Adding Energy Storage Inside PV Wiring Infrastructure
Energy storage key to the world’s transition to renewable energy sources. Hundreds of gigawatt hours (more than one billion iPhone batteries) are needed to reach our goals. Our question is where all of that storage is going to go, what is the most efficient way to meet the diverse needs of the grid, and what can we do to help?
Energy storage technologies like batteries, fuel cells, and supercapacitors have different pros and cons. You can read more about that by clicking here, but basically using one or the other tends to force tough economic and design tradeoffs. There is no one size fits all solution that is perfect on its own. Our products fix that.
Our solution is to combine batteries and fuel cells with supercapacitors to increase their peak power capacity and extend their operating life. Since there are miles of cables distributed throughout the grid are currently used to transport power between panels, energy storage systems, and to various loads on the grid itself - we were inspired to turn wiring infrastructure into energy storage assets.
Our innovation makes it possible to store energy within the existing wiring located inside the farm to complement the batteries and fuel cells that are already. We integrate supercapacitors with those cables to avoid competing with other storage technologies (and solar panels) for space in the system. That opens up new possibilities that can save money, increase performance, drive alternative designs/layouts, and save space when its limited. This could potentially have a global impact on solar energy production by making the transition to cleaner energy require less land, money, and effort.
In a use case where a solar farm is near a metropolitan area (where land is expensive) that was interested in offering ancillary services. Those services include peak power capacity, frequency response, ride through power when clouds pass overhead, and inertia response. They are paramount for the grid moving forward, especially as more renewables are connected. But it can be difficult to justify adding a significant level of storage. Batteries are expensive and would either require more land for the batteries or less space can be used for solar panels.
If there is no energy storage capacity on the farm, another way to offer these services is by curtailing solar production so the solar farm has the power capacity required to meet the demand of the ancillary service. While this is a way for operators to offer ancillary services, they cannot sell the energy that had been curtailed, forcing them to choose which to offer based on their market or economic value.
Alternatively, with high-power energy stored inside the PV cabling, ancillary services can be offered without curtailing solar production, purchasing additional land, or using fewer solar panels. More renewable energy would be delivered to the grid, which generates more revenue for the operator while still offering ancillary services. The best of both worlds. Integrating energy storage systems into the wiring infrastructure of the solar farms themselves solves these kinds of tough economic decisions faced by operators and opens the door to:
Better land utilization
New services to generate more revenue
Higher performance
Greater grid stability
For example, let’s say there is a 50MW solar farm. This solar farm would have ~125 solar trunk busses, which are large cables that distribute ~400kW of power across the farm. Turning the solar trunk bus into an energy storage asset would add over 50MW of peak power capacity from within the existing 125 solar trunk bus connections (approximately 12,500ft of cabling). The total storage capacity would be small, about 125kWh, but this kind of application requires high power capacity more so than long duration storage. If long duration storage is required, the cables would be used to aid the long duration battery.
By integrating the energy storage system into the wiring could, the operator can curtail less solar power. For this example, let’s assume they decrease the amount of energy being curtailed by 5%, so 15% of their total available power capacity instead of 20%. This in turn will increase the operator’s overall revenue. Using the same 50MW solar farm with a 15% curtail, assuming 6 hours of sunlight daily at $0.05 per kWh, the operator can generate $273,750 more each year.
If the farm already has space allocated for traditional battery storage, then these kind of energy storing cables help expand the capacity so that the battery can do more. When paired with the supercapacitors used inside the cables, batteries with a higher storage capacity and lower peak power capacity could have been used to reduce the cost of storage per kWh.
Our cable-type supercapacitors excel in installations with limited space, such as those in major metropolitan areas. This technique of integrating energy storage systems into the wiring infrastructure of solar farms can assist providers in overcoming technical and economic obstacles, which in turn will accelerate the mass market adoption of renewables.