Life cycle costing is the discipline that turns an environmental model into a decision. A carbon number on its own tells you which option is cleaner; it does not tell you what cleaner costs, or whether the money would buy more abatement somewhere else. Pairing the two is the single most useful thing you can do with an LCA once it exists, and it is cheap, because both metrics run off the same inventory.
This article covers what life cycle costing measures, how the discounting works, and what happens when you run a cost analysis and a carbon footprint over one modelled 2000 L CHO fed-batch. Every figure below comes from the bioprocess LCA calculator and the fermentation economics calculator, run on a harmonised input set so both describe the same batch.
What life cycle costing measures
Life cycle costing (LCC) is the total cost of a product, asset or process across its whole life, discounted to a single present value. It counts capital, operating, maintenance and end-of-life cost instead of purchase price alone.
The method predates LCA and comes out of construction and defence procurement rather than chemistry. ISO 15686-5:2017, still the most widely cited LCC standard, is formally a buildings and constructed assets document. That origin shows: the standard is strong on discounting, service life and asset replacement, and silent on functional units and system boundaries. Bioprocess practitioners borrow the financial machinery and take the boundary conventions from ISO 14040 instead.
Three variants get used, and conflating them is the most common source of argument in a review meeting:
| Variant | What it counts | Typical use |
|---|---|---|
| Conventional LCC | Cash flows borne by one actor — usually the owner. Purchase, install, run, maintain, dispose. | Equipment selection, make-vs-buy |
| Environmental LCC (eLCC) | All real cash flows across the whole life cycle, borne by any actor, on the same boundary and functional unit as a paired LCA. | Reporting cost and impact together |
| Societal LCC (sLCC) | eLCC plus monetised externalities — damage costs assigned to emissions and resource use. | Policy appraisal, rarely industry |
Life cycle costing also differs from total cost of ownership, though the terms get swapped freely. TCO is scoped to what the buyer pays. LCC as a method is willing to reach further along the chain and, in the environmental variant, is explicitly required to match the LCA boundary. If your supplier's disposal cost sits outside your P&L but inside the LCA boundary, eLCC counts it and TCO does not.
How to calculate life cycle cost
Sum the capital cost at year zero, then add each subsequent year's cash flow divided by (1 + r)t, where r is the discount rate and t the year. The result is a net present value. Everything else in a life cycle cost analysis is bookkeeping around that one expression.
The net present value expression
C₀ capital and installation cost at year zero
Cᵗ net cash flow in year t (operating + maintenance − salvage)
r discount rate, real if cash flows are real
n study period, in years
Keep the cash flows and the rate consistent. If your operating costs are stated in today's money, use a real discount rate. Mixing a nominal rate with real cash flows silently understates every future year.
The discount rate does most of the work, and it is the assumption reviewers challenge first. A public-sector appraisal might use 3%; a corporate hurdle rate is commonly 8–12%. The effect on a long study period is large enough to reverse a conclusion.
| Rate | Year 1 | Year 5 | Year 10 | Year 20 |
|---|---|---|---|---|
| 3% | 0.971 | 0.863 | 0.744 | 0.554 |
| 6% | 0.943 | 0.747 | 0.558 | 0.312 |
| 8% | 0.926 | 0.681 | 0.463 | 0.215 |
| 12% | 0.893 | 0.567 | 0.322 | 0.104 |
This is the structural asymmetry between the two methods. An LCA has no time preference: a kilogram of CO2e in year ten counts exactly as much as one today. LCC discounts it. Run both over a twenty-year asset and they will weight the late years very differently, which is a feature rather than a bug — but only if you say so in the report.
One inventory, two accounts
The reason to run cost and carbon together is that the expensive part is already done. Building the life cycle inventory — how many kWh, litres, kilograms and hours per batch — is 80% of the work. An LCA multiplies that inventory by emission factors; a life cycle cost analysis multiplies it by prices.
One discipline matters more than any other: the functional unit has to be identical. If the LCA reports per kilogram of purified product and the cost model reports per batch, the ratio between them changes every time yield changes, and every comparison you draw is wrong. Norris made this the central point of his 2001 argument for integrating the two methods, and it is still where most paired studies fall over.
Build the inventory once
The free bioprocess LCA calculator runs entirely in your browser and gives you the energy, water, media and consumables inventory that the cost model needs as well.
Worked example: cost and carbon on one batch
The case below is a 2000 L single-use CHO fed-batch at 1600 L working volume, 3.0 g/L titer, 70% downstream yield and 90% batch success, giving 3.024 kg of purified product per batch. It is the same batch used throughout this site's LCA cluster, costed with the mAb cost structure from the economics calculator on a 17-day cycle and 280 operating days.
