Is it proper to use there is a lot or there are a lot?

computer tv light oven rice cooker etc..... Actually, everything uses electricity, from our bodies and their nervous system, all the way to every (covalent) chemical reaction in the universe, because...

"Wow, there was a lot of children at that picnic..."

Yes.

it depends on the type of business. but now a days every thing is becoming computerised and everyone started to use computers.

Depends on the specific company and if it is a service or supply based company. Generally speaking, a company will use more energy then domestic premises.