And old, 19th Century windmill in contrast to wind turbines today.

Last summer I visited the Netherlands, the original home of the windmill. Surprisingly, I saw hardly any of the quaint structures we associate with Dutch wind power. One hundred years ago Holland had about 10,000 wooden windmills dotting its landscape. Today, barely 10% remain. What I saw instead were high tech wind turbines, white and spare and gracefully generating electricity with wind from the North Sea. Many view these modern day towers as an eyesore, but I see them as a sign of hope. Like giant flowers across a landscape, they symbolize for me a clean energy future. But wind power, and solar, have a handicap that fuels claims that renewables will never be more than a small percentage of U.S. power. These energy sources can't be counted on when night falls or the wind subsides. Their inconsistent and therefore unreliable nature poses a problem for a world with an enormous appetite for electricity. If only excess power could be stored on a grand scale, it might solve many of our energy problems.

It isn't that electrical energy isn't currently storable, but as Andrew Tang, Senior Director of PG&E’s Smart Meter program points out, the current generation of batteries can’t store electricity at a price that's cost effective. But both he and Steve Berberich from California System Operators were optimistic about future storage possibilities. Tang described an experimental project that uses a sodium sulfur battery the size of an 18-wheeler trailer. The battery would be located next to a substation, or somewhere in the network, and its stored power would be used during times of peak demand. He also talked about the future of plug-in electric cars whose batteries could both store energy and in theory put it back onto the grid when the car's not in use. Steve Berberich envisioned several possibilities for storing excess power. He proposed converting it to hydrogen, which could be burned in a gas plant or could be used in a fuel cell. And he suggested using power to compress air, which could be injected into the ground and called upon when the wind's not blowing and the sun’s not shining.

Whatever the final solution to storage, you can guarantee it will be a game changer in the renewable power industry. No longer will wind and solar be looked upon as unreliable. Hopefully this missing puzzle piece will go a long way towards helping us detach from our dependence on fossil fuels. But we’ll still be left with the challenge of getting all that clean, green energy onto the power grid. And you can be sure that environmental concerns, zoning, aesthetics, and cost will undoubtedly be cantankerous issues for years to come.

Watch the Climate Watch: Unlocking The Grid television story online.

Hourly energy use data, now online.

I've never paid much attention to my electric meter. For most of us, it's just that box on the side of the house with a small white disk spinning inside, keeping track of our energy use. But over the next three years, all the meters of PG&E customers will be getting a major upgrade to a new, digital SmartMeter.

I met one customer, Ken Kube in Castro Valley, whose meter has already been upgraded. Since the new meters track his home energy use digitally, Kube can log into his PG&E account and see his real-time energy use. On one level, it's really the ultimate tool for parents who like to remind their kids to turn out the lights. But it's also a powerful conservation tool. Kube could see how much energy he uses at night, when his appliances are drawing power in stand-by more (what's known as "vampire" power).

These meters are just a small piece of the puzzle when it comes to a smart grid. Just what the smart grid is depends on whom you ask, but most people agree it comes down to one thing: communication. The energy landscape is changing rapidly. In addition to increasing demand, there's more renewable power like large-scale solar and wind coming online – which are often far from urban areas and are available intermittently. There's also small-scale solar on building rooftops – which means energy consumers are becoming energy producers. There will also be plug-in electric cars, which need to draw power from grid.

To manage all this, utilities and grid operators need more information than they have. And that's where meters come in. But as Kurt Yeager of the Galvin Electricity Initiative describes, it's a huge networking challenge – and a huge market opportunity.

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A number of companies have jumped into the smart grid market as a result, from Silicon Valley start ups to international corporations. As Eric Miller, the Chief Solutions Officer for Trilliant describes, managing the information flow in smart grid will be the biggest challenge.

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Other smart grid companies are banking on the consumer market. Google is developing the PowerMeter, an online tool that tracks home energy use. They're partnering with GE, who is positioned to work with utilities, with its meter technology, and with consumers, with smart appliances, as Sunil Sharan, the Director of the Smart Grid Initiative explains.

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More on the smart grid: check out the Smart Grid at Home radio report and a slideshow of grid technology, old and new.