Renewables & Energy Efficiency News South Africa

Solving renewable energy's intermittence problem

When Energy Minister, Jeff Radebe, signed deals last year with a further 27 independent power producers, adding 2,300MW of electricity to the South African national grid over five years, it emphasised the country's commitment to renewable energy.

Various African countries have also made headway with their respective renewable energy programmes. The International Energy Agency (IEA) predicts that by 2035, developing nations will constitute 80% of total global energy production and consumption alike. A greater portion of this new generation will be derived from renewable sources in response to adhering to international policies for cleaner energy.

While the costs of renewable generation are declining, there is concern about the intermittence of the total output derived from renewable sources. This means that the renewable energy source used will not be continuously available for conversion into electricity and cannot be controlled directly as the used primary energy cannot be stored. To this end, sources cannot be dispatched to meet the demand of an electric power system. The energy grid must provide a balance between the load and generation, but with such varying levels of electricity production from renewable sources such as wind and solar, this balance is challenging to sustain, and this very reason represents one of the biggest challenges to the power sector.

Battery energy storage system

However, with the advent of a battery energy storage system (Bess), these intermittency concerns have been somewhat appeased as they enable the effective utilisation of these renewable sources. By merging storage and renewable energy, the total output is far less intermittent, thereby solving balancing and system reliability concerns.

Grid scale battery storage can promptly become operational thereby assisting with time shifting, spinning reserve, frequency regulation and load following. When the deployment of renewable energy is coupled with battery storage, a new dimension emerges where utilities are able to compete on a level playing field with conventional electricity power plants. Furthermore, energy storage remains a flexible, scalable and efficient solution.

Technology

“Digital solutions help energy systems to be more effective in different ways, such as assisting in managing the intermittence issues of renewables," Dr Christoph Frei, secretary general of the World Energy Council.

Digital technology lends itself to overcoming intermittence issues in renewables such as intelligent data systems that empower network operators to manage large volumes of intermittent solar, wind and other renewable power, and support more distributed power producers. Building a database that represents a digital replica of the physical plant can create analytics that can prompt service and maintenance functions, prior to issues even occurring.

As renewable energy contributes an increasing proportion of energy to the grid, more sophisticated, accurate, and effective means for predicting power levels must be created to efficiently use the energy being produced. Failing this, the task could become very expensive, and hinder the success of renewable energy in its constant effort to replace fossil fuels as the main source of energy generation in Africa.

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