This document sets out the economic logic for SPARC stream agreements. It is the reference framework for assessing when a coal operator, a renewable operator or another approved delivery party, and the relevant public authorities can rationally support a SPARC transaction.

This framework follows the current SPARC white paper logic and should be read together with the current white paper at sparc.now/whitepaper.

All numerical values and worked examples in this document are illustrative scenario inputs. They are not transaction terms, tariff recommendations, forecasts, offers, or final SPARC parameters. Any transaction model, regulatory submission, or asset-level negotiation must replace them with source PPA data, asset data, market data, and jurisdiction-specific assumptions.

The forward commercial object is the SPARC stream. A SPARC stream is the registered basket of rights and obligations attached to a defined delivery band inside an existing coal PPA. It carries the right to supply power under the band, the right to receive the associated payment, and the embedded right to emit carbon dioxide per delivered MWh. It also carries the corresponding availability, delivery, replacement-power, scheduling, and capacity obligations where these apply.

Individual SPARCs are created only after eligible MWh are delivered under that registered stream and evidenced through the required metering and attribute systems. The economics therefore do not start from a free-standing price for individual SPARCs. They start from the value and obligations of the stream agreement. The parties define the delivery band, the performance obligations, the payment-sharing formula, the risk allocation, and the allocation of ARC value. Actual SPARCs then arise from metered delivery under the registered stream.

The purpose of this framework is to answer one question: can the stream agreement preserve the coal operator's economic position while paying the delivery party enough to perform lower-emission delivery?

A SPARC stream clears only when both sides can be satisfied at the same time. The coal operator must retain enough value to be financially neutral or better compared with self-delivery. The delivery party must receive enough value to cover its delivery cost, performance risk, and required return. Avoided coal cost, transferred risk, transferred obligation value, ARC value, and any recognized grid value create the economic headroom that can make this possible.

1. The Economic Object

A SPARC stream is a defined commercial and operational band inside an existing coal PPA or equivalent coal-backed contractual structure. The stream agreement determines how the value of that band is shared between the coal operator and the delivery party.

The PPA remains intact. The coal operator remains the PPA-facing party in the preferred early model. The delivery party fulfills the agreed stream under the rules recognized by the regulator, system operator, or registry process.

This distinction matters for economics. The object being negotiated is not a pre-issued MWh certificate. The parties negotiate a forward stream. The registry creates MWh-level SPARC records only when eligible delivery occurs. Payment may be expressed per delivered MWh, as an availability fee, as a revenue-share formula, as a true-up mechanism, or as a combination of these elements. The form can vary. The economic test remains the same.

The SPARC stream must be evaluated as a package of value and obligation:

ElementEconomic meaning
Delivery bandThe agreed volume, profile, window, or performance band to be fulfilled by the delivery party.
Settlement valueThe expected value of PPA or market payments allocated to the stream.
Capacity or availability valueThe value attached to capacity or availability obligations where the underlying PPA includes them and the stream agreement allocates them.
Energy valueThe value attached to eligible MWh that are dispatched, scheduled, nominated, delivered, metered, and settled.
Embedded emission rightThe tCO2/MWh value carried by each SPARC created under the stream.
Delivery obligationThe obligation to perform, including replacement power, imbalance, curtailment, and penalty treatment where applicable.
ARC allocationThe commercial allocation of ARC value created when the embedded emission right is unused.
Grid valueAny recognized value created by the delivery profile, injection point, congestion relief, or system benefit.

2. Settlement Value Rather Than Fixed PPA Value

For analytical purposes, all payments and costs should be translated into a consistent MWh-equivalent basis. This framework uses VSETTLE for the expected settlement value allocated to the SPARC stream.

VSETTLE is not simply a posted tariff. It is the expected value of the payments that arise when eligible MWh are dispatched, scheduled, nominated, delivered, metered, and paid under the PPA or applicable market rules, plus any capacity or availability value allocated to the stream.

In an energy-only PPA, VSETTLE may be close to the expected energy payment per MWh, adjusted for dispatch probability, settlement timing, performance deductions, and regulatory treatment.

In a capacity-plus-energy PPA, VSETTLE must allocate the relevant capacity or availability value to the stream and add the expected energy settlement value. Capacity and availability payments are not naturally MWh-based. They should first be allocated to the SPARC stream and then converted into MWh-equivalent value using expected eligible MWh for that stream, not final dispatched MWh that will only be known after system-operator dispatch.

If the stream is a firm daytime band, expected eligible MWh should reflect the MW band, delivery hours, delivery days, and assumed availability for that band. If the stream is seasonal, dispatch-linked, or shaped, the expected eligible MWh denominator should follow the recognized stream parameters. A detailed implementation may apply a periodic true-up if actual eligible MWh differ materially from expected eligible MWh.

Equivalently:

In the second formulation, each numerator is the expected value allocated to the stream for the relevant settlement period. This approach avoids false precision. The stream agreement does not require every payment to be fixed in advance. It requires a formula that can allocate realized settlement value, capacity value, performance adjustments, ARC value, and grid value in a way that both parties can underwrite.

