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Less sunshine, wind and rain could cast shade on renewable energy

The Conversation | Updated on: 10 February 2017, 1:49 IST

Fighting climate change will involve massive changes to the way we produce and distribute energy. Those changes are already happening. Several studies have looked at how our energy systems will change as clean energy increases and fossil fuels are replaced.

But climate change must be planned into this transition.

For instance, temperature is a key driver of demand for electricity, and future increases in heatwaves will probably drive higher electricity demand for air conditioners.

So how could future climate changes affect the ability of the system to generate enough electricity?

Climate and energy

Renewable energy technologies are highly dependent on climate-related factors including sunlight, wind speed and water availability. Water is also a key requirement for coal and nuclear power stations. Heatwaves can impact on the capacity of transmission lines to move energy around the national grid.

The changes to climate in Australia resulting from increased greenhouse gas emissions include more extreme heat events, longer and drier droughts, and longer and hotter heatwaves, as well as stronger storms and rainfall events. Shifts in large-scale circulation patterns may have some impact on wind speed but these effects are less clear.

These climate events and trends affect almost all energy generation and distribution systems, and need to be factored into good management. There is a broad range of intersections between the changing climate and the energy systems of the future that need to be considered.

The future is here

The current mix of generation technologies in the energy system is in a state of flux and undergoing relatively rapid change, as renewable energy, particularly wind turbines and rooftop solar, increase. And the changing climate is already affecting the current energy infrastructure.

Recent years have seen several extreme weather events - with a detectable influence from climate change - that have seriously impacted electricity generation in Australia.

Tasmanian hydro dam levels are currently at record lows. With the Basslink connector also out of action, the shortfall in energy generation is being made up through the use of diesel generators.

Much has been made of this situation already, but the lack of rainfall over the past year is consistent with long-term projections for rainfall in southeast Australia.

In 2014, the Hazelwood mine fire was started by bushfire embers in rural Victoria. It burned for 45 days in the wake of a heatwave that brought temperatures not seen since the extreme heat of 2009.

The 2009 heatwaves themselves shut down the Basslink transformer in Georgetown, Tasmania, reducing the electricity available to Victoria and South Australia. At the same time, two transformers in Victoria failed, leading to supply loss that significantly impacted Melbourne and western Victoria.

In Queensland, the 2010-11 floods caused widespread damage to the electricity network. Substations were flooded, high-voltage feeder lines were damaged and, in the Lockyer Valley, much of the electricity infrastructure was destroyed.

The costs of replacing and repairing electricity networks damaged by extreme weather events can be seen as one consequence of our continuing reliance on fossil fuels.

More variable rain and sun

As the climate changes further, electricity networks will have to manage increasingly variable rainfall - less in southeast and southwest Australia and possible increases in the north.

In 2013, Australia had more than 120 operating hydroelectric power stations, with a total generation of almost 20 terawatt-hours (8% of total energy generated).

Most hydro power is produced at dams on Australia's major river valleys, and only a few of these have been left untouched. As water availability becomes more uncertain, this type of generation is unlikely to expand much further.

Australia has the highest average solar radiation per square metre of any continent in the world. More than five gigawatts of solar photovolaic panels have been installed, both on rooftops and more recently as large-scale installations.

These panels are prone to extreme weather events, such as hail. Events such as Melbourne's 2010 storm and Perth's freak storm the same year could dramatically impact a high-penetration renewable energy system.

Similarly, plans for large-scale solar plants that create steam to drive turbines should take changes to rainfall and available water resources into consideration at the planning stage. Solar radiation is affected by El Niño, with up to 10% less radiation available during La Niña conditions.

Other areas of generation (such as wind, ocean and bioenergy) may also be affected by climate change, as circulation changes result in shifts in wind fields and precipitation patterns (affecting biofuel crop yields).

The likely effects of these changes are much harder to project, but the potential for reduced output needs to be taken into consideration when making plans for future energy systems.

The Conversation

Roger Dargaville, Deputy Director, Energy Research Institute, University of Melbourne and Jane Mullett, Research Fellow, School of Engineering (environmental engineering), RMIT University, RMIT University

This article was originally published on The Conversation. Read the original article.

First published: 17 May 2016, 9:00 IST