The main obstacle to replacing fossil fuels with renewables is the lack of large energy storage mechanisms to power our appliances when the sun isn't shining or the wind isn't blowing. Many countries are unlikely to give up the constant supply of energy provided by fossil fuels unless renewables can overcome their intermittency and become more price-competitive. But with new technological advancements, a global network of renewable energy storage is finally in sight.
A number of battery technologies will be introduced in the next few years. In Nevada, Tesla is building a battery gigafactory that should produce 50GWh (enough to power half a million Tesla vehicles) in annual battery production by 2020. Furthermore, in 2012, MIT materials chemistry professor Donald Sadoway delivered a widely-viewed Ted Talk about his project—a cheap, grid-scale liquid metal battery. Now, Sadoway and his colleagues have created a start-up company, Ambri, for the battery, as well as a new formula that allows the battery to run at temperatures 200K lower than the previous one did.
Another new, unconventional "battery" uses gravel as thermal storage. The process is referred to as Pumped Heat Electrical Storage (PHES), and was developed by Isentropic, a company in the UK. PHES achieves 72-80% output efficiency with its gas cycle machine that doubles as an engine and a heat pump, allowing it to store energy at just $35/MWh, which is even lower than the storage cost for hydroelectricity.
Others argue that a smart, computerized grid would surpass batteries in flexibility to accommodate the intermittency of renewable energy sources by being able to sense the exact real-time electricity demand and make proper adjustments to energy production and flow. Duke Energy Commercial Transmission Managing Director Jeff Gates believes that current battery utilities are not particularly well adjusted to fluctuations in energy supply and storage, but he acknowledges that these technologies are making advancements. The Smart Grid Advisory Committee and Federal Smart Grid Task Force were signed into law in 2007 to facilitate the implementation of a smart grid.
John Zahuranick, president of the Virginia-based AES Energy Storage, says his company "[has] 200MW of energy online . . . and 2,000MW on order." Even more promising, he believes that "there is a demand for 30 GW of new peaker plants by 2024, and by that year, battery production capacity will exceed the peaker need by a factor of four." Peaker plants are specially dedicated to operate when energy consumption is at its peak. Battery production, according to Mr. Zahuranick, will be more than sufficient to meet renewable energy storage needs, even at peak consumption hours.
In Canada, the province of Ontario plans to shut down 13,000MW of nuclear plants in favor of solar and wind energy, which were deemed more suitable for power generation. According to Kim Warren, vice president of operations for the Independent Electricity System Operator (IESO) in Ontario, "[they] already have 9,000MW of wind and solar contracted." Moreover, the IESO plans to conduct a 3 to 5 year study on the combined storage system, following California's lead. Policymakers are finally beginning to catch up with the renewable energy storage advancements, which will be necessary for a streamlined, uniform, and relatively quick transition from fossil fuel to renewable energy in the United States.
Germany is also phasing out nuclear energy and fossil fuels in favor of renewables. Its first renewable energy storage facility, Wemeg AG, opened last month and should help Germany reach its goal of producing 60% of its power from renewable energy sources by 2035. The facility will power approximately 2,500 homes using 25,600 lithium ion batteries.
Renewable energy storage technology is advancing quickly, and even existing technologies can support a green energy future. If the United States institutes a carbon tax, cuts subsidies to fossil fuel companies, and uses that revenue to increase funding to renewables, this can rapidly and significantly reduce carbon emissions. However, while many countries offer strong support for transitioning to renewables and developing energy storage, the United States continues to rely on conventional power sources like natural gas and coal. The United States cannot fall behind in energy storage innovation and needs to be a leader in this transition.