What it means
The structure has three distinct phases and each carries a different risk. Construction risk sits with the private consortium, operating risk is shared according to the contract, and transfer risk is about what condition the asset is in when it changes hands.
Pricing a BOT deal means pricing all three separately. Money is usually raised through a special purpose vehicle, a company set up only to own and run that one project.
Lenders look at the project's own forecast cash flows rather than the parent company's balance sheet, which is why this is called project finance. The sponsors contribute equity, typically a fifth to a third of the cost, and debt provides the rest.
Revenue comes in one of two broad shapes. Either users pay directly, as with a toll road, which leaves the consortium carrying demand risk, or the government pays a fixed sum for keeping the asset available, which pushes demand risk back to the state.
Which model is chosen changes the cost of capital more than almost any other term in the contract. The concession length is set so that the private side can recover its investment and earn a return, commonly 20 to 30 years for large assets.
A longer concession lowers the annual charge but locks the public sector into terms for a generation. Renegotiations are common, and they are usually where value is won or lost.
The nuance that catches people out is the handover condition. A consortium nearing the end of its concession has little incentive to invest in the asset, so well-drafted contracts include maintenance standards, an inspection regime and retained payments to enforce them.
Without those clauses the state inherits a worn-out asset and an immediate repair bill.
In practice
Real-world examples.
Example
A government awards a 25-year BOT concession for a new container terminal. The consortium raises $400,000,000, builds the terminal in three years and charges handling fees to shipping lines for the remaining 22 years before transferring it to the port authority.
Example
A city commissions a water treatment plant on a BOT basis where it pays a fixed monthly availability charge rather than letting the operator bill households. The operator accepts a lower return because it carries no demand risk, and the city keeps control of consumer tariffs.
Example
A toll motorway built under a BOT contract attracts only 60% of the traffic forecast in the bid. The consortium breaches its loan covenants, lenders take control, and the concession is restructured with a longer term and a government guarantee, which is a common pattern wherever demand risk was underpriced.
Formula
Calculation
Simple payback period = total capital cost / annual net operating cash flow
Total cash recovered over a concession = annual net operating cash flow x concession years
A consortium builds a toll bridge for $300,000,000 and expects net operating cash flow of $45,000,000 a year once it opens. The simple payback period is 300,000,000 / 45,000,000 = 6.7 years. Over a 25-year concession the total cash collected is 45,000,000 x 25 = $1,125,000,000, a surplus over the build cost of 1,125,000,000 - 300,000,000 = $825,000,000 before financing and tax. Financing is what turns that comfortable figure into a thin one: at 6% on $210,000,000 of debt, interest in the first year alone is 210,000,000 x 0.06 = $12,600,000, which is 28% of the project's annual cash flow.Case study
Seen in the real world.
Calderidge Energy Partners is an illustrative, fictional consortium that won a 20-year BOT concession to build a 60 megawatt solar plant for a regional utility. The build cost $90,000,000, funded with $27,000,000 of equity and $63,000,000 of debt, and the utility agreed to buy all output at a fixed price per unit.
Because the utility carried demand risk, Calderidge's lenders accepted a lower interest rate, and the project cleared its debt service comfortably in its first full year. The weakness in the contract was elsewhere: the handover clause required only that the plant be operational at transfer, with nothing said about remaining panel efficiency.
In year 17 Calderidge stopped replacing degraded panels, and the utility took over a plant producing well below its rated output. The illustrative lesson is that in a BOT contract the transfer terms deserve as much attention at signing as the construction price does.
Watch out
Common mistakes.
- Judging a BOT bid on construction price alone, when the concession length, the revenue model and the handover standards usually matter more to total cost.
- Assuming the public sector carries no risk because it pays nothing upfront, when a failed concession almost always ends up back with the state.
- Leaving the handover condition vaguely drafted, which gives the operator every reason to stop maintaining the asset in its final years.
Questions
People also ask.
What is the difference between a BOT and a straight construction contract?
In a construction contract the state pays for the asset and owns it from day one, while in a BOT the private side funds it and earns its money back over years of operation.
Who carries demand risk in a BOT deal?
It depends on the revenue model, with user-pays structures such as toll roads leaving demand risk with the consortium and availability-payment structures leaving it with the government.
Why are BOT concessions so often renegotiated?
Forecasts covering 20 to 30 years are rarely accurate, so traffic, costs or interest rates move far enough that one side seeks new terms, which is why contract management matters more than a clever bid.
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