3. Stream Profiles and Delivery Cost

A SPARC stream may take different shapes. The economics depend heavily on that shape.

For coal-linked streams, the main commercial case is likely to be a firm or near-firm band. Coal units cannot easily ramp around intermittent injections. A predictable delivery band is easier for the coal operator, system operator, and regulator to recognize as a true substitute for self-delivery. Examples include a firm daytime band, a 12-hour band, a seasonal block, or another availability-backed profile.

Coal operators and delivery parties may also agree to more flexible stream designs. The default modelling treatment for a flexible stream should be energy-only unless the stream agreement clearly allocates a capacity, availability, balancing, replacement-power, or performance obligation to the delivery party. A gas-fired plant or another rampable resource may be able to accommodate a shaped delivery profile more easily than a coal unit. In those cases, the delivery obligation may be less firm, provided the stream agreement and system rules define how the originating plant, delivery party, and system operator manage the profile.

For a firm band, the simpler default treatment is different. If the parties define a firm SPARC band and allocate the capacity or availability payment layer associated with that band, the delivery party should be treated as assuming the matching firm-delivery, availability, balancing, replacement-power, penalty, and performance obligations for that band. The corresponding value may then enter Otransferred, subject to the coal operator retaining the fixed-cost recovery, debt service, margin, residual PPA standing, and any obligations it continues to carry.

The stream profile determines CDELIVER and RDELIVER.

CDELIVER is the delivery party's cost of eligible performance. For a renewable operator, it may include generation cost, firming cost, storage cost, balancing cost, replacement-power cost, incremental operating cost, settlement administration, compliance, and any metering or evidence cost required by the product code.

RDELIVER is the delivery party's risk premium. It should cover performance risk, imbalance risk, replacement-power exposure, curtailment risk, settlement timing, penalty exposure, and other obligations allocated under the stream agreement.

A firm band usually raises both CDELIVER and RDELIVER because the delivery party must shape intermittent generation into a reliable contractual profile. A shaped stream may reduce delivery cost, but it may leave more balancing and operational risk with the coal operator or system operator. That affects the coal operator's required retained value and the stream's regulatory acceptability.

For a fixed band, annual eligible volume is calculated as:

For a dispatch-linked stream:

For example:

If every eligible MWh is delivered under the registered stream, the registry can create up to 219,000 SPARCs per year, subject to dispatch, metering, evidence, and product-code rules.

4. Coal Operator Economics

The coal operator assigns fulfillment of a SPARC stream only if it is financially neutral or better compared with self-delivery.

When the delivery party fulfills the agreed band, the coal operator does not produce the corresponding MWh itself. It avoids fuel cost, variable operating cost, and some operational risk. It may also transfer defined capacity, availability, firm-delivery, balancing, replacement-power, or performance obligations to the delivery party.

The coal operator still needs to preserve the economic position attached to the underlying PPA. That includes fixed-cost recovery, debt service, required return, and any value it would have retained by self-performing the same band.

The coal operator's minimum retained value is:

Where:

TermMeaning
VSETTLEExpected settlement value allocated to the SPARC stream.
CavoidedFuel cost, variable O&M, avoidable emissions cost, and any fixed operating cost genuinely avoided because the coal operator does not produce or support the relevant delivery band itself.
RreliefMonetized value of risk transferred away from the coal operator under the stream agreement.
OtransferredPortion of stream value that can be released from the coal operator's retained value because the delivery party assumes the matching capacity, availability, firm-delivery, balancing, replacement-power, or performance obligation.
Coal MinimumMinimum retained value the coal operator needs to be financially neutral compared with self-delivery.

The coal operator is economically whole when its retained value under the stream agreement is at least equal to Coal Minimum. If the retained value is below Coal Minimum, the operator is better off delivering the stream itself.

The stream agreement then defines FSTREAM, the expected stream fulfillment compensation allocated to the delivery party per eligible delivered MWh.

Under the preferred bilateral model:

The coal condition is:

After cancelling VSETTLE:

This is the available stream payment for delivery-party compensation in the simplified bilateral model. The coal operator can release value to the delivery party up to the value of avoided cost, transferred risk, and transferred obligation value while remaining economically whole. VSETTLE still matters because it determines the gross value pool, fixed-cost recovery, tariff integrity, and regulatory reasonableness.

4.1 Avoided Coal Cost

Cavoided should be based on plant physics and contract treatment. In a simple model, it includes avoided fuel cost and variable O&M. Where an emissions cost exists, it may also include avoidable emissions cost. Where a transferred stream genuinely reduces fixed operating burden at the relevant scale, it may include the fixed operating cost that is actually avoided. It should not include fixed-cost recovery, debt service, or required return that the coal operator still needs to retain under the underlying PPA.

Where fuel is fully passed through to the offtaker, the analysis must be careful: avoided fuel cost may reduce system cost or customer cost but may not accrue entirely to the coal operator unless the stream agreement or regulatory treatment allocates that value.

