By Pat Pepper, NCWQ Environment Adviser
Update on Climate Change:
Further evidence of the increase in greenhouse gases (carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O)) and the relationship with global temperature: Measurements of greenhouse gases (CO₂, CH₄ and N₂O) in current and archived air samples, air trapped in bubbles in ice cores, and compacted snow have been compiled to cover the past 2,000 years by dozens of laboratories around the world, including CSIRO, the Bureau of Meteorology’s Cape Grim Station, NOAA, AGAGE and the Scripps Institution of Oceanography, among others. The data shows the growth of greenhouse gases began with the onset of the industrial era around 1750 but sharply increased from 1950s and still continues today.
Between 1990 and 2010 the net emissions of CO₂increased by 42 %, which is particularly important because CO₂accounts for about three-fourths of total global emissions. Climate Change Indicators in the United States: Global Greenhouse Gas Emissions www.epa.gov/climate-indicators –Ben Henley(University of Melbourne) and Nerilie Abram (ANU) have shown a close relationship between global temperature and CO₂ since 1850.
Alternative energy resources Most of Australia’s electricity is generated centrally and relies heavily on fossil fuels 86% v 14% renewables. : https://www.originenergy.com.au/blog/about-energy/energy-in-australia.html; Department of the Environment and Energy, Australian Energy Statistics, Table O, May 2017 Fossil fuels can destroy and pollute the environment ; reserves are also limited, expecting to last only another 100 years given are basic rate of consumption. http://www.conserve-energy-future.com/different-energy-sources.php
But there are alternatives to fossil fuels. e.g. Nuclear power. However uranium isn’t renewable and there are issues about safety and disposal of waste; the cost of building and decommissioning nuclear power stations; and the danger of stockpiles of enriched uranium and nuclear plants being targeted by terrorists
On the other hand, Australia has a rich diversity of renewable energy resources with low greenhouse gas emissions. – dispatchable (i.e. biomass, concentrated solar power with storage, geothermal power and hydro) and non-dispatchable, or Variable Renewable Energy or VRE (i.e. ocean power, solar photovoltaics(PV) and wind).
- Bioenergy: While Australia’s potential bioenergy resources are large and there are under-utilised resources in crop residues, plantation and forest residues and waste streams, the proportion of biomass potentially available for bioenergy will depend on the value of biomass relative to competing uses, impact of their removal (retention of biomass in situ returns nutrients to soil, improves soil structure and moisture retention), and global oil prices. http://www.ga.gov.au/scientific-topics/energy/resources/other-renewable-energy-resources/bioenergy
- Hydro power is the most advanced and mature renewable energy technology and has low greenhouse gas emissions, low operating costs, and can response quickly to demand. Much of Australia’s economically feasible hydro energy resource has already been harnessed. http://www.ga.gov.au/scientific-topics/energy/resources/other-renewable-energy-resources/hydro-energy
- Geothermal energy there is significant potential for geothermal energy in Australia. It is estimated that one per cent of the geothermal energy shallower than five kilometres and hotter than 150°C could supply Australia’s total energy requirements for 26 000 years http://www.ga.gov.au/scientific-topics/energy/resources/geothermal-energy-resources
- Ocean Energy
- Tidal energy Australia’s tidal energy resources is restricted to the tide kinetic energy present on Australia’s continental shelf. The regions of shelf that have the largest kinetic energy densities are the North West Shelf and the southern shelf of the Great Barrier Reef
- Wave energy generated by converting the energy of ocean waves into other forms of energy is greatest on the southern half of the Australian shelf, The states with the best wave energy resource are Western Australia, South Australia, Victoria and Tasmania.
In the case of tidal and wave energy resources, the lack of control over the timing, rate or level of delivery can impact significantly on their potential as an electricity source http://www.ga.gov.au/scientific-topics/energy/resources/other-renewable-energy-resources/ocean-energy
- Wind energy Australia has some of the best wind resources in the world. These are located mainly in the southern parts of the continent (which lie in the path of the westerly wind flow known as the ‘roaring 40s’) and reach a maximum around Bass Strait. http://www.ga.gov.au/scientific-topics/energy/resources/other-renewable-energy-resources/wind-energy The biggest disadvantage is the variability of wind
- Solar energy The Australian continent has the highest solar radiation per square metre of any continent and consequently some of the best solar energy resource in the world. The regions with the highest solar radiation are the desert regions in the northwest and centre of the continent. http://www.ga.gov.au/scientific-topics/energy/resources/other-renewable-energy-resources/solar-energy As with wind, viability can be a problem. . However, the sun does not shine all the time.
Renewable energy storage, like pumped hydropower, heat storage and batteries, flywheels, fuel cells and compressed air storage can provide a solution to the intermittency of variable renewable energy sources such as solar and wind These technologies have different characteristics and applications for the electricity grid. As battery costs continue to fall households and businesses with solar photovoltaics can store electricity they generate for use later and minimise the need to purchase increasingly expensive electricity from the grid. The lithium-ion battery has seen rapid cost decreases and is considered to have a range of technical and performance advantages over other battery types (energy and power density, usable life). However other batteries, such as advanced lead-acid batteries and redox-flow batteries are suited to specific purposes – such as stabilising the electricity grid, for longer-term storage or larger energy capacity. Battery storage technology also has the potential to reduce the two biggest contributors to the cost of electricity bills in Australia – the cost of building and maintaining the electricity distribution network and purchasing wholesale energy. They provide an alternative to expanding and upgrading the network, by instead evening out the demand on the network at peak times, and making more effective local use of surplus distributed generation. High levels of variable renewable energy can cause instability in the electricity grid if the generation is not adjusted to match demand.
Powerful Potential: Battery Storage for Renewable Energy and Electric Cars by Andrew Stock, Petra Stock and Veena Sahajwalla (Climate Council of Australia, 2015)
Integration of variable renewable energy into the power system grids is possible with system-friendly variable renewable energies, flexible generation, grid extension, smart grid technologies, and storage technologies. New advances in wind and solar photovoltaics technologies allow frequency and voltage control. Flexible generation requires changes in the energy mix to optimise production from both dispatchable and variable renewable energy resources. IEA-ETSAP and IRENA© Technology Brief E15 – April 2015 Smart grid technologies are made possible by two-way communication technologies, control systems, and computer processing. These advanced technologies include advanced sensors known as Phasor Measurement Units that allow operators to assess grid stability, advanced digital meters that give consumers better information and automatically report outages, relays that sense and recover from faults in the substation automatically, automated feeder switches that re-route power around problems, and batteries that store excess energy and make it available later to the grid to meet customer demand. https://energy.gov/oe/services/technology-development/smart-grid Small variable renewable power plants which produce electricity close to demand sites could be connected to a distribution network. In this way the need for centralised power generation, high-voltage transmission lines could be reduced, as well as transmission and distribution costs. . IEA-ETSAP and IRENA© Technology Brief E15 – April 2015