Wind and solar may be currently leading the way in Australia’s renewable energy race, but there’s another contender lurking in the nation’s oceans.
Australia arguably possesses the world’s largest wave energy resource, around 1,800 terawatt hours. Most of this is concentrated in the southern half of the continent, between Geraldton and Brisbane. To put this in context, Australia used 248 terawatt hours of electricity in 2013-14.
Waves aren’t the only renewable power source in our oceans. The daily movements of the tides shift vast amounts of water around the Australian coast, and technology for conversion of tidal energy to electricity is more mature than any wave converters.
Ocean renewable energy also spans ocean thermal energy conversion, and energy captured from our large ocean currents (such as the East Australian Current). These represent less mature technologies with less opportunity in Australia.
Australia has abundant energy resources – both renewables and fossil fuels. So what will it take to get ocean energy out of the water, and into our homes?
The Paris Agreement, to which Australia is a signatory, aims to limit global warming to well-below 2℃. This will require almost complete decarbonisation of global electricity systems by 2050.
Of the 248 terawatt hours of electricity used in Australia, around 17 terawatt hours of this came from large scale renewable energy technology, equivalent to about half of Australia’s Renewable Energy Target of 33 terawatt hours by 2020.
To keep us on track to meet our international commitments, members of Australia’s Climate Change Authority recently proposed a target of 65% by 2030. This would require a rapid, large scale transition to alternative emission-free energy systems.
Wind and solar are currently leading the way, but we’ll need other technologies. This is not only to boost low emissions energy supply, but also to overcome the problem of intermittency due to the natural variability of the energy sources (when the sun doesn’t shine, or when the wind doesn’t blow).
Ocean renewable energy technologies (including wave and tidal) are emerging as a future contributor to Australia’s energy mix, and have a number of advantages over other sources.
Both wave and tidal energy devices are deployed offshore (not taking up limited land space) and are typically out of sight (deployed under the surface, or sufficiently offshore and low profile to not be obvious to the casual observer).
Although ocean energy resources also vary day-to-day like wind and solar, wave power has only a third of the variability of wind power. It can also be forecast three-times further ahead than wind. Tidal energy is predictable over very long time-frames.
These attributes provide an advantage in a portfolio of clean energy technologies and have led to notable government and other investments in ocean renewable energy technologies in Australia.
The Australian Renewable Energy Agency (ARENA) has contributed more than A$44.3 million to at least nine ocean renewable energy projects to date (two closed before completion owing to technical and financial challenges). With other funds, more than A$122 million has been invested in ocean energy in Australia.
These funds have supported demonstration projects, including notable international successes (Carnegie Wave Energy Ltd, and BioPower Systems), and other research. Several other demonstration projects have also been undertaken in recent years by start-up companies with self-funded support, and unique technologies.
The expected installed capacity from approved ocean projects in Australia is around 3.5 megawatts. So far total global installed capacity of wave energy projects is less than 5 megawatts. The EU has also been a major investor in wave energy projects, with approximately €185 million (around A$275 million) invested to date, for a total expected installed capacity of 26 megawatts by 2018.
Although tidal energy converters are the most ready of ocean renewables, a high-quality assessment of Australia’s national tidal energy resource is yet to be done.
Nevertheless several prospective sites in northern Australia and near Tasmania are attracting national and international attention for potential development owing to their attractive resource. Significant projects are in development, particularly in Europe, where tidal installed capacity is set to increase to about 57 megawatts by 2018.
At the moment, the lifetime costs of ocean energy technologies are high. Until there are more than 10 megawatts of wave energy installed globally, costs will remain around A$500-900 per megawatt hour.
By comparison, in 1981, when there were less than 10 megawatts of installed wind energy capacity, wind turbines cost around A$720 per megawatt hour. In 1990 there were 2 gigawatts, and costs fell to around A$190 per megawatt hour. Now there are around 500 gigawatts of installed wind energy, and the cost of onshore wind is around A$110 per megawatt hour, similar to coal.
This experience suggests that costs for wave energy will decrease to A$170-340 per megawatt hour when installed capacity reaches 2 gigawatts. But costs should not be the only performance indicator for ocean renewables.
Options are being explored to combine and integrate design of other infrastructure (such as wave energy capture as a coastal protection mechanism, powering offshore aquaculture, or recreational amenities) which will reduce relative costs.
To put ocean energy generators in our seas, planners, operators and financiers will increasingly require more knowledge of how much energy is available and where.
These decision-makers also need to understand barriers or constraints to ocean energy (in particular areas such as access to transmission infrastructure, or other uses of the sea such as fishing, aquaculture, tourism, shipping, ports, marine-protected areas).
To help answer these questions, ARENA and CSIRO have developed the Australian Wave Energy Atlas. The atlas provides wave energy resource information together with details of available electricity infrastructure and spatial constraints for deployment. This allows users to identify the most viable sites for future wave energy projects, and ultimately ease the process of attracting capital and negotiating the consenting process.
While ocean renewable energy has many attractive features, there are still many challenges. The advantages of consistency and predictability of ocean energy become diminished if costs don’t fall below those of wind or solar supplemented with storage, which will offer the same advantages.