For coal fuel:

Illustrative physical assumptions:

  • Coal energy content: about 25 GJ/tonne for 6,000 kcal/kg coal.
  • Heat rate: about 10 GJ/MWh for a modern subcritical or supercritical baseload unit.
  • Non-fuel variable O&M: about USD 4-6/MWh.

At a delivered coal price of USD 100/tonne:

At a Newcastle-linked benchmark of USD 132.5/tonne:

The delivered coal price used in a live model should reflect the relevant fuel procurement terms, coal quality, freight, handling, pass-through rules, and settlement period. Any fixed operating cost included in Cavoided should be separately identified and justified. In many early SPARC stream models, this term may be zero.

4.2 Risk Relief

Rrelief should be estimated on an expected-value basis rather than assumed. The calculation should identify expected annual avoided downside cost and divide it by the expected eligible MWh under the stream.

Rrelief may include:

ComponentCalculation logic
Replacement-power exposureProbability of non-delivery multiplied by expected replacement-cost spread during those events.
Penalty and performance chargesExpected value of availability penalties, imbalance charges, liquidated damages, or disallowance exposure transferred to the delivery party.
Fuel and operating volatilityExpected value of reduced exposure to fuel price volatility, forced outage risk, cycling stress, and operating intensity.
Maintenance and outage reliefAnnualized value of avoided thermal stress, reduced forced-outage probability, or lower variable maintenance burden where material.

An illustrative assumption of USD 2-3/MWh may be used for early modelling. A bankable or regulatory model should derive the value from event probabilities, historical outage data, replacement-power spreads, penalty terms, and the actual allocation of risk in the stream agreement.

Rrelief should not double-count payment layers included in Otransferred. Risk relief measures expected downside exposure moved away from the coal operator. Transferred obligation value measures the portion of stream value that can move because the delivery party assumes the corresponding obligation.

4.3 Transferred Obligation Value

Otransferred is the portion of stream value that can be released from the coal operator's retained value because the delivery party assumes the matching obligation. It is not an additional external value source. It is a reallocation of value already inside VSETTLE.

Where the coal operator keeps an obligation, the associated value remains in the coal operator floor. Where the delivery party assumes the obligation, the matching value can be allocated to delivery compensation. The default modelling treatment should stay simple: a flexible stream is usually energy-only unless the agreement says otherwise, while a firm band can transfer the capacity or availability payment layer associated with that band if the delivery party assumes the matching firm obligations. Where responsibility is genuinely shared, the stream agreement can allocate the value through a formula, true-up mechanism, or performance adjustment, but that should be treated as a contract-specific refinement rather than the default case.

For capacity or availability payments, Otransferred is derived from the identified payment layer. The calculation first allocates the relevant MW-based payment to the SPARC stream, converts it into MWh-equivalent value using expected eligible MWh, and then includes the value that corresponds to obligations actually assumed by the delivery party.

The coal operator may need to retain part of that capacity or availability value for fixed-cost recovery, debt service, lender standing, margin, residual PPA standing, retained regulatory responsibility, or obligations it continues to carry. This retained capacity value is expressed as VCAP RETAINED.

For a flexible energy-only stream:

For a firm band where the delivery party assumes the matching firm obligations:

Where VCAP RETAINED is equal to or greater than VCAP EQ, no net capacity-linked value is available for transfer through Otransferred.

This framework assumes that a rational coal operator will not agree to transfer value required for residual PPA standing, fixed-cost recovery, debt service, margin, retained regulatory responsibility, or a retained performance obligation. Those economics remain part of the coal operator floor unless the stream agreement preserves the coal operator's retained position through another payment or risk-allocation structure.

Otransferred may include the value associated with:

Obligation transferredAllocation logic
Capacity or availability obligationAllocate the relevant capacity or availability payment to the stream, convert it to MWh-equivalent value using expected eligible MWh, and count the value linked to the obligation assumed by the delivery party.
Firm-delivery obligationCount the payment layer linked to firm performance where the delivery party carries non-delivery exposure.
Replacement-power obligationCount the value linked to replacement-power responsibility where the delivery party bears the cost of covering shortfalls.
Balancing or imbalance obligationCount the value linked to balancing exposure where the delivery party bears imbalance or settlement risk.
Performance obligationCount the value linked to penalties, liquidated damages, disallowance exposure, or performance adjustments assumed by the delivery party.

The calculation should identify the payment layer, the obligation it supports, the party carrying that obligation, and the expected eligible MWh denominator used to express the value per eligible MWh. If the same exposure is already included in Rrelief, it should not also be included in Otransferred.

5. Delivery Party Economics

The delivery party fulfills a SPARC stream when the compensation it receives is sufficient to cover cost, risk, and required return.

The delivery party's required value is:

Where:

TermMeaning
CDELIVERCost of eligible delivery, including generation, firming, storage, balancing, replacement power, incremental operations, and compliance where applicable.
RDELIVERRisk premium for performance, imbalance, curtailment, replacement-power, and settlement risk allocated to the delivery party.
VARCARC value allocated to the delivery party under the stream agreement and applicable product-code or host-country rules.
VGRIDRecognized grid value allocated to the delivery party, where such value exists.
Delivery Party Required ValueMinimum compensation the delivery party needs under the stream agreement.

