On a remote wellsite, diesel is not a fuel — it’s a logistics chain. The fuel trucks, the tank farm, the road maintenance, the days of convoy travel across desert or tundra, and the generator sets that burn it around the clock. Operators in North Africa routinely spend $2–5 million per year per rig on diesel, with some sites two days’ drive from the nearest fuel distribution center.
Battery energy storage (ESS) cuts that chain down to size. But sizing it wrong — too small, too large, or matched to the wrong load profile — turns a promising investment into an idle asset. This article explains how to size ESS for drilling and workover load profiles, and how to model the payback so the business case holds up under scrutiny.
First, Understand the Load Profile
A rig’s power demand is not a flat number — it’s a spiky, cyclical pattern that repeats every 24 hours:
- Peaks — drawworks hoisting, mud pump startup, top drive inrush. Short bursts, high current, brutal on generator sets
- Base load — circulating, rotating, lights, camp. Hours of steady, lower demand
- Dips — tripping pipe, connections, testing. Near-zero demand that a diesel genset still burns fuel to cover
A diesel genset sized for the peaks runs at low efficiency for most of the day — fuel burn doesn’t drop proportionally with load. This mismatch is exactly what ESS exploits.
How ESS Changes the Fuel Equation
A containerized ESS (like the Heverda 700 kW / 1.687 MWh cabinet) works with, not instead of, the existing generator sets:
- Peak shaving — the battery supplies the short, high-current peaks while the genset runs at its efficient band
- Load smoothing — the genset sees a flatter, more predictable load, so it burns less and lasts longer
- Genset-off periods — during low-load periods (tripping, testing), the battery carries the site and the genset shuts down entirely
- Backup — when the genset faults, the Static Transfer Switch hands the load to the battery in under 20 milliseconds — far below the ride-through capability of any VFD or motor on the rig. No shutdown, no dropped string.
The result operators measure: 60–80% reduction in diesel consumption on hybrid sites — and with it, proportional cuts in fuel trucking, emissions, and generator maintenance.
Sizing by Rig Type: The Cabinet Table
ESS sizing starts from the rig, not from the battery. The Heverda modular approach — one 700 kW / 1.687 MWh cabinet as the building block — maps directly to operation type:
| Operation Type | Configuration | Why It Fits |
|---|---|---|
| Workover, testing | 1 cabinet (700 kW / 1.687 MWh) | Drives 300–500 kW workover rigs continuously; covers a typical site for 2–4 days on stored energy |
| Sidetrack, small drilling | 2 cabinets (1.4 MW / 3.374 MWh) | Adds headroom for milling and directional operations |
| Medium drilling (1,500 HP) | 3 cabinets (2.1 MW / 5.061 MWh) | Peak-shaves drawworks and mud pumps through the drilling cycle |
| Large drilling (>2,000 HP) | 4–5 cabinets (2.8–3.5 MW / 6.7–8.4 MWh) | Full drilling load with high inrush coverage |
The 1,000 kW STS (Static Transfer Switch) in each cabinet handles the inrush from drawworks, mud pumps and top drives — the moment most power systems fail.
The Charging Question That Decides the Design
“How do you charge it?” is the first question every operator asks. The answer in practice: the genset recharges the ESS during naturally low-load periods — when the rig is tripping pipe and the mud pumps are off. A 500 kW genset typically recharges a cabinet in 3–4 hours, which fits naturally inside a 24-hour workover cycle. No dedicated downtime is needed — the system is sized so that recharge happens in the load dips that already exist.
Standby PV can be added where solar makes sense: an MPPT module is available on each cabinet, extending the fuel savings further during daylight hours.
Building the Payback Model
The business case for ESS on a remote rig is a logistics case. Here’s the model an operator should run:
- Baseline fuel cost — annual diesel spend for the site (e.g. $2–5M/year depending on rig size and fuel delivered cost)
- Hybrid savings — apply 60–80% reduction to the fuel line
- Logistics savings — fewer fuel trucks: road wear, convoy security, delivery delays, and the risk of a site running dry
- Maintenance savings — gensets running in their efficient band, fewer starts/stops, extended overhaul intervals
- Risk value — the <20 ms STS backup means a genset fault no longer means a dropped string or a rig shutdown
At a delivered fuel cost of ~$1.0/L, operators on large programs see annual fuel savings in the $3.5–5M range across a multi-rig rollout — the ESS capex pays back within the first year of operation on high-consumption sites.
Deployment Modes That Fit Your Site
The same cabinet works in three configurations:
- Hybrid (recommended) — ESS carries peaks and low-load periods; diesel gensets run as backup and recharging source. The 60–80% fuel reduction mode
- ESS as primary, diesel backup — where grid or PV provides the base energy; the genset only covers failures
- Grid-tied — where a weak or unstable grid exists, the ESS bridges outages seamlessly
Desert-Proof by Design
An ESS that can’t survive the site can’t save the fuel. The Heverda cabinet is built for the places this article assumes: IP54 outdoor enclosure (no additional shelter needed), operating range -20°C to +55°C, sandstorm-resistant cable glands, and roof-mounted AC units that keep the battery within its thermal band in Saharan summer. A unit designed for Algeria’s desert works in the Sahel, the Gulf, and the steppe.
Conclusion
The case for ESS on remote rigs is not about technology — it’s about the logistics chain of diesel. Size the system to the rig type, charge it in the load dips that already exist, and model the payback on fuel, trucks and maintenance. On high-consumption sites, the system pays for itself in the first year.
Tell us your rig type, load profile and fuel logistics, and we’ll respond with a recommended configuration and a payback estimate for your site.
ESS Sizing for Remote Rigs | Cutting Diesel Costs
How to size battery storage for drilling and workover load profiles — and model the diesel-reduction payback on remote rigs.
Heverda Energy — Shenzhen Hexinhe Technology Co., Ltd. ｜ sales@heverda.com ｜ www.heverda.com