Our Climate is Changing. Why Aren’t We?
Climate Reality activist Campbell Scott talks to DesiCollective about why Energy Storage is important for a sustainable economy.
When Texas lost power after two devastating winter storms mid-February 2021, over 4 million homes and businesses lost power for several days. In Austin, people were burning their furniture to cook food and to keep warm.
Campbell Scott says this disaster was preventable. The Texas electrical grid failed to keep up with the demand, and Texas repeatedly failed to protect its power grid against extreme weather.
What is the science behind energy storage?
Can California halt the frequency of its rolling blackouts?
How do you store green energy when the wind doesn’t always blow, and the sun doesn’t always shine? Are there energy storage solutions?
And what can communities do to advocate for a greener future?
We asked Campbell for answers.
A Primer on Green Energy Storage by Campbell Scott
Energy Storage is Key to Green Energy
Why should we start using green energy rather than fossil fuels?
Renewable, carbon-free electric power, generated by solar panels and wind turbines, is now cheaper than from any other source. If we are to reach zero carbon-dioxide emission, fossil fuel must be phased out. Most generating stations providing on-demand power are typically natural gas powered “peaker plants.”
How do we store renewable energy when sunshine and wind are intermittent sources: the sun sets every night or may be clouded over; the wind does not always blow.
The solution is to store electrical energy when supply exceeds demand and to use that stored energy as demand increases. It is just like “saving for a rainy day.”
Demand does not always match supply. Peak demand usually occurs in the evening as people get home from work, cook dinner and turn on other electric appliances. So as electric utilities transition to renewable energy sources, it is necessary to provide a backup power supply.
What are different ways to store energy?
Energy comes in many forms, and each can be stored in several ways.
Wood, coal, oil and gas
These familiar fuels store chemical energy that is released when the fuel burns. It combines with oxygen to form, mostly, carbon dioxide and water. Burning converts the chemical energy into heat, i.e., thermal energy, that we use to heat homes, cook food, heat water, power vehicles, generate electricity and run factories. They are easy to store in bunkers, railcars or tanks, and the fluids, while oil and gas can be distributed in pipes.
Batteries are the most convenient way to store energy.
From the end of the 19th century, the most common battery was lead-acid. Lead-acid batteries can deliver high electric current during discharge and so are still in use today to start cars and trucks with internal combustion engines. In the mid-20th century, they powered vehicles, such as milk-trucks, that travelled short distances with heavy loads. But lead is one of the heaviest metals, making lead acid batteries unsuitable for long-range transport. Gasoline was used until the recent development of affordable lithium-ion batteries
During the charging process, current flows when a lithium-ion battery is connected to an external circuit (a motor, a cellphone etc.), and delivers energy used in charging back into that circuit. Lithium-ion batteries offer a greater advantage because they can be recharged.
For centuries, people ‘stored heat’ by “banking the fire” at night: blazing evening fires were partially smothered with ashes at bedtime to keep the embers hot, while slowing down combustion overnight.
Today storage space-heaters and water-heaters do the same thing. In the electrical era, we heat bricks or water overnight when electricity is less expensive and use stored heat during the day for hot water or to warm the house.
German and Danish companies are developing thermal storage for utilities, by heating rocks, bricks, or concrete block to well above 1,000 deg. C during the day when solar energy is plentiful. At night, high pressure steam is generated to drive turbines.
Gravitational energy is a commonly used storage mechanism for pumped hydroelectricity. When excess energy is available, water is pumped uphill from a lower reservoir to an upper reservoir. When electrical demand increases, the water is allowed to flow back downhill through turbines to generate electricity.
But this form of storage needs dams and there are not enough places suitable for building an upper reservoir.
At the O’Neil Forebay at the bottom of the San Luis Dam near Los Banos for example, the lower reservoir is also used to distribute water for other needs such as irrigation. So, the lack of water availability may limit electrical generation.
One solution is to ‘ invert’ of the roles of upper and lower reservoirs. That means installing the lower reservoir deep underground in old mines for example and building the upper reservoir on the surface to create a large gravitational “head.”
But hydro plants are expensive. So a Swiss-based start-up called Energy Vault, has developed a method to store gravitational energy, not with water, but with massive concrete blocks. The unit uses a six-armed crane to raise and lower the blocks and recapture energy to turn a generator. The costs less than a hydro-plant and power can be ramped up in just a few seconds.
Hydrogen, like oil and gas, can be stored in a container for storage or distributed through pipes. It’s the lightest of all gases, which burns in air/oxygen to produce only water. Unfortunately, the byproduct is carbon-dioxide.
Black or brown hydrogen, depending on the type of coal, has been used in industrial processes for two hundred years; nowadays natural gas and water are combined to produce grey hydrogen. But carbon dioxide is still a byproduct, but, if it’s captured and stored underground you get blue hydrogen. An abundant supply of cheap renewable energy makes it economically feasible to produce green hydrogen directly from water by electrolysis; its byproduct -oxygen – which can be captured for industrial and medical use or just released to the atmosphere.
Ammonia is made by reacting hydrogen and nitrogen in a catalytic converter. Like propane, ammonia is easily liquified and stored under modest pressure. It’s used in many industrial processes such as fertilizer production, but it is also a fuel in its own right, burning under appropriate conditions in air to yield water and nitrogen.
Both hydrogen and ammonia are used in fuel cells to generate electricity and thus to provide backup power for the grid, or to run motors in electric vehicles. It seems increasingly likely that hydrogen, in some form, will play a major role in long-haul, heavy duty transportation: trucks, trains and shipping.
Everything that grows under the sun is a potential biofuel, from algae and seaweed to crops and trees. Even waste foliage from vegetables can be dried and burned.
Biofuel directly harnesses sunlight via photosynthesis. However, in order to avoid soot pollution and returning CO2 to the atmosphere, many schemes are being developed to process crops to yield more pure fuels, such as fermenting corn sugar to produce ethanol, or extracting oils from canola or soy.
Microbes and synthetic catalysts are being evaluated to “digest” various types of biomass to make better fuels, -the goal is jet-fuel. Ideally, these fuels will be used in facilities that capture and store CO2emissions deep underground or use it an industrial process that fixes it in a solid such as concrete.
The future of our energy supply looks increasingly clean and bright, but we must use these new technologies urgently in order to meet zero carbon-dioxide emissions in the coming decades.