The delivery party may receive value through several channels. It may receive a per-MWh delivery fee, an availability payment, a share of realized settlement value, a performance-adjusted service fee, ARC value, grid-value payments, or a combination of these elements.

The delivery condition is:

VARC reduces the delivery party's required cash compensation only if ARC value is allocated to the delivery party and can be monetized with sufficient certainty. If ARC value is allocated to the coal operator, a jointly controlled account, or a public authority, it does not reduce the delivery party's required compensation unless the stream agreement shares that value with the delivery party.

VGRID should be included only when there is a defined mechanism, credible counterparty, or recognized regulatory value. It should not be assumed as a generic benefit. If included, it should be net of eligibility limits, measurement requirements, verification delay, curtailment risk, clawback risk, and probability of payment.

6. ARC Value

An ARC is the unused emission right from a SPARC. Each SPARC carries an embedded emission right expressed in tCO2/MWh. That value is derived from the originating coal plant, an approved benchmark, an ETS allocation, or another host-country-recognized method.

When a SPARC is created from lower-emission delivery, the registry compares the embedded emission right with the verified emissions of the delivered MWh. A positive difference may be issued as an ARC under the product code and host-country framework.

ARC quantity per delivered MWh is:

ARC value per delivered MWh is:

Net ARC Price should reflect gross carbon price, issuance probability, authorization probability, registry fees, transfer discounts, transaction costs, and any required sharing with the host country or other parties.

This value is not automatic. It depends on product-code rules, host-country treatment, authorization where required, issuance controls, and market demand. The calculation should therefore separate physical ARC quantity from monetizable ARC value. In the worked examples below, ARC value is treated as part of the residual value required for the stream to clear, not as a pre-assumed input.

7. Grid Value

A SPARC stream may create grid value if the delivery profile or injection point improves the system position. For example, lower-emission delivery may reduce congestion, relieve a local network constraint, reduce losses, improve the match between generation and load, or reduce reliance on more expensive balancing resources.

VGRID should be treated as recognized value, not assumed value. It should be included only if the regulator, system operator, offtaker, or another credible counterparty can define the benefit and allocate payment or settlement value to the stream.

The calculation should identify:

QuestionPurpose
What system benefit is created?Congestion relief, loss reduction, avoided redispatch, improved injection point, local reliability, or other benefit.
Who recognizes it?System operator, regulator, offtaker, market operator, or another authorized body.
How is it measured?Metering data, dispatch records, settlement outcomes, load-zone comparison, or engineering study.
Who receives it?Coal operator, delivery party, jointly controlled account, offtaker, or public mechanism.
Is it firm or contingent?Determines whether it can be included in base-case economics or only sensitivity analysis.

Unless these questions can be answered, VGRID should be set to zero in the base case.

8. Clearing Condition and Negotiation Band

A SPARC stream clears when both sides can be satisfied at the same time.

The coal operator condition is:

The delivery party condition is:

In terms of FSTREAM, the available stream payment for delivery-party compensation is:

The delivery party requires at least:

A feasible negotiation range exists when:

Substituting the definitions:

This is the compact expression of the methodology. The left side is the delivery party's minimum required compensation. The right side is the available stream payment supported by avoided cost, transferred risk, and transferred obligation value while the coal operator remains whole.

The combined feasibility condition is:

This is the core economic logic of SPARC. The stream can clear when the value created by substitution is large enough to cover the cost and risk of lower-emission delivery while preserving the coal operator's economic position.

The left side contains value sources:

Value sourceRole
CavoidedCoal cost no longer incurred, including fuel, variable O&M, avoidable emissions cost, and any genuinely avoided fixed operating cost.
RreliefCoal-side risk transferred or reduced.
OtransferredStream value released because the delivery party assumes the matching obligation.
VARCMonetizable value of the unused emission right.
VGRIDRecognized system value created by the delivery profile or injection point.

The right side contains delivery-side cost:

Cost sourceRole
CDELIVERPhysical and operational cost of eligible delivery.
RDELIVERRisk premium required by the delivery party.

If the left side is smaller than the right side, no voluntary stream agreement can clear without external support, a lower delivery-cost profile, a different risk allocation, higher ARC value, recognized grid value, or a change in stream design.

If the left side is larger than the right side, a negotiation range exists. The parties can then decide how to split the available surplus through retained coal value, delivery compensation, ARC allocation, grid-value allocation, or risk-sharing terms.

9. Illustrative Calculations by PPA Structure

The following calculations are illustrative. They do not represent a final parameter set for any specific plant or market. The purpose is to show how the framework operates under two common PPA structures. The numerical settlement inputs are anonymized and rounded values adapted from actual Philippine PPA data, simplified to show the method rather than to identify a specific contract or proposed transaction term.

Assume a 50 MW delivery band for 12 hours per day.

