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Green power

The electricity that powers our cities doesn’t have to come from dirty, polluting sources – now you can choose a range of clean energy options that are reasonably priced.

Wind farms

Wind farms - a form of green power.

Credit: iStockphoto

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What is GreenPower?

You’ve probably seen a flyer when you got your electricity bill: the option to spend a bit more on per month and receive ‘green’ electricity. Many energy providers around Australia are now offering some form of green electricity. The question is, what actually is ‘green’ electricity?

It’s not frogs on treadmills. Green electricity is essentially any energy source that helps reduce our negative impact on the environment, primarily through the reduction of greenhouse gas emissions in generating that energy.

The difference between just any old green electricity and GreenPower is that only the green type promotes and supports new sources of renewable energy.

According to the nationwide, state government-backed GreenPower accreditation program – which sets stringent standards for green energy providers – GreenPower is an electricity generator that “must result in greenhouse gas emission reduction, result in net environmental benefits, be based primarily on a renewable energy resource”.

There are three key elements to this description:

  1. The energy is based on a renewable resource. This rules out our traditional fossil fuel favourites, such as coal, oil and natural gas. Typical renewable energy resources include wind, hydro (rivers and dams), wave and tidal power, sunlight or even burning scrap wood or sewage.
  2. It results in a “greenhouse gas emission reduction”. Contrary to popular belief, this doesn’t necessarily mean that it’s 100 per cent greenhouse gas free. Some forms of green energy might release some greenhouse gases into the atmosphere, but they release significantly less than would be emitted by burning coal. This means that if you use this green electricity source, an equivalent amount of coal is not burnt, and this results in less greenhouse gases being released overall. (Why is coal used as a point of reference? Because 86 per cent of our electricity in Australia comes from coal.)
  3. The “net environmental benefits”. Some green electricity sources release a substantial amount of carbon dioxide into the atmosphere, such as burning bagasse (sugar cane stalks after they’ve been crushed to remove the sugar). However, the amount of carbon dioxide released during burning is the same as was absorbed from the atmosphere while the sugarcane was growing. As such, this type of energy source is considered ‘carbon neutral’. This is not quite as good as a source that generates no greenhouse gases, such as solar or wind, but again, it can offset a proportion of conventional electricity generated from ‘dirty’ sources, such as coal, so there is a net benefit at the end of the day.

Where does it come from?

There are many forms of green electricity, ranging from the emission-free solar and wind alternatives through to burning the by-products of sewage treatment. Unfortunately, no single power technology is adequate to replace coal as our primary source of electricity, but each has its particular role to play.

One of the purest forms of electricity generation is solar. According to the National GreenPower Accreditation Steering Group, the average amount of solar energy that lands on Australia each day is enough to handle our energy needs 15,000 times over.

Photovoltaic cells are used to convert a small proportion of that solar energy directly into electricity. Several energy companies are now using solar power as a form of green energy, much of which comes from the largest solar farm in the southern hemisphere, based in Singleton in NSW. This solar farm, partially funded by the NSW government, has an impressive 480 kW capacity, and it alone reduces carbon dioxide emissions by 550 tonnes a year.

Backed by BHP Billiton and Rio Tinto, engineering firm, Worley Parsons recently announced they intend to build the world's largest solar power plant in Australia, operational in three years. It could power 300,000 homes.

Solar power is clean and emits no greenhouse gases during generation, but it’s currently limited in its application due to the expense of photovoltaic cells and the fact that the sun stops shining at night-time. With projects the scale of the solar power plant, the cost is expected to come down. But we will always have night-time. Proponents of solar point out that energy demand is reduced while everyone is sleeping, and suggest that combining solar with wind can address the issue.

Wind is another popular form of green electricity generation, and is rising in popularity worldwide, especially in Europe. All you need to generate power using wind is a big windmill and a consistent breeze – something in the region of 20 km/h to 30 km/h.

However, like solar, wind is unreliable (no wind = no power). Furthermore, there are limited locations where wind power can be used – although Australia is blessed with some ideal locations, especially in the south of the mainland as well as Tasmania. In fact, around 10 per cent of South Australia’s electricity is already generated by wind power – in 2002, they had no wind farms.

The third popular form of green electricity is hydroelectric, which is used as a major form of electricity generation around the world. Hydro can be in the form of dams, from the mighty 3,756 MW Snowy Mountains Hydro plant to the 4.5 MW Wivenhoe dam in Queensland, which nevertheless displaces around 20,000 tonnes of greenhouse gas emissions each year, or in micro-hydro plants based in rivers and other fast-running waterways.

Hydro has the advantage that it releases no greenhouse gases during operation, and it’s often very reliable and flexible: power can be generated at a moment’s notice by simply opening a valve. However, there’s not much more capacity for large hydro plants here in Australia or around the world, as most of the suitable locations are already being used. And in Australia, global warming is making water a bit scarcer every year.

Another very popular form of green energy is derived from biomass, which is basically any organic material. There are two common forms of biomass power: thermal and biochemical. Thermal sources include burning sugarcane bagasse, or tapping landfill and extracting the methane formed from the decomposing garbage, which is then run through a gas turbine. Biochemical processes convert organic matter into fuels, such as ethanol or biodiesel, which can then be burnt or used as fuel in vehicles.

Biomass is currently being exploited in many regions of Australia, with over 650 MW coming from a variety of sources, according to an Australian Business Council for Sustainable Energy report in 2005. Not surprisingly, bagasse is most popular in Queensland, where the majority of sugarcane production takes place. Much of the power generated from bagasse doesn’t go back into the grid: it’s usually used to power the sugarcane mills themselves. Burning methane from landfill gas is another popular source of green electricity, although ironically, as our waste practices improve and we recycle more, landfill gas could actually play a smaller role in the future.

Solar, hydroelectric, wind and biomass are the four most common forms of green energy in use around Australia, although there are other technologies that may be used in the future.

One of these is geothermal, which taps into the natural heat below the Earth’s surface and uses it to run steam turbines. Deep below South and Central Australia lies the equivalent of billions of oil barrels of geothermal energy waiting to be accessed. The heat is trapped in massive slabs of rock, which may one day provide large quantities of renewable, emission-free electricity. Like many wind farms, they are located far from the cities (where the energy is most needed); but efforts are underway to extract the energy and deliver it afar at low cost.

Where do I get it?

There are currently over a dozen electricity providers who offer GreenPower services, covering every state and territory in Australia. If you’re interested in getting GreenPower hooked up, then make sure the provider is certified by the National GreenPower Accreditation Steering Group. Some electricity providers will label a product ‘green’ because it comes from existing renewable sources, but only accredited GreenPower products have the capacity to replace coal by stimulating new investment.

Green Electricity Watch rates green power services.

GreenPower typically costs an additional $400 to $600 a year for the average-sized household, although prices vary with location and the amount of power your household consumes.

By switching energy providers for your home, you can reduce your greenhouse gas emissions from eight tonnes per year down to just one.