This document was orginally sent to Compass Miners in May 2022.

As we move into the warmer summer months, it's important to understand some things about the way Bitcoin mining hardware works and how you might be affected by things like load curtailment.

While we try very hard to keep miners running through the heat, there are some days that we won’t be able to hash. This does not mean there is anything wrong with the miner or the facility. We will adjust scheduling to do reboots daily in the evenings after the heat subsides, based on the availability of staff and the safety of mining hardware. We will also work with the facilities on other heat mitigation steps, but we wanted everyone to be aware that many wholesale power markets are calling for a high amount of demand this summer.

We suggest you keep an eye on the local weather information in the areas where your miner is hosted. This will give you an idea as to why your miner may be offline. In these warmer places, it's a good idea to wait until the evening to submit a ticket for a reboot, considering the miner will only fail again in the heat.

Mining Hardware

There is an ambient temperature cutoff that will shut down the miners on hot days. There is also a chip temperature cutoff. This protection is built-in to prevent damage to the chips and cuts off well before any such damage could possibly occur.

For example, Antminers have a 104F ambient temperature shut off in the manual, but that temperature will decrease if your miner is hosted at a higher elevation. There is also the chip temperature cutoff at 91C on some models and 96C on others. The Whatsminer, on the other hand, has a tuning function in the firmware that will throttle the frequency so the miner can continue hashing but at a lower hashrate.

The Z15 miner can handle a much higher ambient temperature than most other machines since they have a larger ASIC, which has more surface area to disperse heat. All mining hardware is slightly different, but rest assured, we have a close eye on all of this.

Most of our facilities perform preventive maintenance on at least a quarterly basis. This maintenance is to clean dust and debris that may be trapped inside the heatsinks. This will also help your miners deal with high heat days. We also offer additional deep cleaning services for miners that are over a year old. These miners are sent to our service center, broken down and cleaned thoroughly to a like new condition before being sent back to the facility.

Curtailment Expectations

The heat of the day will last for 2-6 hours during the daytime hours in most places. We expect there to be increased demand this summer compared to last summer. This means that facilities will use load shedding or curtailment to respond to the demand coming from residential and commercial facilities. Facilities like hospitals and military bases use this power for mission critical support systems, such as respirators and other types of life support machines, so it's very important to participate in these programs. Without participation in these programs, the cost of power would not be affordable.

Below is the forecast for several of the power markets we are in to ensure that you’ll know what to expect. If you see no reference to your hosting location, there is a good chance you won’t experience much curtailment - if any.

  • IESO, for example, has increased their estimated peak demand by 500MW in Ontario this year. They expect outages to occur on warmer days this summer from June to September, which will trigger load shedding for our facility.
  • SPP in the Central US saw an all-time high demand in July 2021 and expects the same this year. This will affect Compass facilities in Oklahoma mainly.
  • MISO is also expecting record demand of 124GW with only 119GW of generation capacity. The only Compass Mining site this might affect would be Minnesota 1, which will be coming online mid-summer. Missouri does not participate in this power market.
  • ERCOT is estimating 77GW of demand with 86GW of transmission, but they are also warning of outages on some tough triple digit days. This will affect Texas facilities, but at the same time, ERCOT promises another 16GW of generation projects to be online by 2026, thanks to cryptocurrency projects like yours.

As you can see by the figures below, the demand is anticipated to greatly increase compared to last year. Ontario demand outweighs its generation by about 1000MW, and in this scenario, the likelihood of an outage is the greatest.

Source: IESO

Below is a comparison of the demand compared to last year in the US wholesale power markets. Please note that these areas will also see several demand peaks this summer.

We hope this communication helps explain the curtailment we may experience this summer. Compass Mining and its partners are working to minimize the downtime as much as possible. We appreciate your continued support, and we look forward to deploying a record number of miners with you the rest of the year!