If every eligible MWh is delivered under the registered SPARC stream, the registry can create up to 219,000 SPARCs per year, subject to dispatch, metering, evidence, and product-code rules.

The delivery-side assumptions are the same in both examples. VSETTLE differs because the examples represent different PPA payment structures: an energy-only or no-obligation-transfer structure, and a capacity-plus-energy firm-band structure. The comparison intentionally holds the delivery task constant, not the settlement value. Holding VSETTLE constant would hide the economic effect of the PPA structure being tested.

Delivery-side componentValue
Solar generation costUSD 50/MWh
Firming and storage adderUSD 25/MWh
Incremental operating, compliance, and settlement costUSD 3/MWh
CDELIVERUSD 78/MWh
RDELIVERUSD 3/MWh

Total delivery-side cost and risk:

The worked examples do not assume an ARC price or recognized grid value at this stage. They first calculate the available stream payment, then calculate the residual value that must be covered by VARC, VGRID, or another agreed external value source.

For translating a residual value requirement into a required net ARC price, assume:

9.1 Energy-Only or No-Obligation-Transfer Case

In an energy-only PPA, the contract value is embedded in the per-MWh energy rate. Fixed-cost recovery, margin, fuel treatment, and variable O&M may all be reflected in the energy payment. In a flexible stream, or in a firm stream where the capacity or availability obligation does not transfer, Otransferred is zero.

Illustrative assumptions:

TermValue
VSETTLEUSD 102.70/MWh
CavoidedUSD 45.00/MWh
RreliefUSD 2.00/MWh
OtransferredUSD 0.00/MWh

Then:

The coal operator must retain roughly USD 55.70/MWh in expected value for the stream transfer to be rational on a consent basis. The available stream payment for delivery-party compensation is:

At this point, the stream does not clear:

The delivery party's cost and risk exceed the available stream payment. The required external value is:

The stream does not clear from the stream payment alone. It requires USD 34.00/MWh of ARC value, recognized grid value, or another agreed external value source.

9.2 Capacity-Plus-Energy Firm-Band Case

In a capacity-plus-energy PPA, VSETTLE is the MWh-equivalent value of the payment layers allocated to the SPARC stream. It includes the energy component linked to actual MWh production and the capacity or availability component allocated to the stream. The energy component normally includes fuel and variable O&M. The capacity-related component reflects the portion of fixed, capacity, or availability payments allocated to the stream and converted into a MWh-equivalent value using expected eligible MWh for the stream.

For this illustrative case, assume the parties have negotiated a firm SPARC band and the delivery party assumes the matching firm-delivery, balancing, replacement-power, penalty, and performance obligations for that band. The model treats the energy component as the primary avoided-cost layer and the capacity component as the primary retained-value layer. This is a simplifying allocation assumption. Actual PPAs may embed fixed-cost recovery or margin in either layer, and transaction models should replace this allocation with source PPA data.

Illustrative assumptions:

TermValue
Fuel componentUSD 34.39/MWh
Variable O&MUSD 2.37/MWh
Energy component (total)USD 36.76/MWh
VCAP EQUSD 57.89/MWh
VCAP RETAINEDUSD 42.89/MWh
OtransferredUSD 15.00/MWh
VSETTLEUSD 94.65/MWh
CavoidedUSD 36.76/MWh
RreliefUSD 2.00/MWh

The transferred obligation value is the net capacity-linked value released after the coal operator retains the capacity value it rationally requires:

In a real transaction, VCAP RETAINED would be derived from the coal operator's fixed-cost recovery requirement, debt service, lender standing, margin, residual PPA standing, regulatory responsibility, and any obligations it continues to carry.

The coal operator's minimum retained value is:

The available stream payment for delivery-party compensation is:

At this point, the stream still does not clear:

The delivery party's cost and risk exceed the available stream payment. The required external value is:

The stream still does not clear from the stream payment alone, but the shortfall is smaller than in the energy-only or no-obligation-transfer case. The firm-band capacity structure increases the available stream payment because a net portion of the capacity-related value moves with the matching firm obligation.

9.3 Clearing Comparison

The two examples produce different available stream payments and therefore different residual external value requirements:

CaseDelivery cost and riskAvailable stream paymentRequired external value
Energy-only or no-obligation-transfer caseUSD 81.00/MWhUSD 47.00/MWhUSD 34.00/MWh
Capacity-plus-energy firm-band caseUSD 81.00/MWhUSD 53.76/MWhUSD 27.24/MWh

If ARC value and grid value are the only external sources allocated to the stream, the required combined ARC and grid value can be calculated directly:

For the energy-only or no-obligation-transfer case:

For the capacity-plus-energy firm-band case:

This calculation should not be read as a claim that ARC value must carry the economics alone. It shows the residual value required after avoided coal cost, risk relief, transferred obligation value, delivery cost, and delivery risk have been accounted for.

10. Clearing Gap and ARC/Grid Price Scenarios

The residual external value requirement can be met by ARC value, recognized grid value, another agreed external value source, or a combination of these sources. If ARC value and grid value are the only external sources allocated to the stream, recognized grid value reduces the ARC value required for clearing.

