[Digital Today reporter Jinju Hong (홍진주)] An analysis says Tesla's heavy-duty electric truck, the Semi, could post a total cost of ownership (TCO) up to several hundred thousand dollars lower than a diesel truck at current U.S. fuel prices. The savings, however, were highly sensitive to electricity rates and diesel prices, and the analysis found that economics weakened quickly once power costs rose above a certain level.

Electrek, an electric-vehicle outlet, reported on May 4 local time that the Tesla Semi long-range model showed a cost structure up to $404,000 lower than a diesel Class 8 truck on a five- to 10-year operating basis. The comparison was between a 500-mile (804-km) Tesla Semi and a Freightliner Cascadia diesel truck.

The analysis put the Tesla Semi purchase price at $290,000 and depot charger installation costs at $60,000. It used $165,000 for the diesel truck price and assumed annual mileage of 100,000 miles (160,000 km), the U.S. Department of Energy's average for long-haul transport.

With electricity at $0.12 per kWh and diesel at $5.35 a gallon, the Tesla Semi's five-year TCO was estimated at about $486,000. The diesel truck was about $633,000 over the same period. The savings were $147,000 over five years, widening to $244,000 over seven years and $404,000 over 10 years.

By upfront cost alone, the Tesla Semi was at a disadvantage. Initial costs including charging infrastructure were about $350,000, higher than a diesel truck. But over time, differences in fuel and maintenance costs accumulate and offset that gap. The analysis put diesel fuel costs at about $0.67 per mile, while the Tesla Semi's energy cost under the same conditions stayed at about $0.2.

The maintenance cost gap was also large. The Tesla Semi was estimated at about $0.06 per mile because it does not have an engine, transmission, exhaust after-treatment equipment or the burden of managing diesel exhaust fluid. The diesel truck was $0.18. At 100,000 miles a year, the maintenance cost difference alone reached $12,000.

The part that drew the most attention in the analysis was not the savings figure itself but sensitivity to electricity rates. If electricity costs $0.08 per kWh, savings rose to $181,000 over five years and $472,000 over 10 years. If electricity rises to about $0.25, savings shrink to $37,000 over five years and $183,000 over 10 years.

In particular, economics weakened sharply above $0.30. Over five years, it showed a loss of about $6,000 compared with a diesel truck, and at $0.4 or more the diesel truck was cheaper across all periods. Electrek said, "The real key is the electricity-price sensitivity curve rather than the savings figure itself," adding, "The Tesla Semi needs power that is not cheap, but not excessively expensive either."

Recently surging diesel prices also changed the results. The analysis said savings were limited when it initially used a 2026 diesel price forecast of $3.5 a gallon, but economics improved sharply at the current level of $5.35. Diesel prices have risen more than 40 percent since early 2026, and in parts of California they exceed $7.5 a gallon.

Rising diesel truck prices are another variable. Due to the impact of a 25 percent tariff on U.S. Class 8 trucks and parts, new-vehicle prices including federal excise tax are rising to about $238,000. In that case, the initial price gap with the Tesla Semi narrows from $125,000 to about $52,000, and the analysis said the electric truck's payback period could also become shorter.

Expansion of charging infrastructure is also a variable. Tesla is building 66 Megacharger network sites centered on major freight routes. But public fast-charging fees can vary widely by region and time of day, so how much long-haul operators rely on public charging remains a key factor in real-world economics.

Ultimately, the Tesla Semi's competitiveness depends more on how power is procured and operating conditions than on the vehicle itself, the analysis said. The industry sees Tesla as having shipped its first vehicle from a high-rate production line and designed a factory with annual capacity of 50,000 units, and believes the pace of scaling up supply may become more crucial to adoption than economics.