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Solving the Renewables Riddle: Investing in Energy Storage

Imagine a world powered totally by renewable energy. One still, winter night, you nestle in your favorite chair, switch on the lamp beside you, and turn up the thermostat before watching a classic movie. The sun is not shining, the wind does not blow, and coal and natural gas have been out of use for decades. Still, you have access to the electricity necessary for light, heat, and playing an old film. How?


Energy storage is the key to this supply-and-demand riddle. Renewable energy can be supplied by the sun and wind only intermittently. The wind blows sporadically, and demand for energy often peaks when the sun is not shining. By reserving excess energy when output from renewable sources is high, energy storage systems create a reliable supply of energy when output is low but demand is high. Eliminating the need for carbon-based backup generators, energy storage systems are critical to a future of renewable energy.

Home energy use and solar energy production over one day. Although home energy use peaks when production is low, energy storage provides a reliable source of power at any time of day.


What is Energy Storage?


Energy storage is important to our everyday lives. Consider your cell phone–you do not always have access to a charger. Instead, you might charge your phone at night when you are not using it. The next day, you can use this stored energy. Even more fundamentally, your body stores energy. You cannot constantly eat and sleep. Instead, you perform these crucial activities to supply yourself with energy for future use.


Likewise, renewable energy sources fluctuate greatly based on time. Sunlight and wind supply vary greatly from season to season, day to night, and even from minute to minute. No human technology can control the weather. The flexibility of energy storage, however, makes up for the rigidity of renewable energy supply.


The National Renewable Energy Laboratory projects that in 2050, if the US uses 80% clean energy, 120 gigawatts of energy storage will be needed across the nation. A myriad of energy storage systems are being developed to fulfill this need.


Lithium-Ion Batteries


Best known of all energy storage systems are batteries, which are improving in efficiency and declining in cost rapidly. Lithium-ion batteries create an electric current by moving lithium cations from the battery’s anode to the cathode. When the battery recharges, the lithium cations return to the anode.


Commonly used for electric cars, laptops, and cell phones, lithium-ion batteries can also supply large-scale power grids. Racks of batteries are stored beside a monitoring system within a compact unit. These units are remarkably efficient, storing vast amounts of energy and leaving a minuscule footprint.


Lithium-ion batteries are fast and reliable. Crucially, they are reversible: they can both store and release energy. Additionally, storage and release can occur in fractions of a second. The speed of lithium-ion batteries is especially useful in emergencies. A disruption in the power grid in cases of natural disasters (think ice storms in Texas), computer disruptions, or human error, can easily and quickly be remedied with energy stored by lithium-ion batteries. The affordability of these batteries, however, means that they are advantageous for regular grid operation and not just as emergency backups.


Lithium-ion batteries are already slated to replace aspects of the modern power grid based solely on efficiency. The current power grid generates power when it is cheapest and then releases the power throughout the day as it is needed. However, when the demand for electricity is too high for the regular system to support, peaker plants supplement the needed electricity. Peaker plants house large, speedy natural-gas generators which typically run for only a few hours each month. Thus, the energy they produce is not only the priciest but the dirtiest on the power grid— for every one unit of energy, peaker plants emit up to twice as much CO2 as normal power facilities. CO2, a leading culprit in climate change, air pollution, and acid rain, is detrimental to environmental and human health. Lithium-ion batteries provide a viable alternative solution to peaker plants. During costly, high-demand periods, efficient, inexpensive lithium-ion batteries can supplement power (peak shaving) or totally meet the high demand (peak leveling).


Already, lithium-ion batteries have proven to be significant competitors against costly, CO2-spewing peaker plants. For instance, Tesla, known for its lithium-ion battery-powered cars, constructed a 100 megawatt (MW) lithium-ion battery, known as the Hornsdale Power Reserve, to store energy in South Australia. (100 MW can fuel about 75,000 homes per year.) In just 140 milliseconds, the battery can go from off to full capacity. After only one year, the Hornsdale Power Reserve saved nearly $40 million. Its tremendous success led Tesla to expand the battery’s capacity to 150 MW. Tesla also has plans to build another Australian battery, this time with a 300 MW capacity. Additionally, Tesla has developed a residential lithium-ion battery to store excess energy captured from home solar panels.


Lithium-ion batteries do have disadvantages. They can overheat and even catch on fire in extreme circumstances. Additionally, lithium-ion batteries lose capacity and frequency over time from repeated charging. After about 2-3 years, they require complete replacement. However, their energy density is almost unparalleled and makes them an ideal choice for energy storage.