Using the illustrative ARC quantity of 0.95 tCO2/MWh:

CaseRequired external value before gridVGRIDRequired VARCRequired net ARC price
Energy-only or no-obligation-transfer caseUSD 34.00/MWhUSD 0/MWhUSD 34.00/MWhUSD 35.79/tCO2
Energy-only or no-obligation-transfer caseUSD 34.00/MWhUSD 5/MWhUSD 29.00/MWhUSD 30.53/tCO2
Energy-only or no-obligation-transfer caseUSD 34.00/MWhUSD 10/MWhUSD 24.00/MWhUSD 25.26/tCO2
Capacity-plus-energy firm-band caseUSD 27.24/MWhUSD 0/MWhUSD 27.24/MWhUSD 28.67/tCO2
Capacity-plus-energy firm-band caseUSD 27.24/MWhUSD 5/MWhUSD 22.24/MWhUSD 23.41/tCO2
Capacity-plus-energy firm-band caseUSD 27.24/MWhUSD 10/MWhUSD 17.24/MWhUSD 18.15/tCO2

If recognized grid value is zero, the full residual external value requirement must be met by ARC value or another agreed external value source. If recognized grid value exists, the required ARC value falls. The model should therefore show grid value as a recognized and contingent clearing source, not as an assumed benefit.

11. Sensitivity Analysis

The feasibility of a SPARC stream is most sensitive to avoided coal cost, delivery cost, firming cost, delivery risk, ARC quantity, net ARC price, and recognized grid value. The tables below use the energy-only or no-obligation-transfer case as the reference case unless stated otherwise, because it isolates each driver without adding the firm-band capacity allocation.

11.1 Avoided Coal Cost

This sensitivity holds CDELIVER + RDELIVER at USD 81/MWh, Rrelief at USD 2/MWh, Otransferred at zero, VGRID at zero, and ARC quantity at 0.95 tCO2/MWh.

CavoidedAvailable stream paymentRequired external valueRequired net ARC price
USD 45/MWhUSD 47/MWhUSD 34/MWhUSD 35.79/tCO2
USD 58/MWhUSD 60/MWhUSD 21/MWhUSD 22.11/tCO2
USD 65/MWhUSD 67/MWhUSD 14/MWhUSD 14.74/tCO2

Higher avoided coal cost improves clearing because it increases the available stream payment while the coal operator remains whole.

11.2 Firming Cost

This sensitivity holds solar generation cost at USD 50/MWh, incremental operating, compliance, and settlement cost at USD 3/MWh, RDELIVER at USD 3/MWh, Cavoided at USD 45/MWh, Rrelief at USD 2/MWh, Otransferred at zero, VGRID at zero, and ARC quantity at 0.95 tCO2/MWh.

Firming and storage adderCDELIVERCDELIVER + RDELIVERRequired external valueRequired net ARC price
USD 25/MWhUSD 78/MWhUSD 81/MWhUSD 34/MWhUSD 35.79/tCO2
USD 15/MWhUSD 68/MWhUSD 71/MWhUSD 24/MWhUSD 25.26/tCO2
USD 10/MWhUSD 63/MWhUSD 66/MWhUSD 19/MWhUSD 20.00/tCO2

A lower-cost firming configuration, better generation profile, lower replacement-power exposure, or more flexible delivery obligation can materially reduce the external value required for the stream to clear.

11.3 Combined Drivers

The most important insight is not that one variable solves the gap. It is that several modest changes can compound.

ScenarioCavoidedFirming adderAvailable stream paymentCDELIVER + RDELIVERRequired external valueRequired net ARC price
Reference caseUSD 45/MWhUSD 25/MWhUSD 47/MWhUSD 81/MWhUSD 34/MWhUSD 35.79/tCO2
Higher avoided coal costUSD 58/MWhUSD 25/MWhUSD 60/MWhUSD 81/MWhUSD 21/MWhUSD 22.11/tCO2
Lower firming costUSD 45/MWhUSD 10/MWhUSD 47/MWhUSD 66/MWhUSD 19/MWhUSD 20.00/tCO2
Higher avoided coal cost plus lower firming costUSD 58/MWhUSD 10/MWhUSD 60/MWhUSD 66/MWhUSD 6/MWhUSD 6.32/tCO2

This is why the stream design matters. The clearing gap is not a fixed ARC-price problem. It changes with fuel cost, delivery profile, firming cost, transferred obligations, and recognized grid value.

11.4 ARC Quantity and Net ARC Price

ARC quantity also matters. The same USD/MWh clearing gap requires a higher net ARC price when the verified emissions of the delivery resource are above zero.

CaseRequired external value before gridNet ARC price at 0.95 tCO2/MWhNet ARC price at 0.75 tCO2/MWhNet ARC price at 0.55 tCO2/MWh
Energy-only or no-obligation-transfer caseUSD 34.00/MWhUSD 35.79/tCO2USD 45.33/tCO2USD 61.82/tCO2
Capacity-plus-energy firm-band caseUSD 27.24/MWhUSD 28.67/tCO2USD 36.32/tCO2USD 49.53/tCO2

The model therefore does not depend on ARC value alone. ARC value becomes one component in a broader value stack that also includes avoided coal cost, risk transfer, transferred obligation value, firming cost reduction, ARC quantity, and any recognized grid value.

