Beneath Tesla Inc's (NASDAQ:TSLA) basic top line numbers, there was lots of moving parts within the business that helped earnings to nearly double in the fourth quarter.
Elon Musk's listed vehicle is not just on an electric vehicles maker, after all.
READ: Tesla earnings almost double but come in short of Wall Street forecasts
The energy business also grew last year, with energy storage deployments growing above three gigawatt hours (GWh) for the first time, Tesla said, with total battery deployments increasing 83% compared to the prior year.
While the Powerwall domestic product continued to grow, the major growth was sparked by demand for the Megapack, its utility-scale storage product.
“While we have made progress on production, we should see even further increases in supply in the next few months,” Tesla said.
Indeed the backlog that has constrained its energy storage business has also affected the larger automotive arm.
Rolling out its first electric 'Semi' articulated lorry has been hampered gear because of battery supply issues too, with a lack of the special battery cells needed but the engineering work is now complete and it plans to deliver the first of these big rigs “by the end of the year”.
Musk articulated the reasons behind the battery issue on the earnings call with analysts, after the results were released.
“Scaling production is very hard,” Musk said.
“The main reason we have not accelerated new products – like for example Tesla Semi – is that we simply don’t have enough cells for it,” Musk said.
“If we were to make the Semi right now, and we could easily go into production with the Semi right now, but we would not have enough cells for it.”
READ: Tesla's Musk promises 700km range cars soon, with 1,000km battery in development
Musk said that starting production on the new 4680 battery pack – the battery cells unveiled at its 'battery day' last September with six times more power and 16% additional range than its current Panasonic 2170 batteries – should give Tesla enough battery cells to meet its needs.
Tesla aims to “exponentially” ramp up battery cell production to 200 GWh per year by 2022.
Tesla's battery suppliers are also working to make a big step up in production, including Panasonic planning to add invest in another production line to its joint venture plant in Nevada, where production will include the 4680 cell.