Tesla's fiscal 2023 annual report, filed with the SEC on January 29, 2024, finally contains the sentence storage analysts had been waiting four years to read. The 10-K attributes an improvement in its energy-segment gross margin to a lower average Megapack cost per MWh and to a higher proportion of Megapack in the mix. After years of being able to confirm only that storage was growing, the filing confirms that storage is getting more profitable as it scales.
This is the does-it-pencil question answered in the company's own words. The two drivers the 10-K names — lower cost per MWh and a richer Megapack mix — are exactly the levers a containerized-product business pulls to expand margin: manufacturing scale brings the unit cost down, and a shift toward the higher-margin product lifts the blend. The filing is telling you both moved the right way in fiscal 2023.
Cost per MWh is the cleanest single metric in utility storage, and a falling one is the strongest evidence that a factory is learning. As Tesla's Lathrop Megafactory ramped, the per-unit cost of a Megapack came down — the classic manufacturing cost curve playing out in a product that is, essentially, batteries in a box at industrial scale. The FY2023 10-K is the filing where that cost-down stops being a thesis and becomes a stated cause of margin.
The mix point is just as important from a markets seat. Megapack carrying a higher proportion of the energy segment means the segment's blended economics increasingly reflect the better product. A business can scale revenue while diluting margin if growth comes from the wrong mix; the FY2023 language says Tesla's storage growth came with a favorable mix shift, which is the more valuable kind of growth.
What to hold in reserve is that a single year's improvement is a data point, not a permanent regime. Cost curves can flatten and ASPs can move; the filing confirms the direction in fiscal 2023 without promising it forever. Still, after years where the only honest answer was 'too early to tell,' a 10-K stating that Megapack cost per MWh fell is a genuine inflection in the storage story.
We analyze, we don't advise. The FY2023 annual report is the filing where Tesla's storage business crosses from 'growing' to 'growing profitably' in the company's own disclosure — the answer to a question this desk has been asking since the first Megapack shipped.
Figures from the filing on sec.gov, indexed by EdgarBeast.