Diesel generator sets are widely used by offices, factories, hospitals, commercial buildings, and other facilities for reliable backup power. However, older DG sets can produce higher levels of particulate matter and other exhaust emissions compared with newer emission-compliant models.

This is where an RECD retrofit for old DG sets can become an important option. Instead of immediately replacing an existing generator, an organisation can evaluate whether installing a Retrofit Emission Control Device (RECD) is technically suitable and financially practical.

But the main question is: is RECD retrofit for old DG sets cost-effective?

The answer depends on the generator's age, condition, capacity, operating hours, maintenance history, and the cost of replacement.

What Is RECD for DG Set?

RECD stands for Retrofit Emission Control Device. It is an after-treatment system installed in the exhaust line of an existing diesel generator to control emissions.

An RECD is designed to reduce particulate matter from the exhaust and must meet the applicable testing and approval requirements. CPCB's RECD procedure specifies minimum PM-reduction requirements for applicable older engine/genset categories and requires RECD suppliers to obtain type approval and follow conformity-of-production requirements.

Unlike buying a completely new generator, an RECD retrofit allows the existing DG set to remain in service, provided the generator is technically suitable and meets the applicable regulatory requirements.

Why Consider RECD Retrofit for an Old DG Set?

Replacing an old DG set with a new emission-compliant model can require a significant investment. There may also be additional costs related to transportation, installation, electrical work, foundation changes, and disposal or replacement of the existing equipment.

An RECD retrofit for old DG sets can offer an alternative when the existing engine is still mechanically healthy.

Some important advantages include:

• Lower initial investment compared with complete generator replacement in suitable cases

• Continued use of an existing generator asset

• Reduced exhaust particulate emissions

• Potentially less disruption to backup-power arrangements

• Opportunity to upgrade emission control without replacing the complete DG set

However, RECD should not be treated as a solution for a generator that already has serious mechanical problems.

Is RECD Retrofit for Old DG Sets Cost-Effective?

The answer depends on the overall condition and economics of the DG set.

For example, if a 250 kVA generator has a healthy engine, good maintenance history, acceptable fuel consumption, and sufficient remaining service life, retrofitting may be worth evaluating.

On the other hand, if the same generator has frequent breakdowns, excessive oil consumption, poor compression, major cooling problems, or expensive repair requirements, investing in emission-control equipment may not provide the best long-term value.

Therefore, is RECD retrofit for old DG sets cost-effective cannot be answered by looking only at the RECD purchase price.

You should compare:

When Is RECD Retrofit a Better Option?

An RECD retrofit may be worth considering when the existing DG set:

• Has a healthy and reliable engine

• Is regularly maintained

• Does not have major mechanical problems

• Still has useful operating life remaining

• Has acceptable fuel consumption

• Is important to the facility's backup-power requirements

• Can technically accommodate an appropriately sized RECD

The generator's capacity, exhaust flow, backpressure requirements, engine condition, and site arrangement should be evaluated before selecting the system.

CPCB guidance also makes clear that applicable in-use DG sets have specific requirements regarding RECD performance and approval, so selecting a properly type-approved system is important.

When Should You Consider Replacing the DG Set?

RECD is not a replacement for engine maintenance or major mechanical repairs.

A new DG set may make more sense when the existing generator has:

• Frequent breakdowns

• Severe engine wear

• High oil consumption

• Poor fuel efficiency

• Major cooling-system problems

• High repair and maintenance costs

• Very limited remaining useful life

• Significant operational reliability issues

In such cases, spending money on emission-control equipment may only solve the emission-control part of a much larger equipment problem.

What Affects the Cost of RECD Retrofit?

The cost of an RECD installation can vary depending on several factors.

1. DG Set Capacity

A larger DG set generally requires a suitably sized emission-control system. The RECD must be matched to the generator's technical requirements.

2. Engine Condition

A well-maintained engine is generally a better candidate for retrofit than an engine with serious mechanical problems.

3. Exhaust Arrangement

The existing exhaust piping, available space, mounting arrangement, and installation conditions can affect the retrofit work.

4. Installation Requirements

Fabrication, piping modifications, electrical connections, monitoring equipment, and commissioning requirements can influence the total project cost.

5. Compliance Requirements

The selected RECD should meet the applicable CPCB testing and approval requirements. CPCB's procedure requires type approval and conformity-of-production compliance for RECD suppliers.

How to Decide: Retrofit or Replace?

Before making the decision, conduct a practical assessment of the existing DG set.

Check the following:

Step 1: Check the generator's age.
Identify the manufacturing date and applicable regulatory requirements.

Step 2: Inspect the engine.
Check compression, oil consumption, cooling performance, fuel system condition, and general engine health.

Step 3: Review maintenance history.
A generator with regular servicing and fewer breakdowns may be a better retrofit candidate.

Step 4: Calculate the total retrofit cost.
Include the RECD, installation, fabrication, commissioning, and future maintenance requirements.

Step 5: Compare replacement cost.
Consider the cost of a new compliant DG set along with installation and related expenses.

Step 6: Check compliance requirements.
Confirm that the proposed solution is applicable to your specific DG set and regulatory situation.

FAQs

1. What is an RECD for DG set?

An RECD is a Retrofit Emission Control Device installed in the exhaust system of an existing diesel generator to control particulate emissions and meet applicable emission-control requirements.

2. Is RECD retrofit for old DG sets cost-effective?

It can be cost-effective when the existing DG set is mechanically healthy, reliable, and has sufficient remaining service life. The final decision depends on retrofit cost versus replacement cost.

3. Can every old DG set be fitted with RECD?

Not necessarily. Suitability depends on the generator's engine, capacity, exhaust system, operating condition, and applicable regulatory requirements. A technical assessment should be completed before installation.

4. Does RECD replace the need for DG set maintenance?

No. RECD controls exhaust emissions, but the generator still requires regular engine, fuel, lubrication, cooling, electrical, and exhaust-system maintenance.

5. Should I buy a new DG set or install RECD?

If your existing DG set is healthy and has useful life remaining, RECD may be worth evaluating. If the generator has major mechanical problems or high repair costs, replacement may be a better option.

6. Why is proper RECD selection important?

The RECD needs to be appropriate for the specific generator and meet applicable testing and approval requirements. CPCB's procedure includes type approval and conformity-of-production requirements for RECD suppliers.

Conclusion

An RECD retrofit for old DG sets can be a practical and cost-effective option when the existing generator is mechanically sound and has useful service life remaining. It can help control particulate emissions without immediately replacing the complete DG set.

However, retrofit decisions should be based on more than the RECD price. Generator condition, operating hours, maintenance costs, installation requirements, remaining life, and applicable regulations should all be considered.

If the existing DG set is reliable and suitable for retrofit, RECD can be worth evaluating. If the generator is already suffering from major mechanical and operational problems, replacement may provide better long-term value.

For businesses evaluating their options, the right approach is to compare the total cost of RECD retrofit with the total cost of replacing the DG set before making a final decision.