Battery Storage for Open Access Users: 4 Ways It Can Improve ROI and Reliability!

Green energy open access is booming in India.

Between FY23 and FY24 alone, the C&I open access market saw a 90.4% increase in annual installed capacity.

Open access solar, in particular, has become a popular option for industrial and commercial consumers to cut electricity costs and meet ESG targets.

But solar comes with one big challenge: it’s an intermittent resource. During non-solar hours, consumers usually have to fall back on the utility grid to meet their energy needs.

And if there is a grid failure, they could experience power disruption, which can affect operations and lead to production downtime.

This is where Battery Energy Storage Systems (BESS) come into the picture.

In this blog, we’ll break down how BESS can solve the limitations of open access solar and significantly boost your ROI.

Under the Green Energy Open Access Rules, 2022, consumers with a contracted demand of 100 kW or more can purchase renewable electricity directly from a power developer and bypass the local DISCOM’s supply.

However, the electricity still flows through the local grid infrastructure, and consumers have to pay transmission and wheeling charges to access it.

Since many businesses consume power heavily in the evening or at night, they can benefit from a Battery Energy Storage System (BESS).

BESS allows consumers to store excess solar power that isn’t used immediately and discharge it later. It bridges the gap between generation and demand to ensure uninterrupted power supply.

Under the Time-of-Day (ToD) tariffs for C&I consumers, electricity is cheaper during solar hours and more expensive during peak hours (usually 6 PM to 10 PM).

This creates a challenge for businesses that consume a major portion of their power in the evening.

But with BESS, consumers can store excess solar power generated during the day and discharge it during peak tariff hours. This helps them:

• Avoid buying expensive grid power in the evening
• Extend the financial benefits beyond solar hours, in the case of a solar PPA
• Reduce their per-unit power cost across the day

In states like Tamil Nadu, Rajasthan, or Karnataka, solar developers are occasionally asked to reduce or stop generation during mid-day. This happens when solar output is high, demand is low, and transmission capacity is overburdened.

This practice is known as curtailment.

While curtailment directly affects the developer, it can also impact Open Access consumers.

For example, if you’ve signed a generation-based billing PPA, where you pay only for the units actually delivered, curtailment means the developer may only be able to deliver a fraction of the committed power.

As a result, you’ll have to draw the shortfall from the grid, typically at a higher tariff than your solar PPA.

BESS changes that.

If the developer integrates storage at the plant, the curtailed solar energy can be stored instead of being wasted. This stored energy can then be discharged later in the day

By using BESS, the developer can offer a more consistent, blended power supply, helping you maximize the value of your PPA, reduce dependence on high-cost grid power, and improve predictability of your energy costs.

Even when using Open Access, your power still comes through the state grid infrastructure. So, if the local grid fails or becomes unstable, your supply is interrupted.

This affects the production, operations and can even damage sensitive machinery and equipment.

With BESS, you can maintain power flow during short-term grid failures and voltage fluctuations.

On the developer side, BESS ensures consistent round-the-clock power. On the consumer side, BESS provides an instant backup and fewer disruptions.

Most industrial facilities rely on diesel generators as backup during power cuts. But diesel is expensive and polluting.

When paired with BESS, your system can use stored solar energy instead of diesel, reducing both fuel costs and your carbon footprint.

Using BESS with renewable energy sources also enhances a company’s sustainability profile and improves the ESG score.

This is the most common for captive or third-party Open Access solar projects.

• The renewable energy developer owns the BESS.
• It is installed at the solar plant, not at your factory.
• The developer uses BESS to store mid-day solar and supply round-the-clock power to you.
• You get a blended tariff that includes energy supply from both solar + storage.
• It is ideal for users who want evening RE supply and don’t want to install/maintain batteries

This model is becoming common where you already consume Open Access solar during the day, but want to store it on-site for use in the evening or during outages.

• You own the BESS
• It is installed at your facility
• You can store the daytime solar received via Open Access and discharge it during evening or grid outages.
• It is ideal for users with backup needs, or those who want to reduce peak demand charges and reliance on diesel generators.

Follow this simple checklist to make the right decision.

• Do you consume a significant portion of your power during evening or peak hours?
• Are you located in a state with ToD tariffs, curtailment issues, or grid instability?
• Do you rely on diesel generators during outages?
• Are you seeking to improve your ESG score or reduce emissions?
• Do you want greater control over power quality and cost predictability?

If you answer yes to most of these, your business can benefit from integrating BESS with Open Access power.

Also Read:

How Battery Energy Storage Systems (BESS) Are Powering India’s Renewable Future

BESS for C&I Consumers in India: Benefits, Policies & Use Cases

Understanding BESS: Smarter Storage for a Reliable Solar Future in India

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