By Thibault Worth

Lawrence Berkeley Nat'l Lab

Tommy Conry loading a lithium coin cell for testing at LBNL's battery lab.

We’ve reported extensively about AB 32, California’s 2006 greenhouse gas reductions law that calls for 1990-level carbon emissions by 2020.

But what happens to carbon reduction efforts beyond that date?

A less publicized, yet more aggressive 2050 target calls for slashing carbon emissions to 80% below 1990 levels by mid-century.  That goal was established by an Executive Order by Governor Arnold Schwarzenegger in 2005. Achieving such an ambitious target will require a range of initiatives, including building better batteries.

AB 32 calls for 33% of California’s energy to come from renewable sources by 2020. But while solar and wind energy produce zero carbon, they also fluctuate. The current solution is to balance those fluctuations with fast-ramping natural gas-fired power plants. And they produce carbon aplenty.

Jim Williams, chief scientist at San Francisco-based consulting firm Energy and Environmental Economics, says that as renewable energy penetration increases, carbon emissions will drop — but only to a point. According to a study he authored in the Nov. 2011 edition of Science, once we get beyond 74% renewable sources, carbon emissions will swoop upwards again. The cause would be the rapid on-off cycling of natural-gas fired power plants, which emit the most carbon dioxide at startup.

“Storage devices are going to be essential to reaching the goals of Executive Order S-3-05,” says Williams. “They’re essential to a low-carbon future.”

Not all storage devices are batteries. Hydro pumps, compressed gas and flywheels are already in limited use to store excess energy. But batteries are ideal for the grid. They can provide power instantly, and from any location. The problem is, they still can’t store very much energy.

Lawrence Berkeley Nat'l Lab

Barbara Le-Roux at the SEM ( scanning electron microscope), used to characterize the microstructure of the different materials.

The Bay Area is already home to more than 30 startup battery companies, many of which are struggling with ongoing R&D hurdles, as well as the lack of a clear market.

Recently, researchers and policymakers convened at the 2012 Silicon Valley Energy Storage Symposium to assess the state of the regional battery industry, and how to strengthen it.  Much of the “electrical buzz” was around CalCharge, a recently formed consortium between Lawrence Berkeley Labs and the California Clean Energy Fund (CalCEF), which will connect local battery startups with the world-class research facilities at Lawrence Berkeley Labs.

The California Public Utilities Commission is currently establishing procurement guidelines for energy storage, which will create a more stable environment for startups aiming to market their innovations.

Tesla Motors

Elon Musk is the founder of Tesla Motors and SpaceX, and supported the creation of SolarCity.

Elon Musk is well-known in Silicon Valley as the founder of the luxury electric vehicle company Tesla Motors, and of SpaceX, the private space transport company.

What’s less well-known is Musk’s contribution to SolarCity, the solar installer and energy efficiency auditor. Musk inspired–and helped fund–the creation of the San Mateo-based solar company. And Tesla is working closely with SolarCity on a clean energy storage solution that would combine Tesla’s lithium-ion batteries with SolarCity’s rooftop solar arrays. The collaboration makes sense: not only is Musk the chairman of SolarCity, but the founders of the company, brothers Lyndon and Peter Rive, are his first cousins.

The Tesla-SolarCity clean energy storage program would couple batteries with solar arrays, providing a way to store solar energy for, say, a cloudy day. Stage one of the project began in 2010, with $1.8 million in funding from the California Public Utilities Commission (CPUC) to launch a research program. Now, stage two seeks to commercialize the program on a modest scale, with over 70 applications pending under the CPUC’s  Self-Generation Incentive Program (SGIP), which provides rebates to customers using self-generated energy systems.

Although the subsidies have yet to be approved, CPUC information officer Andrew Kotch told GigaOm last week, “this emerging technology has a great amount of potential to contribute towards California’s climate and energy goals.” At present, the projects have a “conditional reservation,” and the CPUC will make a decision in the next 18 months.

As chairman of SolarCity, Elon Musk is not involved in such details or the day-to-day operations of the solar company, and CEO Lyndon Rive admits that his cousin’s time is very limited. He only contributes “maybe two hours a month” to the company — by phone — and three hours every quarter for board meetings. For your average chairman, that’s not much time to have a significant impact on a company. But Musk appears to have a rare gift for out the box thinking and strategizing.

