Module 4

Harvesting the wind

Traditional fuels are running out in many parts of the world. For example, the size of the desert regions is increasing in areas such as the Sahara Desert. There is less vegetation for fuel. In other parts of the world, fossil fuels (oil, gas, coal) are the mainstay of modern societies. They too are being rapidly depleted. Burning of plants, oil, gas and coal creates carbon dioxide and other greenhouse gases. This also contributes to pollution and to global warming (Oram, 2013). 

As a consequence countries and people are looking for sustainable low cost resources. Some countries such as New Zealand have abundant natural resources in the form of water and geothermal energy. However, building large scale industrial power generation plants is expensive, requires much resources (e.g. steel, concrete) and energy intensive activity to build. Such systems are often controversial. For instance damming natural waterways disrupts aquatic life and the life of other animals such as migratory birds that rely on the natural environment for a habitat and breeding and / or feeding area. It also prevents the use of recreational activities such as kayaking, bush walking and white water rafting (Martin, 2012).

 Although the space taken up by geothermal plants is typically smaller, they too have environmental consequences. For instance, geothermal fields produce large amounts of poisonous metals, such as Arsenic. They also deplete the ground water and are often are at the expense of the spectacular display of natural phenomena such as geysers (Stewart, 2012). Tidal plants may be either on the surface (disrupting the flow of ships and recreational vessels or submarine but the latter still affects marine animals as well (EECA, 2008; Ministry of the Environment, n.d).

As mentioned above, many places do not have such natural resources. Many do not have geothermal reserves nor abundant fresh water with the necessary change in water levels due to the mountainous and hilly terrain and may be landlocked with no tidal flow. Solar (EECA, n.d.) and wind (EECA, 2010) energy represent potential technologies in such regions.

 Both technologies too have limitations. The sun does not always shine and the wind does not always blow. So batteries are usually required to store surplus generation for dark/cloudy periods or still days. I am going to concentrate on wind energy in this report (Ministry of the Environment, n.d.). 5% of New Zealand’s current energy needs are generated from wind energy with the potential for further development. On still days when the wind does not blow enough to generate electricity in wind plants New Zealand has enough stored hydro power in dams to quickly generate additional power needed (EECA, 2010).

 There are concerns though with the environmental impact of wind generation. These impacts include visual and noise pollution (Standards New Zealand 2010).

There are wind plants in places close to human habitation such as Wellington. The picture shows one such large scale wind farm above the Makara Coast in Wellington. This location is very windy and is exposed to salt spray from the Tasman Sea (New Zealand Wind Energy Association, n.d).

Source: West Wind Makara Wind Farm

Other large wind farms may be located from some distance from their customers. For instance Meridiam Energy’s Te Ari wind farm in the Waikato has 28 large wind turbines (pictured below being transported to the location) generates up to 64.4 MW, sufficient energy to power 28,000 homes (Meridian, n.d.).

Source: Te Uku Media Gallery

The value of wind energy can be seen in the world’s most southerly wind farm. The use of wind turbines at Scott Station has reduced the need for oil fueled generators and the possibility of diesel spills in a fragile environment (One News, 2010).

Antarctic wind farm. Source: - ONE News

Video: Antarctic wind farm blows into life at Scott Base

Small power wind plants also have the potential to generate power for small communities (<20kW) and individual dwellings  (5kW). Small wind turbines are most suited to rural settings exposed to strong and consistent wind, and where there is no connection to the electricity network. The cost of such turbines is typically between $10,000 and $15,000 per kW of rated capacity but it may be economical to install them as connecting to the grid can cost as much as $25,000 per kilometre (EECA, 2010). Most such turbines are usually mounted on towers but there are alternatives that are integrated into the roof of the building (EECA, 2010).

Such small scale wind generators have been used in New Zealand for many years. They have to be tested to operate and to be maintained in New Zealand’s harsh windy, often salty environment (Independent Power, n.d).

 Source: Independent Power

Windmills have been used for many centuries for tasks such as drawing water out of the ground and milling flour. 21^st Century technology has improved the designs to allow modern wind turbine generators to operate in many conditions, including windy and marine environments. There is a large range of options to which they may be put. These include wind farms owned and operated by energy companies such as Meridian Energy. They can be used as sustainable alternatives to fossil fuel and can be alternative sources of power generation to their main hydro electric stations. Wind turbines can also be used in remote locations where they provide an economically feasible alternative to building expensive power lines to small communities and individual dwellings. Such installations typically need battery storage to store generated power that is in excess of current needs. The batteries can then be used when there is no wind or the wind speed is too low to allow the turbines to operated to generate electricity. In places connected to the grid grid-connected wind power generators can be used to power homes and businesses and to feed surplus power back into the grid.

 References

EECA (2008) Development of Marine Energy in New Zealand. Retrieved on 15 October 20, 2013 from http://www.eeca.govt.nz/node/6123.

EECA (2010) Wind Energy. Retrieved on 15 October 20, 2013 from http://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/wind-energy-in-nz

EECA (n.d.) Solar Energy. Retrieved on 15 October 20, 2013 from http://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/solar-energy-in-nz

(Independent Power, n.d). Wind Turbines. Retrieved on 19 October 20, 2013 http://www.indepower.co.nz/wind.html

Martin, J (2012). Hydroelectricity - Hydro, 21st century. Te Ara - the Encyclopedia of New Zealand, Retrieved on 15 October 20, 2013 from http://www.TeAra.govt.nz/en/hydroelectricity

Meridian (n.d.) Te Uku Retrieved on 19 October 2013 from http://www.meridianenergy.co.nz/about-us/generating-energy/wind/te-uku/

(Ministry of the Environment, n.d.). Case study 3: Issues and barriers in the development of a wave and tidal energy industry. Retrieved on 15 October 20, 2013 from http://www.mfe.govt.nz/publications/oceans/government-interventions-ocean-resources-may06/html/page7.html

New Zealand Wind Energy Association (n.d) West Wind Makara Wind Farm. Retrieved on 19 October 20 http://windenergy.org.nz/nz-wind-farms/operating-wind-farms/project-west-wind

One News (2010) Antarctic wind farm blows into life at Scott Base (January 16 2010). Retrieved on 19 October 20 from http://tvnz.co.nz/national-news/antarctic-wind-farm-blows-into-life-scott-base-3330985

 

Oram, R. (2013). Digging deeper on coal. Sunday Star Times, D24, October 20 2013.

Standards New Zealand (2010) NZS 6808:2010 Acoustics - Wind farm noise. Retrieved on 19 October 20, 2013 from http://shop.standards.co.nz/catalog/6808%3A2010%28NZS%29/view

Stewart, C (2009 ) Geothermal Energy. Te Ara - the Dictionary of New Zealand. Retrieved on 15 October 20, 2013 from http://www.teara.govt.nz/en/geothermal-energy