Depreciation of Outdated Energy Infrastructure

1. Introduction

Depreciation of outdated energy infrastructure deals with how the remaining value of old or obsolete energy assets should be treated for accounting and electricity-tariff purposes.

Energy infrastructure includes power plants, transmission lines, substations, transformers, distribution networks, hydro projects, pipelines and other long-life assets. Normally, their cost is recovered gradually over their useful life. But an asset may become outdated before its expected life because of technological change, environmental rules, energy-transition policies, safety problems or economic changes.

This creates an important legal question: Can the utility continue recovering the unrecovered cost from consumers after the asset is no longer being used?

Recent Indian Supreme Court authority makes this question especially important.

2. Meaning of Depreciation

Depreciation is the allocation of the depreciable cost of an asset over the period in which the asset is expected to provide useful service.

It is not simply a measure of the market price of the asset. In Delhi Electricity Regulatory Commission v BSES Yamuna Power Ltd. (2007), the Supreme Court explained that depreciation is an allocation of cost over the expected useful life of an asset. (Indian Kanoon)

For example, if a power plant costs ₹100 crore and has a regulatory useful life of 20 years, the regulatory framework may allow its depreciable cost to be recovered gradually over that period.

3. When Infrastructure Becomes Outdated

An energy asset may become outdated because of:

Technological obsolescence – newer technology becomes more efficient.

Environmental regulation – pollution standards make continued operation difficult.

Energy transition – coal or other conventional assets may be replaced by renewable energy.

Economic changes – operating the asset may become too expensive.

Safety concerns – an old facility may require retirement or major replacement.

Change in system requirements – the electricity network may no longer need the asset.

Therefore, technical useful life and actual regulatory/economic use are not always identical.

4. Regulatory Depreciation and Consumer Interest

Electricity depreciation is important because it can become part of the regulated tariff.

Section 61(d) of the Electricity Act, 2003 requires the appropriate commission to safeguard consumer interests while allowing reasonable recovery of the cost of electricity.

This creates two competing concerns:

Utility: It should recover legitimate investment made for providing electricity.

Consumer: Consumers should not be required to pay for an asset that has stopped providing them electricity without a proper legal basis.

The regulator therefore has to examine the circumstances of the asset's retirement.

5. Important Case: DERC v Tata Power Delhi Distribution Ltd (2026)

A particularly important recent Supreme Court decision is Delhi Electricity Regulatory Commission v Tata Power Delhi Distribution Ltd., 2026 INSC 461.

The dispute concerned the Rithala Combined Cycle Power Plant in Delhi. The plant was originally approved as a temporary facility with an operational period of approximately 5–6 years. It stopped supplying electricity to consumers after March 2018.

DERC had allowed depreciation for the period during which the plant supplied electricity but refused to pass the remaining capital cost through tariff after the plant stopped supplying consumers.

APTEL took a different approach and directed recovery of the capital cost over the plant's 15-year useful life. The matter reached the Supreme Court. (Indian Kanoon)

Importance of the case

The Supreme Court considered whether depreciation must automatically be allowed for the entire technical useful life, even when the asset had stopped supplying electricity.

This case is highly relevant to outdated infrastructure because it directly examines the relationship between:

useful life;

actual utilisation;

regulatory approval;

capital recovery; and

consumer interests.

6. Useful Life Is Not Always the Same as Actual Use

The Rithala case demonstrates an important distinction.

An asset may have a technical useful life of 15 years, but this does not automatically mean that consumers must pay depreciation for all 15 years.

The legal question also includes:

For how long was the asset authorised to operate?

Was it actually used to supply consumers?

What conditions governed its approval?

Was its early retirement foreseeable?

Has the utility already recovered part of its capital?

Would further recovery impose an unjustified burden on consumers?

Therefore, technical useful life alone cannot necessarily determine tariff recovery.

7. Case: DERC v BSES Yamuna Power Ltd.

In Delhi Electricity Regulatory Commission v BSES Yamuna Power Ltd. (2007), the Supreme Court dealt with the appropriate depreciation rate for electricity distribution assets.

The Court explained the basic accounting meaning of depreciation as the allocation of depreciable cost over the expected useful life of an asset. (Indian Kanoon)

The decision is important because it establishes that depreciation for regulatory purposes must be understood according to the purpose of the regulatory exercise, rather than being treated simply as a measure of the asset's current market value.

