Generators are needed in the construction industry to supply high start-up amperages (e.g., 1250 KvA) encountered with intermittent power requirements. However, hybrid batteries can supply smaller but vital loads such as alarm systems, electronics, security lighting and more. In addition, preventing generator idling in between high-load cycles is another compelling factor favoring hybrid battery economics.
With higher use of renewable energy resources raising the risk of energy being intermittent, battery systems can alleviate power stability concerns. This is why corporate-wide energy efficiency programs are targeting low and cyclic loads. Further accelerating this dynamic is the onus of complying with environmental regulations, including EPA Tier 4 emissions limits, compelling a reduction in generator idling, which results in improved reliability.
The cyclic loads typical of construction project operations are ideal for energy efficiency improvements. These hybrid units only require generators to support high-amperage peaks for relatively brief segments and then switch to a battery source when lower power requirements are needed to keep jobsite lights, security systems and computers running while eliminating idling, cutting fuel costs and reducing emissions—regardless of the fuel source. In one year-long construction project, five hybrid units providing 500 kW of total power delivered $1,500 to $1,600 in fuel savings per week — more than $80,000 in savings in one year.
The conundrum in these cases comes with balancing periodic peak loads with the more frequently occurring low loads. Low load periods contribute to a disproportionate amount of fuel consumption, emissions and maintenance downtime.
Diesel-driven generators result in escalating reliability problems when run at low loads. In other instances, generators may be running four to five hours fully loaded and then eight to 10 hours just idling. The gradual replacement of diesel generator fleets with gas-driven generators can alleviate a significant amount of wasteful fuel consumption and related concerns during idling, but additional benefits are cost-effectively realized with the hybrid battery option.
In addition to complying with environmental mandates, the transition to lean-burn and rich-burn gas engine technology coincides with efficiency-driven power management strategies for competing in a narrow margins environment. However, the high capital costs incurred with gas engine technology limit the pace to which businesses can invest in the technology. Against this backdrop, a scalable power management strategy for meeting the client’s needs could include a power automation/hybrid battery option controlling a network of generators, whether diesel or gas-driven.
Low-load duty cycles are where energy efficiencies can be captured with hybrid battery/inverter UPS-type systems. They are about the size of a commercial electric forklift battery with approximately 1170 amp-hours of battery storage. The battery’s monitoring system with auto generator start controls will automatically restart the generators when batteries deplete (about 2000 charging/discharging cycles can be extracted from the battery). When the battery is charged and demand for power is low, the generator can turn off and the energy stored in the battery is used to supply the load.
Multiple cases have shown how hybrid battery packs integrated into a power automation system can run low power-consuming loads, such as communication systems. Battery pack enhanced networks also allow a linked generator to start and stop whenever there’s a surge in demand for larger loads.
Hybrid battery units can help reduce costs while also improving operating efficiencies. However, the ultimate benefit of these installations can only be realized by partnering with a provider with the right technical expertise to engineer a power management solution.
