Energy companies are facing an uncomfortable truth: one day not all households will require their services.
Some people have been generating their own energy, instead of tapping into a national power grid, for decades.
Early-adopters included former US president Jimmy Carter, who in 1979 had 32 solar panels installed at the White House. “No one can ever embargo the sun or interrupt its delivery to us,” he declared, referring to the Arab oil embargo earlier in the decade.
But self-generated power has been held back by high costs and inefficient technology: panels of the type Mr Carter used are now mostly to be found in museums.
Until now that is. The concept is finally taking off, thanks to increasingly powerful batteries that can store wind and solar energy for use when the sun is not shining or wind blowing.
In Germany, about 20,000 households are already part of an initiative, launched by energy storage company Sonnen, which connects homes that independently produce energy. Sonnen’s virtual network allows them to buy and sell excess energy to each other at a reduced cost.
Sonnen is Europe’s largest maker of rechargeable energy storage packs. When the company launched in 2010, its battery packs sold for €25,000. Today, they cost €5,000.
“It’s a very good investment,” said Jens Heuson, a resident outside Munich who has solar panels on his shed and a Sonnen pack in his basement.
Mr Heuson no longer dreads the monthly letter from his power company, because it now contains a cheque rather than a bill.
In Brooklyn, a start-up called LO3 Energy is testing a similar system that allows neighbours to buy and sell energy on a microgrid.
Such ideas could change lives in a way that compares with what mobile phones have done in the past decade, said Frank Rijsberman, director-general of the Global Green Growth Institute in Seoul.
“Mini-grid electricity based on solar and batteries is a revolution that can bring affordable energy to all citizens,” he said.
Another factor is that the prices of renewable energy now rival or, in some cases, beat fossil fuel-based power.
“Renewable energy became the cheapest form of electricity in 58 emerging economies last year,” said Mr Rijsberman.
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