A major concern that has been raised by many energy experts and policy makers over the country’s electricity supply plan is the looming electricity challenges and the need for a sustainable alternative base load supply. .
Energy experts who study the electricity supply plan over the years have indicated that beyond 2025, Akosombo and Kpong hydropower plants, which currently serve 32% of peers as a load supplier base of the country, would have dropped considerably to around 25%.
As a result, there have been persistent and urgent calls for alternative and diverse generations to support existing grassroots powerhouses.
Even though the report did not specify which energy source would be prudent, it appears that Ghana is strongly considering nuclear as it guarantees the supply of sustainable, reliable and affordable energy to advance the country’s industrialization agenda. .
Energy Minister Dr. Matthew Opoku Prempeh during his parliamentary review confirmed the government’s desire to introduce nuclear energy into the country’s generation mix to help propel economic growth.
At the time, he noted that the selection of a supplier – the country whose nuclear technology Ghana would like to partner with to build the world’s first nuclear power plant – was a top priority, as the Cabinet had received the full report from the nuclear power program on the country’s nuclear. future and its prospects.
But the key question on the minds of many is what type of nuclear technology is Ghana heading towards?
A large reactor nuclear power plant that would feed 1,000 megawatts and more into the national grid as a single unit or a small modular reactor (SMR) – which typically produces the equivalent of 300 megawatts or less, modular in nature and can be scaled to meet growing demand.
Large reactor nuclear power plant
Major progress has been made towards realizing the case for including nuclear power in Ghana’s generation mix.
However, the type of technology to adopt is at stake.
Speaking recently to B&FT on the security and stability of the country’s transmission network, Eng. Norbert Anku, former director of GridCo, indicated that the important role of the electricity network system to which the nuclear power plant would be connected is a determining factor in the choice of a technology.
Ideally on an economy of scale, a single large reactor tends to be more economical than a single SMR.
However, technical issues of network security and reliability coupled with demand levels over time are critical.
A reliable, balanced, and well-maintained power grid is crucial for the adoption of a large reactor online nuclear power plant and its operation in a cost-effective and safe manner.
Eng. Anku warned that given current electricity demand levels of over 3,500 MW and efforts to bring additional generation, preferably nuclear, which is the way forward, a heavy injection that does not support the the current state of the network and the stability of the supply situation will be detrimental; “If there were to be a situation where this power plant is disconnected from the grid, it means you have lost 1000 megawatts and the grid can fail over and crash.” he underlined.
He added that huge investments would be required to manage the incident load structure of the national grid and ensure that there would be no huge damage if such a case occurred.
According to experts, a large reactor nuclear power plant, when connected to the grid, will certainly be the largest generating unit in Ghana’s GID system.
This is important because there is a practical limit to the size of the generating unit that can be installed in a power supply system if the system is to remain stable and secure, especially after an unplanned disconnection of that generating unit .
An injection of 1000 megawatts or more into a nuclear plant in a single unit would mean that the nuclear plant would represent more than 10% of the total installed capacity, even in 2030, when the nuclear plant is expected to be commissioned.
Such a situation would likely cause technical and safety issues on the nuclear power plant and the transmission grid system at the same time, unless a substantial investment is made to modernize the transmission grid infrastructure.
Without such an investment, the grid system cannot be reliably and safely connected to the nuclear power plant.
What does it mean?
The only option available to Ghana to connect a large reactor nuclear power plant to the current state of the transmission system is to invest heavily in grid infrastructure.
It is important to note that the current total installed capacity is approximately 5,000 megawatts. in terms of unit capacity, the largest in the network is currently less than 200 megawatts.
Therefore, a nuclear plant of 1000 megawatts or more as a single unit on the grid would have a significant impact on other generators if the nuclear unit shut down.
This technical complexity should not be overlooked notwithstanding the economy of scale for large reactors.
Small Modular Nuclear Reactors (SMR)
SMRs are advanced nuclear reactors typically equivalent to 300 megawatts or less. SMRs are “small” – physically a fraction of the size of a large reactor nuclear power plant and “modular” – allow systems and components to be factory assembled and transported as a unit to site for installation .
SMRs are simple in design and have economy of scale associated with factory production and cost reduction, can be installed module by module to meet growing demand, small power means countries with power grids smaller and weaker ones can still connect SMRs with very little or no network investment, modules can be managed independently so that maintenance and refueling stops can be made while other modules are still in operation.
The challenge is that currently there are none in operation. However, some countries are in advanced stages of connecting SMRs to their network.
Would Ghana be the first to operate an SMR?
Not really, just this month China National Nuclear Corporation (CNNC) announced the completion of concrete pouring for the foundation slab of the ACP100 Multipurpose Small Modular Reactor (SMR) Demonstration Project at Changjiang Nuclear Power Plant. on the Chinese island. Hainan province according to World Nuclear News.
The construction of the 125 MWe multipurpose reactor officially started on July 13, 2021 after the final approval of its construction by the regulator of their country.
CNNC announced in July 2019 the start of a project to build an SMR ACP100 reactor in Changjiang. The site already houses two CNP600 PWRs in operation.
In development since 2010, the preliminary design of the integrated ACP100 REP was completed in 2014.
The main components of its primary coolant circuit are installed in the reactor pressure vessel.
In 2016, the design became the first SMR to pass a safety review by the International Atomic Energy Agency, the report notes.
World Nuclear News also reports large-scale production of NuScale SMR technology.
Under a recently signed agreement between NuScale Power (a US supplier) and Korean energy company Doosan Enerbility, the Korean company is to begin manufacturing core equipment for NuScale Small Modular Reactors (SMRs).
“Under an agreement signed on April 25, the Korean company could begin production of forging materials for reactors this year, with full-scale equipment manufacturing expected to begin by the second half of 2023. Specifically, Doosan will begin production of forging dies for the reactor upper pressure vessel.
These are expected to be used in the first commercial deployment of a NuScale VOYGR power plant for the Utah Associated Municipal Power Systems (UAMPS) Carbon-Free Power Project (CFPP) to be built at a National Laboratory site. from Idaho in the United States. .”
The NuScale SMR is the first SMR design to receive US Nuclear Regulatory Commission approval. The NuScale power module with a single unit generating 77 MWe is available in 4-module (308 MWe), 6-module (462 MWe) and 12-module (924 MWe) modules.
Clearly from these two examples above, Ghana is unlikely to be the first SMR country if it decides to go for SMR technology as some countries are already at SMR integration.
With the current energy quagmire facing the country, future energy plans need to be accelerated, but this must be done in a technically prudent manner to achieve the best outcome.