Power to the People

Climate change is one of the most challenging issues currently facing the world. Earth is speeding headlong into irreversible environmental disaster unless we begin reducing greenhouse gas emissions immediately.

While climate variation and global warming are natural processes, human activities have accelerated global warming. The burning of fossil fuels releases greenhouse gases, like carbon dioxide, into the atmosphere. In addition, land clearing reduces the amount of carbon dioxide absorbed by plants.

Fossil fuels, especially coal, generate about eighty percent of the world’s electricity and are responsible for a twenty-five percent increase of the greenhouse effect.

Electricity is integral to modern living, but with the demand of electricity expected to double by 2030, we must change to clean power to prevent the catastrophic effects of human-induced global warming. Clean electricity production is already used across the world, utilizing both renewable and non-renewable sources, but more needs to be done.

Opinions differ amongst authorities as to the positive and negative points of various ways to produce electricity cleanly. Listed here are some clean technology options, including some of these main points.

Solar Power
The Sun is the original energy generator, not only providing heat but also the source of wind and wave power.

Until recently, solar energy has mostly been used on an individual scale, limited to uses such as heating water via rooftop solar panelling. Even so, over twenty-nine million homes worldwide use solar energy for hot water and heating.

Changes in technology mean solar power is now viable on a large scale. Solar collectors concentrate sunlight from a large area on to a central vessel, heating water. The water becomes steam, which turns the turbine, generating electricity.

Germany and Japan are world leaders in solar power, in both manufacturing and usage, although Australia leads in solar pool heating. Australia’s National University has the biggest, freestanding solar concentrating dish in the world as part of its solar research program, and there is a large solar power plant planned for Victoria.

Positives
• Renewable

• No direct greenhouse emissions

• Enough solar capacity available, even in colder countries like Britain

• Improved technology means solar energy is cost-effective

• Limited environmental impacts

Negatives
• Not a continuous source, so storage facilities and back-up power required

• Lower energy outputs than coal-powered plants (but technology is closing gap)

Wind Power
Wind power is old technology, with windmills used for more than a thousand years to grind grains and pump water.

Wind turbine blades rotate due to pressure differences created by the movement of air over the surface of the blades. The blades turn, driving a shaft that then drives a generator, producing electricity. Many modern wind turbines have their own internal computer to monitor the wind’s speed and direction, adjusting their blades to suit the wind conditions.

Germany and Spain are leaders in wind technology. In Australia, only a small percentage of our electricity supply currently comes from wind, although the market is growing and our capacity to generate electricity from wind is enormous.

New Zealand already uses wind power and has one of the world’s greatest capacities for wind-generated electricity.

Positives
• Renewable

• No direct greenhouse emissions

• 20% of Australia’s power needs can be met using 1000 sq km of land

• Cost competitive

• Low environmental impacts

• Up to 17% more efficient than traditional power plants

• Agricultural practices can continue on same land as wind turbines

• New technology is relatively quiet and must meet strict noise pollution standards

Negatives
• Wind supply not continuous, so storage facilities and back-up power resources required

• Turbines may have to be shut down in very strong winds

• Area for wind turbines must be free of turbulence caused by buildings and trees

• Some noise and visual pollution created, considered especially unacceptable if turbines are placed in scenic or ecologically sensitive areas

• Inappropriately placed wind farms may kill endangered birds

Hydro and wave power
Water-generated power has been around for a long time, using the momentum of falling water, to generate power. Australia’s biggest hydro powered plant, the Snowy River Scheme, centres on an immense dam, and a system of reservoirs and aqueducts.

The natural flow of a river or wave power can also be harnessed to generate electricity. Electricity from natural river flow is a micro-hydro system and generally does not feed into the electricity grid, but provides power directly on a small scale. Wave technology is still very new, but has good potential for power generation.

Positives
• Renewable (as long as we are careful)

• Dam storage ensures a continuous supply of water

• Does not contribute to greenhouse emissions

• Both river flow and wave techniques have negligible environmental impact

• Australia and New Zealand have access to vast coastlines for wave power

Negatives
• Large dams are detrimental to natural environment

• Natural river flow may not provide enough water in dry seasons.

• Salt water is corrosive so special equipment needed for wave power

• Floating devices for wave power potentially hazardous to shipping

• Wave power’s potential untested in providing significant electricity needs

Geothermal Power
‘Geothermal’ refers to the heat stored in dry rocks beneath the earth’s surface. Trace elements of minerals contained in these rocks break down, called radiogenic decay, releasing heat.

Water pumped down a borehole helps to open existing cracks, increasing permeability. The heat in the rocks converts the water to steam, channelling it up another borehole to drive a turbine, generating electricity.

Hot springs, geysers, bubbling mud pools and volcanos are forms of geothermal energy. Some countries, such as New Zealand, already use geothermal energy for heating and electricity production.

Although Australia has very few hot springs and geysers, it has excellent reserves of hot dry rocks, with the heat generated in the crust double that of the global average.

Positives
• No large-scale excavations, so won’t ruin look of the landscape

• Free source of energy (although extraction costs involved)

• No direct greenhouse gas emissions

• Australia has enough hot dry rocks for centuries of power generation

Negatives
• Steam may run out if rocks cool down

• Suitable sites restricted (Hunter Valley, NSW and Eromanga Basin near South Australian and Queensland border are best locations)

• Long-term effects of forcing cracks to open up are unknown

Nuclear Power
Uranium is the main mineral used for electricity production. Unstable atoms are broken up releasing neurons, which heats up the reactor producing steam to drive the generator.

Nuclear energy generates sixteen percent of the world’s electricity. Many countries generate at least some of their electricity from nuclear energy; including France with seventy-eight percent of its electricity needs supplied by nuclear power.

Positives
• No direct greenhouse gas emissions

• Continuous, reliable electricity supply on a large scale

• Efficient with very little uranium needed compared to coal

• Minimal wastage compared to coal

• Australia owns nearly 40% of world’s uranium, so good for our economy

• Only energy industry to take full responsibility for wastes and disposal costs

• Australia’s stable rock provinces provide ideal conditions for disposal of spent uranium rods

Negatives
• Non-renewable

• Large amounts of fossil fuels used for mining and refining, which will increase with depletion of concentrated uranium ore

• Nuclear power plants emit significant amounts of radioactive gases and other elements into the atmosphere annually

• Thousands of tons of solid waste accumulates in the cooling pools of nuclear power plants around the world

• Nuclear waste remains radioactive for thousands if not millions of years

• No guarantee that everyone in industry is responsible for managing waste responsibly (as a recent case in Russia demonstrates, where concrete waste storage containers corroded by seawater)

• Huge government subsidies required to make nuclear power economically viable

• Decommissioning nuclear power stations very expensive, so many countries continue using them, with possible disastrous outcomes

• A failure or meltdown potentially dangerous (8,385 cases of thyroid cancer between 1987 and 2001 resulting from the Chernobyl disaster)

The issues surrounding clean power generation are complicated. Governments are now making decisions about the future direction of electricity production that will affect us for the next fifty or more years. I encourage everyone to do their own research, and urge you to influence our governments as to the types of clean power technology they implement.

Earth is depending on us!