|Energy Efficiency and Greenhouse Gas Emissions
Hydro Tasmania’s target for the key performance indicator of reducing energy was 0 per cent for 2006/07. However, the result was a reduction of 10 per cent, possibly due to the lower volume of energy consumed by hydropower generating units.
Hydro Tasmania addresses energy efficiency and greenhouse gas emissions principally through participation in the Australian Government’s Greenhouse Challenge Plus program. Hydro Tasmania has been a member since 1997 and reports annually on the direct and indirect greenhouse gas emissions arising from business operations. Information can be found on the environmental publications page of our website.
Hydro Tasmania’s Energy and Greenhouse Program, in its second year of operation during 2006/07, aims to:
- facilitate improvement in energy efficiency and greenhouse gas (GHG) management across Hydro Tasmania
- implement projects for energy and GHG savings.
Some progress was made during the year, with the key achievements being:
- identifying a range of projects to meet annual interim targets for energy reductions for the vehicle fleet, diesel power stations, buildings and facilities
- raising awareness of the importance of energy efficiency and greenhouse gas management to staff and management through various initiatives such as a management level steering committee.
An initiative to reduce energy consumption in Hydro Tasmania offices from office equipment and lighting was the Switch Off! campaign, which was launched in November 2006. A six-month progress report showed that on average the switch off rate for computers increased from 33 per cent to 43 per cent. This is estimated to decrease annual consumption by 72,000 kWh, equivalent to a saving of $8,600. The campaign is continuing in 2007/08.
Greenhouse gas intensity
Hydro Tasmania’s key performance indicator under its Greenhouse Challenge Plus membership is GHG emissions intensity. This allows us to be compared with other electricity generators. The GHG intensity is measured in tonnes of carbon dioxide equivalent per GWh of energy generated (t CO2-e/GWh).
Our performance for 2006/07 was 68.6 t CO2-e/GWh (see Table 5). This has increased by 79 per cent from 38 t CO2-e/GWh in 2005/06, due to increased use of the Bell Bay power site during the 2006/07 period, and reduced hydro generation owing to the low water levels. It should be noted that Basslink imports are not included in emission intensity calculations.
Excluding Bell Bay, Hydro Tasmania’s emissionsintensity also increased from 1.8 t CO2-e/GWh to 2.4 t CO2-e/GWh.
Table 5 Summary of GHG Emissions and Emissions Intensity for key emitters 2006/07
* In the 2005/06 Annual Report the target for 2006/07 for this indicator was 1.7 (Hydro Tasmania excluding Bell Bay)
Table 6 shows the quantities of the various energy types consumed by Hydro Tasmania during 2006/07. Electricity consumption for power stations, buildings and other facilities was 109 GWh.
||Table 6 Energy Use
||Note: Natural gas consumption units in the 2005/06 Annual Report were incorrectly named as PJ instead of TJ. All figures were accurate
Natural gas consumption increased by 61.9 per cent compared to the previous year due to increased generation from the Bell Bay power site.
Vehicle fuel use increased over the year and can be attributed to the increase in the number of vehicles in the Hydro Tasmania fleet and total kilometres travelled.
Greenhouse gas emissions
Hydro Tasmania’s GHG emissions for 2006/07 were 641,693 tonnes CO2-e (Figure 4).
In keeping with the past four years, almost 97 per cent (621,961 t CO2-e) of these emissions were from the Bell Bay power site. Contributions of more than 10 per cent of the remaining three per cent of total emissions (19,868 t CO2-e) were from the diesel power stations on the Bass Strait islands, electricity used within the hydro power generation system and the vehicle fleet.
Although still small in total, emissions from sulphur hexafluoride (SF6) increased significantly in this reporting period due to two spills, one of 50kg and one of 3kg. These spills translated to 1380.4 t CO2-e, which is over
11 times the 2005/06 total of 123 t CO2-e. During the year an investigation into SF6 storage, tracking, recording and management was conducted and an implementation plan for better management put in place for the 2007/08 period.