Tool to measure energy new refrigerator initially consumes (7)
'tool' is the definition.
(spanner is a kind of tool)
'measure energy new refrigerator initially consumes' is the wordplay.
'measure' becomes 'span' (span is a kind of measure).
'energy' becomes 'e' (physics symbol as in E=mcp).
'initially' indicates taking the first letters.
'consumes' indicates putting letters inside.
The initial letters of 'new refrigerator' is 'nr'.
'e' going inside 'nr' is 'ner'.
'to' is the link.
(Other definitions for spanner that I've seen before include "Tool, often adjustable", "Wrench for nuts", "Nut tightener", "Tool for tightening or loosening", "Nut-tightening tool".)