Testing Solar. Energy Storage and the Path to 100% Renewable Energy
September 12, 2017
Every 18 months, the moon moves between the earth and the sun, blocking the sun’s light from reaching earth. This astronomical event, the solar eclipse, wasn’t visible in mainland U.S. since 1979. At that time, solar energy was still in its infancy. The first solar tax credits were being offered in America and the world’s largest PV factory began construction.
CALMAC’s founder Cal MacCracken was rolling out his latest innovation, IceBank energy storage, a thermal storage technology which would capture energy at night and store it in the form of ice to offset the next day’s peak power demand caused by the increasing demands for air-conditioning.
Today, 38 years since the last eclipse, demand for energy storage and renewable energy is growing exponentially. Worldwide, there’s over 1GW of ice thermal storage installed. ACHR News reports that the thermal storage market is set to grow from $3.67B in 2017 to $6.20B by 2022.
The sun, once revered by ancient cultures has become a source of electricity to power the modern world. Over 100GW of solar power has been installed globally. There are 1,900 solar plants in the U.S. including some that power several million properties in California. However solar is an intermittent form of energy unlike coal and oil which are stored until later use and we have a long a way to go before we have 100% adoption.
The problem with solar
When a cloud or moon covers the sun, solar intensity drops. Grid operators turn to flexible resources like natural gas, energy storage or demand response programs that can fill the gap. When there isn’t enough flexible resources available, utilities are forced to call on older, more polluting peaking plants to avoid blackouts.
Anticipating the potential problems associated with the loss of solar during the 2017 eclipse, utilities planned for what Reuters says represents the biggest test of the renewable energy era. The weather service predicted that U.S. solar generation potential would decrease less than 50%.
Over 90% of sunlight would be blocked in the Carolinas, a drop in solar output from 2.5 GW to 0.2 GW. Regions in the path of solar totality would plunge into darkness. Solar obscuration ranges would shoot up to 76% in California. As a precaution, CA Grid Operator CAISO told Business Insider, “We're making extra special preparations for this day, because we don't typically lose [six gigawatts] of solar energy over an hour and 20 minutes."
The solar eclipse would test the grid on an unprecedented scale. In preparation for the solar eclipse, grid operators planned to rely on a combination of energy storage and natural gas plants to fill the solar gap. In California, for example grid operators were supported by 3,000MW of energy storage. Businesses and schools equipped with thermal energy storage could ease their reliance on the grid.
According to the California Energy Storage Association (CESA), “The eclipse is an important example of how energy storage can help the grid.” The vast majority of the day’s demand would be met by natural gas. Some would be imported from neighboring states.
The future grid
Fortunately, during the solar eclipse, the grid passed the test with flying colors.
During a solar eclipse solar power is greatly reduced as the moon covers the sun. The quick loss of power creates a potential bottleneck on the grid. “Things went very, very well” according to Bloomberg Technology.
Moving forward, the next total solar eclipse will be in 2024. How prepared will the grid be then? Natural gas will still be in ample supply. Natural gas is expected to last until the end of this century. However, natural gas prices have a history of volatility and there are also environmental concerns associated with its production.
The grid also faces the ongoing problem of aging infrastructure. Coal and nuclear plants are retiring. Today solar only accounts for 2.6% of U.S. power generation. By 2040, renewable sources are forecast to supply just as much of America’s electricity demand as gas. Solar and Wind are already cost competitive with fossil fuels and offer utilities unlimited low cost energy after the initial investment is made.
Utilities are also bullish on demand side-management and behind the meter energy storage which will add more reliability and flexibility as investments in renewable resources grow and fossil fuels and gas diminish. According to the 2017 State of the Electric Utility Survey, over the next ten years, 52% of utilities will increase distributed energy storage moderately.
In extreme circumstances like a heatwave or solar eclipse, energy storage can help the grid ramp up or down quickly. Customer sited or distributed energy storage can also benefit businesses, hospitals and schools by dramatically reducing energy costs and serving as a source of back-up power during outages caused by hurricanes and other disasters.
Business outlook
Utilities recognize that the way energy is used is changing. More customer investments in distributed energy resources like solar mean electricity load is falling. Still utilities are responsible for providing sufficient electricity generation at peak periods. In the late afternoon when the sun is setting or during a hot summer day when AC is running full blast, energy storage resources and grid assets are needed to ramp up to meet demand.
To recover costs associated with providing sufficient electricity generation utilities rely on expensive demand charges. These charges make up 30% to 70% of the commercial energy bill. Other popular rate options that utilities are looking to are fixed charges and time-of-use rates. Unfortunately, as NREL reported in a recent whitepaper, customers often do not understand how demand charges are structured or calculated leading to missed energy storage opportunities.
Want to know how your businesses can reduce demand charges? Check the following.
1) Look up your demand charge at OpenEI for utility data. An ice thermal energy storage system may be economical with demand charges as low as $4/kW.
2) Stay ahead of the rising rates. Conduct energy efficiency upgrades, implement passive design techniques and install solar or geothermal systems to reduce energy use.
3) Participate in the smart grid. Enroll in demand response to avoid peak demand periods.
4) Employ cool thermal energy storage for permanent demand reduction. 40% of grid
peak demand is caused by air-conditioning.
5) Protect yourself from renewable’s variability. Invest in batteries to smooth out electrical loads and provide resiliency.
Well on our way
Renewable energy and energy storage are an important part of the path to a low carbon future. In fact, some would attest that 100% renewable energy is possible with just help from energy storage and coordination between grid operators.
To that end the state of Hawaii has introduced legislation for 100% renewable energy and mayors from 250 U.S. cities have agreed to go 100% wind and solar by 2035. 100 companies have also committed to 100% renewable.
To compliment this investment in renewable energy, all types of energy storage (ice storage, flow batteries, solar thermal, etc) are being added to the grid. Massachusetts Bill H.4568 includes provisions to increase adoption of renewable energy resources and energy storage technologies. New York Mayor Bill de Blasio announced an initiative that promotes more energy storage installations in commercial properties. Maryland has embraced energy storage with a first ever tax credit. California is calling for 1.3GW of energy storage by 2020.
In a sense, the 2017 solar eclipse was like dress rehearsal for the future. Renewable resources will have even bigger tests in the coming years and energy storage will play a greater role in the power supply.
