In late 2020, President of Ghana, Nana Addo Dankwa Akufo-Addo, commissioned Ghana’s first Hydro-Solar Hybrid power generating system.  Now in 2023, the first floating solar PV array has been connected to the grid to generate 5MW per annum. This forms part of the first phase of a 250MW solar project, which is being implemented in phases of 50MW. 

Challenge

Bui Power Authority (BPA) identified the potential for solar resources in Ghana. They have been developing the expansion of this resource as part of the Government of Ghana’s effort to increase the contribution of renewable energy in the energy mix by 10% by 2030. 

Increasingly low water levels at the Bui Hydroelectric Dam are exasperated during the dry season, resulting in reduced ability to the run the hydropower plant during the evening. BPA decided to add a solar element to complement the existing plant to supplement the energy required to be operational all year round. 

Solution

This first 50 MW solar plant has resulted in the doubling of Ghana’s grid-connected solar energy and is expected to cut greenhouse gas emissions by more than 47,000 tons per year.  

The Bui Switchyard was expanded accordingly to accommodate and evacuate 250MW of solar power for the creation of a hydro-solar PV hybrid (HSH) system within the Bui enclave. The HSH facility is aimed at augmenting and preserving the Bui reservoir by the generation of solar power when complete. This will be Ghana’s first hybrid plant utilizing both solar and hydro resources to generate and supply power to the national grid. 

The SMEC team completed the following scope of works in January 2023: 

• Grid Assessment for  six PV development sites  including static and dynamic studies 
• Tariff studies for the solar PV portfolios 
• Transmission line studies and sizing for 200 MW combined generation from floating and land-based PV projects within the Bui Enclave 
• Assessment of GRIDCo substations for suitability for injecting generation from proposed Northern Region PV sites 

• Hybridization study of PV with the existing 404MW Hydroelectric dam 
• Energy Storage System sizing for ramp control for HSH project 

Impact

This project enables the plant to operate during the day, harnessing the vast solar radiation resources in northern Ghana while giving grid operators more flexibility to run the hydropower plant during the evening. 

Other benefits include: 

• Contributes towards the Government’s effort to increase renewable energy in the energy mix by 10% by 2030, as part of the National Determined Contribution (NDC) towards the United Nation’s Framework Convention on Climate Change (UNFCC). The estimated solar generation output from the six selected sites in Northern Ghana in 888 MW. 
• The project increases the efficacy of the Bui reservoir by creating a hydro-solar PV hybrid system. The Bui hydroelectric dam utilises three 133 MW generators at the site, giving a total output of 404MW. An additional 50 MW of power is generated from the solar installations on site, with the total renewable power output contributing around 6-7% of the total power generated in-country. 
• Provision of clean energy, to help combat climate change. 
• Provide electricity to an estimated 450,000 households, contributing to ensuring the availability of stable and cost effective power. 

The project, when completed in late 2023, will add 250 megawatts of power to augment the Bui Generating Station’s 404MW hydroelectric dam.