Discussion and Notes on Statistical Summary

1. Represents the number of facilities that were audited during the year. In past reports, we reported the number of audits conducted in the year. Several of our facilities in similar regions have one integrated EH&S management system due to their jurisdiction. As such, these facilities are audited simultaneously. The figures do not include audits that were conducted but were outside of the scope of this statistical summary.
   
   The Mexican facilities were audited against ISO 14001 standards while under construction in 2002 and 2003, as required by the company's agreement with the Federal de Electricidad (CFE). During construction, internal management system audits were conducted but these audits are not reflected in these statistics as these facilities were not operational. Campeche was commissioned in May 2003 and Chihuahua was commissioned in September 2003.
2. Net generation and emissions statistics for 2001 from TransAlta's Canadian coal plants differ from the 2001 Sustainable Development Report and have been restated to reflect updated data.
   
   Net generation and emissions statistics for 2003 from TransAlta’s Mexican gas plants have been updated from the 2003 Report on Sustainability due to a calculation error resulting in double counting.
   
   Nitrogen oxide emissions are expressed in tonnes of nitrogen dioxide (NO₂).
   
   We have revised the 2003 total particulate matter estimates from the 2003 Report on Sustainability to reflect improved data.
   
   In 2004, the methodology used to estimate mercury emissions was reviewed and revised. As a result historic emissions have been updated.
3. In keeping with the reporting format recommended by the GHG Protocol, we have reported the impact of each GHG separately. GHGs have been converted into tonnes of carbon dioxide equivalent (CO₂E), using global warming potential factors developed by the Intergovernmental Panel on Climate Change. We have also revised historical corporate emission intensities and emission totals.
   
   We have revised historical corporate emission intensities and emission totals as better emission factors have been applied to some sources. This improvement is the reason for discrepancies between the data in this report and previously reported data.
4. We have calculated methane emissions from coal mining, using the methodology described in the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2001. All historical values have been recalculated. It has been assumed that the methodology used to calculate methane emissions from coal mines and coal combustion is discrete.
5. The corporate net emission rate is a result of TransAlta's emission reduction initiatives in Canada and purchased offsets from international projects. The U.S. net emission rate is only a result of reductions from the Centralia plant's fly ash sales. Gas-fired generation at Binghamton and Pierce Power do not have a lower emission rate than the grid average and, therefore, TransAlta claims no offsets from the operation of those facilities as they did not displace more CO₂E-intensive power from the grid.
   
   As there is no recognized Australian methodology for calculating potential offsets from independent power plants and due to the isolated location of TransAlta's Australian plants, we claim no offsets from the operation of these facilities.
   
