Welcome to the new ice age
The answer to peak power problems has always been storage, but that has proven to be a difficult feat to achieve. As E&T discovers, the answer may be found in ice.
In every commodity market in the world, except electricity, storage is used to address the periodic imbalance between supply and demand. We store food, water and fuel to dampen price volatility, create efficiency in consumption, and increase reliability in delivery. Only the electricity market meets peaks in demand by overbuilding generation, transmission, and distribution assets, which then sit idle most of the time.
In many ways, storage is the missing link. "Our industry needs storage for the successful integration of renewable energy into the grid, to increase efficiency of existing power plants and transmission facilities, and provide better power quality," Therese Wells of Ice Energy says. "Without energy storage, we're locked into following the outdated practices of the last century, a practice of building and supporting a power network designed to meet the highest peak load on the hottest day of the year. We do it even when it means over 50 per cent of the system sits idle most of the year."
Storage can create a flatter and more efficient load shape on the grid, reverse the trend of deteriorating load factors, and transform energy system efficiency, grid reliability and security in the process. To many, storage is the Holy Grail of power generation given that it improves the value of investment in intermittent renewable generation, reduces carbon emissions, and offers the promise one day of true ratepayer relief.
"For our solution in particular, by leveraging the higher efficiencies associated with generating, transmitting and storing power at night, and dispatching it during times of peak demand, Ice Energy delivers a sustainable new energy solution equivalent to hundreds of megawatts of clean peaking power for utilities," she continues. "Our technology cost effectively stores energy off-peak and delivers it on-peak, at the point of consumption, without incurring significant inefficiency or losses. This makes it possible for utilities to use cleaner, more efficient and less expensive off-peak power to produce and store energy to meet peak demand."
There have been other, more traditional storage mediums pushed to the fore. Batteries, pumped hydro and more recently compressed air storage and Wells is adamant that they will all be needed. "We believe that energy storage - in all its forms - must be considered as part of any integrated energy solution by utilities. Its benefits are many and varied."
Storage enables intermittent solar, stores off-peak wind energy; provides clean and highly responsive voltage regulation services; shifts peak demand and energy consumption to off peak; and boosts the market for efficient base load generation resources.
"We leverage the daily rotation of the planet, taking advantage of thermally efficient, night-time power to produce and store energy for daytime use by air conditioners - the single largest component of peak energy consumption," Wells explains.
The Ice Energy technology, called the Ice Bear, is an integrated energy storage system that, when combined with conventional building air conditioning, creates a hybrid cooling system that draws upon each technology when it is most efficient and cost-effective.
The system stores cooling energy at night-peak by freezing water within an insulated storage tank. It cools during the day by circulating chilled refrigerant from that tank to the conventional A/C system, eliminating the need to run the energy-intensive compressor during peak daytime hours. During off-peak hours, the system operates as usual.
"By decoupling daytime air-conditioning use from peak energy demand, this hybrid system surpasses the overall efficiency and performance of conventional equipment alone," Wells says.
But the real boon for the system comes with the advanced software Smart Grid architecture, called the CoolData Controller. This can interface, integrate, and intelligently control individual Ice Energy units, creating an aggregated utility resource that is interoperable, scalable and dispatchable, providing utilities with the ability to intelligently shape peak demand by managing the load profile of a single building, a feeder, a substation or a region.
The ability to aggregate and control thousands of units and to bundle their performance as a single utility resource enables the integrated resource planning group of a utility to evaluate the solution in much the same way as they evaluate new peaking generation. It also provides significantly more incremental value across the entire value chain, from source to consumption.
It seems such an intuitive solution that it begs the question, why has it not been developed before? "It's a deceptively simple idea that was extremely complex to execute," Wells explains. "There's a lot that goes on behind the curtain.
"Creating a packaged thermal energy storage system required simultaneous innovations to address efficiency, compatibility, cost, reliability, and control. This led to technology advances in refrigerant management, smart grid architecture, HVAC control, and mechanical integration."
Through a dedicated research effort started 20 years ago by a small company called Powell Energy Products, the original developer of the foundational technology, the main heat exchanger design requires no valves or active controls to direct refrigerant through the coils - it is a self regulating, gravity-based system.
As a result of the past five years of R&D, the IB30 introduced a patented thermosiphon process for reliability and efficiency, which isolates the ice-making process with minimal energy cost. "It was the coordinated advancement of innovations in multiple areas, capturing the convergence of building control, smart grid, and thermal storage, which was required to provide a truly viable solution for grid reliability and system efficiency," Wells adds.
The company are currently in contract discussions with utilities in all major North American geographies on multiple orders ranging from $5m to $100m, representing the potential to shift more than one gigawatt of peak energy demand. "These projects are 'shovel-ready' and can be fully deployed within 36 months of contract," Wells says.
By fundamentally changing how - and more importantly when - energy is consumed, the technology can provide utilities with a dispatchable, distributed resource that can offset the need for peak generation, relieve summer transmission congestion, improve the overall reliability and power factor of the system, and enable the reliable integration of renewable energy resources by reshaping the load on the system, feeder by feeder, at the substation level, or for an entire region.
Unlike load management cycling or other curtailment programmes that require changes in consumer behaviour, or negatively impact customer comfort and economic productivity, the solution permanently shifts energy use from high-impact daytime hours to low-impact nighttime hours, enabling commercial buildings to slash peak electricity demand, manage energy costs and improve their environmental footprint without compromising comfort.
As for the future, Wells is not surprisingly bullish. "Pardon if you will the bad pun, but what we're talking about today is only the tip of the iceberg for us," she says. "Now transitioning from proof of concept to scale deployment, our platform is capable of addressing the 80GW market of refrigerant based HVAC market, forever changing the way the grid operates and eliminating the market inefficiencies and reliability issues created by this thermally driven load.
"By improving efficiency across the entire energy delivery chain, this represents the first utility-scale, distributed energy storage solution to fundamentally reshape the load curve, increase energy system efficiency, improve grid reliability, and reduce green house gas emissions. And that changes everything."