Renewable energy, combined with prolific battery storage, will soon result in vastly cheaper electricity -- and solar power that's less expensive than what fossil fuel-based power plants can produce.

Additionally, solar power with lithium-ion and flow-battery storage systems will make the combination of renewable energy so inexpensive that it will surpass nuclear power and obviate the need for futuristic power sources such as fusion.

That was consensus view from a several keynote speeches delivered at the Intersolar Conference in San Francisco this week.

Eicke Weber, director of the Fraunhofer Institute for Solar Energy Systems, said that in sun-rich countries, the cost of solar power is already below 5 cents per kilowatt and it will continue to plummet as battery storage systems become more prolific and less expensive.

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"We are looking forward to create electricity for 2 to 4 cents per kilowatt hour. Compared to this, you can forget everything else, especially nuclear power plants and the quest to try to obtain nuclear fusion on earth," Weber said, explaining that solar will be less costly than any other power source.

Tesla CTO JB Straubel said he expects photovoltaic and battery storage systems to continue dropping in price, soon even passing fossil-fuel powered plants in price per kilowatt.

New installations of solar power capacity surpassed those of wind and coal for the second year in a row in 2014, accounting for 32% of all new electrical capacity, according to a report released earlier this year from GTM Research and the Solar Energy Industries Association (SEIA).

Tesla has a lot of skin in the battery storage game, as the all-electric car maker has announced two new batteries: one for businesses and one for homes.

Tesla is also constructing a its first "Gigafactory," which will churn out lithium-ion batteries to the tune of 500,000 a year, or enough capacity for 50,000 gigawatt hours of power.

Tesla is far from alone in creating lithium-ion batteries for home and commercial use. Last month, Mercedes-Benz announced its own brand of energy storage products to allow those with solar systems to store surplus power.

Earlier this week, U.K.-based OXIS Energy announced that next year it plans to bring to market a "super efficient lithium-sulfur battery" that it believes will undercut Tesla's in price. OXIS Energy also announced a partnership with Anesco, a leading commercial and home energy storage installer.

Straubel said the combination of solar and cheap batteries will create a constant flow of electricity that will beat coal and oil-fired fossil fuel plants; the U.S. is already within "grasping distance of that goal."

"I think we're at the beginning of a new cost decline curve. Almost no one today would have predicted photovoltaic prices would have dropped as fast as they have, and storage is right at the cliff heading down that price curve," Straubel said.

GTM Research Solar power installation costs per watt of capacity.

The decreasing cost of lithium-ion batteries will allow mass adoption in the power grid, which will then offer utility customers a "firm" and "buffered" source of renewable energy "that's cheaper than fossil fuel energy.

"That same battery cost decrease will drive batteries into the grid."

Straubel said he believes the "tipping point" will happen within the next 10 years.

For some large utilities, battery storage projects are well underway. SunEdison and Advanced Microgrid Solutions, for example, announced this week they will partner to deploy 50 megawatts of energy storage for Southern California Edison.

Southern California Edison will purchase capacity from the storage systems under a 10-year capacity contract, and expects to use the electricity stored in these fleets of hybrid-electric buildings in part to offset the power once produced by the decommissioned San Onofre nuclear power plant and other soon-to-be retired gas-fired plants. The power storage program is part of Southern California Edison's plan to modernize the grid by adding 2.2 gigawatts of newer, cleaner resources including energy storage and renewables by 2022.

PV systems working in conjunction with energy storage systems are the most popular type of project in the new energy market right now, according to EnergyTrend, a division of market research firm TrendForce.

EnergyTrend projects that the market scale for Tesla-style energy storage systems will climb rapidly from 226 megawatt hours (MWh) this year to 1,628 MWh in 2018.

"Furthermore, the market growth for household energy storage systems will surpass that of the industrial and enterprise applications," said Duff Lu, research manager of EnergyTrend. "In the future, energy storage systems will become more available in both household and industrial applications (including uses in the new energy sector)."

According to Lu, demands in the energy storage market in general have steadily risen because of the following factors:

The current demand for batteries is growing because of the widespread use of consumer electronics.

The feed-in tariff (FiT) rates for electricity generated by PV systems are lowered yearly worldwide, while retail electricity prices remain high.

The power generation industry has increased its overall conversion efficiency, which has lifted the market demand for energy storage.

Energy storage systems are seeing a steady price drop.

Currently, energy storage systems for home use have been promoted and supported by government programs around the world. Japan, Germany, the United States and China have created subsidy schemes for energy storage products.

Lu further noted that industries in China's renewable energy sector are seeing accelerated growth, and they all complement developments in energy storage systems. These include grid-tied projects, distributed generation projects, micro-grids and plug-in vehicles.

The market for energy storage systems in China is still in its early phase, with lead-acid batteries being the mainstream products. The scale of the country's energy storage installations currently in operation is above 50MW.