Bulk terminal storage is the buffer that lets a plant run every day while ships arrive in batches, and sizing it is one of the first questions a prospective tenant puts to us. Too little, and a late ship stops your plant. Too much, and your capital sits in steel that rarely turns.
This guide gives you a four-step method for tanks and silos alike, two worked examples (a palm oil tank farm and a clinker store), and what it means for SIIPE‘s planned port.
Last updated: 27 October 2026
What Bulk Terminal Storage Has to Absorb
Bulk terminal storage exists because ships and plants run on different clocks. A refinery works continuously, while a vessel delivers or collects a whole parcel in a day or two and then does not return for a week or more.
The storage between them absorbs the full parcel, the production that continues while a ship is late, and the speed at which cargo crosses the quay. Our guide to bulk terminal operations covers the handling chain itself; this one sizes the buffer at its end. Two flows need separate treatment:
- Export flow (plant to ship). Storage fills from production and empties into the ship, as at a palm oil refinery shipping olein.
- Import flow (ship to plant). Storage fills from the ship and empties into production, as at a cement grinder receiving clinker.
The 4-Step Sizing Method for Tanks and Silos
The same four steps size a tank farm for crude palm oil and a silo or shed for dry bulk. Only the units change.
Step 1: Set the Parcel
The parcel is the tonnage one vessel delivers or lifts. Your contract sets it and the berth depth caps it, because depth decides the largest vessel that can call fully laden. Plan around the largest parcel you will actually move, not the average.
Step 2: Add the Buffer
Ships arrive late: weather, a berth queue, an inspection that runs over. The buffer is the days of production or consumption your storage must still hold when that happens. In both flows:
Working capacity = largest parcel + (daily rate x buffer days)
For an export plant, inventory climbs to one full parcel at the scheduled arrival and keeps climbing for every day the ship is late. For an import plant, inventory falls to the safety stock just before arrival, then jumps by one parcel.
Step 3: Convert Working Capacity to Nominal Capacity
A tank never empties completely and is never filled to the brim. The heel below the suction stays behind, and the top is kept free for thermal expansion and safe ullage. A silo loses volume to its discharge cone and the slope the product settles at.
So the nominal capacity you buy is larger than the working capacity you use. Ask your designer for each vessel’s usable fraction; the examples below assume 90%, a planning placeholder rather than a standard.
Step 4: Split by Grade and Check the Intake Rate
Every grade that cannot share a tank needs its own capacity, ideally in at least two tanks, so one receives from the plant while the other is gauged, sampled and pumped to the ship.
Then check the intake rate. Storage receiving from a ship must accept cargo as fast as the berth discharges it, far faster than any plant consumes it, so conveyors and pipelines are sized to the ship, not the factory.
Sizing tankage for a plant in North Sumatra? Message our team on WhatsApp for the published Sumalacca port design before you fix your tank count.
Parcel Size by Vessel Class
Berth depth sets the largest ship that can call fully laden, and the ship sets your parcel. The table uses the vessel ladder from our deep sea port guide. Deadweight includes fuel, water and stores, so actual cargo sits a little below it.
| Vessel class | Deadweight | Loaded draft | What it means for storage |
|---|---|---|---|
| Mini bulk carrier | 3,000 to 15,000 DWT | under 10 m | Small parcels and frequent calls, so storage can stay lean |
| Handysize | 15,000 to 40,000 DWT | around 10 m | The workhorse of minor bulk; at shallow berths often part-loaded |
| Handymax / Supramax | 40,000 to 60,000 DWT | 11 to 12.2 m | Larger parcels and fewer calls, so more storage per call |
| Panamax | 65,000 to 90,000 DWT | 12 to 14 m | Large parcels for high-volume terminals; beyond SIIPE’s planned design depth |
| Capesize | 90,000 to 200,000 DWT | 17 to 18 m | Long-haul ore and coal trades; beyond SIIPE’s planned design depth |
A bigger ship lowers freight per tonne but raises the storage you must hold. A part-loaded ship is a smaller parcel in disguise, so size against what the berth depth lets it carry.
SIIPE’s planned port is designed with a basin of -8 to -10 m LWS and a 13 nautical mile approach channel. That suits mini bulk carriers comfortably and Handysize vessels at or near their limit; a fully laden Supramax, Panamax or Capesize does not fit.
Worked Example 1: A Palm Oil Tank Farm for Export
This example sizes bulk terminal storage for an export flow: a plant shipping one grade of crude palm oil at 1,000 tonnes a day, about 365,000 tonnes a year, in 10,000-tonne parcels. Every input is an assumption for illustration.
| Step | Input | Result |
|---|---|---|
| 1. Parcel | 10,000 t per lifting | 10,000 t; one lifting about every 10 days |
| 2. Buffer | 5 days x 1,000 t a day | 5,000 t, so working capacity is 15,000 t |
| 3. Volume | Relative density 0.891 to 0.899 at 50°C | About 16,800 m³ working |
| 4. Nominal | 90% usable fraction (assumption) | About 18,700 m³ nominal |
| 5. Grade split | One grade, three tanks | About 6,200 m³ nominal per tank |
The density is from the Codex Standard for Named Vegetable Oils, which gives crude palm oil a relative density of 0.891 to 0.899 at 50°C. Convert at your storage temperature, because warm oil takes more room per tonne.
Three tanks keep one free to receive while a second is sampled and the third pumps to the ship. Each is typically a welded steel tank built to API 650; heating and segregation are covered in our guide to liquid bulk terminal design.
