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.

When I first began researching this story for QUEST, I was surprised that I hadn't heard more about geothermal power. It's never lumped into that renewable energy laundry list that's recited by politicians and journalists alike — you know, "…solar, wind, hydroelectric and biofuels". But it turns out that geothermal energy has really great potential.

To start, it's reliable. Geothermal is base load power, which means that the plants generate power at a constant rate around the clock. In fact, geothermal plants often have capacity factors of 86-95%, well above traditional base load generation such as coal.

It's clean. Geothermal power plants give off little or no sulfur compared to fossil fuel-fired power plants and they emit no nitrogen oxides. Emissions of CO2 per megawatt-hour are extremely low or absent for the newer flash plants. A typical geothermal plant may produce 1 lbs. of CO2 per MW hour. This figure compares with 1030 lbs. per MW hour of CO2 for a natural-gas fired plant, 1600 lbs. per hour of CO2 for an oil-fired plant, and 1820 lbs. per MW hour for a low grade coal-fired plant.

And, if the USGS assessment is accurate, and it probably is, geothermal power is abundant. According to the study:

"the power generation potential from identified geothermal systems range from 3,675 MWe (95% probability) to 16,457 MWe (5% probability); the power generation potential from undiscovered geothermal systems range from 7,917 MWe (95% probability) to 73,286 MWe (5% probability); and the power generation potential from Enhanced Geothermal Systems range from 345,100 MWe (95% probability) to 727,900 MWe (5% probability)."

So, what's wrong with it? As we touched on in the TV segment, there are several little drawbacks that no doubt should be considered. These include induced seismicity (little earthquakes that are triggered by geothermal developments), the initial expense of geothermal exploration and development, and the challenges of connecting the electricity generated by a geothermal plant to the grid at a point where there is sufficient available capacity to sell the electricity.

However, I was never really able to find a strong reason why geothermal energy should not be in everyone's renewables laundry list. And considering Obama included geothermal energy in his list during his last debate against John McCain, I would imagine we will all be hearing more and more about geothermal energy development in the months to come and beyond.

Watch the Geothermal Heats Up television story report online. And don't miss the steamy, behind-the-scenes photos for this story.

Senior Radio Editor Andrea Kissack also contributed to this post.

When we started working on this project, we thought it would be easy to find people to interview: D.I.Y.ers with a passion for sustainable building who were testing out new technologies in their backyards. We called consultants, local suppliers, green-minded architects, and collected as many leads as we could. We found a handful of great subjects, but we never quite tapped into that centralized hub we'd envisioned. And that, it turned out, was the point. When you're a D.I.Y.er, you tend to D things Y.

Which is what's so appealing about these projects. Green innovators like those we meet in the radio piece and slideshow are working on their own initiative, spending much more time and money than they would with more conventional technologies, and running a high risk of failure. Ultimately, though, we'll all learn from their mistakes.

Wind Turbine

Chris Beaudoin fits one type of these backyard innovators: He's a long-time environmentalist willing to spend some extra cash trying out something new. San Francisco's Department of the Environment put Beaudoin in touch with Blue Green Pacific, a local company that will ultimately have two turbines up and running on Beaudoin's garage. So far there are only about five "micro-wind" projects like this in the city, about half of them operational. But stay tuned. Gavin Newsom is encouraging homeowners to experiment with wind turbines, and the state of California is already offering rebates on home turbines.

Dixon Beatty and Stephanie Parrot, who live in West Oakland, fall at the other end of the spectrum, what I'd call extreme do-it-yourselfers (though I'm sure they'll disagree). They've spent years remodeling a beautiful old Victorian in West Oakland that they still call a work-in-progress, despite well-functioning solar thermal and photovoltaic systems that keep the house warm and lit with almost no help from PG&E.

Dixon Beatty

When Lisa and Michael Rubenstein wanted to build their green dream home in Hillsborough they thought they would derive the majority of their energy from photovoltaic rooftop solar panels. PV Panels, afterall, have been the energy technology of choice for eco-friendly buildings. But as the Rubensteins waded further into construction, their architect suggested a geothermal heating cooling system. They were told geothermal can provide the most energy efficient, environmentally friendly home and so, they decided to go for it. Together, with PV solar and solar thermal panels, the Rubenstein's monthly energy bill is only eight dollars. Not bad for a 6,000 sq. foot home. It was an expensive project but what they have created is an experimental, contemporary home that gives living green a whole new aesthetic.
Lisa and Michael Rubenstein

Also merging modern design with eco-practical, is Sunset Magazine's idea house for 2007. PIX Located in San Francisco's Mission District, Casa Verde is Sunset's first idea house to be focused in an urban setting, The model home features solar and wind power, a green roof and a sleek, eco-friendly aesthetic.

Listen to the"Beyond Solar: Do It Yourself Home Energy radio report online, and watch our Web Extra: Generating Energy Right at Home slideshow.