Summer Curtailments Slash Bitcoin Production for US Miners Amid Grid Pressures
The summer heat is taking a toll on U.S.-based Bitcoin mining operations, with multiple public miners reporting lower realized hashrates in June due to curtailments to avoid high power costs and grid penalties.
Cipher Mining (NASDAQ: CIFR) said on Tuesday that it expanded its installed hashrate capacity to 16.8 EH/s during the month. However, the production of 160 BTC implies a realized capacity of 10.58 EH/s on average, representing just 62.95% utilization.
That figure marked a decline from the 11 EH/s realized in both April and May, despite the addition of new capacity from its Black Pearl site, which began hashing at the end of June.
Cipher attributed the drop to its decision to curtail power usage more aggressively as part of a “4CP avoidance strategy,” a practice designed to limit electricity consumption during peak demand periods that can trigger higher grid charges. Cipher added that data from June would guide further curtailment refinements through the summer months.
MARA, the largest public Bitcoin miner by installed capacity, also reported a production slowdown. Its realized hashrate dropped to 47.13 EH/s in June—down nearly 20% from 58.15 EH/s in May and equating to 82.11% of its total energized fleet.
“The decrease was primarily due to reduced uptime from weather-related curtailment and the temporary deployment of older machines in Garden City while storm-related damage was being remediated,” said CEO Fred Thiel. He also cited natural variation in block production, a factor MARA is exposed to due to operating its own mining pool.
The production slowdowns from curtailment come at a time when Bitcoin’s network hashrate experienced a notable pullback in the latter half of June. After peaking near 950 EH/s earlier in the month, the network’s seven-day average dipped to around 850 EH/s, drawing attention to possible causes ranging from U.S. summer heatwaves to geopolitical tensions.
The timing of the decline overlapped with a U.S. military strike on an Iranian nuclear facility, prompting speculation that Iranian miners may have gone offline, contributing to the hashrate contraction. But the more concrete data from public North American miners underscores that grid-related curtailments—particularly during periods of peak electricity demand—remain a dominant and recurring force shaping network dynamics each summer.
