How Power Grids Could Embrace the Era of Renewable Integration December 19, 2017 | by

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Renewable Energy (RE) has been growing in the past years in the power sector around the world.  This growth contributes to (1) energy system decarbonisation, (2) long-term energy security, and (3) expansion of energy access to new energy consumers in the developing world (IEC White Paper, 2012). Considering that fact, many countries are committed to include RE in their national energy plan to meet the environmental, social, and economic challenges of the future.  It also worth noting that the inclusion of RE could enhance energy access in rural areas, which in turn with improve the overall economy of the country.

Renewables’ shares in power generation in the world reached over 22.3% in 2014. It represented the second largest contributor to global electricity production, after coal. It was also recorded that the share of electricity from renewable has grown on average of 3.6% per annum since 1990 until 2016 globally (IEA, 2016).

In accordance with the commitment to enhance energy security, accessibility, affordability, and sustainability in the region, ASEAN is willing to take part on involving renewable sources in the energy mix. This spirit is interpreted in ASEAN Plan of Action for Energy Cooperation (APAEC) 2016-2025 with an aspiration to achieve 23% renewable energy (RE) mix in the primary energy supply by 2025.

However, significant RE growth in the power sector does come with challenges. Power grids experience direct technical impact caused by RE penetration.  An example was shared by Thomas Stetz in his presentation, ‘The Integration of PV Plants in Distribution Grids’, during Ostbayrisches Technologie-Transfer-Institut PV Monitoring Workshop (2011), in Germany.  He mentioned that distributed solar generation integration with power grid caused the network operator to lose control over the grid. In Germany, 80% of the solar generation was interconnected with the distribution network. The measurement of connection points between distribution and transmission was available in the distribution control centre. This measurement was no longer available when a lot of solar generations were interconnected in the network. RE sources which belong to non-dispatchable sources or also known as variable renewable energy (VRE) (i.e. ocean power, solar photovoltaics, and wind) have major issues of intermittency. This intermittency issue has caused these technologies to require specific measures for integration into the power system, such as additional monitoring tool for measuring stability, flexibility and responsiveness of the electricity grid, as well as to some extent the introduction of energy storage.  The intermittency is due to the following VRE’s characteristics: (1) variability due to temporal availability of resources; (2) uncertainty due to unexpected changes in resource availability; (3) location-specific properties due to the geographical availability of resources; (4) low marginal cost since the resources are freely available (IRENA, 2015). In other words, power grids can become unstable with RE penetration because of its mentioned characteristics.

RE is also often utilised as a distributed power generation in rural area where the grid is close with the demand area. For example, rural areas electrification by harnessing solar or wind potential in the area. Power system stability can be disturbed if these distributed generations are connected to the grid.  In the point of penetration, the power quality can be lowered, since VRE creates harmonics from the utilisation of converter and inverter (Passey, 2011). The stability can also be defied due to the fluctuation of power supply from RE generation. For example, large injection from large distributed solar generation can destabilise power grid whilst injecting high power during the day and create great loss of power during the night.

Not only that, many RE distributed generations which are connected to the grid could cause safety problem for the grid operator during maintenance. All RE generations should be set in island mode, during any maintenance, to assure that the operator is safe to do the maintenance. However, when there are a lot of distributed generations, it is difficult to ensure all the distributed generations to be set in island mode, unless there are established communication to detect some technical changes in the grid.  This issue can be a massive problem when a lot of distributed generations of RE are connected to the grid.

It is clear that RE growth should be in line with the technological evolution of power grid. Power grids should be designed to be more resilient and reliable when RE utilisation is planned to be increased in the power generation. In the near future, power grids should be equipped with communication technology which allows controlling and monitoring power in the system to obtain optimal performance. Safety and reliability can be enhanced when such system is built. Smart grid concept is likely to be implemented to prepare the power grid in facing the RE power generation era. Smart grid technologies enable VRE to be injected to power grids, due to its ability to reduce the variability by allowing integration into diverse electricity sources, including load control and grid protection. In short, transforming the power grid with smart grid is an important phase to be prepared alongside with increasing RE mix in the power generation. Accordingly, by the time large RE generation is integrated to the grid, the power grids are ready to face the challenges.

Therefore, it is important for regulators and policymakers to consider power grid transformation while composing RE target for their countries.  It is expected that ASEAN RE target is supported with the firm plans of power grid enhancement which can be integrated in APAEC, mainly in ASEAN Power Grid plan to assure the readiness of power grids to embrace RE in the near future. (Featured photo credit:  pixabay.com)

 

 

 

 

 

References

ASEAN Centre for Energy. (2015). ASEAN Plan of Action for Energy Cooperation (APAEC) 2016-2025. Jakarta: ASEAN Centre for Energy.
International Electrotechnical Comission. (2012). IEC White Paper on Grid Integration of large-capacity Renewable Energy sources and use of large-capacity electrical storage.
International Energy Agency. (2016). Key Renewables Trends 2016.
Passey, R. (2011). The potential impacts of grid-connected distributed generation and how to address them: A review of technical and non- technical fixes. Energy Policy 39 (2011) 6280-6290.
International Renewable Energy Agency. (2015). Renewable Energy Integration in Power Grids Technology Brief.
Stetz, Th. (2011). ‘Integration of PV plants in distribution grids’. OTTI PV Monitoring Workshop, Munich, Germany.

 

 

 

 

The views, opinions, and information expressed in this article were compiled from sources believed to be reliable for information and sharing purposes only, and are solely those of the writer/s.  They do not necessarily reflect the views and opinions of the ASEAN Centre for Energy (ACE) and/or ASEAN Member States.  Any use of this article’s content should be by ACE’s permission.