The lithium-ion storage market has seen significant growth in the past decade. Between 2013 and 2018, global sales of lithium-ion batteries doubled. In 2019, the lithium-ion storage market was worth $36.7 billion; experts project that number will rise to $129.3 billion by 2027.

Anticipated lithium-ion energy storage in all markets.


Flow Batteries


Another promising battery is the flow battery. Flow batteries consist of two tanks, one positive and one negative. Ions are exchanged through a membrane connected to the two tanks; this process creates electric current.


While lithium-ion batteries are preferred for electronic devices and electric vehicles, flow batteries are suitable for stationary, large-scale functions. Although lithium-ion batteries are less costly and more energy dense than flow batteries, flow batteries have a much longer lifespan. Flow batteries last for about 30 years, 10-15 times as long as lithium-ion batteries. Over time, the large initial investment in a long-lasting flow battery pays off. The parts of a flow battery can be individually replaced, while a lithium-ion battery must be totally replaced when it ages. Additionally, flow batteries can operate in a wider variety of climates and are less susceptible to starting on fire. Finally, flow batteries can easily be scaled up. Therefore, flow batteries are especially suited for large-scale, long-term energy storage: the initial cost of flow batteries pays off in the long run.


While many flow batteries use expensive metals, such as vanadium, researchers are developing less costly flow batteries. USC scientists utilize iron sulfate, a cheap waste material from mining processes, for their novel flow battery, which could last for up to 25 years. Other researchers are exploring sulfur, manganese, and zinc-bromide flow batteries.


The market for flow batteries, worth $130.4 million in 2018, is expected to grow. Demand for lithium-ion batteries, widely used for electric vehicles and personal electronics, will likely cause lithium prices to increase. Innovative flow batteries using inexpensive materials will be viable competitors. Additionally, flow batteries are more easily recyclable than lithium-ion batteries, giving them an environmental advantage. Consequently, experts project that the flow battery market will grow, reaching $403.0 million in 2026.

Projected flow battery usage for energy storage, charging, and distribution.


Thermal Energy Storage


Thermal Energy Storage (TES) is another method of caching energy. TES stores heat rather than electricity. Both the sun and the earth release heat, and waste heat is a byproduct of industrial and other processes. Rather than losing this heat, TES allows it to be captured and stored. Eventually, the heat is released to supply energy (to thermovoltaic panels, for instance).


There are three major methods to store thermal energy: sensible heat storage, latent heat storage, and thermo-chemical storage. In sensible heat storage, heat is stored by raising the temperature of a solid or liquid with high heat capacity and a high boiling point. (Molten salts are one commonly used substance.) When the heat is released for use, the solid or liquid correspondingly drops in temperature. Sensible heat storage is commonly used for Concentrated Solar Power. Although this heat storage technique is less efficient than the other two TES methods, its low cost and straightforwardness make it the most widely-used method.


Latent heat storage harnesses thermal energy to convert a solid to a liquid. This phase change requires considerable energy. Conversely, reversing the phase change releases this heat energy. Latent heat storage is much more compact than sensible heat storage due to the high enthalpy of fusion (heat required for melting).


Thermo-chemical storage is the most efficient and storage-dense of all thermal energy storage methods. In thermo-chemical storage, heat is an input into a chemical reaction (an endothermic reaction). The input energy is then stored within the bonds that hold molecules together. When these bonds are later broken and the reaction is reversed, the heat is then released (an exothermic reaction).


TES has numerous applications; it is especially useful in business and heavy industrial uses because it captures waste heat and allows it to be reused to supply more energy. Efficient and relatively inexpensive, TES is expected to grow in the coming years. In 2019, the TES market was valued at $4.204 billion; by 2025, it is projected to grow to $8.466 billion.

Projected TES usage by region. The Asian-Pacific region is particularly promising due to growing demand for air-conditioning as well as government incentives for clean energy development.


Pumped-Storage Hydropower


Most widespread of all energy storage systems—95% of energy storage in the US—are pumped hydroelectric facilities, which consist of two reservoirs at different heights. When demand for electricity is lower, electrically-powered turbines pump water from the lower to the higher reservoir. In the process, the input energy is converted to potential energy. At peak-demand hours, the water is released, and energy is harnessed. (Check out our recent article on hydropower here.)


Pumped-storage hydropower is able to store vast amounts of energy. Currently, pumped hydroelectric facilities account for 22 gigawatts—88%—of all US energy storage. However, the large scale of these facilities has disadvantages as well. Large water reservoirs cannot easily be constructed in densely populated areas, where the demand for electricity is highest, and therefore have less opportunity for expansion.