12. Efficient Fossil or Flexible Lower-Emission Delivery

The delivery party does not have to be renewable in every case. A more efficient or more flexible lower-emission generator may fulfill a SPARC stream where full renewable substitution is not yet technically or economically feasible.

The same economics apply. The delivery party's CDELIVER includes its fuel cost, variable O&M, emissions cost, operational cost, and balancing or replacement obligations. Its RDELIVER reflects its own performance and settlement risk. ARC quantity is lower if verified emissions are above zero, because the ARC records only the unused portion of the embedded emission right.

For example, if the embedded emission right is 0.95 tCO2/MWh and a lower-emission thermal delivery party verifies emissions of 0.40 tCO2/MWh, ARC quantity is:

The stream may still create value if the delivery party's lower fuel cost, lower emissions, better flexibility, or improved dispatch profile reduces total system cost or creates ARC value. This pathway may be useful as a transitional step, but the claim must remain precise: the substitution is lower-emission delivery, not renewable delivery, unless linked REC or equivalent renewable-energy evidence exists.

13. Required Diligence Inputs

A credible SPARC stream economics analysis should collect the following inputs before presenting a clearing case.

InputRequired detail
PPA structureEnergy-only, capacity-plus-energy, availability payment, minimum generation threshold, pass-through treatment, penalties, disallowance clauses.
Delivery bandMW, hours, season, dispatch linkage, firmness, expected eligible MWh, curtailment treatment, term, location, injection point.
Settlement rulesDispatch, scheduling, nomination, metering, payment timing, settlement intervals, payment deductions.
Capacity allocationWhether capacity or availability value attaches to the stream, how the MW-based payment is allocated, which expected eligible MWh denominator converts it to MWh-equivalent value, what capacity value the coal operator must retain, whether a true-up applies, and who assumes corresponding obligations.
Coal avoided costFuel price, heat rate, variable O&M, emissions cost, fuel pass-through treatment, cycling effects, and any genuinely avoidable fixed operating cost.
Risk reliefReplacement-power exposure, outage risk, fuel volatility, penalties, disallowance risk, operating stress.
Delivery costGeneration cost, storage, firming, balancing, replacement power, losses, compliance, metering, settlement operations.
Delivery riskImbalance, curtailment, non-delivery, replacement-power price spikes, equipment outage, force majeure, payment delay.
Embedded emission rightPlant factor, benchmark, ETS allocation, operating-license value, or host-country-recognized method.
ARC treatmentIssuance conditions, allocation, authorization, cancellation rules, corresponding adjustment treatment where relevant, marketability.
Grid valueRecognized benefit, payment mechanism, measurement method, beneficiary, probability, clawback exposure.
Regulatory recognitionRequired approvals from regulator, system operator, environmental authority, registry, offtaker, lenders, or other parties.

14. Practical Interpretation

The economics of a SPARC stream are not driven by one price. They are driven by whether the stream agreement can align internal value released from the coal operator floor, external or incremental value, and delivery-side cost.

The internal value released from the coal operator floor consists of avoided coal cost, coal-side risk relief, and transferred obligation value. ARC value and recognized grid value can add external or incremental value where they exist and are allocated to the stream economics.

The two cost categories are delivery cost and delivery risk.

The coal operator does not need to lose the PPA or surrender its fixed-cost recovery. It can retain the value required to remain whole while avoiding cost, reducing selected risks, and reallocating payment layers where corresponding obligations move to the delivery party. The delivery party does not need to buy a speculative certificate. It performs an approved stream and receives compensation tied to delivery, transferred obligations, ARC allocation, grid value, or a combination of these sources. The regulator does not need to force immediate plant retirement. It can recognize a defined delivery band, preserve system reliability, and allow emissions to fall through verified lower-emission delivery.

The mechanism is strongest where the stream can be designed so that avoided coal cost, risk relief, transferred obligation value, ARC value, and recognized grid value exceed the delivery cost and risk of lower-emission performance. That is the economic center of SPARC.

