A 1000J or 1kJ of energy in 1 second implies that in 1 minute there will be 60kJ of energy converted.
Work is the defined as energy consumed thought time.
[tex]W=\dfrac{E}{t}[/tex]
In our case,
[tex]W=\dfrac{60\mathrm{kJ}}{60\mathrm{s}}=1\cdot10^3\dfrac{\mathrm{J}}{\mathrm{s}}=\boxed{10^3\mathrm{W}}
[/tex]
Hope this helps!
