Are the electricity system design decisions going to change when the climate changes?

We recently hosted a talk from Smail Kozarcanin, a visiting researcher from Aarhus University, who is working with Associate Professor Gorm Bruun Andresen. He has very kindly agreed to write us a blog post, on the same topic of his talk, the impacts of climate change on the electricity system design decisions for the 21st Century. You can also download a copy of the slides from his talk [PDF].

Pexels: Pollution of the atmosphere

The increase in global average temperature has already put its fingerprints on the eco-environment and human activities. But what are the impacts of climate change on the design decisions of future large-scale electricity systems?

It is well recognized that the design of future electricity systems with low CO2 emissions may rely heavily on large penetrations of renewable power. Wind, solar and hydro are the major developed sources of renewable energy, and they all depend strongly on the weather.

In itself, this is a challenge due to the unpredictable and variable nature of the weather. With a changing climate, the weather patterns are projected to change, which consequently may bring even more pronounced challenges to the design of future electricity systems.

Longer periods with low or even zero renewable power production would be present and would in turn challenge the electricity system infrastructure. On the other hand, long periods with more extreme weather would also challenge the infrastructure.

One possible way of analysing how climate change affects the best designs of a renewable energy based systems is to approach the question of interest by using state-of-art mathematical models that describe the global climate along with different projections of temperature increases. When combined, these are able to provide state-of-art projections of possible climatic outcomes.

The figure below shows an example of the spatial distribution of historical temperatures, Th, along with future temperature differences, Tf – Th, under the impact of three different CO2 emission scenarios provided by the IPCC.

Increasing temperatures by up to 6 oC are observed for Northern Europe in comparison to historical values for the RCP8.5. These will in turn bring prominent changes to our globe, changes that will be difficult to approach.

Spatial distributions of the 20 year average temperatures over the EURO-CORDEX domain extracted from the regional climate model HIRHAM5 downscaling the global climate model ICHEC-EC-EARTH. Historical period ranges between 1986-2006 and RCP periods ranges from 2080-2100.
Spatial distributions of the 20 year average temperatures over the EURO-CORDEX domain extracted from the regional climate model HIRHAM5 downscaling the global climate model ICHEC-EC-EARTH. Historical period ranges between 1986-2006 and RCP periods ranges from 2080-2100.

The design decisions of future electricity systems are determined by changes in important infrastructure metrics as described in the following:

  • In periods with low renewable power production, different non-renewable technologies have to provide the additional dispatchable power. A robust measure of this quantity is the amount of average dispatchable energy over a certain time period.
  • Peak demand and production periods may be eliminated by using geographical dispersion by means of transmission lines, which can be measured by the benefit of transmission.
  • A third metric is the average dispatchable capacity as it provides a measure of how large dispatchable energy capacities are needed in order to provide the additional amount of energy to cover the demand.
  • A last metric is the variability of the dispatchable power needs as it provides a measure of the on demand reserve capacity. By evaluating the variability, it is possible to capture the magnitude of extreme weather events, which in turn provides important information on storage needs in electricity systems.

A cautious investigation of these metrics over the 21st Century reveals that our current electricity systems are robust and negligible climate change impacts are evident on the important infrastructure metrics. In addition, a paired t-test uncovers that the 0-hypothesis cannot be rejected with 95% confidentiality.

0-hypothesis: Climate change has no impact on the relevant electricity system key metrics .

The figure below exemplifies the European annual need for dispatchable power during the 21. Century for the different IPCC climate projections. None of the climate projections leads to severe changes in the need for dispatchable power during this century and no clear distinctions are observed among the projections.

European annual dispatchable energy normalised to the consumption. Bold plots represent the 20 year running average and corresponding shaded regions represent the 20 year running variance for the regional climate model HIRHAM5 downscaling the global climate model ICHEC-EC-EARTH.
European annual dispatchable energy normalised to the consumption. Bold plots represent the 20 year running average and corresponding shaded regions represent the 20 year running variance for the regional climate model HIRHAM5 downscaling the global climate model ICHEC-EC-EARTH.

A closer investigation shows that the design of electricity systems should focus on reaching an optimal share of wind and solar power that minimizes the need for dispatchable power regardless of the climatic outcomes.

A coupling of the electricity and heating sector might provide different results as the need for heating and cooling is highly dependent on the ambient temperatures.

Smail Kozarcanin

Smail KozarcaninSmail is a PhD Fellow at the Sustainable Energy System group at Aarhus University, supervised by Associate Professor Gorm Bruun Andresen. His research topic considers the impact of climate change on highly renewable large scale energy systems of the 21st century.

This topic of interest is highly related to his masters thesis: “Impact of nodal mismatch correlations on the power flows in renewable energy networks, 2015” supervised by Professor Martin Greiner.

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