Diesel Reduction Using Rooftop Solar Power - Constraints and Considerations - India Renewable Energy Consulting – Solar, Biomass, Wind, Cleantech
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Constraints and considerations that determine the extent of diesel reduction from the use of solar power

In another post, I discussed why 100% replacement of diesel is currently unrealistic for many industrial and commercial establishments.

In this post, I provide more details on this by analysing in detail the various factors / parameters that result in the challenge.

Part of the content for this post was derived from Solar Mango – the Rooftop Solar resource.

Some of the limits facing rooftop solar PV, specifically in the context of diesel replacement, are
  • Solar power is generated only during the daytime on non-rainy days – but power cuts/load shedding could happen any time. While load shedding might not happen regularly during night times, it is quite possible for load shedding to happen in the early morning hours or late evening hours, times when solar power generation is not at its highest.
  • Solar power may not handle the heavy starting currents required by heavy machinery – the starting current requirements for many heavy machinery and for chillers, air conditioners etc., could be quite high for a short duration but solar power is generating electricity at almost constant or rates or only with gradual differences over a 6-8 hour period. Unless a battery system is used that can provide the sudden spurt in load requirements, solar power systems might be ill-equipped to handle this spike. While this indeed could be a challenge, some of the early movers in India to use rooftop solar for diesel abatement appear to have succeeded in using the diesel/solar combination for large starting currents as well, without the use of batteries.
  • The output of the solar plant varies as the sun moves across the sky, and as clouds move across the sun – even when solar power is used for light loads requiring an almost constant load during the day time, there are times even during sunshine hours when solar power output could momentarily drop significantly.
  • Limited roof area constrains the capacity of solar PV plant that can be installed – A kW of solar power plant requires about 100 sq.ft, not exactly a small amount of space. For a company that has a grid connected load of 1 MW, this could mean installing much more than 1 MW of solar power system, requiring in excess of 3 acres (120,000 sqft) of rooftop space!

Due to the above reasons, and with currently available technology solutions, rooftop solar ideally acts in conjunction with diesel generators, taking up part of the load and saving, but not eliminating, diesel expenditure. The extent to which it can reduce diesel consumption depends on the answer/input to each of the four factors listed above. In most cases however, do not expect more than 30-40% of present diesel consumption to be reduced by solar power (there could be exceptions such as telecom towers which have low load requirements where replacements above 50% of diesel use could be possible).

See also this blog post – Can rooftop solar completely eliminate diesel use from diesel gensets?

EAI’s Diesel to Solar Report – The one and only such report in the world

EAI has published the only report that provides inputs on how companies can go about using rooftop solar power to reduce their diesel consumption. The Diesel to Solar report is a comprehensive rooftop  solar implementation guide that assists you in your need to reduce diesel consumption for power.

Related posts for replacing diesel with solar

Substituting Diesel with Rooftop Solar PV – Economics and Costs

Rooftop Solar – Solutions to Support Different Loads While Offsetting Diesel Consumption

Integrating Rooftop Solar with Diesel Generator for Diesel Reduction

Can Rooftop Solar Power Replace All Diesel Consumption from Gensets?

Replacing Diesel Gensets with Solar on Rooftops – Something Really Worth Exploring for Indian Industry

Also: Check out an interesting site on solar: Suncyclopedia, the Solar Encyclopedia

About Narasimhan Santhanam (Narsi)

Narsi, a Director at EAI, Co-founded one of India's first climate tech consulting firm in 2008.

Since then, he has assisted over 250 Indian and International firms, across many climate tech domain Solar, Bio-energy, Green hydrogen, E-Mobility, Green Chemicals.

Narsi works closely with senior and top management corporates and helps then devise strategy and go-to-market plans to benefit from the fast growing Indian Climate tech market.

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