“Elon is a phenomenal genius, so when he gives you the time and you lay out the plan, he can quickly identify the hole in the plan,” Rive told me. “This is the true definition of quality versus quantity. You can fix whatever potential pothole you might run into, just in a ten minute discussion with Elon.”

Musk manages to juggle all these projects — plus go to Burning Man — as Lyndon Rive explained in a recent Fresh Dialogues interview. In 2004, on a road trip to Burning Man, Peter Rive told Musk he wanted to do something that had a larger environmental impact, and Musk came up with the initial idea for SolarCity.

Was it was the profusion of attendees using free-standing solar panels to power their RVs? The atmosphere of radical creativity? Or was it just witnessing all that carbon going up into the desert air? Whatever fueled the conversation, it has had a profound impact on the US solar installation market. Last year, SolarCity had the largest share of residential solar installations in the US, and thanks to investments from Google and others, it’s growing rapidly, currently hiring four new employees a day. Like his cousin, Lyndon Rive has stratospheric dreams. Rive told me his ambitious goal is world domination in the energy market, no less. An IPO is anticipated later this year.

A 2 MW battery at the AES Huntington Beach power plant. (Photo: Lauren Sommer)

Energy storage is something we’ve come to take for granted in everyday life. Our cell phones, iPods, cars and computers all depend on batteries. But storing large amounts of energy for the electric grid is another matter entirely. It’s a technical challenge that has yet to be met–but will need to be for the coming age of renewable energy.

California’s grid is designed to deliver electricity on a real-time basis. Every four seconds, the grid operators at the California Independent System Operator (ISO) have to ensure that the energy supply meets the demand in the state, something that’s known as “balancing” the grid (you can see today’s electricity forecast on the ISO site). As a result, they coordinate the one piece of the system that they have control over: the power plants.

Traditional “baseload” generators like gas and nuclear plants produce a steady stream of electrons. But California is adding increasing amounts of solar and wind power to the grid each year. Since the output of a solar or wind farm depends on the sun or wind, the power they produce is intermittent (here’s a time-of-day profile of renewable energy on the grid today). That causes problems for the grid operators on a number of levels. Wind farms produce most of their power at night, but that’s when demand for power is lowest. Energy from solar farms using photovoltaics can drop off substantially when the sun disappears behind clouds. And large solar-thermal arrays ramp up extremely fast when first hit by the sun in the morning.

Energy storage is one of the ways that utilities and grid operators can address this intermittency. By having some extra electricity on hand, they can smooth out the bumps caused by these renewables. Here’s a review of some tried and new technologies for grid storage:

Batteries

There are a number of different kinds of batteries that can be used in grid-scale installations. I visited a two-megawatt battery in Huntington Beach that uses lithium-ion cells, much like a hybrid car or newer power tools. Southern California Edison is working on an 8 MW battery project near the Tehachapi wind farms. But lithium-ion technology has plenty of competitors, many of which have been awarded federal stimulus funding. The primary barrier for batteries is the cost.

A Beacon Power flywheel.

Flywheels

This technology uses rotational energy to store power. Flywheels have an internal rotor that uses electricity to spin at high speeds. When energy is needed, the rotor slows down and generates electricity through a motor. This is used for what’s known as “frequency regulation” on the grid. Since they can charge and discharge power on a second-to-second basis, flywheels smooth out the short-term fluctuations on the grid. Beacon Power has installed flywheels in Tehachapi, California as part of a demonstration project there.

Compressed Air

Using energy produced at non-peak times (at night), compressed air storage projects pump air into large underground caverns. When demand for energy is high, it’s released to run power turbines. PG&E is now planning a 300 MW compressed air facility in Kern County.

Of course, for all these technologies, cost is a major issue, not to mention the siting and planning considerations. To see how they stack up, check out these technology comparison charts from the Energy Storage Association.

Pumped Hydro

In the energy storage world, this is as old-school as it gets. Hydro-power uses water and gravity to generate electricity. Storage is added by pumping that water back uphill to the reservoir, so it can generate power again. Of course, it takes electricity to run the pumps, so the uphill run generally happens at night, when there is cheaper or excess power on the grid. California’s largest pumped hydro facility is PG&E’s Helms Pumped Storage Project outside of Fresno, which has a 1.2-gigawatt capacity (more about that in this Powerpoint presentation). PG&E is reportedly considering two gigawatts of new pumped storage at two other sites in California.

For more, listen to my radio story online and check out the rest of our stories in our ongoing series: 33 x 20: California’s Clean Power Countdown.