Optimizing Mobile Power With Battery Energy Storage Systems

Mobile power solutions are the lifeblood of remote and off-grid jobsites. For decades, contractors have relied on portable generators to power equipment and tools, sizing them for peak loads and often running them 24/7. But forward-thinking companies are shifting their mobile power strategies as they recognize the ability of battery energy storage systems to dramatically reduce inefficiencies and put money back in the budget.
 

The Hidden Costs of Traditional Generator Sizing

The “better safe than sorry” approach of sizing generators for peak loads can lead to generators being oversized by as much as 75%. Large generators use more fuel and cost more to run than smaller generators, even when they operate at a fraction of their capacity. Diesel generators are designed to run near their designed load. At lower loads, combustion is incomplete, which decreases the efficiency of the engine.

Contractors may view this fuel inefficiency as the cost of doing business, but the dollars spent on diesel add up — especially when generators operate day and night.

In addition, the larger the generator, the larger the cost of the unit. Running a generator around the clock further increases the rental cost by triggering triple-shift rates.

Of course, on jobs with sustainability targets, oversized generators also make it challenging to comply with greenhouse gas emissions targets.

How BESS Technology Transforms Mobile Power

Battery energy storage systems (BESS) change the mobile power equation and often generate savings that far outstrip the cost of investment.

Rather than outsizing generators to meet the highest anticipated load, contractors can size them for average demands and let a BESS bridge the gap during load surges. This strategy is particularly valuable when loads are variable. For example, a BESS can power a welder while it’s in idle mode and automatically activate the generator for arc starts and welding bursts.

When powering jobsite trailers, a BESS will keep the refrigerator cold at night and keep charging stations powered. During the day, the generator will run as needed to recharge the battery and power the HVAC, lights and computers when work is in full swing.

In some cases, a BESS can handle a full load on its own until it needs to be recharged. For instance, a large BESS can power a tower crane. When the battery runs low, the BESS will automatically turn the generator on.

Dramatically Reduced Run Times

As contractors begin to implement BESS units, reduced generator run times are yielding significant cost and fuel savings.

One firm reduced generator run time on a tower crane operation by 91%. The general contractor had been using a 300-kilovolt-ampere (kVA) generator 24 hours a day to power an 8-ton, 70-meter-tall tower crane. By switching to a hybrid power system that included a Termaco TREE 500-kilowatt (kW) BESS, they were able to downsize to a 125kVA generator and reduce generator runtime to just 2.5 hours a day. The shift produced an estimated 77% reduction in fuel use and carbon emissions.

Another company implemented a hybrid system to power several jobsite trailers and reduced generator run time to 2.5 hours per day. By pairing a POWRBANK portable energy unit with a 70kVA generator, the contractor saved over $12,000 per month in combined fuel and rental costs while reducing carbon dioxide emissions by nearly 34,000 kilograms.

Operational Advantages of Hybrid Power Systems

In addition to fuel and emissions savings, hybrid power systems deliver operational advantages.

• Reduced equipment wear and tear — Reduced generator run times translate to extended equipment lifespans.
• Reduced maintenance — Running a generator at low loads for extended periods can cause wet stacking, which reduces performance and may lead to equipment failure. Hybrid power systems prevent generators from operating at low loads. Moreover, unlike a generator, a BESS requires little to no maintenance.
• Quieter jobsites — Excessive noise can harm workers’ hearing and create fatigue that affects performance. Quieter jobsites benefit the health of crews and enable contractors to meet noise restrictions and work at night in urban and residential areas.
• Increased resilience — Adopting a hybrid power strategy reduces dependence on a single power source, which preserves uptime in the face of mechanical failures and other outages. By reducing diesel consumption, hybrid power systems also help protect a firm’s bottom line, especially during periods when fuel prices surge.

Strategic Considerations for Adopting Hybrid Power Systems

To realize fuel and cost savings from a hybrid power strategy, contractors can begin by analyzing the mobile power needs of a jobsite. Whenever generators are run throughout a shift or around the clock to power variable loads, adding a BESS may be worth considering.

A knowledgeable vendor with expertise in temporary power equipment, including battery energy storage systems, can play a critical role in helping contractors optimize their mobile power strategy. They can assist with accurately assessing power needs based on load profiles, duty cycles and other inputs. On connected jobsites, tracking the load of telematics-enabled generators can reveal generators that are oversized for the task.

Based on jobsite-specific power needs, a vendor with a large inventory of best-in-class temporary equipment can recommend solutions using optimally sized generators and BESS units. In some cases, the ideal solution may be a product that houses a generator and a BESS together. A BESS can also be paired with a renewable power source such as a solar array for a zero-emission solution.

Too often, mobile power strategies follow the formula of “do what we’ve always done.” The common traps of oversizing generators and running them 24/7 locks contractors into ongoing overspending. For companies looking to reduce fuel use, cut costs and increase operational efficiency as part of their efforts to maintain a competitive advantage, looking beyond generators to hybrid power systems makes sense.