Labour inputs needed for a particular project or activity may be expressed in terms of person-hours of work. Part-time positions and contract work arrangements are converted to FTE based on the inputs required, actual hours worked, or the duration of a work contract.
Ideally, labour inputs or job impacts are expressed in terms of full-time equivalent for comparability across different sectors of the economy. One FTE job is equal to one person working full time over the course of a year (specific definitions of how many hours per work week constitute full-time vary, depending on national legislation or local practice).
Not all jobs are full-time. FTE calculations are ultimately about hours worked rather than number of employees. For example, four employees each working a quarter of full-time are equivalent to 1 FTE job.
Conceptually, FTE is linked to formal employment with regulated hours of work per day and length of workweek. Jobs in the informal sector are typically not assumed to conform to full-time equivalency.
Another distinction concerns the duration of a given job. Along segments of the energy supply chain, jobs in construction and installation are typically considered to be of limited duration; i.e., once a wind or solar farm is fully constructed, the specific job ends (unless a worker’s contract stipulates employment for multiple projects). Jobs in operations and maintenance, by contrast, are effectively “permanent”, given the long lifetimes of most energy-generating facilities.