supply and demand of electricity in nz

8/7/2019 Supply and Demand of Electricity in NZ

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Supply and Demand ofElectricity in New Zealand

ENGR101 Assignment 1

Akshay Kumar

University of Canterbury

31 March 2011


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1 Summary

The major energy providers are described in detail to provide us with an understanding of

their electricity contribution to the national grid. Utilisation of renewable energy is compared

to our use of non-renewable sources of energy. This is to understand how much each

contributes to New Zealand's total supply. Also the demand of electricity is evaluated to

provide us with an idea of the future developments ahead including the Kyoto Protocol.

2 Introduction

In New Zealand there are five major energy companies who produce electricity. These

include Meridian, Contact Energy, Genesis Energy, Mighty River Power and Trustpower.

Meridian Energy provides approximately 30% of New Zealand's entire electricity generation

making it the largest electricity generator in New Zealand. To produce electricity they

predominately use renewable sources of energy including hydro energy and wind energy

(Meridian, 2010). Contact Energy has power stations which provide around 25% of New

Zealand's electricity. They produce electricity by using a broad number of sources including

renewable sources that are geothermal energy, wind energy, hydro electricity and non-

renewable sources with gas-fired peaking power stations (Contact Energy, 2010). Genesis

Energy supplies 19% of New Zealand's electricity by the use of thermal energy and renewableenergy (Genesis Energy, 2010). Mighty River Power provides up to 16% of New Zealand's

electricity during peak times. This electricity is generated by thermal sources and hydro

sources (Mighty River Power, n.d). Trustpower is a smaller company providing electricity

through 36 medium to large hydro generating centres and a large wind farm (Trust Power,

2008). This report considers New Zealand's main energy providers, different sources of

renewable energy and future developments for sustainability and meeting international

commitments.

3 Technical Information

Renewable energy formed around 35% of Total Primary Supply in 2009 (Figure 2). The main

sources of renewable energy are geothermal, hydro, bioenergy, solar and wind. As shown in

Figure 1 geothermal energy provided the largest amount of total renewable energy at 45% in

2009. Geothermal energy comes from the heat from the centre of the earth so is a clean and

efficient energy. This heat is sourced from volcanic activity so is predominant in the Taupo

Volcanic Zone where many geothermal plants are. One example is the Wairaki-Tauhara


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system which was built in 1958 and is north of Taupo (Energy Efficiency and Conservation

Authority, 2011b). Hydro energy is produced through hydro dams and provided around 32%

of New Zealand's total renewable energy in 2009. Many of these large dams are in Benmore,

Manapouri, and Clyde where large masses of water are available to build a dam (Energy

Efficiency and Conservation Authority, 2011c). Bioenergy and solar energy jointly provided

21% of our renewable energy in 2009. Bioenergy is conserved in biological materials such as

wood, wood waste and manure (Energy Efficiency and Conservation Authority, 2011a).

Figure 1. Renewable Primary Energy Supply (data from Ministry of Economic

Development, 2009a)

Non-renewable energy is sourced from fossil fuels which include oil, gas and coal and are

unsustainable. In 2009 non-renewable energy formed around 65% of Total Primary Energy

supply (Figure 2). An example of a thermal electricity generator is Genesis's combined cycle

gas turbine at its Huntly facility which burns natural gas to provide enough electricity for

around 400,000 homes (Power Technology, 2011).

4 Future Developments

To remain effective in supplying electricity New Zealand must address a number of key

issues. One issue is the sustainability of the renewable energy sources used by key sectors

such as the industry. The second is an international issue relating to New Zealand meeting the

commitments of the Kyoto Protocol while covering increased demand.

4.1 Total direct use for renewable energy sources


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Table 1 below shows the total direct use for renewable energy sources. Woody biomass is

used to the greatest extent by the industry at 42.85 PJ. Woody biomass includes limbs, tops,

leaves and other wood parts of trees and woody plants (US Forest Service, 2008). Therefore

they are a sustainable renewable source of energy if the rate of trees being cut down is

balanced by trees being planted to replace them. In analysing the table it appears that in the

future the industry will need to reduce the total direct use of woody biomass and increase their

utilisation of geothermal energy. Geothermal energy is from the heat of the earth and does not

require constant replacement such as planting trees.

Table 1. Renewable Energy direct use by Sector for 2009 (data from Ministry of

Economic Development,2011c)

PJ Geothermal Solar Biogas Woodybiomass TotalDirect Use

Agriculture, Forestryand Fishing

0.73 - - - 0.73

Industrial 6.31 - - 42.85 49.16Commercial 2.52 - 0.28 - 2.80Residential 0.28 0.34 - 7.64 8.26

4.2 Demand of Electricity and the Kyoto Protocol

Demand of electricity is increasing at a rate of 1.5-2 % each year (Transpower, n.d). This

extra demand will need to be remedied by New Zealand's energy output increasing each year

in order to cope with the added stress. The Total Primary Energy Supply for New Zealand is

shown to be broadly divided up into renewable and non-renewable sources in Figure 2 using

data from Ministry of Economic Department (2010). Figure 2 shows how the ratio of

renewable to non-renewable energy has remained fairly constant over the past decades. As

demand has increased renewable and non-renewable sources of energy have increased their

output at a fairly constant rate. To meet the Kyoto protocol demands, New Zealand must

reduce its greenhouse gas emissions on average to 1990 levels (Ministry for the Environment,

2010). This means that New Zealand needs to invest to a greater extent in renewable sources

of energy to meet that agreement and concurrently meet demand.

