Clean Energy Storage Solutions: Challenge Meets Opportunity

A key challenge for renewable energy, as most people know, is what to do when the sun doesn’t shine or the wind doesn’t blow. Addressing that challenge is one of the emerging trends reported this week in the Clean Energy Trends 2009 report (see Sarah’s post from Tuesday on the report’s look at emerging clean energy markets).

Utility scale energy storage, along with electrical distribution, transmission, and grid infrastructure upgrades, stand as the “number-one barrier to significantly scaling renewables in the energy mix of a utility, state, or nation”, says the report. As such, energy storage technology is a key area receiving major attention, innovation, and investment.

Lux Research sizes the current global market for energy storage at $2.4 billion and estimates that market could expand to $50 billion for batteries alone if just 10% of the world’s wind farms currently online used them for storage.

Where there is significant challenge, there is also significant opportunity.

No clear technological winner

There are several technologies vying for prominence in the field, with as yet no clear winners. Among the most promising solution are:

  • Batteries – including redox flow, vanadium (read our previous post about vanadium batteries), zinc, and large-scale lithium-ion
  • Compressed air energy storage
  • Flywheels
  • Molten salts for solar thermal storage

Each of these technologies hold promise, but entrepreneurs and manufacturers still battle learning curves and high costs – what matters most to utilities:
“Our main concerns are what’s the cost to implement it,” says Xcel Energy’s John Bryan, “What’s the cost to run it, and how does the concept of storage add value to our company?”

Top of the project watch list

Xcel energy, in partnership with Japanese battery supplier NGK Insulators and the National Renewable Energy Laboratory is proceeding with a closely-watched test project using a 1 megawatt sodium-sulphur battery from NGK on a wind farm in western Minnesota. When fully charged, the battery, actually consisting of 20 modules each storing 50 kilowatts, could power 500 homes for up to seven hours.

Understanding physics for better storage

Thinking back to your high school or college physics class, you may remember that it is easier to store heat than it is electrons. This basic law of the natural world comes into play for energy storage at concentrating solar power (CSP) thermal plants. Several companies including SkyFuel, Abengoa Solar, Andasol, and SolarReserve (which the Clean Energy Trends report singled out as receiving $140 million in venture capital last year and a select company to watch) store solar-generated heat in tanks of molten salt. The heat is then used to heat liquid that makes steam to turn turbines.

Abengoa plans to use molten salt storage technology for a 280 MW CSP plant in Arizona (where there is plenty of heat), one of the largest planned solar generation plants in the world.

When the going gets tough…

While there is as yet no clear winner in the “energy storage race,” there should be little doubt that there will come to the fore a solution (or solutions), working in tandem with smart-grid and infrastructure upgrade projects, that will bring clean, renewable energy into an ever increasing number of homes and businesses, both here in the states and across the globe. It’s a tough economic climate out there, and not every start-up is going to survive. But the place to be right now is surely in the clean energy sector. Those companies that do successfully innovate and navigate the recession and strangled credit markets will most surely not only survive, but thrive.

Clean Energy Trends 2009 top headlines for 2008 for energy storage

  • Hamilton Sundstrand to Commercialize Concentrated Solar Power Technology
  • Xcel Energy to Test Storage of Wind Power Using 1 MW Battery System
  • Energy Storage and Power Champions Compressed Air Energy Storage
  • GridPoint Teams Up With NGK and Xcel Energy for Wind-to-Battery Project
  • Oregon BEST and BPA to Fund Wind Energy Storage Research
  • Saft and ABB Develop New Battery System to Enhance Stability of Power Grids
  • SolarReserve Gets $140M Series B Funding
  • Beacon Power and National Grid to Study Flywheel Energy Storage

Select companies to watch

Further reading

For more on energy storage, John Timmer has great article on ars

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Tom is the founder, editor, and publisher of and the TDS Environmental Media Network. He has been a contributor for Triple Pundit since 2007. Tom has also written for Slate, Earth911, the Pepsico Foundation, Cleantechnia, Planetsave, and many other sustainability-focused publications. He is a member of the Society of Environmental Journalists

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