Pumped-storage hydropower ultimately operates at a net loss of electricity: more electricity is consumed in moving the water uphill than produced in releasing the water. For instance, US pumped storage plants consumed a total of 29 billion kilowatt-hours (kWh) in 2011 but produced only 23 billion kWh. This loss of energy, however, ultimately makes the energy grid more reliable through load shifting–energy is used when demand is lowest so it can be released at peak-demand times.

Pumped-storage hydropower consumes more electricity than it produces but increases cost-effectiveness and grid reliability.


A new variety of pumped-hydro storage could offer even greater flexibility.  Underground pumped-hydro storage facilities, like their surface-level cousins, pump water from a lower to a higher reservoir and then release the water when electricity is needed. Located beneath the earth, however, underground pumped-hydro facilities do not rely on topographical features, can be placed closer to population centers, and are less likely to disrupt ecosystems.


Although no large-scale underground pumped-hydro storage facilities exist, they show tremendous potential. Existing hollows in the earth, including former mines, are promising locations. Downsides to this burgeoning energy storage method include a high initial investment and lengthy construction times. Additionally, the physical movement and stress of rocks could cause difficulties.


Water, Flywheels… Even Bitcoin


Other forms of energy storage also utilize water. Researchers are developing systems to pressurize water in underground cisterns. Electric energy is used to pump water underground. The water is eventually released to power a motor and create electricity.


Another energy storage method uses electricity or solar power to break apart water, H2O, into its constituent hydrogen and oxygen gases. Hydrogen gas is a valuable fuel that is totally clean. Alternatively, the hydrogen produced from the breakdown of water can be used in battery cells.


Flywheels are yet another technology to meet the growing demand for energy storage. Flywheels convert electric energy to mechanical energy (energy of motion): electricity is used to spin a nearly frictionless rotor. When this energy is eventually needed for consumption, the rotor slows down as mechanical energy is then converted back to electricity.


Flywheels are extremely efficient, have almost no negative environmental impact, can operate for long stretches of time, and can go from zero to full charge in just seconds. They can even recover energy that would otherwise be lost. For instance, they can capture braking energy from electric trains. Flywheels are especially useful for stabilizing the energy levels on wind farms and as backup energy sources at manufacturing plants.


Interestingly, Bitcoin can be considered a method of energy storage. (Read our most recent article on Bitcoin here.) Bitcoin mining is notoriously energy consumptive. In the past year alone, Bitcoin mining has consumed about 14.84 gigawatts of power (the equivalent of nearly 47 million photovoltaic panels). Bitcoin advocates argue, however, that Bitcoin can actually “store” energy by using excess renewable energy from remote locations to mine Bitcoins. Transporting electricity is costly and inefficient, so rather than letting energy from isolated places go to waste, mining can convert this excess energy into coins.


Investing Opportunities


The transition to renewable energy is accelerating. Congress and President Biden consider the climate an urgent issue. The White House recently proposed plans to promote clean energy investment and development. Congress will continue the clean energy momentum with climate change legislation, and several states, including New York, California, and Massachusetts, have revealed clean energy initiatives.


Crucial to the success of these policy efforts are energy storage systems. The US Energy Storage Association projects that the US will install 100 gigawatts of new energy storage by 2030. In 2020 alone, a record-breaking 1.2 gigawatts of new energy storage were installed in the US. This figure will grow to almost 7.5 gigawatts in 2025.


COVID-19 lockdowns have especially accelerated the demand for energy storage. As the pandemic forced many to work, learn, and socialize from home, awareness of our dependence on electricity rose. Meanwhile, major storms, natural disasters, and disruptions in the power grid reminded us that the present energy grid is not always reliable. The demand for home energy storage systems is therefore rising. In just four years, Wood Mackenzie projects, the residential energy storage sector will be six times larger.


Energy storage investors will also benefit from federal incentives. The US government has enacted an investment tax credit (ITC) and the Modified Accelerated Cost Recovery System (MACRS) for privately owned energy storage systems. Individuals and businesses with personal or commercial solar panels and energy storage systems may benefit from these incentives, which will fuel the demand for more energy storage.


As the world shifts to renewable energy, investing opportunities in energy storage will continue to grow. The ALPS Clean Energy ETF (ACES), mentioned in previous posts, is our favorite renewable energy fund. With its exposure to energy storage and fuel cells as well as smart grid and residential energy optimization technologies, ACES is a diversified, innovative fund that will help you to contribute to the renewables revolution.

To learn more about how you can invest with purpose in energy storage, contact Servant Financial today.

