"Iceland‘s electricity infrastructure is under pressure and some output may need to be dialed down come the winter.
The very cold start to summer meant that glacial ice was slow to start melting and the late thaw meant that river levels were lower than usual. This has resulted in hydroelectric reservoirs holding much less water than expected for the time of year.
Hálslón, the large lake created by the Kárahnjúkar hydroelectric dam in East Iceland, is currently about 30 meters below its expected level, Vísir reports.
A warm August and September could make all the difference, but if weather and climatic conditions continue as they have been so far this spring and summer, it is possible the amount of electricity produced could have to be reduced this winter, to ensure the reservoir does not run dry before next spring’s melt.
Kárahnjúkar only produces electricity for the aluminum smelter in Reyðarfjörður, but over 80 percent of all Iceland’s electricity comes from hydroelectric power stations, so others could also be affected." via No Tricks Zone