Energy and Capital Investment

Financing Hybrid Power When Diesel Costs Squeeze Cash Flow

4 November 2026 · Chahinaze Ayadi, CPA, MBA · 5 min read

Solar panels beside tanks and containerised equipment at the Sunshift solar and diesel demonstration plant in Queensland. — The Sunshift solar and diesel demonstration plant in Queensland, Australia. Source: Australian Renewable Energy Agency (ARENA), CC BY 2.5 AU. Illustrative photograph; no CSP involvement is implied.

A higher diesel bill can absorb cash already allocated to a generator overhaul or the next phase of an expansion. For a business generating its own electricity, reducing fuel consumption may become more valuable just as the money available to invest becomes tighter.

The financial decision is how much fuel exposure the business can afford to reduce while preserving reliable power and the investments it still needs to make.

How much cash is left to invest?

Consider a hypothetical site where operating cash payments absorb 90% of customer cash receipts. Fuel accounts for 40% of those payments, equivalent to 36% of receipts. The remaining operating cash surplus is 10% of receipts, before tax, debt service and capital expenditure.

If the fuel bill rises by 15%, with consumption, receipts and all other operating payments unchanged, the additional spending absorbs 5.4% of receipts. The surplus falls from 10% to 4.6%, a reduction of 54%.

That is the pressure the investment decision needs to address. The same business may now struggle to fund equipment renewal even though the case for saving fuel has strengthened. Any recovery from customers must enter the forecast on the date it is expected to be collected.

Establish the diesel investment the business would otherwise make

The comparison starts with a credible plan for continuing diesel generation. Include fuel consumption at expected operating loads, scheduled overhauls, generator replacement and the capacity required to maintain production. A diesel efficiency upgrade may also deserve assessment.

Compare each feasible hybrid configuration against that plan over a consistent operating period. Include the remaining useful life of the site and any supportable residual value. The relevant benefit is the change in future cash flows created by the investment, including additional integration and renewal costs.

A solar installation may reduce annual diesel generation while the engines remain necessary at night, during peak demand or when renewable output is low. In that situation, the cost of keeping them available remains in the plan. Any claim that an overhaul or replacement can be deferred needs technical support.

Storage requires the same discipline. Its additional cost should be assessed against the extra fuel savings and operating flexibility it provides, including the spending needed to maintain performance as the battery ages.

Test the funding gap during construction

Deposits, installation and commissioning may fall due while the business continues paying its full diesel bill. A delay extends this overlap and postpones the savings expected to help fund the project.

For each system that can meet the site’s needs, compare buying the equipment with purchasing power under a suitable agreement. Use the same operating assumptions to assess the value each option adds compared with continuing diesel generation, allowing for the timing and risk of future cash flows. Then map loan receipts, repayments and existing commitments into the company’s cash forecast to identify when funding would be tightest.

A power purchase agreement may reduce the initial capital payment while creating minimum purchases or price escalation. Those obligations need to remain affordable if production falls or the site closes earlier than expected.

Test a fall in diesel prices as well as a sustained increase. Then examine whether a commissioning delay or lower production would require funding beyond the facilities already committed.

Make the approval conditional on value and liquidity

I would recommend proceeding when the project creates more value than continuing with the planned diesel system and the company has confirmed funding to keep essential payments covered if commissioning is delayed. The cash reserve also needs to allow for lower production or smaller fuel savings than expected.

If the full installation would leave too little cash, assess a smaller first phase and include the cost of expanding it later. That first phase must work reliably and justify its cost on its own. If it cannot, the business needs a different funding arrangement or a revised project before committing.

The resulting recommendation should state how much capital to release now, which diesel investments remain necessary and what evidence would justify the next commitment. That connects the energy decision to the business’s ability to maintain production and invest over the years ahead.