Worked example — the two accounts side by side
LCC account — cost per batch
facility (17 d × $10,000) $170,000 36.3%
media (1600 L × $60) $96,000 20.5%
downstream ($20/g crude) $96,000 20.5%
labour (17 d × $3,000) $51,000 10.9%
feed (1600 L × $20) $32,000 6.8%
QC $15,000 3.2%
consumables $8,000 1.7%
──────────
total $468,000
COGS = $468,000 ÷ 3,024 g = $154.76 /g = $154,762 /kg
LCA account — emissions per batch (grid 400 g CO₂e/kWh)
electricity 28,759 kWh 11,504 kg CO₂e 95.6%
waste incineration 243 kg CO₂e 2.0%
single-use resin 204 kg CO₂e 1.7%
water 51 kg CO₂e 0.4%
media 35 kg CO₂e 0.3%
──────────
total 12,036 kg CO₂e (components rounded)
footprint = 12,036 ÷ 3.024 = 3,980 kg CO₂e /kg
carbon intensity of spend = 0.026 kg CO₂e per $ of COGS
Note how differently the two accounts are shaped. Cost is spread across seven line items with no single one above 37%. Emissions are 95.6% electricity, and 93.5% of the electricity is cleanroom HVAC. A cost model built to find savings will not look where the emissions are.
That asymmetry is the whole argument for running both. The largest cost line, facility overhead, is an allocated daily rate that contains the HVAC load but does not expose it. The largest emissions line is that same HVAC load, itemised. Neither model on its own shows you a facility whose air handling dominates its footprint while hiding inside an overhead rate.
Where cost and carbon part company
Run the same seven improvement levers through both models and they sort into three groups: levers that cut both, levers that cut carbon far harder than cost, and levers the cost model cannot see at all.
| Lever | kg CO2e/kg | Δ carbon | Δ cost |
|---|---|---|---|
| Baseline | 3,980 | — | — |
| Titer 3.0 → 5.0 g/L | 2,388 | −40.0% | −31.8% |
| Downstream yield 70 → 80% | 3,483 | −12.5% | −12.5% |
| Batch success 90 → 95% | 3,771 | −5.3% | −5.3% |
| Batch duration 14 → 12 days | 3,471 | −12.8% | −5.6% |
| Cleanroom HVAC 80 → 60 kW | 3,091 | −22.3% | not modelled |
| Process water 58,000 → 40,000 L | 3,939 | −1.0% | not modelled |
| Renewable tariff, grid 400 → 100 g/kWh | 1,127 | −71.7% | not modelled |
Three observations fall straight out of that table.
- Titer is the only lever that is large on both axes. Going from 3 to 5 g/L cuts emissions 40% and cost 32% in one move, which is why every sustainability roadmap in biologics starts with cell line and media rather than with facilities.
- Downstream yield and batch success give identical percentage moves on cost and carbon. Both act purely on the denominator, so they scale the two numerators by exactly the same factor. That is not a coincidence, and the next section shows what it implies.
- Shortening the batch is carbon-weighted. Two days off a 14-day batch cuts emissions 12.8% but cost only 5.6%, because HVAC runs against the clock while media, downstream and QC costs do not.
Marginal abatement cost
Marginal abatement cost (MAC) is the net cost of avoiding one tonne of CO2e with a given intervention. It is the number LCC produces that an LCA structurally cannot, and it is what lets you rank interventions that have nothing else in common.
Computed on the shared functional unit, MAC is the change in cost per kilogram of product divided by the tonnes of CO2e avoided per kilogram of product. Costs for the three utility levers use stated prices — $0.12/kWh industrial electricity, a $0.02/kWh renewable tariff premium, and $0.004/L for purified water including generation and effluent — because the COGS model bundles those into the facility rate.
| Lever | Δ kg CO2e/kg | Δ $/kg | $/tCO2e |
|---|---|---|---|
| Batch success 90 → 95% | −209 | −8,145 | −38,884 |
| Downstream yield 70 → 80% | −498 | −19,345 | −38,884 |
| Titer 3.0 → 5.0 g/L | −1,592 | −49,206 | −30,907 |
| Batch duration 14 → 12 days | −509 | −8,598 | −16,877 |
| Process water 58,000 → 40,000 L | −41 | −35 | −846 |
| Cleanroom HVAC 80 → 60 kW | −889 | −267 | −300 |
| Renewable tariff, grid 400 → 100 g/kWh | −2,853 | +190 | +67 |
Six of the seven levers sit below the axis. In a mature sector that would be surprising; in biologics it is the expected result, because the product is so valuable that anything raising output per batch dwarfs any plausible carbon consideration. Amasawa and colleagues reached the same conclusion running impact and operating cost across mAb cultivation scenarios in 2021.
