Green Energy and Reliability

September 15, 2021

Fact/Fiction

Photo showing solar panels in the foreground and wind turbines in the background. Behind the turbines there's a body of water.

You’ve probably heard the claim before that a 100% clean energy economy cannot happen because renewable energy is unreliable. “The wind doesn’t always blow and the sun doesn’t always shine,” say some people, so we will always need fossil fuels in our energy mix to provide constant energy. Yet with the many energy storage techniques available to us today, this claim is simply false.

Green Energy Storage - Brief History

Humans have been storing energy in one form or another for thousands of years. Over 2,000 years ago, the Ancient Greeks knew how to store water using dams so that the water could flow downhill and do work such as grinding grain when it was needed. It wasn’t until the 1800s, however, that scientists figured out how to store electricity in the form of batteries. This technology, invented nearly 200 years ago, has spread so thoroughly in society that it’s hard to find a room in any house or apartment that doesn’t have at least one battery-powered device. Storing renewable energy is not a formidable challenge that we lack the technology to address. We can start by adapting existing technology to store green power.

Pumped Hydro Storage

One way to store renewable energy is known as pumped hydro storage. This strategy is already widely used in nuclear power plants and could be adapted to clean, renewable energy. During times of low demand, the excess energy generated by the plant is used to pump water up a hill. Then, when demand increases at peak times (such as mid-afternoon during the summer months), the water is allowed to flow back downhill, turning a turbine to create electricity as it moves. The same principle can be applied to renewable energy. When the sun is shining brightest and the wind is blowing most strongly, the excess energy can be used to move water uphill. Then, during nighttime or if the wind ceases to blow, this water can be used to produce a reliable stream of electricity as it flows back to lower ground.

Pumped hydro storage is a great option for places with a lot of water and hilly terrain. Australia already has plans to build several such plants for the purpose of storing renewable energy. But energy storage strategies also exist for regions that are flat and dry.

Compressed Air Storage

Even the air around us has the potential to store energy if we can harness it! Another way to store clean energy is through compressed air. When air is compressed, the denser result has potential energy that is released once the air is allowed to expand again. The excess energy generated by renewable power stations is used to compress the air, which, similar to the water used in pumped hydro storage, is then used for electricity generation during times of peak demand.

Compressed air storage is an older idea than you might expect - the first storage facility was built in Germany in 1978 and is still operational. As scientists perfect techniques for offsetting the temperature increase from compressing the air, it is likely that this storage strategy will be much more widespread in the near future. Small-scale compressed air batteries now exist, and do not require any of the rare earth minerals that regular batteries sometimes need. In addition, these batteries can also have a longer lifespan than traditional ones.

Batteries by Any Other Name

In order to store renewable power, we can also use simple batteries scaled up to meet the demands of a large population. After a series of severe blackouts several years ago, Australia decided to form a contract with Tesla to create a battery farm. This facility can store enough energy to power 30,000 homes for an hour, and receives energy from nearby wind and solar farms. Tesla has since constructed a battery farm three times larger in Australia. A Tesla subsidiary is now constructing a battery farm near Houston, Texas, and this facility is slated to have the storage capacity to handle the energy demands of 20,000 homes on a hot summer day.

Rather than continuing to invest in fossil fuel infrastructure, state and federal governments can instead choose to help with the transition to cheap renewable energy, in doing so saving consumers health and financial costs.

Scaling It Down

Advances in renewable energy storage have not just come at the industrial scale. Homeowners who are interested in solar installation can also have a backup battery installed that stores the excess energy generated by these solar panels for later use. Several companies, including Tesla, now produce batteries specifically intended for storing the renewable energy that small buildings generate. With an increased interest in rooftop solar, home batteries are a perfect way to store renewable energy at the local level.

Being Smart

We’re familiar with smart phones and smart TVs. Smart grids are also important to a 100% green energy power grid. In addition to helping integrate more renewables into our power mix, smart grids also act to increase security, reduce outage risk, and lower energy costs. Smart grids will also be needed to get the most out of a scale down energy solutions allowing industrial sized operations to understand the impact small solutions may have on the supply and demand curve.

Smart grids include many types of communicators that relay information about demand, faults, and outages. These technologies act together to reroute electricity around a faulty part of the grid, automatically report outages so that they are repaired faster, and give consumers an overall more reliable energy system. Our energy sources need to be updated to serve the 21st-century nation, so our grid infrastructure should be modernized as well.

What Happened In Texas?

You may have heard about the disastrous power outages in Texas earlier this year in the midst of a severe winter storm, weather that is not common in the state. Millions of people in Texas were left without energy for days this March, and some individuals blamed renewable energy for this crisis.

Yet the facts don’t bear this explanation out. At its worst about 30 GW of coal and natural gas became unavailable, while less than 10 GW could be attributed to renewable sources (7). And this is all happening while the cold temperatures caused millions of Texans to plug in electric heaters. The massively increased demand resulted in enormous strain on the energy grid when it was most vulnerable. Texas’ lack of connection with other state’s power grids exacerbated the situation further.

While it’s true that turbines froze during the event, gas pipelines also froze and coal plants shut down because their infrastructure was not equipped to deal with such cold temperatures. The issue is not that these energy sources cannot function in the cold, rather instruments not properly weatherized cannot function in extreme cold.

During an unusual freezing event ten years ago, the state government recommended that energy suppliers put in weatherizing measures, but since these suggestions weren’t mandatory and would cost money, no utility did them. A decade later, when another severe winter storm struck Texas, the residents of this state paid for these energy companies’ shortsightedness and greed.

It is simple to weatherize wind turbines for colder climates; wind power is produced reliably in Alaska, Greenland, and Siberia. To avoid future issues with climate change and our energy delivery system, it is wise to invest in climate-smart infrastructure now.

Conclusion

A variety of strategies allow us to store renewable energy in many types of environments and at different scales. The technology to switch to a 100% energy grid isn’t coming in several decades; it is here now and continues to improve. We need political willpower to invest in these technological solutions!

Looking for a visual? Check out this one-page handout on green energy.