Grass clippings could be turned into solar cells using inexpensive chemicals and materials, according to new research.

Within a few years, a special powder sold in little plastic baggies could turn your grass clippings into an electricity-generating solar cell, scientists reported Thursday.

"That's the dream," Andreas Mershin, a researcher at the Massachusetts Institute of Technology and co-author of a paper describing the process, told me.

The powder in the bag is an inexpensive chemical cocktail that stabilizes the molecules in green plants that carry out photosynthesis known as photosystem-I so that they can be used to generate electricity.

Instructions on how to build the rest of the so-called biophotovoltaic would be printed on a cartoon included with the baggie.

One step is to extract and concentrate photosystem-I from yard waste, for example, with a membrane such as cheesecloth and spinach. "It is not that hard," Mershin promised. "The green stuff is easy."

In addition, these do-it-yourselfers will need to roughen up a piece of glass or metal, which increases the surface area, to stick the stabilized green goo onto.

Wires connected to this plate would deliver the trickle of electricity to a battery, cell phone or a light.

Mershin and his colleagues explain their process for building one of these biophotovoltaics in the open access journal Scientific Reports. 

The research improves on previous work by Mershin's MIT colleague Shuguang Zhang, who coated photosystem-I on a flat glass surface. 

This produced an electric current, but such a small amount that it was practically useless. In addition, the stabilizing chemicals used were expensive and assembling it all involved expensive lab equipment.

Mershin looked to nature for inspiration and found a potentially better design in forests of pine trees that allow "for more light to be absorbed," he said.

He mimicked this forest effect with zinc oxide nanowires and a sponge-like titanium-dioxide nanostructure. 

When this chip is coated with the light-harvesting material extracted from plants, it creates a solar cell with 0.1 percent efficiency.

"At 0.1 percent, you can only do this as a proof-of-principle," Mershin said. "Nobody is going to be doing this in real life until we get to about 1 or 2 percent efficiency and about 12 months of lifetime."

The hope is that researchers around the world will replicate the results — which can be done with inexpensive materials and equipment — and improve on the design to reach that milestone.

If so, this technology could be a way to bring electricity to the 1.2 billion people in the world who live without it today.

Ideally, he said, not even the plastic baggie with the powder will be required. "We'll just send out fliers that have the information."

More on solar energy technology:

• Tree power could save forests from fires
• Quantum dots: A big boost to solar tech?
• Sunflowers inspire improved solar power plant
• Ant frying tech could make solar cheap

Georgia Institute of Technology / DOE

A map generated by Georgia Tech's tidal energy resource database shows mean current speed of tidal streams.

Next-generation technologies that harvest electricity from ocean waves and tides sloshing along the U.S. coasts could provide about 9 percent of the nation's demand by 2030, according to a pair of recent studies.

The findings, which include maps of these ocean energy resources, should help guide companies looking to develop them.

"We have believed for a long time that the resource was significant and these assessments add a tremendous level of confidence to what that potential is," Mike Reed, water power team lead with the U.S. Department of Energy's Wind and Water Program told me Monday. 

Today, about 6 percent of the nation's electricity comes from traditional hydropower projects, such as the Grand Coulee Dam, that direct the flow of the river through turbines to generate power.

Since such dams plug up rivers and make it difficult for migrating fish species such as salmon to reach their spawning grounds, they have lost favor in recent years. 

Looking forward, energy developers see promise in technologies that capture the energy in waves and tides off the coasts. 

Designs to do this range from buoys that harness the up-and-down motion of passing waves to turbines on the ocean floor that are spun by the ebb and flow of the tides.

The studies released earlier this month from the U.S. Department of Energy could help nudge along the development and deployment of these technologies by showing the resource is there to be captured.

Motion of the ocean
The U.S. uses about 4,000 terawatt hours of electricity per year. The maximum theoretical electric generation that could be produced from waves and tides is approximately 1,420 terawatt hours per year, the assessments found.

"We are never suggesting that all of that would be captured," Hoyt Battey, team lead for water power market acceleration and deployment with the DOE Wind and Water Program, told me. 

But based on the resource assessments and current understanding of what it will take to scale up and deploy the technology, wave and tidal power could be upwards of 9 percent by 2030.

The DOE has set a goal that water power, including traditional hydroelectricity, total 15 percent of the nation's supply by 2030.

To measure the wave resource, the DOE worked with the Electric Power Research Institute and Virginia Tech to develop a model that accurately predicted past wave regimes and used it to predict future wave climate.

Those predictions are converted into wave power densities. As surfers know, waves from one day to the next are not the same, but they know what beaches tend to have the best waves when conditions are right, Reed noted.

Like surfers trying to figure out where and when to vacation, utility owners and operators can use the new resource data to figure out where the best reliable waves are to put their converters.

This knowledge, combined with reliable forecasts out several days on wave heights, will allow utilities to balance their loads with other sources such as a natural gas fired power plant.

"Wave energy is predictable and forecastable," he said. "If you are a utility operator or utility owner, that predictability adds value."

Tides are even more predictable, noted Battey. "You know down to the second years ahead of time what the tidal regime will be," he said.

The tidal resource maps were created by researchers at Georgia Tech and are available online.

Realizing the potential
Resource assessments such as these, as well as others mapping potential geothermal, solar and wind resources, can nudge development of green energy technologies.

But a key word in such assessments is "potential." As long as generating electricity from coal, oil, and natural gas remains cheap and politically salable, wave and tidal resources will struggle to compete.

Reed takes the long view. Although wave and tidal energy projects today are expensive, he said, their costs should fall as the technology is improved and scaled up over the next few decades.

"A good comparison would be to go back 15 to 20 years in the wind and solar industry and see how their costs have dramatically come down," he said.

While wind and solar still struggle to compete with traditional sources today, the falling prices of the technologies and abundance of the resources are beginning to make them attractive.

Given the size of the wave and tidal resource identified, Reed said there's plenty of room for wave and tidal energy developers to get their feet wet and begin to drive down costs.

More on wave and tidal energy:

• $28 billion in wave energy projects proposed
• IBM sees energy, money in motion of the ocean
• Here's an idea: Floating webs that capture sun, wave power
• Oregon coast could be wave energy hub
• Maine offers testbed for power from tides

California's investments in renewable energy help make San Diego one of the hottest markets for green jobs in the U.S.

In 2013, the cost of solar power in San Diego will be cheaper than electricity from the local utility grid, according the predictions of an energy policy analyst who created a handy graphic to illustrate when so-called grid parity will be achieved.

Sam Mircovich / Reuters

A prototype sun tracking solar panel made by Concentrix Solar collects energy from its location at the University of California San Diego in this file photo.

The interactive graphic posted on the Energy Self Reliant States website shows when this moment will be reached in major U.S. cities between now and 2027. 

Parity is a "tipping point, when democratization of the electricity system not only makes political and economic sense, but becomes more competitive than using utility-delivered electricity," writes analyst John Farrell.

His calculations assume that the cost of solar will continue to fall by 7 percent a year and grid electricity will rise at 2 percent a year. 

If true, then San Diego will be the first to reach the parity milestone, followed by New York in 2015. From there, parity is progressively reached across the southern tier of the U.S. with my cloudy, rainy, northern hometown of Seattle not reaching parity until 2027.

More on solar power:

• Solar power is beginning to go mainstream
• Google pulls plug on solar power plan
• U.S. trade panel to probe solar dispute with China
• Ten hot green energy trends to watch
• Himalayas: The future of solar?
• PG&E makes deal for space solar power