The renewable energy sector is rapidly codifying a new unwritten rule: Battery storage must be co-located with new PV and solar tracker installations. 

No, there aren’t any new regulations or legislation mandating this—at least, not yet, anyway. Nonetheless, recent S&P Global Market Intelligence data indicates that deploying a trifecta of PV, solar trackers, and storage is nearing a tipping point in becoming the de facto standard practice for utility-scale solar developments.

Consider the numbers S&P shared from current interconnection queues:

• More than 98% of the solar capacity proposed is hybrid in the California Independent System Operator (CAISO) footprint

• Around 87% of new solar capacity is hybrid in the non-ISO portions of the western United States

• Nearly 50% of the proposed solar projects in the Electric Reliability Council of Texas (ERCOT) are hybrid

It’s worth noting that although CAISO currently houses the most storage capacity, ERCOT is expected to surpass California by the end of 2024. Additionally, while PJM and Midcontinent ISOs have yet to experience the same surge in hybrid projects, industry analysts anticipate an increase in these regions.

Like any unwritten rule, this one also includes hidden knowledge. In this case, the secret is that as co-locating storage with PV and solar trackers becomes the industry standard, the key to utility-scale solar success for EPCs and developers will hinge on one-stop-shop procurement.

What’s Driving the Growth in Co-Located Solar and Storage?

Interconnection Congestion and Solar Curtailment

Rising interconnection congestion and solar generation curtailment are contributors. Utility-scale solar (and wind) output curtailment in CAISO has surged from 2022’s high of 200,000 MWh to 839,582 MWh in April 2024. Meanwhile, with ERCOT facing a doubling of Texas solar production by 2035, the U.S. Energy Information Administration (EIA) forecasts the state’s solar generation curtailment, increasing from its current 9% to 19% of generation during that period.

As the country eagerly awaits electric transmission expansion and faster interconnection queues, EPCs and developers have turned to battery energy storage systems (BESS) to help utilities reduce the amount of renewable energy wasted by growing curtailment. A BESS can reduce curtailments by charging and storing the excess energy when solar produces more capacity than needed.

A Distorted Duck Curve

Another contributor to the growth of hybrid solar + storage projects has been an increasingly distorted duck curve, the whimsical name for the shape created on a graph plotted with California's daily net energy load.

The rapid pace of solar growth creates spikes in generation during the middle of the day when irradiance reaches its highest point. Unfortunately, this spike coincides with the lowest daytime energy demand. Then, at the end of the day, when people turn on their lights and appliances and start charging electric vehicles (EVs), solar power is no longer available to meet the higher demand.

This shifting duck curve makes it difficult for utilities to balance electricity generation and consumer demand. Overgeneration wastes energy, while undergeneration can lead to brownouts or blackouts. Thankfully, rather than feeding excess solar energy back into the grid when it's not needed or curtailing generation, utilities can store it in batteries to deploy later.

Eliminate Procurement Headaches

As PV, solar trackers, and batteries converge into the standard design, utility-scale solar EPCs and developers will face more procurement responsibilities and deal with more vendors, raising the potential for supply chain risks, delivery delays, and budget overruns. A total solar solution helps EPCs and developers mitigate supply chain risk by procuring all major components from one supplier.

That’s why the TrinaPro utility-scale total solar solution bundles best-in-class Vertex modules, TrinaTracker, and the TrinaStorage battery energy storage system (BESS) — all manufactured by a single bankable company, Trina Solar US. TrinaPro also bundles central inverters and any necessary racking equipment in its total solar solution to further streamline procurement and ensure optimized component interoperability.

In addition to TrinaPro’s one-stop solar shop procurement offering, Vertex modules enable a unique low-voltage, high-string power system design. This feature reduces soft costs and balance-of-system (BOS) costs to lower levelized cost of electricity (LCOE) and deliver more utility-scale solar value than ever before.

Interested in more of the benefits TrinaPro’s total solar solution delivers for utility-scale solar projects? Reach out to talk to our team of experts!