Data centers are evolving from small IT-load servers for businesses to large hyperscale facilities for cloud-based technology and colocation services. The data center evolution requires ever higher capacities of electrical power, and it’s becoming progressively more problematic for distribution-network operators to keep up with increasing demand.
Distribution-network operators can often plan on lead times of up to 12–24 months to upgrade and expand the main power-distribution system and its substations, ring mains and cabling. Also, the rapid expansion of an aging grid can hinder its security and resilience. This situation can be troublesome for network operators, which are legally obliged to control power quality without reducing network reliability.
There is a solution: temporary gas power generation. For example, Ireland is already taking advantage of temporary gas power generation after delays in expansion of the electricity network forced developers to find another way to power the commissioning and operation of data centers. With robust gas-supply networks already in place, the teams there have installed mini gas power stations to keep projects on track.
Let’s explore the benefits of gas-powered rental generation and how it can keep critical data center programs on schedule.
When facing prohibitive costs and time delays to secure a new site’s grid connection, most developers will move on and look for an alternative with ready-to-go power. But few locations already have the multi-megawatt supply readily connected. Similarly, an expanding data center’s options are limited when it can’t get additional electrical capacity from the grid. Operators can either delay expansion work or look to colocation companies to help meet their growing storage requirements.
Traditionally, developers have faced the following options when a delay in electricity-infrastructure upgrades has occurred:
- Delay new sites, or the expansion of existing ones, until the required electricity supply is available. Waiting for the supply can be costly, especially if the delay lasts for many years.
- Schedule a new site/site upgrade to coincide with the mains-on-site date. Delays to the electricity supply often still occur, however, consequently delaying the site’s commissioning and operation.
- Use temporary on-site diesel generation to commission the site, thereby minimizing the delay, so the data center is ready to be switched on as soon as the mains supply is available, but lose backup
- Bridge the gap between commissioning and the actual mains-on-site date, using on-site diesel generation to operate the data center (again, losing the backup power supply).
Move Over Diesel
For many years, data center operators have used diesel generators as an emergency backup or as standby power to overcome grid-supply challenges and help bridge the power-supply gap to get their new data servers online on time. But using diesel generation as a substitute for mains power over long periods is neither cost effective nor sustainable.
First, diesel generators need a robust and often costly fuel-management strategy, considering the logistical and safety issues surrounding regular refueling. Second, they have long-term environmental implications. Many local governments have raised concerns about the long-term use of diesel generation in densely populated areas because of NOx pollutants. Changes in building regulations and a tightening of planning controls mean developers are expected to explore alternatives to minimize energy waste, reduce greenhouse-gas emissions and improve air quality.
In recent years, power-generation companies have invested heavily in R&D programs to advance gas generation technology. As a result, temporary gas generators are now a viable alternative to their diesel counterparts. Not only can they help bridge the gap when electricity networks are unable to meet a data center’s demands, they can also provide a more sustainable long-term substitute for mains power.
The flexibility of today’s gas generation technology offers a number of features making it suitable for data centers.
The Perfect Grid Match
Similar to diesel variants, gas generators can also be effectively synchronized with the electricity grid so they operate in parallel with the incoming electricity supply. As a result, electricity consumption drops while gas generation produces a constant power output, providing base load power at a potentially lower price than electricity. Then the data center uses the grid supply to meet varying loads above the base load.
Gas generation serves in addition to the grid supply, offering additional capacity. Typically, the gas generators would still take the site’s base load and the grid would support any varying load. These options provide a broad scope for local power circumstances. For example, being able to serve increased peak loads can be beneficial for sites that urgently require additional power for expansion but are limited to a maximum supply under a preexisting electricity contract.
Gas generators can also run alone—not connected or synchronized with the electricity grid. This approach is suitable for sites that have enough medium- or high-pressure gas (or possible with a shorter lead time than the electricity supply) but no available mains power. The operator effectively uses the gas generators as the site’s utility provider, building its mini power station to primarily supply its operations. These advancements in gas generation capacity have made temporary gas generators a more cost-effective long-term power source than electricity from the grid.
For gas generation to be effective, sites must be able to configure a setup that meets the highest resilience standards. Most operators design their data centers with a minimum level of redundant power to ensure high resilience to downtime because of UPS malfunctions, standby-generator failures or total mains-power outages. A site’s primary infrastructure must be fully redundant to achieve Tier IV of the Uptime Institute’s tier system and deliver 99.995% uptime per year.
Gas-powered generation can reach Tier IV and the necessary redundancy using different generator configurations, although every project is different. System resilience would match the sensitivity of the site. The configuration may also involve diesel standby generators, just in case of gas mains failure, even though they’re extremely unusual. Also, rental gas generation offers a flexible and modular approach that allows power to scale up or down in stages to suit the site’s demands at a given time.
As with all on-site generation, preventative maintenance is essential, and capacity should be carefully planned to achieve system operational efficiencies. Additionally, remote monitoring is useful to cut response time to any issues before they become more serious.
Flexible, Cost-Saving Options
In the long term, gas generation offers sustainable and cost-effective benefits that data center operators can exploit to help power and cool their infrastructure as well as save money:
- Using combined heat and power technology, waste heat from the generators’ cooling system could produce an additional electricity supply for the site.
- Once a grid connection is installed, surplus gas-generated electricity can be exported to the local grid and sold on the electricity market (under an agreement with the network operator).
Insufficient mains power should no longer be an obstacle to building or upgrading data center infrastructure. The availability of a gas supply provides a natural and practical solution to on-site electrical power. Gas generation allows a site to be commissioned, become operational and expand, in addition to improving its resilience and security.
About the Author
Mark Stavrakis Sr. is a senior technical sales specialist at Aggreko, a leading temporary-power-generation provider.