F2004	F2005	F2006	F2007	F2008	F2009
ASAI (percentage)
Target*	99.970	99.970	99.970	99.970	99.970	NR**
Actual, including major events	99.949	99.955	99.957	99.870	99.935
Normalized, excluding major events	99.960	99.966	99.969	99.967	99.961
CAIDI (hours)
Target*	2.15	2.15	2.15	2.15	2.15	2.15
Actual, including major events	2.77	2.69	2.10	4.09	3
Normalized, excluding major events	2.41	2.27	1.82	2.16	2.26
CEMI-4 (percentage)
Target*	N/A	N/A	N/A	11	10	9
Actual, including major events	N/A	N/A	N/A	20	17.8
Normalized, excluding major events	N/A	N/A	14	7.3	8.6
CELID-6 (percentage)
Target*	N/A	N/A	N/A	17	16	NR**
Actual, including major events	N/A	N/A	N/A	40	24.2
Normalized, excluding major events	N/A	N/A	17	13.5	15

* Targets based on normalized data, excluding major events.
** ASAI and CELID-6 metrics will no longer be reported, effective fiscal 2009. Therefore, fiscal 2009 targets have not been provided.

Reliability is defined as a combination of Average System Availability Index (ASAI) and Customer Average Interruption Duration Index (CAIDI). These indices are electric utility industry standards. Customers Experiencing Multiple Interrupts (CEMI) and Customers Experiencing Longest Interruption Duration (CELID) are new customer reliability measure to further support the reliability issue.

• ASAI refers to the percentage of time power is available.
• CAIDI refers to the average interruption hours per interrupted customer.
• CEMI-4 (customers experiencing multiple interruptions) refers to the percentage of customers experiencing four or more outage interruptions per year, excluding major events.
• CELID-6 (customers experiencing longest interruption duration) refers to the percentage of customers experiencing longest interruption duration of six or more hours, excluding major events.

ASAI and CAIDI actual results, including major events, were better than Plan based on the five-year (fiscal 2003-07) average due to the absence of sustained storm activities that buffeted the distribution system a year earlier. In fiscal 2008, two weather events, namely the windstorm in the Lower Mainland, Vancouver Island and South Interior in mid-November and the snow and windstorm in the Fraser Valley and Vancouver Island in early December, caused significant power interruptions in these areas resulting in three million lost customer hours. However, excluding major events, ASAI and CAIDI normalized were worse than their respective annual targets due to longer outage durations. Normalized customer hours lost in fiscal 2008 were 17 per cent higher than prior years, with adverse weather and motor vehicle accidents being the leading causes of the increased hours lost.

CEMI-4 and CELID-6 are customer-focused reliability measures implemented in fiscal 2007 to provide an intuitive understanding of BC Hydro's reliability performance from the customer's perspective. Fiscal 2008 year-end CEMI-4 and CELID-6 were better than targets due to targeted maintenance spending on our aging distribution infrastructure, continued focus on improving performance of feeders that are below customer expectations and initiatives to streamline the trouble call response process. At year-end, CEMI-4 is 8.6 per cent which translates into 151,000 customers having experienced four or more outages in fiscal 2008. CELID-6 is 15 per cent, which means that 266,000 customers have had an outage lasting six or more hours in fiscal 2008. Including major events, CEMI-4 is 17.8 per cent or 315,000 customers have experienced four or more outages and CELID-6 is 24.2 per cent or 427,000 customers have had outages of six hours or longer durations.

BC Hydro was in the fourth quartile of Canadian and U.S. utilities for ASAI and CAIDI in fiscal 2007 due to the unprecedented impact of winter wind and snow storms on the distribution system. Data for ASAI and CAIDI benchmark comparison in fiscal 2008 is not yet available as the study is just under way. Benchmark comparison for CEMI-4 and CELID-6 is not available as these measures are not yet widely used in the utility industry.