Solar equipment manufacturing · Renewable energy and clean technology
Solar manufacturing costed per watt, by power class and by batch
A solar manufacturer buys cells, glass and frames at one price and sells modules months later at another, sorted into power classes it cannot fully predict. We cost each power class and batch per watt and test inventory against what it will sell for, so margin is known by product rather than discovered at the stock count.
In one paragraph
Makers of solar modules, cells, inverters and mounting structures, usually on ₹50–2,000 crore turnover, sell to EPC firms, developers and distributors. Their managing directors and finance chiefs work with volatile, largely imported input prices. Output is binned into power classes after production, and performance warranties last decades. Access to some markets depends on approved-list and domestic-content requirements.
Managing director or chief financial officer
The economics
How the money moves in this trade
A module line converts cells, glass, frames, encapsulant and junction boxes into modules that are tested and sorted by rated power. Material is most of the cost, much of it imported and bought on letters of credit, and its price can move faster than the finished-goods market. When prices fall, stock bought earlier may be worth less than its cost, and the gap has to be recognised. Yield, breakage and the distribution of output across power classes decide the real cost per watt.
Sales into government-linked projects depend on approved lists of models and manufacturers. The module list is now tied to a separate approved list for cells, and some schemes also require domestic cells. The firm must be able to trace which cells went into which modules and invoices. Production-linked incentives, where a firm participates, depend on production, sales and value-addition data that must be reconciled and supported. Performance warranties commonly run for twenty-five years or more, and product warranties for a decade or more, so both need a provision with a basis behind it.
The problem
Where the numbers usually break down
Cost per watt is averaged across power classes
Every module carries the same cost, so higher-power classes look more profitable than they are and lower bins, which absorb the same material, look like failures.
Inventory is not tested against realisable value
Cells and finished modules bought or made when prices were higher are carried at cost, and the write-down is found at year end rather than as prices move.
Domestic-content traceability is kept outside the books
Which cells went into which modules sold as domestic content is tracked on a production sheet that does not reconcile with purchase and sales invoices.
Warranty provisions have no basis
A flat percentage of sales is provided for warranty, without reference to return rates, claim history or the length of the warranty given.
Incentive claims rest on unreconciled data
Production, sales and value-addition figures for incentive claims are compiled separately from the accounts and do not agree with them.
What we do
The work, and the result each part produces
Cost per watt by power class
Material, conversion, yield loss and breakage costed for each batch and spread over the power classes actually produced.
Pricing and product mix are decided on true cost per watt.
Inventory at realisable value
Raw material, work in progress and finished modules compared with current market prices every month.
Write-downs are recognised as prices move, not at year end.
Cell-to-module traceability
Cell purchases linked to production batches and to the sales invoices of modules sold as domestic content.
Any domestic-content claim can be supported from the books.
Warranty provisioning basis
Provision built from sales by year, warranty terms, return and claim history and replacement cost.
The provision can be explained to an auditor or an investor.
Incentive data reconciliation
Production, sales and value-addition figures for incentive claims reconciled to the accounts and the production record.
Claims are supported by records that already agree.
Import and working-capital view
Letters of credit, import duties, currency exposure and inventory days tracked against customer collections.
Cash needs from import cycles are planned rather than met by emergency borrowing.
Where we start
The first steps of an engagement
Production, purchase and stock records
We ask for batch production reports with power-class output, cell and material purchase invoices, the stock ledger, current selling prices by class, and warranty claims to date.
Cost per watt and stock value
Material, conversion, yield loss and breakage for recent batches are spread over the power classes produced. Stock on hand is then valued against current prices.
Cell-to-invoice traceability
Cell purchase lots are linked to production batches and onwards to sales invoices, so modules sold under domestic-content or approved-list terms can be traced in the books.
Margin and inventory report
The first report shows cost per watt by power class and batch, margin by class at current prices, any inventory write-down needed, and gaps in cell traceability.
How it is measured
The reports the work is judged on
Each is recorded as a baseline before the work starts, so later reports have an honest comparison.
- Cost per watt by power class and batch
- Yield and breakage, by line
- Inventory against realisable value
- Warranty provision against claims experience
- Incentive data reconciled to the books
- Cash conversion cycle including import lead time
Who it suits
Written for, and not the right fit for
- You install plants rather than make equipment; our solar EPC page is a better fit.
- You need a statutory audit, a cost audit or a certificate for an incentive claim on its own; those are signed by an independently engaged professional.
- Manufacturers of solar modules, cells, inverters or mounting structures selling to EPC firms and developers.
- Manufacturers adding capacity or moving into cell production with incentive or domestic-content obligations.
- Firms preparing for bank limit increases, an equity raise or a listing.
Services
Services this work draws on
Costing and profitability
What each product, line and customer really contributes.
Explore service ↗Internal controls and risk
Controls sized to your business, documented and actually tested.
Explore service ↗MIS and financial planning
Reporting built around the questions you actually need answered.
Explore service ↗Banking, funding and due diligence
Information a lender or investor can verify without a reconstruction.
Explore service ↗GST, TDS and tax compliance
GST, TDS and income-tax prepared from reconciled data, not a working file.
Explore service ↗Every other service, also available in this trade
Common questions
Questions owners in this trade ask
Why cost by power class rather than by module?
Because every module uses broadly the same material but sells at a price tied to its rated power. Averaging hides which classes earn their cost, and that's the information you need when you're deciding cell quality and pricing.
Who prepares and certifies production-linked incentive claims?
We reconcile the production, sales and value-addition data and prepare the supporting schedules. Any certificate the scheme requires from a chartered accountant or cost accountant is issued by an independently engaged professional.
How often should inventory be tested against market prices?
Monthly in a market that moves as fast as this one. A quarterly or annual check usually finds the problem after the stock has already been sold below cost.
5th Quadrant performs costing, inventory, provisioning and reconciliation work. Statutory audit, cost audit, tax-audit reports and certificates required for incentive or domestic-content claims are issued by an independently engaged chartered or cost accountant, coordinated through 5th Quadrant. Full detail is on our Professional Scope page.
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