This was asked previously: https://www.googlenestcommunity.com/t5/Nest-Protect/How-much-wattage-power-do-Nest-Protects-Gen2-con...
…but never answered. The "Community Specialist" posted five messages, none of which answered the question and most of which were asking if OP still needed an answer (hint; yes).
The spec sheet linked to does not show wattage. How many watts does the Nest Protect consume?
Answered! Go to the Recommended Answer.