How Much HTS Tape Can All Those Pennies Make?

For all of you who have tried to keep up with the myriad of appointments, executive orders, and other goings-on in the second Trump administration, one of the more curious ones was his order on February 10, 2025 directing the Treasury Department to stop minting pennies. While the rationale in this executive order was the cost of minting pennies (each one reportedly costs 3.7 cents per every penny made, the penny has had mixed reviews for several decades. Who hasn’t found it to be annoying to have a pocket (or purse or a jar or a car ashtray) full of pennies? Interestingly enough, the nickel costs more to make ($0.14 per nickel) than it is worth as well, but there is no discussion of eliminating the nickel. Additionally, it is unclear whether the president can simply eliminate the penny (or any other coin), or whether it is in the purview of Congress.

Stopping the Minting of the Penny Would Free Up a Lot of Copper, Right?

Just to put things in perspective, in 2014 the US Mint made 8.15 billion pennies, using roughly 562 tons of copper. Pennies also include zinc (actually, zinc makes up 97.5% of the penny) – in 2014, it was 21,888 tons of zinc. The amount of copper used for pennies nearly equals the copper used in “consumer products” (appliances, electronics, utensils, and ammunition), though that does not count the copper utilized by the building and aeronautics industries. What else could you use this copper (and zinc) for?

How Much HTS Tape Could That Copper Make?

One use for all of this copper is high-temperature superconductor (HTS) wire and tape. Unlike low-temperature superconductors (LTS) which require expensive liquid helium cooling to remain superconducting, HTS tapes superconduct at temperatures that can be supported by less expensive (and less exotic) liquid nitrogen. The two leading formulations for HTS are yttrium barium copper oxide (YBCO) and bismuth strontium calcium copper oxide (BSCCO). Without jumping into how HTS tapes are made, YBCO contains 60% copper by weight, not including the tape substrate, which takes up a minimal percentage of YBCO HTS tape’s weight.

If we assume that copper is 50% of the net weight of YBCO HTS tape, that means that all those pennies could make 1,124 tons of tape. While the take make-up depends significantly on the rated current, the tape used in Commonwealth Fusion Systems (CFS) SPARC machine’s magnets weighs 9,265 kg for 267 km of tape (about 34 kg per kilometer, or 34 grams per meter). Using this metric, all those pennies could make 30,000 kilometers of tape (1,124 tons * 2000 lbs per ton, divided by 2.2 kilograms per pound, divided by 34 kilograms per kilometer of tape).

How Many Fusion Machines Does This Equal?

Now the last math problem (at least for this blog today) – if we took 30,000 km of HTS tape and turned it into fusion machines similar to the CTS SPARC fusion machine (which uses 267 km of tape), we could build enough HTS tape for roughly 110 fusion machines per year.

While SPARC is expected to be a smaller reactor producing ~100MW of power, 110 of these machines would produce 11GW of electricity, or 88 billion kWh of electricity (assuming roughly 92% duty cycle). The US used 4049 BkWh of electricity in 2023. Those pennies, if used for HTS tape, could support enough power plants to produce 2.17% of the electricity used by the US in 2023. While it would take roughly 10 years to produce enough fusion machines for fusion energy to reach 20% of all US electricity, this isn’t bad for the lowly penny 😊.