Soak Up the Sun — Investing in Solar Power

Solar photovoltaic (PV) energy is 2020’s fastest growing renewable energy source. According to the National Renewable Energy Laboratory, the United States installed a record-high 7.2 gigawatts (GW) of direct current PV in the first half (H1) of 2020, up 48% from H1 in 2019. Gains in the solar industry are making PV power sources increasingly competitive with fossil fuels.

The solar utility sector saw more growth than the commercial and residentials sectors in 2020. Solar in the utility sector saw 89% year-over-year growth in H1 2020. Commercial sector PV installations decreased 14% and residential PV installations were relatively flat. 

Almost 60% of US PV capacity installments this year took place in California, Texas, and Florida. Environment America’s Shining Cities 2020 report found Honolulu has the highest solar PV installed per capita, with 840.88 watts per person in 2019. Los Angeles leads the nation in total installed solar PV capacity, with 483.8 MW by the end of 2019. 

Solar energy provided about 2% of the total electricity produced in the United States in 2019. Last year, the solar industry employed around 250,000 people and generated $18.7 billion of investment in the U.S. economy. The country has over 85 GW of installed solar capacity, enough to power 16 million homes. 

U.S. electricity generation from renewable sources
U.S. Energy Information Administration

Solar power is now one of the cheapest sources of electricity. In the past decade, the solar industry has seen a 90% drop in the cost of solar modules. From 2010 to 2019, electricity costs from large-scale solar PV installations dropped from about $0.38 per kilowatt-hour to $0.07 per kilowatt-hour. 

Despite higher upfront installation costs, solar power is less expensive than carbon-based power in the long-run. The cost of a residential solar system depends on its geographic location, size, and brand. Installed residential solar systems in the U.S. have an average price of $2.57 per watt and total costs ranging from $10,250 to $12,528 after the solar Investment Tax Credit (ITC)

The ITC is a 26% tax credit for solar systems on residential and commercial properties. Since the implementation of the ITC in 2006, the U.S. solar industry grew by more than 10,000%. Furthermore, the industry saw an average annual growth of 50% over the last decade alone.

U.S. tariff policy also plays an important role in the success of the solar industry. According to the Congressional Research Service, 98% of solar cell and module production occurs outside of the United States. The cost of imported panels has decreased significantly, enabling record-high levels of solar imports despite continued tariffs: 14.2 GW of PV modules and 1.3 GW of PV cells in H1 2020.

These leading five markets collectively installed 24 GW of PV in the first half of 2020, approximately the same level as in 2019 (NREL 2020 Solar Industry Update)

Gains for solar in the early 2020 stock market diminished with the COVID-19 induced economic downturn in March. At the time, the solar sector experienced stronger than expected demand and good financial performance from companies. Consequently, solar stocks outperformed the rest of the market.

According to the MAC Global Solar Energy Stock Index, solar stocks bounced back since spring 2020 due to affordability, the viability of solar-plus-storage, and Joe Biden’s apparent presidential victory and clean energy agenda. Bloomberg New Energy Finance (BNEF) forecasted U.S. solar installs in 2020 will grow by +21% to 13.4 GW.

The Invesco Solar ETF (TAN) represents  solar stock performance very well. In September 2020, TAN outperformed the broader market with a total return of 77.3% over the past year. In comparison, the Russell 1000 Index saw a total return of 13.8%. Expectations about Joe Biden’s election victory and increased investment in renewable energy drove TAN up over 120% from the beginning of 2020 to date.  

Sunrun (RUN) and Tesla (TSLA) are the largest solar installation companies in the United States. Sunrun spiked over 300% this year and acquired Vivint Solar for $3.2 billion in July a deal that merged the nation’s two largest rooftop solar companies. 

Companies' % of Residential Installs
Source: Corporate filing, SEIA/Wood Mackenzie Solar Market Insight Q3 2020 (NREL 2020 Solar Industry Update)

In June 2020, Tesla announced they will deliver the lowest price for solar of any national provider with a price-match guarantee. The company currently charges $1.49 per watt of solar on existing roofs and installed over 3.6 GW of clean solar energy across 400,000 roofs—the equivalent of 10 million traditional solar panels

Tesla CEO Elon Musk expects Tesla Energy to eventually grow to the size of Tesla Automotive. Musk believes energy storage will play a key role in that process. “In order to achieve a sustainable energy future, we have to have sustainable energy generation… so you need to have a lot of batteries to store [renewable] energy because the wind doesn’t always blow and the sun doesn’t always shine.” 

