1 3-1-1 for carry-ons = 3.4 ounce (100ml) bottle or less (by volume) ; 1 quart-sized, clear, plastic, zip-top bag; 1 bag per passenger placed in screening bin. 2  One-quart bag per person limits the total liquid volume each traveler can bring. 3.4 ounce (100ml) container size is a security measure. 3  Be prepared.
Variable costs. A solar power plant is one of the cheapest to operate because there are no fuel costs involved. A solar PV (photovoltaic) power plant requires fixed expenses of $11.40 per megawatt hour, or just 1.14 cents per unit. Whatâs more, it doesnât require any variable expenses.
Installing solar panels on one home costs about $20,000 to$50,000. Many states now offer discounts to families who want to install solar panels, so the actual cost is not that high. The average cost of electricity from coal-burning power plants is around 10 cents per kilowatt hour. A kilowatt hour is the amount of energy used if you leave a 100 watt light bulb turned on for 10 hours. The cost of electricity from a solar power plant is about 30 cents per kilowatt hour.