能源企业正面临一个令人不安的事实：有一天，并非所有家庭都会需要它们的服务。
Some people have been generating their own energy, instead of tapping into a national power grid, for decades.
数十年来，一些人一直在自己发电，而不是接入国家电网。
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.
自发电的先行者包括美国前总统吉米•卡特(Jimmy Carter)。1979年，他在白宫屋顶上安装了32块太阳能电池板。“没人能够对太阳实施禁运，或者阻止阳光照射到我们这里，”他宣称，暗指20世纪70年代初阿拉伯国家的石油禁运。
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.
但高成本和低效率的技术阻碍了自发电的发展：卡特当年使用的那种太阳能电池板现在大多只能在博物馆看到了。
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.
到目前为止是这样没错。得益于日益先进的电池，这个概念终于开始起飞。这些电池能够储存风能和太阳能，以便在不出太阳或者不刮风的时候供电。
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.
在德国，大约2万个家庭已经加入了能源储存公司Sonnen发起的一项行动。该行动将自发电的住宅相互连接起来。在Sonnen的虚拟网络中，各家庭能够以较低的成本相互购买和出售多余的能源。
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.
Sonnen是欧洲最大的可充电能源储存组生产商。2010年该公司成立时，其电池组的售价是2.5万欧元。如今，这些电池组的售价为5000欧元。
“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.
“这是非常好的投资，”居住在慕尼黑郊外的延斯•霍伊森(Jens Heuson)说。他在自己的棚屋上安装了太阳能电池板，并在地下室中放置了一组Sonnen能源储存组。
Mr Heuson no longer dreads the monthly letter from his power company, because it now contains a cheque rather than a bill.
霍伊森再也不用害怕接到电力公司每月寄来的信了，因为现在信封里装的是支票而不是账单。
In Brooklyn, a start-up called LO3 Energy is testing a similar system that allows neighbours to buy and sell energy on a microgrid.
在布鲁克林，初创公司LO3 Energy正在测试一个类似的系统，该系统允许邻里间在微型电网中购买和出售能源。
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.
位于首尔的全球绿色增长研究所(Global Green Growth Institute)的所长弗兰克•里斯伯曼(Frank Rijsberman)表示，这样的想法将像过去10年的手机那样，给人们的生活方式带来巨变。
“Mini-grid electricity based on solar and batteries is a revolution that can bring affordable energy to all citizens,” he said.
“以太阳能和电池为基础的迷你电网电力是一场革命，将给所有居民带来用得起的能源，”他说。
Another factor is that the prices of renewable energy now rival or, in some cases, beat fossil fuel-based power.
另外一个因素是，基于可再生能源的电力价格现在已经可以媲美，甚至有时还优于基于化石能源的电力价格。
“Renewable energy became the cheapest form of electricity in 58 emerging economies last year,” said Mr Rijsberman.
“去年，在58个新兴经济体，可再生能源变成了最廉价的电力类型，”里斯伯曼说。
