The United States’ solar energy market is booming, and 2016 was a remarkable year for renewable energy growth. In fiscal Q3 and Q4, the industry saw record growth in new photovoltaic installations, which increased the total nationwide solar capacity to 35.8 gigawatts. That’s enough solar energy to power 6.5 million U.S. homes and reduce carbon emissions by 41.7 million metric tons annually, according to a report by the Solar Energy Institutes Association.
Solar energy capacity grew so fast that a new solar project was installed every 84 seconds, culminating in a new megawatt every 32 minutes, the SEIA report states. In 2016 the overall solar energy capacity in the U.S. increased by 14.1 gigawatts, which is an 88 percent increase from 2015’s total. The additional solar energy resources created in 2016 alone can power more than 1.8 million homes, according to data from the U.S. Energy Information Administration.
Of these new photovoltaic installations, 12.6 gigawatts are small-scale capacity and generation, which means they produce or store one megawatt or less. Of this capacity, 56 percent was in the residential sector, 36 percent in the commercial sector, and 8 percent in the industrial sector, according to EIA data.
As an article by Scientific American points out, solar power on a utility-scale still represents a tiny fraction of the electricity supply in the U.S. Although solar power generation was expected to have grown by 44 percent in 2016 and is expected to grow more than 30 percent in 2017, EIA estimates show all of this growth will only provide around 1 percent of the nation’s electric power, the Scientific American story states.
So what’s holding solar back?
The answer is surprisingly simple: batteries.
Photovoltaic technology has advanced to a point where the capture-to-storage ratio is high enough to meet an average household’s day-to-day needs, but our storage options are lagging far behind.
When the sun stops shining, the batteries stop charging and people using electricity start depleting the stored energy. If the demand is higher than the reserves, then whoever is drawing that electricity is going to be out of luck until the next sunny day.
The good news is nearly 89 percent of new solar capacity in 2016 was small scale. Our current lithium-ion batteries, particularly RELiON’s LiFePO4 chemistry, work well for handling day-to-day storage needs from a single home or commercial building—sometimes even two or three. But those homes and businesses must have a lithium-ion battery bank to store that energy, and having the solar panels and lithium-ion battery combo in every home and business in America isn’t feasible.
Plus, that’s not how the solar industry commonly works. The often-seen practice is leasing photovoltaic systems from the utility company to create energy and offset how much reliance a home or business has on the city electrical grid. But once the panels stop producing energy, typically shortly after sunset, the users go back on the grid to pick up the slack.
As an article in IEEE Spectrum remarks, “even in sunny Los Angeles, a typical house roofed with enough photovoltaic panels to meet its average needs would still face daily shortfalls of up to about 80 percent of the demand in January and daily surpluses of up to 65 percent in May.”
Without an opportunity to store all the energy solar panels collect in an on-site battery bank, the country will continue to rely on environmentally-destructive power sources like coal, nuclear and natural gas.
The solution has yet to present itself, especially for mega cities like New York, Shanghai or Hong Kong where the daily energy needs far surpass the storage capacity lithium-ion batteries provide.
Let’s take California’s largest announced storage system as an example. In Long Beach, AES Corp. is building a massive lithium storage system comprising of more than 18,000 lithium-ion batteries. When it’s completed in 2021, the storage bank will be capable of running at 100 megawatts for roughly four hours, which is a total of 400 megawatt-hours. Yet as the IEEE Spectrum article states, that 400 megawatt-hours is still two orders of magnitude lower than what a large Asian city would need to get through the day.
Although the technology might not be readily available to power a mega city off solar energy, if you need an energy solution for small or mid scale residential buildings, or commercial and industrial needs, then we can help. Get in touch with the RELiON team to see how lithium can solve your energy needs.