There is no question that the energy landscape is evolving dramatically. As millions of electric vehicles hit the roads, and new data centers and manufacturing plants are constructed, additional megawatts of generation and transmission capacity are urgently needed.
This new generation capacity is needed within timelines that would have been unthinkable even a few years ago. That’s why reciprocating engines are emerging as a feasible option for quickly meeting this growing load with new, highly reliable generating capacity.
Filling the Gap Quickly
Reciprocating engines have long been favored for their ability to load-follow renewable energy. They are designed to accommodate frequent starts and stops with fast response times and flexibility to operate as peaking or baseload resources. But their true value lies in their ability to be engineered, procured and deployed quickly, making them an ideal solution to fill unique gaps in the power generation resource mix. Utility-scale engine models include 10- to 20-megawatt (MW) classes and higher. All are heavy-duty, medium-speed engines offering competitive heat rates and multishaft reliability.
Data center developers are considering reciprocating engines to fast-track approvals and permitting for projects that often exceed 100 MW in new load, demand that often taxes the capacity and resources of local utilities or other regional power providers.
According to the Electric Power Research Institute (EPRI), the growth in data center developments is expected to result in a total load of 35 gigawatts (GW) by 2030. With that rate of projected growth, developers of data centers are confronting the reality that grid capacity will soon become stressed and are turning to other solutions that can be implemented quickly.
Currently, many developers are turning to high-speed reciprocating engines in configurations of 100 or more. These engines offer lower power outputs per unit — generally ranging from 2 MW to 4 MW.
Medium Speed Offers Optimal Alternative
As more data center developers enter the market, proposals that can bring power generation with them have advantages in gaining quicker approvals from jurisdictional authorities. These projects are also more attractive for financing as they address the critical issue of power supply.
Projects that include on-site power generation can proceed with assurance that the data center can operate for an extended period until a grid interconnection is approved. In these scenarios, medium-speed reciprocating engines generating up to 20 MW per unit can provide the flexibility needed to operate as a baseload source of power, with the additional benefit of being able to quickly ramp up or down as power needs fluctuate.
Though most data centers have relatively stable load resulting in capacity factors of 90% or greater for generation units, some have loads that may swing wildly. In those cases where instantaneous power correction could be needed, battery or capacitor banks could be considered as options to maintain power quality with low risk of power quality issues or voltage sags, surges or outages.
Although initial capital costs-per-kilowatt (kW) of medium-speed engines would be higher than those for high-speed engines, levelized lifetime costs tilt toward medium-speed configurations due to the lower costs for operating and maintaining fewer engine shafts. Additional cost advantages can be realized through shorter procurement lead times for medium-speed engines, as well as lower costs for the balance of electrical components needed for the units.
Other Advantages
Under the Environmental Protection Agency's New Source Performance Standards, the agency has, for now, chosen to exempt any gas-fired power source that generates under 25 MW, a threshold that all reciprocating engines currently meet.
Even if the exemption is rolled back, there are still two primary pathways for reciprocating engines to meet EPA standards and remain in the mix as a viable source of energy.
The first option is to burn clean fuels. Ongoing tests have shown that reciprocating engines can safely burn blends of gas and hydrogen or ammonia at ratios of up to 25%. Hydrogen and ammonia blending shows promise as a cleaner alternative, and ongoing research and development by engine manufacturers indicate that these engines will be able to burn 100% hydrogen within a few years.
The second pathway involves converting the on-site reciprocating engine power supply to emergency backup status once the data center has secured approval to connect with the local utility grid power as its primary source of power. Market-based emissions credits from clean energy sources could then be purchased to offset any power that would be needed by the on-site gas-fired engines.
Beating the Rush
There is little question that power demand will be a major factor as larger data centers go online. With speed-to-market and operational advantages of reciprocating engines, it’s likely that these technologies will increasingly be in demand.
While many data centers are striving for clean energy solutions and examining the feasibility of nuclear power, the reality is that permitting and regulatory challenges — such as licensing and availability of high-assay low-enriched uranium (HALEU) fuel — won’t make nuclear an immediate solution in today’s booming data center market. In the short term, utilities must explore alternative large-scale, low-carbon energy sources to meet rising demand.
Utilities and independent power providers exploring solutions for the power needs of data centers may find value in considering reciprocating engines as part of the technology mix. These engines offer flexibility, with the capability to operate at higher capacity factors for baseload power and later transition to peaking or backup roles as needed. This adaptability can help streamline project development and potentially improve timelines for achieving operational status, addressing some of the challenges associated with powering advanced computing infrastructure.
With numerous advancements in power generation technology, natural gas is well positioned to provide grid stability while keeping power affordable and reliable.