The energy challenge

 

Not surprisingly, demand for electricity worldwide is expected to nearly double from 2004 to 2030, while NZ’s is projected to increase by 45% to 50% by 2025.

We need to secure continuous electricity and we also need energy sources that are ‘eco efficient’.  

 

At this stage, solar, wind, ocean and geothermal technologies supply only a few percent of the world’s energy, with a current electricity mix of 40% coal, 16% nuclear power generation, 15% natural gas and hydro, 10% oil and other 19%. 

 

NZ is much better placed, with nearly two thirds of electricity produced by renewable sources, mostly generated by hydro systems. The rest comes from burning gas, coal or oil at power stations, with wind power contributing about 3%, along with a small amount generated by geothermal sources and biomass.

 

 

So to promote sustainability and help NZ respond to climate change, $6.7million annually has been directed at alternative energy sources such as liquid biofuels, solar, hydrogen, windpower and low carbon fossil fuels.

 

Reports show hydroelectricity, the largest renewable resource used for electricity generation worldwide, dominates NZ’s power supply, but expansion is limited by environmental and land use issues, plus the challenge of inconsistent rainfall.  Wood burning is being replaced by gas domestically, while natural gas growth is mainly driven by the increasing use of gas in electricity generation, and power generators are looking to Liquefied Natural Gas (LNG) and coal to replace local gas.

 

Today imported oil is a big primary energy supply for NZ but demand will be affected by technology advances and diversifying energy supplies. Coal is also a sizable resource in NZ, particularly lignite in Southland with development of ‘clean coal’ technologies and coal gasification as a priority.

 

In relation to biofuels, NZ is looking to utilise biomass resources for bioenergy production providing clean burning fuels from trees or crops grown specifically for their energy content, or waste products, but studies show enormous quantities of the input material are needed to be a useful resource.    

 

Solar energy is the most abundant energy source on the planet and international research is underway to understand its source (nuclear fusion). Unlike nuclear fission power, where heavy atoms such as uranium are split, solar nuclear fusion is a process in which light nuclei fuse together to form heavier ones releasing a very large amount of energy.

 

Meanwhile, we use solar energy by converting it directly into electricity by Photovoltaic (PV) cells, usually in the form of bolt-on panels, to power a range of equipment as well as solar water heating systems. 

 

Because NZ lies across prevailing westerly winds it has one of the best wind resources in the world. Eight wind farms now harness wind energy and convert it to electrical energy, sufficient for 77,000 households. 

 

Line’s company Vector has launched a year’s trial of small silent wind turbines, which could be used domestically. Ten turbines weighing around 50kgs each will be trialed in various locations around the country to see where and how they work best.

 

New Zealand Wind Energy Association says the average grid connected households use about 20 Kilowatt hours (kWh) of electricity per day and a 5kWh wind turbine is often able to supply their power needs. Furthermore small domestic size wind turbines may be suitable for off-grid houses, or those who wish to supplement electricity use.

 

Being a renewable form of energy, wind power will never run out and does not emit anything into the atmosphere or waterways, though some are concerned about the impact of windfarms on the landscape.

 

In another take, the first floating wind turbines, set up in the North Sea, could be generating electricity by 2009.  More costly than on land, it is hoped prices will fall with mass production.

There’s a possibility of using tidal phase differentials to generate power too, like the Tidal Barrage system at La Rance in Brittany, France, where a tidal range of 8m provides 240MW of power, sufficient for 350,000 households.

 

The use of wave motion was the topic of a recent business article, in relation to manufacturing Pelamis in NZ. Invented by Scottish company Ocean Power Delivery, each 120m long machine generates up to 750kW of power, enough for about five hundred homes, useful for small communities whose remoteness makes national grid supply difficult. To be viable, about thirty machines need to be made.

 

Several car companies are developing hydrogen powered cars, based on hydrogen fuel cell technology, the only by-product being steam or water.Although it is easy to extract hydrogen from water using existing technology, the process requires a lot of electricity. So while the aim is to use renewable energy sources, there is a transitional period when hydrogen production would mainly come from fossil fuels.

 

And then there is nuclear power, described as the most environmentally benign way of producing electricity on a large scale and providing 17% of world electricity. Thirty-one countries use nuclear energy to generate up to three-quarters of their electricity and many depend on it for a quarter to half of their supply. 

 

Groups opposed say it can never be clean, as it involves waste products and may release radiation into the environment.   Those for it, say nuclear wastes are contained and managed, rather than creating an environmental problem. 

 

Independent scientist, author, researcher and British environmentalist, Dr James Ephraim Lovelock, says, “Nuclear energy is one of the most viable solutions to the global warming energy crisis. It is the most ‘eco-efficient’ of all energy sources because it produces the most electricity in relation to its minimal environmental impact. There are no significant adverse effects to water, land, habitat species and air resources”.

 

Thorium in particular is described as a green response to future power requirements. The naturally occurring, slightly radioactive metal is considered an alternative to uranium. Energy contained in one kilogram equals that of four thousand tons of coal. Global reserves of thorium (India, Australia, Norway and the U.S. especially) could cover the world’s energy needs for thousands of years.

 

Thorium Power Ltd’s, CEO Seth Grae, explains, "We are making strides in bringing thorium-based fuel designs to the forefront as a viable solution to nuclear proliferation concerns and environmental issues around the world. Thorium Power's proprietary technology is proliferation resistant - fuel designs do not produce weapons-usable materials in spent fuel and significantly reduce nuclear waste, yielding approximately fifty percent reduction by volume, seventy percent reduction by weight, and ninety percent reduction in long-term radio-toxicity."

 

Bryan Leyland, energy consultant of Auckland and chair of the economic panel of The New Zealand Climate Science Coalition agrees, “Modern nuclear power stations do not produce anything that can be easily used to make nuclear weapons. If nuclear power generation changes from uranium to thorium, the problem is eliminated entirely”.

 

Nuclear aside, for the foreseeable future, Stephen Hallett, Director, Alternative Power Solutions, supplying wind, solar and hydro power solutions, says our best options would be distributed generation, making the most of locally available renewable energy resources and becoming more energy efficient.

 

Hallett says, “There is a wide range of products currently on the market designed for both stand alone or grid interactive applications, from solar panels and   invertors to batteries and charge controllers, more suited to one application or the other”. 

 

Looking to the greater future, Dr. Jim Watson, fellow of The Royal Society of New Zealand, concludes that in NZ, it is unlikely nuclear power will become a source of electricity but nuclear energy has the ability to produce power without carbon emissions. Watson says the use of coal, development of biomass-based fuels and biomaterial, harnessing CO and CO2 from gaseous emission, photosynthetic energy and the hydrogen field, appear of paramount interest to NZ’s immediate and long term energy security and economy. “What is clear is that there are many opportunities to apply innovative science and technology to underpin our future”.

 

© 2007 L Donald

Images & Words
contact Linda