POWERING GHANA: THE ROLE OF HYDRO AND THERMAL PLANTS IN ELECTRICITY GENERATION

Power generation remains  key to Ghana’s economy, driving industries, powering homes and supporting livelihoods. Over the decades, Ghana has relied on two main sources of energy generation: initially hydroelectric and later thermal power plants. While each plays a critical role, they come with unique advantages and operational challenges.

Hydropower in Ghana: The Akosombo Dam Legacy

Ghana’s journey in electricity generation began with the iconic Akosombo Dam, built on the Volta River in the 1960s. This hydropower plant has been a cornerstone of the country’s energy supply, providing clean and renewable electricity for decades. The Akosombo Dam, along with the smaller Kpong Dam (constructed in the 1980s) and the Bui Dam, harnesses the energy of flowing water to drive turbines that generate electricity.

Hydropower has been instrumental in Ghana’s economic development, offering an affordable and sustainable energy source. However, hydropower is heavily dependent on rainfall, which makes it vulnerable to drought. In periods of low rainfall, as experienced during Ghana’s severe droughts in the 1980s and 2000s, the water levels in the Volta Lake drop significantly, leading to reduced energy output and load-shedding crises.

Hydropower Advantages:

• Renewable and clean energy source.
• Low operational costs once the infrastructure is built.
• Helps mitigate greenhouse gas emissions.

Hydropower Disadvantages:

• Vulnerable to drought and seasonal rainfall fluctuations.
• High initial construction costs.
• Can disrupt local ecosystems and communities.

Fig 1. Aerial View Of The Akosombo Dam

Thermal Power Plants: The Shift Towards Stability

As Ghana’s population and energy demands grew, reliance on hydropower alone became insufficient. To bridge the gap, the country turned to thermal power plants generate electricity by burning fuel such as natural gas, diesel, or Heavy Fuel Oil (HFO) to produce heat. This heat is used to convert water into steam at high pressure. The steam is then directed to spin turbines, which are connected to generators. As the turbines rotate, they drive the generators to produce electricity..

Thermal plants have the advantage of being less dependent on weather conditions. They can generate electricity consistently, provided fuel supply is available. However, thermal power generation is more expensive due to the cost of fuel imports and maintenance. 

Another challenge is the “cold start” issue. When thermal plants are shut down, restarting them takes considerable time and effort, leading to delays in restoring electricity during outages. This technical challenge often exacerbates load-shedding periods.

Thermal Power Advantages:

• Reliable and consistent electricity generation.
• Can support the grid during hydropower shortages during droughts.

Thermal Power Disadvantages:

• High fuel and operational costs.
• Emits greenhouse gases, contributing to climate change.

Fig 2: Tarkoradi Thermal Plant

Balancing the Grid for Ghana’s Future

As Ghana continues to grow, balancing hydropower and thermal generation is essential to ensure a stable and reliable electricity supply. Investments in renewable energy sources such as solar and wind are also gaining traction, offering an opportunity to diversify the energy mix and reduce dependency on fossil fuels.

By learning from past challenges and leveraging technology, we can create a resilient energy system that powers its future sustainably for all Ghanaians.