The next step that Phil Nail, IT manager at ISP AISO.net, intends to take to improve the energy efficiency of his datacentre is to put a layer of dirt on the roof.
It’s called a “green roof” and it involves putting 8-10cm of dirt on the roof and planting bush-type, drought-resistant plants. It will cost AISO.net about US$30,000 (NZ$43,000) to cover 2,000 square feet over a datacentre that houses about 300 servers. But Nail believes his green roof may cut datacentre cooling needs by half.
For those who need convincing of the effectiveness of dirt to cool datacentre servers, Nail’s advice is to stick their hands in some. “It’s cool down there,” he says.
Nail is ahead of most in adopting green technologies. His firm already uses solar panels that generate 12 kilowatts of electricity, enough to power his servers and lighting. But California wants to see many more companies add solar power to the mix and began offering this month a US$2.50-per-watt tax rebate for systems of up to 1 megawatt in size. Its California initiative has budgeted US$2.9 billion for incentives over ten years.Globally, solar energy use is an approximately US$15 billion industry. But research firm IDC estimates that US spending accounts for only about 10% of the global market.
“For most companies to invest in what is perceived as novel energy technologies is a tough sell,” says Nicholas Lenssen, an IDC analyst. “Most companies want a two- to three-year payback. But, by and large, there isn’t a whole lot of interest in onsite generation.”
The costs are often high, making incentives critical. For instance, a solar-power-based 500-kilowatt system would cost about US$3.5 million, based on an estimated cost of about US$7 per watt to buy and install it. California’s credits can cut that cost by about US$1.5 million, and US Federal Government tax credits would reduce it by another US$1 million or so, according to Rhone Resch, president of the Solar Energy Industries Association, a Washington, DC-based industry group.
Resch estimates that the bottom-line cost of system would be about US$1.3 million.
Any return on investment depends on how much a user is paying for electricity, although Resch says a six- to eight-year payback for a large user would not be unusual. And since a business would likely finance the project, it could generate a positive cash flow from the investment immediately, he says.
Another green approach was taken by Alan Hirsh, executive vice president of Sea Gull Lighting. Last year, he completed a 500-kilowatt system that provides 20% of the power needs for a 500,000-square-foot warehouse five days a week. On weekends, the panels can provide all the power needed. The solar panels take up about 60,000 square feet on his warehouse roof.
Hirsh’s company is using SunEdison, a solar services company that installs the system and continues to own it. Sea Gull, however, pays a rate for the electricity it uses that’s below what it would pay if it bought from a local power provider, he says.
As long as the price of electricity doesn’t go down, Hirsh says, the agreement with SunEdison makes sense. “I don’t know of anybody who thinks electricity is going to be cheaper,” he says.