Other challenges include the technological advances needed to make generation devices ready and reduce costs; policy and regulatory barriers to project development; lack of awareness of ocean renewables and the potential they provide; limited body of knowledge on the environmental effects of large scale deployments; and the finance mechanisms to support the growing industry.
To overcome these challenges we’ll need to bring decision-makers, researchers, manufacturers, and businesses together to unlock the potential of our oceans.
The Australian Ocean Renewable Energy Symposium, running from today until October 20.
Mark Hemer, Senior Research Scientist, Oceans and Atmosphere, CSIRO; Irene Penesis, Associate professor, Mathematics, University of Tasmania; Kathleen McInnes, Senior research scientist, CSIRO; Richard Manasseh, Associate professor, Centre for Ocean Engineering, Swinburne University of Technology, and Tracey Pitman, Project Manager, Data61, CSIRO
Over the weekend, international leaders meeting in Kigali, Rwanda, agreed to a remarkable deal to phase-out hydrofluorocarbons (HFCs), used as refrigerants and propellants. HFCs are potent greenhouse gases.
The agreement ended a decade of negotiations under the Montreal Protocol, established in 1987 to protect the ozone layer. Under the new agreement, developed nations will reduce HFCs 85% below current levels by 2036.
So how will the deal work?
The Montreal Protocol was established under the Vienna Convention for the protection of the ozone layer. It followed evidence that chlorine atoms were damaging the stratospheric ozone, which protects the Earth from the most energetic ultraviolet radiation coming from the sun.
These chlorine atoms came from refrigerant and propellant gases, the chlorofluorocarbons (CFCs), that we were releasing into the atmosphere.
By 1990, nations had agreed to restrict production and consumption of CFCs and a timetable for their eventual phase-out over the next two decades. More time was allowed for developing countries and a multilateral fund was established to help them meet their targets.
With just a few exceptions, complete phase-out has been achieved. As well as ozone protection, there was a climate benefit from phasing-out the CFCs because they are much stronger greenhouse gases than carbon dioxide.
Related gases that were less damaging to the ozone layer, the hydrochlorofluorocarbons (HCFCs), were next targeted and they will have been phased out by about 2020.
In developed countries such as Australia they have largely disappeared already, although there is still a lot of one HCFC, R-22, in older air-conditioners. Other ozone-depleting substances such as the fumigant methyl bromide and a number of solvents were also targeted for elimination under the Montreal Protocol.
Major replacements for the CFCs were the hydrofluorocarbons (HFCs). Their molecules contain no chlorine so they are “ozone friendly” but like the CFCs these substances are serious global warmers.
HFCs are not manufactured in Australia but we import several thousand tonnes each year, which is a small proportion of world production. Our imports will be capped from 2018 following a recent government decision.
Nations under the Montreal Protocol realised that by using HFCs to replace ozone-depleting substances they had contributed to another environmental problem – global warming and climate change.
Despairing of any action under the climate change-centred Kyoto Protocol, the representatives of developed countries began to push for addition of HFCs to the Montreal Protocol where production and consumption data could be monitored and there was potential for an agreement to phase them out.
The process was fractious. Some parties argued that the Montreal Protocol could not be extended to cover substances that were not ozone-depleting. Others pointed to a clause in the preamble to the protocol that would allow HFCs to be covered.
This was a practical view, but perhaps it also contained an element of guilt: “we created the problem so it’s up to us to fix it”.
Resistance came from developing countries that were struggling financially to achieve the phase-out of HCFCs and did not want the expense of retooling for whatever would replace the HFCs.
In the corridors one could hear cynical voices saying that the phase-outs of CFCs and HCFCs would leave delegates and officers with nothing to do, so an extension to HFCs was needed to keep the “Montreal Club” alive.
Sensing that change was likely, the chemical industry in the US had already produced HFC replacements that are neither ozone-depleting nor global warming – the hydrofluoroolefins (HFOs).
These substances are designed to rapidly degrade in the lower atmosphere so that releases would not contribute to environmental problems. Other industrial players, strongly backed by environment groups, opted for natural refrigerants such as ammonia (already coming into widespread use in Australia), carbon dioxide (yes, the villain in new clothes!), and low-boiling hydrocarbons such as isobutane that can be “dropped in” to air-conditioners to replace the HFC R-134a.
Last week in Kigali, countries agreed to a phase-out schedule they could live with. Reductions will occur in steps: developed countries have until 2036 to reduce HFC consumption to 85% of current levels, while developing countries have until the mid-2040s. This is too slow for some observers but the experience of the last decade’s negotiations showed that measured pace would be important in securing the agreement.
Australian delegates had been involved all along in the group pushing for the extension of the Montreal Protocol to cover the HFCs. More than that, our lead delegate, Patrick McInerney (Department of the Environment) was co-chair of the working group that fashioned the Kigali consensus and enabled the 197 parties to bring the matter to conclusion.
Even the most pedantic observer, while questioning the validity of extending the Montreal Protocol, would have to agree that it was the right thing to do.