LITTLETON, Colorado, June 11 (Reuters) - The Japanese government has called for homes and businesses to curb power use this summer, but emissions trackers are still bracing for a sharp uptick in Japan's power pollution as higher temperatures trigger increased air conditioner use.
Recent weather forecasts call for Japan's temperatures to average nearly 4% above normal in July and 3% higher than normal in August, according to Refinitiv.
Those forecasts equate to an average of more than 25 Celsius (77 Fahrenheit), while temperature readings at the hottest parts of the day will be substantially higher and may only be bearable with the aid of air conditioners.
Air conditioner use accounts for about 30% of household electricity consumption in Japan, according to Japan's Ministry of Economy, Trade and Industry (METI), and historically tends to peak in July and August, the hottest months of the year.
Those same months are when Japan's use of coal for electricity generation also typically peaks, along with power sector emissions, data from think tank Ember shows.
This year, those usage and pollution patterns look set to be repeated, regardless of the government's recent pleas to curb power use.
In addition to weather forecasts that call for above-normal temperatures this summer, Japan's imports of thermal coal also suggest the country will produce and consume more energy than usual over the coming months.
Japan will import more than 10 million metric tons of thermal coal this month, according to ship tracking data from Kpler.
That total is over 2 million metric tons more than the average monthly import tally during April and May; 1.2 million metric tons more than the June average since 2017; and the highest June total since at least 2017.
Such a high import tally indicates power producers are gearing up for increased electricity use over the coming months.
Power production trends show Japan's energy usage tends to have two distinct periods of strength when the country's weather is at its most severe - during winter and summer.
Energy use forecasts show energy consumption in Japan this July will be consistently above the long-term average, with power firms set to produce roughly 6,400 megawatt hours (MWh) more electricity per day compared to the long term average, Refinitiv data shows.
In August, generation looks set to exceed the average by roughly 5,200 MWh.
Coal will not be the only power source for electricity in Japan this summer, as clean energy sources such as from solar, wind, hydro and nuclear facilities generate roughly a third of the electricity supplied each month.
Natural gas accounts for another 30%-33%, although that share is down from around 37% before 2022, when Russia's invasion of Ukraine tightened global gas markets and sent prices soaring.
Coal, however, has accounted for a solid 32% of Japan's electricity generation for the past six months, and looks set to at least retain that share over the coming summer as nighttime use of air conditioners lifts overall electricity demand just as production from solar sources drops off.
This means that Japan's power sector emissions look set to remain elevated at around 38 million to 40 million metric tons of carbon dioxide per month, Ember data shows, and could veer even higher if coal's share of the energy mix climbs relative to natural gas.
Ultimately Japan's residents may have the final say over just how much electricity they consume.
If they heed the government's call to consistently restrain power use, then further pressure on the country's energy system may be averted.
But if temperatures get too high, households may resort to cranking up air conditioner units regardless of government missives, triggering steep increases in coal-fired generation and emissions in the process.
The opinions expressed here are those of the author, a columnist for Reuters.
Reporting By Gavin Maguire; Editing by Tom Hogue
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