PV Gap

Sam Said:

Does solar energy provide enough output to generate sustainable energy in a cost efficient manner?

We Answered:

20 year old PV cells output almost 90% of the energy they did when new, we don't know how long they will last, they are usually replaced for more efficient models. According to one dealer most new panels come with 20 to 25 year warantees. New technology is now becoming available to make PV panels more affordable, under $1 a watt, www.avasolar.com for example.

For those of you that want to make the argument that we don't have enough space available to put that many solar panels, Just look at the roofs of all the industrial buildings, homes and churches in the US and tell me that. Most new panels can produce 10 to 13 watts per square foot. A small warehouse may have 100,000 square feet. thats 1000 kw. Granted thats max output but you can usually rely on 40% of that (400kw). Now multiply that by the thousands and thousands of building this size in the US.

So the answer to your question is yes! just keep in mind this is a longer term investment than most companies are willing do. Unfortunatly without government involvement I doubt we will see any major changes soon.

Darryl Said:

How much would it cost to build a solar energy unit for our business 40,000 kwh p/ month?

We Answered:

A lot depends on where the business is located. But let me assume that this is in my area of California, where the average peak sun is 5 hours / day.

5 x 360 = 1800 hours / year.

Your energy requirement is

40,000 x 12 = 480,000 kWh / year

480,000 / 1800 = 260 kW array

That's a good size project, so bids may be agressive. With the federal rebate, you might be a $4 / watt price in the near future, making the price tag about $1 million net.

Knock off the final digit to approximate the square feet required for the array - 26,000 square feet, a little more than half an acre. If it won't fit on the roof, maybe it would fit on a parking structure.

This exceeds the size of any commercial array I'm aware of, except those of Google, Cypress, and Hewlett-Packard.