy, increase generation capacity and the distribution of productive power, as well as the ‘power to empower’ the community,” he says.

Kalahari GeoEnergy wants to advance not only the generation of electricity, but development and social uplift in the communities in and around the Bweengwa project through the agricultural and industrial uses of the residual thermal energy.