Diesel: The Lifeblood of the Recovery Effort
October 31st, 2012 By: Jason Verge
Much of the Internet is currently running on diesel fuel and priority service contracts. Emergency backup generators powered by diesel are helping many East Coast data center providers weather Superstorm Sandy. The importance of diesel in the post-Sandy economy is hard to overstate. In the wake of Sandy, diesel is the lifeblood of lower Manhattan, where generators are currently providing virtually all the area’s electricity.
Data centers often tout their ability to operate for days, if not weeks, on diesel reserves stored on site in case of disaster. There are two potential problems that can arise when a data center relies on diesel generation to get it through a disaster. The first is running out of diesel fuel. While data centers are preferred customers and have contracts in place, there are others ahead in the line such as hospitals and water plants during disasters. There’s also the challenge of fuel contamination, which is closely tied to maintenance practices.
Issues and Complications
First, let’s start with a high-level primer on diesel generators. Data centers spend millions of dollar on their emergency power so they may continue to run during events like Sandy. Should power go out, first a UPS kicks in while the powerhouse of emergency power, the diesel generators, get warmed up. A diesel generator is a combination of diesel engine and electrical generator, and is used in lieu of the power grid during a utility failure. Once the generators are running, a data center is still not totally in the clear. Issues and complications can arise when switching back and forth to emergency power, as well as while the generators are running.
As we’re seeing with Sandy, an extended outage may result in some sites burning through their initial reserves. That’s what happened to Internap, for instance, which ran out of diesel at 75 Broad and had to seek out a refueling arrangement and workaround. Flooding submerged and destroyed the building’s diesel pumps, further complicating the problem. Peer 1 Hosting, on the other hand, reported that its diesel was lasting longer than expected and has extended its generator life by using a human bucket brigade in place of fuel pumps.
The switch over to generators isn’t always smooth, as issues can arise during and after the switchover, as illustrated by a series of outages in 2010 in which automatic trasnfer switches failed to handle the transition properly. However, most data centers seamlessly switched over during this storm.
Supply and Demand
During extended disasters, the supply of diesel can be strained. Although data centers support many critical communications services, they aren’t alone in needing priority access to fuel. NYU Langone Medical Center’s backup generator failed, forcing a mass evacuation of patients. So there are higher priorities, and in a serious situation like this one, there is a chance that immediate supply might run low, straining even those with preferred contract. Reuters recently noted that low stocks of some diesel distillates have affected pricing this fall.
Great article! We all at Patriot Clean Fuel could not agree more!
CarlPosted November 1st, 2012
Propane does not go bad.
Hey Carl, it’s my understanding that Propane should only be used for smaller generators. Diesel generators have the lowest installed cost per kW, take a lot of abuse, and serviceability and local support is usually very good. Start time for diesel is faster as well, which can matter because it needs to kick in in a short window very often. Propane has less power than diesel for comparable physical size and have greater failure rate.
DCPosted November 3rd, 2012
Seven back up generators did not fail at Langone. The system failed. They failed to do something. What? If the hospital is reopening on Monday, then the problem has to have been identified and repaired or they couldn’t legally open.
Propane burns hotter than nat gas or diesel. Therefore the engines typically get derated for use with LP. SO, you buy more and get less. That goes for spark ignited gensets. The converted diesel engines above 150kW offer greater capability for power output, but again deration is more severe with LP and then you run into the issue of EPA emission compliance. Lastly, while propane doesn’t go bad, it’s by far the most difficult fuel to properly plumb to larger units for adequate supply and demand.
Bi-fuel gens that start on diesel and transition to gaseous are another option. They still meet the NFPA 110 requirement for life safety that the engine starts and transfers power in less than 10 seconds. The start on diesel and then transition to a mix of 25/75 extending greatly the run time of the diesel fuel present. Of course, if natural gas is being used, then the supply also must remain constant. And, if LP is used, the on site fuel storage must be refilled.
Sadly, the best solution is diesel and a minimum 72 hour fuel supply at 100% load.
George BPosted November 4th, 2012
The propane vs. Diesel choice has lots of factors, and each factor has factors. Certainly, large generators tend to be Diesel. But Diesels are a PITA; as the article said, you have to coddle and rotate the fuel. With propane, you burn the vapor, so whatever might be in the liquid is a non-issue. And it stores forever, never spoiling or growing bugs.
But the #1 issue is always: what does the Fire Marshal/EPA/Building Dept. say?
I do think *lots* of backup system users will see the light re: not the genset must be dry, but also the tankage and transfer pumps to refill the day tank.