The identical MAC for downstream yield and batch success is worth pausing on, because it generalises. Any lever that changes only the product mass scales cost per kilogram and emissions per kilogram by the same factor f. The factor cancels:
Abatement cost of a pure denominator lever
Δcost = C(1/f − 1) C = baseline cost per kg
Δcarbon = E(1/f − 1) E = baseline kg CO₂e per kg
MAC = Δcost / (−Δcarbon / 1000) = −1000 × C / E
= −1000 × 154,762 / 3,980 ≈ −$38,885 / tCO₂e
The result does not depend on f. Every pure denominator lever in a given process shares one abatement cost, set entirely by the ratio of cost intensity to carbon intensity. (The table above gives −$38,884; the difference is rounding in C and E.) Titer sits above the line at −$30,907 because higher titer also raises downstream cost per batch, so it is not purely a denominator move.
Should you price carbon into the LCC?
For a monoclonal antibody, no. An internal carbon price at any realistic level is smaller than the rounding error on a mAb COGS estimate, and folding it in destroys the environmental signal rather than sharpening it.
| Carbon price | Shadow cost ($/kg product) | Share of COGS |
|---|---|---|
| $50/tCO2e | $199 | 0.13% |
| $100/tCO2e | $398 | 0.26% |
| $150/tCO2e | $597 | 0.39% |
| $250/tCO2e | $995 | 0.64% |
| $500/tCO2e | $1,990 | 1.29% |
This is a property of high-value biologics specifically, not a general finding. The same economics calculator puts a bulk yeast metabolite at $906/kg — roughly a 170th of the mAb cost intensity — so for a commodity fermentation product the same carbon price is a materially larger share of cost, and energy prices genuinely do move decisions. The higher your product value, the more completely carbon pricing disappears.
The practical consequence is that a single monetised score is the wrong output format here. At $100/tCO2e, societal LCC would value the renewable tariff's 2,853 kg/kg reduction at $285/kg — 0.18% of COGS — and bury the largest environmental move available to this process inside the noise. Report the two axes separately, rank interventions by abatement cost, and let the reader see that the tariff buys nearly three-quarters of the footprint for $67 a tonne. That is a decision; a combined number is not.
Run the cost side on your own process
The fermentation economics calculator gives COGS per gram, a batch versus fed-batch versus perfusion comparison, and a sensitivity tornado from 18 inputs.
Capital decisions and the crossover point
Discounting earns its keep on capital questions, where a large cost at year zero trades against small recurring costs for a decade. The classic bioprocess case is single-use versus stainless steel: low capex and high consumables against high capex and low consumables.
Take the two configurations from the LCA calculator. The single-use train uses 60,000 L of water and no clean steam per batch; the stainless train uses 84,000 L and 1,400 kg of steam for CIP and SIP, with 73 kg less polymer. In this configuration the modelled footprints are 3,980 and 3,971 kg CO2e/kg — a 0.2% difference, effectively a tie, and a result that is highly sensitive to how much CIP water each train actually uses. The cost difference is not close.
Worked example — NPV crossover, 10-year study period at 8%
Capex figures below are illustrative assumptions, not calculator outputs. Operating deltas come from the two engines at $0.12/kWh, $0.004/L water and $0.03/kg steam.
stainless capex $6.5M consumables $1,500
+ water $96
+ steam $42
+ power $43 = $1,681 /batch
operating gap $6,319 /batch in favour of stainless
annuity factor, 10 y at 8% 6.710
crossover = capex gap / (annuity × operating gap)
= $4,500,000 / (6.710 × $6,319)
= 106 batches per year
at a 17-day cycle the ceiling is 21 batches/yr (365 d)
at 16 batches/yr: single-use NPV $2.86M vs stainless NPV $6.68M
The crossover sits five times above what the cycle time allows, so on these assumptions single-use wins across the entire feasible range. Put differently, single-use consumables would have to exceed $43,600 per batch — 5.4× the assumed $8,000 — before stainless recovers its capex at this scale.
Read that result carefully. It is not a claim that single-use always wins; it is a claim about a 2000 L suite running 16 batches a year. Crossover scales with throughput, so a facility running many short microbial campaigns lands somewhere else entirely, and the capex gap is the assumption most worth challenging. The environmental comparison is genuinely a separate question, covered in more depth in the single-use vs stainless steel guide.
