G&W Electric manufactures medium-voltage utility power equipment for electrical distribution and transmission. The Illinois company has been in business since 1905, but in recent years recurring electric-grid supply problems have resulted in significant costs and production disruptions – which have impacted revenue for G&W Electric. Alarmed by the cost of these disruptions, the business decided to fix the problem and improve profitability.
The G&W plant in Bolingbrook, IL, covers over 371,000 sq ft, and the 24x7 manufacturing operations include injection molding, ceramic parts production, assembly, office, warehouse, and engineering / R&D. Even short power outages can cost millions of dollars in lost production time and materials.
Being in the electric industry, G&W was well positioned to evaluate alternative power options for its manufacturing operations. They already had an on-site backup electric generator, but it took too long to begin producing power, and it could create power-quality issues while it was running.
Recent advances in hardware and software provided an opportunity to design a state-of-the-art, alternate power system that would match the needs there, one that offers much more than emergency power generation. G&W completed installing the microgrid in 2022 – adding solar generation and a flywheel to the existing generator, along with battery energy storage to provide backup power, electric-bill savings, and new revenues.
Significant incentives were available to help pay for the microgrid. The state of Illinois offers exceptional incentives for storage, and solar components are paid for by the utilities. The G&W project earned a $2.6-million cash rebate from ComEd through Illinois’ Smart Inverter Rebate program. Federal incentives included investment tax credits and accelerated MACRS (modified accelerated cost recovery system) depreciation.
Now, when electric outages occur, the G&W microgrid automatically isolates itself from the main grid so that operations continue with an instantaneous switch to backup power. During its first year in place, the microgrid saved $2 million in avoided losses.
As of November 2024, the system has been in operation for two years, during which time eleven outages were prevented, avoiding significant downtime and lost productivity.
The 2-MW battery energy storage system is managed by a third-party company, Intelligent Generation (IG), which specializes in energy storage optimization. IG fosters opportunities for revenue and bill savings by doing strategic dispatch of stored energy. For G&W, IG has saved $420,000 per year in electric bill reductions and it earns $250,000 annually from utility grid ancillary services market opportunities.
The projected ROI for the system is under four years, and once the installation has been paid off the microgrid assets will continue to generate revenue to improve G&W profitability through its estimated 25-year lifecycle.
Key components of the microgrid system include:
Solar panel array – A 2-MW solar farm with nearly 6,000 solar panels was installed on the roof G&W plant, covering over 370,000 sq. ft., and creating one of the largest rooftop solar photovoltaic systems in North America. These bi-facial solar panels generate energy from both sides and optimize the use of direct sunlight and light reflected from the white roof surface.
Recloser – G&W Electric Viper-ST Reclosers participate in an automatic throwover scheme to transfer the campus to an alternate power source within 5 to 12 seconds in the case of the loss of the primary feeder. A flywheel ensures no detectable loss in power during this switch.
Switchgear – The G&W Electric Trident-SR with SafeVu is a 15.5-kV class switchgear that performs a 3-4 cycle operation (open or close.) The three switches are operated in a FLISR (Fault Location, Isolation and Service Restoration) loop scheme using ABB REC670 relays, to provide power to the campus using utility, using solar array and energy storage as the main sources.
Flywheel – A flywheel is one of the most critical components of the system. When energy is being stored, electricity drives the motor that spins the flywheel. When stored energy is being recovered, the motor acts as a generator to convert the spinning motion back to electricity.
The heavy mass of the flywheel spins at up to 2,800 rotations per minute. The flywheel system will detect an electric supply outage in ¼ cycle, instantly providing 1 MW of backup power to critical loads for up to 68 seconds, giving time for the battery or generator to kick in.
Diesel generator – A two-megawatt diesel generator provides power continuity if the duration of a utility power outage exceeds the capacity of the battery complex. While renewable power sources rely on some uncontrollable factors (i.e., sunlight for solar panels), the generator can produce power for the microgrid when no other energy sources are available.
Battery complex – The core of the microgrid is the Flow Battery Energy Storage System. It uses a vanadium electrolyte solution, which is both non-degrading and fireproof, and it can store power generated by the solar array and diesel generator in the event of an external outage. The total power capacity is 2 MW for four hours, or 3 MW for two hours.
Control room – The control room allows G&W to control, manage, and display all operations of the microgrid. G&W LaZer automation, combined with SurvalentONE ADMS software, captures critical data and is fed to the control room.
POWR:Suite platform – This software, built on Google Cloud, includes Intelligent Generation’s patented algorithms that predict the most profitable use of each resource at every moment, and dispatches it via the site controller. It integrates electric market bids, weather forecasts, asset status and other constraints to optimize its delivery in real-time. POWR:Suite maximizes the utility bill savings of an energy-storage asset and earns revenue from wholesale power markets.
The centerpiece of the microgrid is the large battery complex using flow battery technology from CellCube. While several industrial-scale battery systems are available, CellCube was chosen because G&W wanted to avoid the potential disposal costs for lithium-ion based systems at the end of the battery life (20 years.)
Another huge benefit of this flow battery is that it does not have the risk of thermal runaway, fire, explosion and emissions liabilities that can occur with lithium-ion systems.
The design and implementation of the G&W Electric microgrid was a major project. G&W enlisted the help of outside consultants and contractors to help choose and design the system to meet their requirements. The result is a state-of-the-art system that is scalable to meet the needs of virtually any manufacturing operation.
Electricity needs are different for every manufacturer and custom solutions are required to optimize savings for a microgrid. TDI Energy Solutions works with the consulting team that helped design and operate the G&W microgrid; contact TDI to discuss how such a microgrid can be tailored to your plant’s specific requirements.