   With the implementation of mandatory GHG reporting in Canada and an anticipated Canadian climate change regulatory regime, as of 2003 TransAlta will no longer report offsets, credits, net GHG emissions or net GHG emission intensities. The concept of net emissions (direct emissions reduced by offsets and credits) has been subjective, and, while satisfactory in a voluntary reporting world, can be confusing in a regulatory one. Therefore, we will report our GHG gross emissions consistent with the requirements of federal and provincial reporting policies. We will continue to undertake emission reduction actions through such things as international and domestic offset purchases and internal projects that have GHG benefits. In a compliance regime, these will ultimately take the form of compliance instruments or credits used to meet reduction obligations and are, therefore, treated as proprietary information.
6. Decreased land use by plants, offices and equipment in 2002 was the result of the sale of the former transmission business unit in April 2002. 2003 does not include Sarnia, Campeche and Chihuahua land use.
7. Increased non-hazardous waste disposal in 2001 and 2002 reflected improved tracking and reporting of wastes. The 2001 U.S. non-hazardous waste totals have been restated to reflect improved tracking and reporting of waste at the Centralia mine.
8. Increased hazardous waste disposal in 2001 was the result of the removal of 1,162 tonnes of contaminated soil from a former transmission yard.
9. Due to the tracking process at our head office in Calgary, Alberta, the quantity of paper recycled by TransAlta cannot be determined separately from other building tenants. This results in a quantity of recycled paper that is greater than that used.
10. In recent years, we have made changes in reporting methodologies to enhance reporting of TransAlta's impact on surrounding watersheds. In 2000, for example, mine water drainage was included in total water released. In 2001, the methodology to calculate water usage at the Wabamun plant was revised. In the 2002 report, we reviewed water statistics to ensure that consistent methodologies have been used and, based on our review, have restated statistics for historic water intake, release, consumption and intensity. In any year TransAlta's water use largely reflects the operation of our Wabamun plant at Wabamun, Alberta. In 2001, the decrease in water consumption and water consumption intensity was mainly because of limited plant operation. In 2002, the increase in water use reflected near-capacity power production at the plant.
11. This is the total water consumed by TransAlta's operations as measured by total water removed from the environment and total water returned to the environment. As such, the consumption intensity tends to be overstated as these figures do not account for evaporation losses from our cooling ponds, which is also water returned to the environment.
12. These are incidents that may impact the environment, but are out of the scope of air, land and water contraventions that require reporting to an external regulatory agency. Examples could include equipment failures and permit non-compliance.
13. These are contraventions reported to an external regulatory agency and resulting in a fine, penalty or corrective action.
14. This is cash flow from operating activities only and does not include cash flow from investing or financing activities.
15. This is one of three stock-based compensation programs offered to TransAlta employees. The company grants stock options to employees based on the market price of the shares as determined on the date of the grant.
16. This includes TransAlta's registered pension plan with defined benefits and defined contribution options and a supplemental defined benefits plan. All employees have a future benefits plan, although the defined benefit of the pension plan ceased for new employees on June 30, 1998.
17. This includes TransAlta's purchase of Vision Quest Windelectric in 2002. Investment in distributed generation companies is not included in 2002 totals as it has been in previous annual totals.
18. This includes capital expenditures for environmental protection, such as environmental monitoring, pollution abatement and administrative costs. The increase in capital expenditures in 2001 and 2002 is due to the installation of air emission control equipment at our Centralia plant and the construction of a water treatment facility at our Sundance plant.
19. This includes operating and maintenance expenditures for environmental protection, such as environmental monitoring, pollution abatement and administrative costs. The 2001 figures are not based on comprehensive accounting and do not include the costs associated with mine land reclamation, waste management and administrative costs. The 2002 and 2003 figures account for these expenditures. The increase in operating and maintenance expenditures in 2003 is a result of better accounting of these expenses at our plants and mines and an increase in mine reclamation work.
20. These are health and safety incidents resulting in a regulatory enforcement action. Enforcement actions could take the form of a warning letter, fine or non-financial reprimand or restriction on operations. This definition differs from previous TransAlta sustainable development reports. We have adjusted historic data to account for this change in methodology.
21. All TransAlta employees on December 31. Each non-full-time employee (part-time, contract or hourly) is the calculated equivalent of 0.70 full-time.
22. In 2002, TransAlta's corporate EH&S department was reorganized. Staffing resources were reallocated and relocated as part of a corporate-wide initiative to promote consistent practices.
23. The recordable injury frequency rate (IFR) measures work-related medical aid and lost-time injuries per 200,000 hours worked. During the course of the year, all work-related safety incidents are investigated. These investigations sometimes provide new information that results in an incident being reclassified. In this report, we have restated our 2002 injury frequency rate from that reported in our 2002 Fourth Quarter Sustainable Development Report due to a change in an incident classification.
24. The disabling injury frequency rate is based on the number of injuries requiring absence from work or lost-time incidents only.
25. The data presented for 2000 to 2003 does not include injuries from our Centralia plant and mine.
26. This reflects the number of days lost due to absenteeism from work, up to six months in duration. Absence may be due to work-related incidents or injuries incurred outside of work. In 2000, the number of days lost to short-term disability was not tracked at the Centralia mine and, therefore, is not included in aggregated totals. In 2001 and 2003, the number of days lost at the Centralia mine due to short-term disability was tracked and included in the indicator and is one reason for the resulting rate increase. In 2002, the number of days lost to short-term disability was not tracked at the Centralia plant and mine. This is one reason for the resulting rate decrease.
27. This reflects the number of employees absent from work for more than six months. Absence may be due to work-related incidents or injuries incurred outside of work.
28. In 2003, one vehicle accident resulted in a medical aid injury to an employee. All other accidents resulted in minor equipment or property damage.
29. Community investments include all community donations and community sponsorships and are aggregated based on budget allocation, not location of recipient.
30. This includes volunteer activities organized by TransAlta such as volunteering during work hours as part of United Way campaigns. This does not include volunteer activities that employees engage in outside of their employment at TransAlta.
31. In 2004, the classification of environmental incidents was reviewed and revised. The stack environmental contravention was eliminated and an administrative category was added. The stack incidents from 2003 and 2004 have been classified according to these new categories for comparison purposes between the two years.