At the jetty, a 10,000-tonne parcel pumped at 300 tonnes an hour takes about 33 hours; at 600, about 17. Have the full parcel in tank before the ship berths.
Finally, check storage turns: 15,000 tonnes of working capacity against 365,000 tonnes a year turns about 24 times. Far more turns means thin buffers; far fewer means capital parked in steel.
Worked Example 2: A Clinker Store for Import
Now reverse the flow. A cement grinding plant consumes 1,500 tonnes of clinker a day, delivered in 25,000-tonne parcels on part-loaded Handysize vessels. Again, the inputs are illustrative.
| Step | Input | Result |
|---|---|---|
| 1. Parcel | 25,000 t per call | One call about every 17 days |
| 2. Safety stock | 7 days x 1,500 t a day | 10,500 t |
| 3. Working capacity | Parcel plus safety stock | 35,500 t |
| 4. Volume | Tonnes divided by tested bulk density | Set by your product test |
| 5. Intake rate | 25,000 t at 6,110 t per ship per day | About 4.1 days alongside; about 255 t an hour into storage |
The buffer is longer than for export because an importer is exposed to the voyage as well as the berth; set yours from your supply route’s record. Convert tonnes to volume with the bulk density your supplier tests, since it varies with grading and moisture.
The intake rate uses a real benchmark. Pelindo Multi Terminal Belawan reported dry bulk productivity of 6,110 tonnes per ship per day in 2026 up to August, against 1,722 for general cargo, according to branch figures reported by Portibi. At that rate the store must accept about 255 tonnes an hour around the clock, about four times the plant’s own draw of 62.5 tonnes an hour.
Silos keep a product dry on a small footprint; a covered shed spreads the same tonnage over more ground and needs reclaim equipment. Either starts from 35,500 tonnes.
Shared Terminal Tankage or Storage on Your Plot
In an integrated estate, storage is split between the terminal and the tenant, and the split changes the plot you need. Tanks on your plot remove a handover and give you control of segregation and heating, but tie up capital and land. Shared terminal tankage saves both and needs a throughput agreement.
Settle the land question early. Under NFPA 30 the bunded area must hold at least the volume of the largest tank inside it, and spacing, roads, pump slabs and a future tank all need room. Size the storage first, then choose your plot size band.
How Bulk Terminal Storage Fits SIIPE’s Planned Port
SIIPE, the Sumalacca Integrated Industrial and Port Estate in Medan Belawan, North Sumatra, is planned around both flows in this guide, and none of its port or storage facilities operates today. The Sumalacca Dry & Liquid Bulk Port is planned, not built, and is a medium-term objective on our roadmap.
The masterplan allocates 400 hectares to the deep seaport within the current 3,000-hectare development phase of a 5,600-hectare total planned area, of which about 840 hectares has been acquired. A Chemical Storage Tank facility and a Jetty Facility are on our planned infrastructure list, and the plan states plainly: “Capacities and operational status are not stated in the plan.” We will not quote a tank volume the design has not confirmed.
What the masterplan does fix is distance: industrial plots are designed to sit under 5 km from the estate’s own planned jetty, so your tanks and the ship’s manifold would share one short corridor.
Until the port is built, the operating gateway is Belawan Port, 4.7 km away, about 10 minutes by road. Its liquid bulk terminal is rated at up to 6 million tonnes and handles 3.5 to 4 million tonnes of CPO exports a year, according to the SPMT Belawan branch manager speaking to ANTARA in March 2025. Our Indonesia bulk terminal map sets that beside the other Sumatran gateways.
Frequently Asked Questions
How do you calculate bulk terminal storage capacity?
Working capacity equals your largest parcel plus the daily production or consumption rate times the buffer days you want against a late ship. Divide that by the usable fraction of each tank or silo to get nominal capacity, and size every grade that cannot share storage separately.
What is the difference between working and nominal tank capacity?
Nominal capacity is the full shell volume of a tank or silo. Working capacity is the part you can actually fill and empty, after the heel left below the suction and the space kept free at the top. You buy nominal capacity but size by working capacity.
How many tanks does one liquid bulk grade need?
At least two, and three is more comfortable. One tank receives from the plant while another is gauged, sampled and pumped to the ship. Grades that cannot share a tank, such as crude and refined palm oil, each need their own set and their own lines.
How long does a dry bulk vessel stay alongside at Belawan?
Pelindo Multi Terminal Belawan reported dry bulk productivity of 6,110 tonnes per ship per day in 2026 up to August. At that rate a 25,000-tonne parcel spends about 4.1 days alongside, so the storage receiving it must accept roughly 255 tonnes an hour while the ship discharges.
Does SIIPE have bulk storage tanks today?
No. The Sumalacca Dry & Liquid Bulk Port at SIIPE is planned, not built, and the Chemical Storage Tank and Jetty Facility on the estate’s infrastructure list are planned items with no capacity stated. Belawan Port, 4.7 km away, is the operating liquid and dry bulk gateway today.
Request Sumalacca Port Specifications
If you are sizing tanks or a clinker store for a plant in North Sumatra, design against the berth your plant will actually use. SIIPE is a planned 5,600-hectare estate in Medan Belawan, 4.7 km from Belawan Port, with every industrial plot designed to sit under 5 km from its planned jetty. The port and its storage are planned, not operational, and we say so in every document.
Tell us your cargo, parcel size, grades and throughput, and our team will share the published port design, the status of each component and the plot size bands that fit, from under 5 Ha to above 50 Ha. Review the distance table and target sectors on our industrial estate page, then message us on WhatsApp at +62 811 860 980 or send an enquiry through the form.