What life cycle costing does not tell you
Life cycle costing inherits every weakness of its price data, and prices are less stable than emission factors. An LCA factor for grid electricity moves a few percent a year; an electricity tariff can double in one. Any LCC conclusion that turns on a utility price needs a range, not a point estimate.
- It is silent on anything without a price. Water scarcity, land use and biodiversity carry no cash flow at the factory gate. This is exactly the gap the paired LCA fills, and it is why environmental LCC deliberately excludes monetised externalities rather than inventing prices for them.
- Discounting is a value judgement. Choosing 12% over 3% is a statement about how much the future matters. It is defensible, but it is not a measurement, and it should be declared alongside the result.
- Allocated overheads hide the physics. The facility rate in the example above is 36% of cost and contains the single largest emissions source in the process. Any lever inside an allocated rate is invisible to the cost model by construction.
- It says nothing about capital availability. A negative-cost abatement measure still needs someone to fund it, and a positive NPV does not create a budget line.
None of that argues against doing it. It argues for reporting cost and impact as two numbers on one inventory, with the discount rate, the price set and the functional unit stated in the same breath. That is the whole content of the environmental LCC code of practice, and it is not complicated — it is just easy to skip.
See the full LCA methodology first
Our worked example runs this same batch through all four ISO 14040 phases, so you can see the inventory that both the impact and the cost account are built on.
Frequently asked questions
What is life cycle costing (LCC)?
Life cycle costing is the total cost of a product, asset or process across its whole life, discounted to a single present value. It covers capital, operating, maintenance and end-of-life cost rather than purchase price alone. ISO 15686-5:2017 is the most widely cited standard for the method.
What is the difference between LCA and LCC?
They read the same inventory through different accounts. LCA multiplies each flow by an emission or impact factor and reports kg CO2e or another impact score. LCC multiplies the same flows by prices and discounts them over time to a net present value. The physical model underneath is identical, which is why running both costs little extra once one is built.
How do you calculate life cycle cost?
Sum capital cost at year zero, then add each year's operating, maintenance and disposal cash flow divided by (1 + r) raised to the power of the year, where r is the discount rate. The result is a net present value. At an 8% discount rate a cost incurred in year 10 counts for 0.463 of its nominal value.
What is environmental life cycle costing?
Environmental life cycle costing (eLCC) is a life cycle cost analysis built on the same system boundary and functional unit as an accompanying LCA, counting only real cash flows borne by actors in the life cycle. The SETAC code of practice published by Swarr and colleagues in 2011 defines it. Societal LCC goes further and monetises externalities; eLCC does not.
Should you put a carbon price into a bioprocess life cycle cost?
For a monoclonal antibody, no. At 3,980 kg CO2e per kg of product and a COGS near $154,800/kg, an internal carbon price of $100/tonne adds $398/kg, which is 0.26% of cost. Even $500/tonne reaches only 1.3%. Monetising carbon hides the environmental signal inside rounding error, so report the two axes separately.
Which bioprocess levers cut both cost and carbon?
Anything that raises product mass per batch. Titer, downstream yield and batch success rate all divide both the cost and the emissions by the same product mass. Raising titer from 3 to 5 g/L cuts modelled emissions 40% and COGS 32% at once. Grid decarbonisation and HVAC setback cut carbon but are invisible to a standard COGS model.
References
- Swarr, T.E., Hunkeler, D., Klöpffer, W., Pesonen, H-L., Ciroth, A., Brent, A.C. & Pagan, R. (2011). Environmental life-cycle costing: a code of practice. The International Journal of Life Cycle Assessment. doi:10.1007/s11367-011-0287-5
- Norris, G.A. (2001). Integrating life cycle cost analysis and LCA. The International Journal of Life Cycle Assessment, 6, 118–120. doi:10.1007/BF02977849
- Amasawa, E., Kuroda, H., Okamura, K., Badr, S. & Sugiyama, H. (2021). Cost–benefit analysis of monoclonal antibody cultivation scenarios in terms of life cycle environmental impact and operating cost. ACS Sustainable Chemistry & Engineering, 9, 14012–14021. doi:10.1021/acssuschemeng.1c01435
- Bunnak, P., Allmendinger, R., Ramasamy, S.V., Lettieri, P. & Titchener-Hooker, N.J. (2016). Life-cycle and cost of goods assessment of fed-batch and perfusion-based manufacturing processes for mAbs. Biotechnology Progress. doi:10.1002/btpr.2323
- Pietrzykowski, M., Flanagan, W., Pizzi, V., Brown, A., Sinclair, A. & Monge, M. (2013). An environmental life cycle assessment comparison of single-use and conventional process technology for the production of monoclonal antibodies. Journal of Cleaner Production. doi:10.1016/j.jclepro.2012.09.048