Figure 2. Total Primary Energy Supply by Renewable and Non-renewable sources (data

from Ministry of Economic Development, 2010b)

5 Conclusions


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To keep up with the increasing demand for electricity New Zealand will need to increase

output of electricity from its renewable and non-renewable sources. It will need to concentrate

on increasing renewable sources of energy to a greater extent in order meet the requirements

of the Kyoto Protocol. The industry will have to invest in using other renewable sources of

energy such as geothermal energy which are easier to replenish than woody biomass.

6 References

Contact Energy. (2011). Our Company. Retrieved from

http://www.contactenergy.co.nz/web/shared/ourcompany?vert=au

Energy Efficiency and Conservation Authority. (2011a). Bioenergy. Retrieved from

http://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/bioenergy

Energy Efficiency and Conservation Authority. (2011b). Geothermal Energy. Retrieved from

http://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/geothermal-

energy

Energy Efficiency and Conservation Authority. (2011c). Hydro Energy. Retrieved from

http://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/hydro-energy

Genesis Energy. (2010). About Genesis Energy. Retrieved from

http://www.genesisenergy.co.nz/genesis/about-us/company-

information/about_genesis_energy_home.cfm

Meridian. (2010). 2010 Meridian Energy Annual Report. Retrieved from

http://www.meridianenergy.co.nz/AboutUs/Company+Reports+and+Presentations/Presentati

ons/2010AnnualResultsInformation/

Mighty River Power. (n.d). Power Stations. Retrieved from

http://www.mightyriver.co.nz/Generation/PowerStations/

Ministry for the Environment. (2010). The Kyoto Protocol. Retrieved from

http://www.mfe.govt.nz/issues/climate/international/kyoto-protocol.html

Ministry of Economic Development. (2009a). Renewables. Retrieved from

http://www.med.govt.nz/templates/ContentTopicSummary____21274.aspx
http://www.contactenergy.co.nz/web/shared/ourcompany?vert=auhttp://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/bioenergyhttp://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/geothermal-energyhttp://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/geothermal-energyhttp://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/hydro-energyhttp://www.genesisenergy.co.nz/genesis/about-us/company-information/about_genesis_energy_home.cfmhttp://www.genesisenergy.co.nz/genesis/about-us/company-information/about_genesis_energy_home.cfmhttp://www.meridianenergy.co.nz/AboutUs/Company+Reports+and+Presentations/Presentations/2010AnnualResultsInformation/http://www.meridianenergy.co.nz/AboutUs/Company+Reports+and+Presentations/Presentations/2010AnnualResultsInformation/http://www.meridianenergy.co.nz/AboutUs/Company+Reports+and+Presentations/Presentations/2010AnnualResultsInformation/http://www.mightyriver.co.nz/Generation/PowerStations/http://www.mfe.govt.nz/issues/climate/international/kyoto-protocol.htmlhttp://www.med.govt.nz/templates/ContentTopicSummary____21274.aspxhttp://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/bioenergyhttp://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/geothermal-energyhttp://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/geothermal-energyhttp://www.eeca.govt.nz/efficient-and-renewable-energy/renewable-energy/hydro-energyhttp://www.genesisenergy.co.nz/genesis/about-us/company-information/about_genesis_energy_home.cfmhttp://www.genesisenergy.co.nz/genesis/about-us/company-information/about_genesis_energy_home.cfmhttp://www.meridianenergy.co.nz/AboutUs/Company+Reports+and+Presentations/Presentations/2010AnnualResultsInformation/http://www.meridianenergy.co.nz/AboutUs/Company+Reports+and+Presentations/Presentations/2010AnnualResultsInformation/http://www.mightyriver.co.nz/Generation/PowerStations/http://www.mfe.govt.nz/issues/climate/international/kyoto-protocol.htmlhttp://www.med.govt.nz/templates/ContentTopicSummary____21274.aspxhttp://www.contactenergy.co.nz/web/shared/ourcompany?vert=au


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Ministry of Economic Development. (2010b). New Zealand Energy data file 2010. Retrieved

from http://www.med.govt.nz/templates/StandardSummary____15169.aspx

Ministry of Economic Development. (2011c). Renewable Energy Direct Use by Sector.

Retrieved from http://www.med.govt.nz/templates/MultipageDocumentTOC____45617.aspx

Power Technology. (2011).E3P 385MW CCGT at Huntly Unit 5, New Zealand. Retrieved

from http://www.power-technology.com/projects/EP3/

Transpower. (n.d). Electricity Demand. Retrieved from

http://www.systemoperator.co.nz/demand-status#cs-1506506

Trust Power. (2008). Information Centre. Retrieved from

http://www.trustpower.co.nz/index.php?section=12

US Forest Service. (2008). Woody Biomass Utilisation. Retrieved from

http://www.fs.fed.us/woodybiomass/whatis.shtml

Word count excluding title page, references, graphs and tables: 950
http://www.med.govt.nz/templates/StandardSummary____15169.aspxhttp://www.med.govt.nz/templates/MultipageDocumentTOC____45617.aspxhttp://www.power-technology.com/projects/EP3/http://www.trustpower.co.nz/index.php?section=12http://www.fs.fed.us/woodybiomass/whatis.shtmlhttp://www.med.govt.nz/templates/StandardSummary____15169.aspxhttp://www.med.govt.nz/templates/MultipageDocumentTOC____45617.aspxhttp://www.power-technology.com/projects/EP3/http://www.trustpower.co.nz/index.php?section=12http://www.fs.fed.us/woodybiomass/whatis.shtml

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