Prospects For Environmental Sustainability Of Global Data Centers
The global data center sector is estimated to account for approximately 416 terawatts, equivalent to approximately 3 percent of all energy demand. Southeast Asia is in high demand, and energy needs are rising as countries in the region add new data center infrastructure.
Concerns about the environmental impact of data centers have prompted some countries and city-states to impose restrictions on the construction of new facilities. For example, Singapore suspended new data center development in 2019. Now that moratorium is over -- but new data centers can only be built "with best-in-class resource efficiency."
The pressure to improve the environmental performance of data centers does not only come from governments and regulators. Hyperscale data center operators such as Google (Alphabet), Apple, Facebook (Meta), Amazon and Microsoft (GAFAM) are increasingly looking to improve. Last year, Google Data Centers set a goal to power all of its cloud data centers with carbon-free energy 24 hours a day by 2030.
But what does the move to cleaner, more sustainable facilities mean for equipment like diesel generators?
It should be noted that generators in data centers are not big emitters of carbon because they are used infrequently and only for short periods of time. However, diesel generators still hold promise for improved environmental performance through generator optimization, reduction in periodic field testing, and the addition of exhaust aftertreatment and biofuels.
Develop a sustainable development roadmap
Broadly speaking, data centers in Southeast Asia include three major energy groups—on-site power generation or utilities; facility systems, such as cooling and power distribution; and IT systems. Improvements in each of these areas can significantly contribute to increased sustainability.
Generators belong to the first group and represent mission-critical on-site power generation, mainly from diesel, but sometimes from natural gas. Tier 1 data center operators in countries such as Singapore, South Korea and Japan are specifying higher-rated generators to help them achieve operational efficiencies and reduce costs.
A 4MW diesel generator set provides most of the required backup power. They provide a highly reliable response to power failures in the local transmission grid. Larger power nodes pack high performance into a small footprint—critical when space is at a premium. Additionally, diesel is common in most regions and can be safely stored on site, while generator spares and repairs are easy to arrange.
This mission-critical role means they are rarely invoked, limiting carbon dioxide emissions. That said, manufacturers are keenly aware of the need to continuously improve environmental performance, thereby significantly optimizing generators.
For example, Kohler generators are engineered to meet all relevant emission standards in Southeast Asia and other important regions, including Europe and the United States. This compliance can be achieved through highly optimized internal generator design and post-processing.
Advances in Generator Maintenance
Many diesel generator operators often experience "wet buildup" where under-combusted gases are removed from the exhaust system, causing the generator to degrade and drastically reduce its useful life, and can also lead to violations of emissions regulations . This mainly occurs when generators are often run with little or no load because the data center generators are not sized for the required power, or because there is not always enough load available during operation.
The most effective way to avoid a wet stack during monthly workouts is to run the generator at the recommended minimum load. But since data center operators don't want to transition to building loads, monthly practices require the use of load bins, which can be used to supplement or perform load maintenance activities. This load bank test serves as a means of artificially increasing the load on the generator to burn the accumulated load.
Many facilities have load reserves based on maintenance regimes created many years ago. Modern diesel generator designs now use a variety of techniques to improve operating efficiency and reduce the gap between the piston and piston rings, allowing unburned fuel to escape. Combined with advancements such as common rail systems, this advancement reduces motion loads by including combustion gases and promoting the formation of shaped charges.
The savings from switching from monthly load testing to annual load testing are significant. For example, a 3250kW load bank cycle running for 30 minutes per month burns approximately 660 gallons of diesel fuel and emits 186 pounds of pollutants per year. In comparison, the same monthly no-load exercise consumes less than 300 gallons per year, reducing total pollutant emissions per pound by about 82% per year.
Renewable biofuels enter the mix
Another area of environmental advancement is the adoption of the latest renewable fuels such as hydrotreated vegetable oils (HVO), which often include paraffinic bio-based liquid fuels produced from existing farm feedstocks including canola, sunflower and soybean oils. These are straight chain hydrocarbons that are free of aromatics, oxygen and sulfur and can provide high cetane numbers.
Importantly, HVO represents a simple and efficient renewable energy solution that is up to 90% carbon neutral. They are easier to store than biodiesel, and they provide a "plug-in" solution that can be used in conventional diesel generators.
It can also be blended with diesel to ease the transition. As a result, many of Kohler's diesel industrial generators are already compatible with HVO paraffinic synthetic biofuels.
Batteries and Fuel Cells
What about step-by-step revolutionary solutions like batteries and fuel cells?
Utility-scale batteries based on advances in lithium-ion technology combined with renewable energy supplies could be a potential solution. Some hyperscalers are working on megawatt-scale battery systems.
Interestingly, renewable energy-plus-storage technologies could potentially be used in grid service applications—on-site batteries in facilities such as data centers could be used to help utilities manage grid fluctuations. Challenges to battery-based systems include reliability, quality, and cost-effectiveness, but research and development activities are being undertaken to overcome these concerns.
Hydrogen fuel cells also represent an exciting technology as an environmentally friendly backup power solution. Likewise, data center operators and their industrial partners are implementing proof-of-concept proton exchange membrane fuel cells that combine hydrogen and oxygen in the process of producing water vapor and electricity. In one experiment, a 250-kilowatt fuel cell system was used to power a row of data center servers for 48 hours continuously.
The challenges for hydrogen come from scalability and cost. It is estimated that 100 tons of hydrogen are required to operate 30MW of IT equipment for 48 hours. A delivery truck can carry 2 tons of hydrogen, so a two-day outage would require about 50 shipments of hydrogen. But hydrogen does remain an exciting possibility, and Kohler is developing a prototype 60 kW hydrogen generator using polymer electrolyte membrane fuel cell technology.
Next-generation data centers located in Southeast Asia will need to be greener and more sustainable than ever. This shift could come from continued advancements on multiple fronts—from new maintenance strategies and the adoption of renewable fuels to the use of advanced fuel cells and batteries to help ensure more sustainable data centers become a reality.