Tesla’s lithium-ion battery energy storage business has a new publicly traded competitor, Eos Energy Enterprises. Eos developed the Znyth® aqueous zinc battery to “overcome the limitations of conventional lithium-ion technology.” Eos promotes their Znyth® battery as a more sustainable, scalable, efficient, and safer energy storage alternative to lithium-ion batteries.

Solar Power’s Bright Future

Solar power converts sunlight into electricity. It is a clean energy alternative to fossil fuels, with a smaller environmental impact and carbon footprint. Solar panels are most effective in direct sunlight. However, they can still generate electricity in cloudy weather or cold temperatures. 

The sun is a promising energy source that can produce billions of years of electricity. On the contrary, fossil fuels are finite resources that could be used up within the next few centuries. The U.S. Energy Information Administration estimates the United States has enough dry natural gas to last about 92 years and enough recoverable coal reserves to last about 357 years.   

Greater investment in solar power can lead to greater national energy independence and less dependence on foreign fossil fuels. There are plenty of regions in the US, especially the Southwest, with sufficiently  high annual percentages of sunlight. 

Individual homeowners can attain a degree of energy self-reliance by buying into solar for its increasing efficiency and decreasing costs. Many solar array warranties cover about 25-30 years and arrays often last longer due to their durability. The median average photovoltaic degradation rate is a 0.5% loss of energy efficiency per year, so the solar panels on a roof could still be operating at 88% of their original capacity after a 25-year warranty. 

According to EnergySage, the typical solar panel payback period in the U.S. to break even on a solar energy investment is 8 years. After 20 years, a solar panel investment on your home or business can accrue savings ranging from $10,000 to $30,000. 

Solar’s Dark Side

Solar power is an intermittent energy source because the sun does not shine at all hours of the day. The intermittent nature of solar power makes it a non-dispatchable energy source. This means the electricity produced cannot be used at any given time to meet electricity demands. 

Electricity storage solutions address the intermittent nature of renewable energy like solar, wind, and wave power. MAC Solar Index believes solar-plus-storage will become even cheaper in coming years. Lithium-battery prices already dropped by 85% from 2010 to 2019. MAC predicts they will drop by another 52% by 2030.

Kauai Island Utility Cooperative solar plus storage plant
Kauai Island Utility Cooperative solar plus storage plant (PV Magazine)

Photovoltaic cells contain rare earth metals like cadmium, gallium, and indium. These metals are limited resources  their extraction for solar panels and other electronics must be carefully monitored in order to prevent total depletion.  

Solar modules are hard to recycle. Their components including plexiglass, metal framing, wires, glass sheets, and silicon solar cells must be separated in order to be recycled. This is a tedious process that requires advanced machinery. Complexity and cost increase the risk that a landfill becomes a solar panel’s final resting place. 

Improper disposal and breakage of solar panels can cause toxic chemicals like lead and cadmium to leach into the soil.  The International Renewable Energy Agency (IRENA) in 2016 estimated there was about 250,000 metric tonnes of solar panel waste in the world at the end of that year. 

IRENA projected solar waste could reach 78 million metric tonnes by 2050. Many experts are pushing for mandatory recycling of solar panels to curb future solar panel pollution. The cost of the recycling process currently exceeds the value of the materials that would be recovered. Policies that ban or incentivize solar recycling will be critical to the long term sustainability of solar operations. 

Soak Up the Benefits of Solar Power and Invest in Solar Energy

If you’re looking to invest in solar energy, TAN is the best pure solar ETF. To invest in solar and other clean energy companies, the ALPS Clean Energy ETF (ACES) suggested in our previous blog continues to be our favorite diversified renewable energy play.

For those wanting to invest closer to home, you can install solar panels on your own roof. Residential solar is a sustainable energy option that can increase the value of your home. In addition, solar panels pay for themselves after approximately 8 years of savings. Calculate how much you can save with solar here

How Does Community Solar Work?
Clearway Community Solar 

If you don’t want to install solar panels on your home, consider subscribing to a community solar project. Subscribers receive cost-reducing community solar credits on their electric bills for the renewable power produced. 

Trajectory Energy Partners and Clearway Energy is one such community solar project that offers Illinois residents with a ComEd or Ameren electric bill a 20-year community solar contract with no upfront investments. The program helps subscribers support local renewable power operations and save up to 50% on annual electricity supply costs. 

The future of solar energy is bright. Solar power is an indispensable element of the transition to a net-zero carbon emissions future. Solar energy’s marginal cost of production is zero we simply need to capture its rays. By letting solar PV soak up the sun, the more sparkling our environment will be for future generations.


To talk more about investing in solar, or other investment opportunities, contact us today. Together, we can find the right investments for you, the ones that align with your values and help you to reach your financial and life goals.