Chest freezers don’t actually use a lot of electricity. They’re a big insulated box that’s closed most of the time, and since they open from the top rather than the front, the temperature doesn’t change much when opened (since hot air rises, while cold air stays lower). The compressor doesn’t have to run for very long to maintain the temperature.
In the USA, Energy Star estimates 215kWh per year for Energy Star certified chest freezers (open from the top) and 395kWh per year for certified upright freezers (open from the front): www.energystar.gov/products/freezers