8. Case: Maharashtra State Power Generation Co. Ltd. v MERC

In Maharashtra State Power Generation Co. Ltd. v Maharashtra Electricity Regulatory Commission (2008), the Appellate Tribunal explained that depreciation for tariff purposes may differ from depreciation shown in a utility's financial accounts.

The Tribunal observed that the regulatory approach seeks to allocate the depreciable value over the useful life so that the generator can obtain reasonable recovery of the depreciable amount over time. (Indian Kanoon)

Relevance

This is important when dealing with old infrastructure because accounting depreciation and regulatory depreciation are not necessarily identical.

9. Accelerated Depreciation

Where an asset is expected to become obsolete earlier than originally expected, regulators may consider accelerated depreciation where permitted by the applicable regulatory framework.

For example:

A power plant has an expected 25-year life, but environmental rules require closure after 15 years.

If the regulatory framework permits it, the remaining depreciable amount may need to be recovered over the shorter period.

However, accelerated recovery can increase electricity tariffs during the remaining operating years. Therefore, the regulator must carefully balance asset recovery and consumer affordability.

10. De-capitalisation of Old Assets

Another important mechanism is de-capitalisation.

When an asset is permanently removed from service, its capital cost may need to be removed from the regulatory asset base according to the applicable tariff regulations.

The CERC Tariff Regulations, 2019 contain specific provisions concerning depreciation, useful life and adjustment of cumulative depreciation when assets are de-capitalised. (Indian Kanoon)

This prevents an obsolete asset from remaining indefinitely within the regulatory capital base.

11. Life Extension and Renovation

An old asset does not always have to be immediately retired.

Sometimes renovation, modernisation or replacement of machinery can extend its useful life.

For example, an old hydroelectric station may receive:

new turbines;

new generators;

upgraded control systems; or

improved safety equipment.

In such situations, regulators must distinguish between:

old depreciated capital and new approved investment.

The CERC framework specifically contemplates proposed capital expenditure and proposed life extension as projects approach the end of their useful lives. (Indian Kanoon)

12. Stranded Assets

An outdated energy asset may become a stranded asset.

A stranded asset is an asset whose expected economic value cannot be fully realised because circumstances have changed.

Examples include:

coal plants affected by climate policy;

old gas plants made uneconomic by renewable generation;

obsolete transmission infrastructure;

outdated grid equipment; and

infrastructure replaced by distributed energy systems.

The major legal issue is whether the remaining investment should be recovered from consumers, shareholders, government support, or another mechanism.

13. Consumer Protection and Intergenerational Fairness

Depreciation also raises an issue of fairness between different groups of consumers.

If today's consumers have already paid for most of an asset through earlier tariffs, future consumers should not unnecessarily pay the same cost again.

Similarly, if a utility made a legitimate investment that was approved under the regulatory system, completely denying recovery could affect its financial stability.

Therefore, the regulator should examine:

whether the investment was prudent;

how much depreciation has already been recovered;

why the asset became obsolete;

whether early retirement was foreseeable;

whether consumers benefited from the asset; and

whether further recovery is legally justified.

14. Energy Transition and Depreciation

The issue is becoming more important because energy systems are changing rapidly.

The transition involves movement from:

coal → renewable electricity

centralised generation → distributed generation

traditional grid → smart grid

fossil-fuel transport → electric transport

These changes can make existing infrastructure economically outdated before its physical life ends.

Therefore, future tariff regulation must increasingly consider technological change, environmental policy and stranded-asset risk when determining depreciation.

15. Conclusion

Depreciation of outdated energy infrastructure is not simply an accounting issue. It is a major electricity-regulation issue involving tariff recovery, consumer protection, investment security and energy transition.

The key principles are:

Depreciation allocates the cost of an asset over its useful life.

Technical useful life does not always equal actual regulatory use.

An asset that stops supplying electricity may raise difficult questions about further tariff recovery.

Accelerated depreciation may be relevant where early retirement is legally recognised.

De-capitalisation prevents permanently retired assets from remaining improperly in the regulatory asset base.

Renovation and life extension can justify a different regulatory treatment.

Consumer interests must remain central to tariff decisions.

The 2026 Supreme Court decision in Delhi Electricity Regulatory Commission v Tata Power Delhi Distribution Ltd is particularly significant because it directly addresses whether the remaining capital cost of a plant that has stopped supplying electricity can automatically be recovered through depreciation. (Indian Kanoon)

Thus, the central principle is that depreciation of outdated infrastructure must balance legitimate recovery of investment with the protection of consumers from paying for assets that no longer provide the regulated service.