15. Core Formulas

TermDefinitionFormula
VSETTLEExpected settlement value allocated to the SPARC streamCapacity or availability value allocated to the stream and converted using expected eligible MWh, plus expected realized energy settlement value where applicable.
VCAP EQCapacity or availability value expressed on a MWh-equivalent basisAllocated capacity or availability payment for the SPARC stream divided by expected eligible MWh under the SPARC stream.
VCAP RETAINEDCapacity or availability value retained by the coal operatorCapacity value required for fixed-cost recovery, debt service, lender standing, margin, residual PPA standing, retained regulatory responsibility, or retained obligations.
CavoidedCoal cost avoided when another party fulfills the streamAvoided fuel cost plus avoided variable O&M plus avoidable emissions cost and genuinely avoided fixed operating cost where applicable.
RreliefMonetized risk relief for the coal operatorExpected annual avoided downside cost divided by expected eligible MWh under the stream.
OtransferredStream value released because the delivery party assumes the matching obligationFor capacity or availability value, VCAP EQ minus VCAP RETAINED, counted only where the corresponding capacity, availability, firm-delivery, balancing, replacement-power, or performance obligation transfers.
Coal MinimumMinimum retained value required by the coal operatorVSETTLE - Cavoided - Rrelief - Otransferred
FSTREAMExpected stream fulfillment compensation allocated to the delivery partyPer-MWh fee, availability payment, revenue share, true-up, or blended compensation expressed in expected USD/MWh.
FSTREAM maxAvailable stream payment for delivery-party compensation while the coal operator remains wholeCavoided + Rrelief + Otransferred
CDELIVERDelivery party cost of eligible performanceGeneration cost plus firming, storage, balancing, replacement-power, incremental operations, and compliance.
RDELIVERDelivery party risk premiumExpected downside cost from performance, imbalance, curtailment, replacement power, and other allocated obligations.
ARC quantityUnused emission right per delivered MWhEmbedded emission right - verified emissions of delivered MWh.
VARCMonetizable ARC value allocated to the relevant partyARC quantity x net ARC price.
VGRIDRecognized grid value allocated to the relevant partyExpected net grid benefit per eligible delivered MWh.
Delivery Party Required ValueMinimum value required by the delivery partyCDELIVER + RDELIVER - VARC - VGRID.
FSTREAM minMinimum delivery-party compensation required for performanceCDELIVER + RDELIVER - VARC - VGRID.
Negotiation rangeFeasible compensation bandFSTREAM min <= FSTREAM <= FSTREAM max.
Clearing conditionCombined feasibility testVARC + VGRID + Cavoided + Rrelief + Otransferred >= CDELIVER + RDELIVER.

16. Data Source Discipline

The settlement figures used in Chapter 9 are anonymized and rounded values adapted from actual Philippine PPA data. The remaining market and delivery assumptions are illustrative. The figures are included to show how the formulas work, not to establish current market values or transaction terms.

All market inputs should be dated and replaced with asset-specific data before a transaction model is used for negotiation or regulatory submission. The model should distinguish between physical parameters, contract parameters, market parameters, policy parameters, carbon-value parameters, and grid-value parameters.

Input typeTreatment
Physical parameterUse plant, asset, or engineering data where possible.
Contract parameterUse source PPA, side letter, settlement rule, or approved tariff data.
Market parameterDate the source and test sensitivity.
Policy parameterSeparate current rule, expected rule, and desired rule.
Carbon-value parameterSeparate ARC quantity from monetizable ARC value.
Grid-value parameterInclude only when recognized by a credible counterparty or authority.

The illustrative solar cost assumption should be checked against country-specific project data. IRENA's 2024 global weighted average LCOE for newly commissioned utility-scale solar PV was USD 0.043/kWh. A higher value may still be appropriate for a financed Southeast Asian project where country risk, WACC, interconnection, curtailment, and project development costs are material.

The coal-price sensitivity should be updated against the relevant delivered fuel cost, not merely an index. ICE's Newcastle coal futures are financially settled against the globalCOAL Monthly NEWC Index. Public market snapshots can provide a benchmark, but the model should use the plant's delivered coal price, quality, freight, and handling assumptions.

Carbon-price scenarios should not be treated as forecast values. They are scenarios for testing how ARC value affects stream feasibility. Carbon-price context should be checked against the latest World Bank State and Trends of Carbon Pricing report, domestic ETS prices where relevant, and buyer-specific ARC eligibility assumptions.

17. Canonical Wording for Shorter Materials

SPARC stream economics test whether a defined delivery band inside an existing coal PPA can be fulfilled by a lower-emission delivery party while preserving the coal operator's financial position. The coal operator's floor is the expected stream settlement value minus avoided coal cost, transferred risk, and transferred obligation value. Transferred obligation value is not an external subsidy or additional value source; it is the portion of stream value that can move because the delivery party assumes the matching capacity, availability, firm-delivery, balancing, replacement-power, or performance obligation. Capacity and availability payments should be allocated to the stream and converted to MWh-equivalent value using expected eligible MWh before any transferred obligation value is counted. For capacity or availability value, transferred obligation value is the net released value after the coal operator retains the capacity value required for fixed-cost recovery, margin, residual PPA standing, and retained obligations. A flexible stream is usually energy-only unless the agreement transfers defined obligations. The delivery party's required value is its delivery cost and performance risk, reduced only by ARC value and grid value actually allocated to it. A SPARC stream clears when avoided coal cost, risk relief, transferred obligation value, ARC value, and recognized grid value are sufficient to cover the cost and risk of lower-emission delivery.

Individual SPARCs are not priced as forward commodities. The parties negotiate the SPARC stream. Individual SPARCs are created only when eligible MWh are delivered under the registered stream and evidenced through the required metering and attribute systems.