How much does it cost a warehouse to run 80 x 250 watt high pressure sodium lights?

Question

for 125 hours a week ?????

Answer 1

Simplest method is following:

80 * 250 = 20'000 watts per hour

20'000 * 125 = 2'500'000 watts per week or

2.5 Mwt per week

Reserve (starting and extra hours limit consumption) = +5%

2.5* 1.05 = 2.625 Mwt per week

Repairs/spare parts/service= X

Credit cost = i

Investments divided by weeks till full depreciation (cost of equipment/installation) = Y/t

Depreciation per week = D

Total cost = X + 2.625 * c + Y*i/t + D

c - cost of one MegaWatt from your local energy supplyer

Answer: Total cost = X + 2.625 * c + Y*i/t + D

More complex evaluation could include NPV tools and opportunity costs.

Answer 2

There's no such thing as a "watt per hour"! (A watt is a joule per second, the rate of consuming or producing energy.)

250 watts is a quarter of a kilowatt, so let's use kilowatts in our calculations.

80 x 0.25 = 20 kW. For 125 hours, this amounts to 20 x 125 = 2,500 kW h.

A kilowatt-hour (kW h)is commonly known as a "unit" of electricity. Suppose it costs 10p a unit (your price may vary!), then the cost of 2,500 kW h is 2,500 x 0.10 = £250.

So the running costs are about £250 a week. As the previous answer points out, there are additional costs to take into account. The lighting equipment's value will depreciate over time, and the capital invested in it could be earning interest elsewhere.

Are you thinking of setting up a cannabis farm?  ;-)