New bills and proposals are popping up all the time to get our country to 100% carbon-free, renewable energy. More states, cities, counties and businesses are committing to 100% renewable energy by 2050 or sooner, with the biggest solar energy adopters leading the way.

But skeptics aren’t so sure this goal is attainable.

While most do still support adoption of renewable energy sources, some argue that renewables will ultimately fall short of their goal and require shoring up by other, more reliable sources, like nuclear or gas.

Let's take a look at the arguments on each side and the possible solutions.

Clean vs. Renewable: An Ongoing Debate

Most stakeholders are pushing for 100% carbon-free energy, but how they get there is where the debate lies.

Some states, like Hawaii, are shooting to get all their power from renewable energy sources like wind, solar, and hydropower and abandon other sources completely.

Other states, like California and New York, have only pledged to 100% clean energy, meaning that they will not require all their energy to be from renewable sources, and will allow other types of energy that don’t emit carbon, like nuclear, to remain.

The Argument Against 100% Renewables

The number one obstacle cited by doubters is the variability of wind and solar power sources.

Wind turbines depend on the wind to blow to generate electricity, while solar needs sunshine. If the wind doesn’t blow, or something blocks the sun (or it’s simply nighttime), then no energy is produced.

Since we can’t depend on the weather to be stable all the time, we can’t completely depend on these sources to supply all of our power, all the time. We will need some backup for days when production is down.

… or do we?

Energy Storage Is the Answer

While we can’t control mother nature, or stop the Earth from spinning, we can harness the energy we produce during peak times and store it for later use.

Energy storage is the future of renewables. Storage has the potential to fix the problem of variable energy production in solar and wind power. We can use batteries to store energy for use during times when energy production is low.

The real question is, can we afford to install enough energy storage to support our entire electricity grid’s needs?

Or will we fall short and need to rely on other sources?

This will depend on the cost of storage falling enough to make it an economically viable option.

How Cheap Must Storage Be to Reach Our Goal?

A new report gives hope to 100% renewable supporters, showing exactly what would be needed to make our ambitious energy goals a reality.

MIT researcher Jessika Trancik recently published a study in Joule on August 7, 2019 showing just how cheap storage solutions would need to be in order for the US to meet its 100% renewable target.

Her team assumed a world in which renewable energy and storage provide 100% of US energy and asked the question:

How cheap would storage have to be for this to be the cheapest option?

The answer: $20/kWh or lower. Or over 90% cheaper than current costs.

While a 90% decrease in costs seems like a lot on the surface, it is actually within the realm of possibility, when you consider real-world energy requirements compared to lab tests.

Trancik’s study sets the bar very high with all renewable energy and flexibility handled entirely by storage solutions for every hour of every day for 20 years.

Loosen up these tight constraints, and the price becomes much more attainable. For example, lower the target from 100 to 95% and the cost requirement for storage shoots up to $150/kWh, which is much easier to reach with existing technology.

No energy system runs 100% of the time. There will always be blackouts and brownouts.

Plus, we won’t rely on storage for all flexibility - we have other grid flexibility systems in place that can handle some of the burden, such as long-distance transmission, load flexibility, microgrids, and legislative reforms.

And renewables will likely get cheaper over time, reducing the overall cost faster than we expect.

So, in reality, the $20/kWh price (and even the $150/kWh price) is much more strict that what real world applications will likely require. The real price range would likely be more like $150-200/kWh.

Will Storage Costs Get Cheap Enough? 

Will energy storage prices drop fast enough and far enough to meet renewable energy goal deadlines?

A 2017 report from the International Renewable Energy Agency (IRENA) predicted that by 2030, the cost of installed lithium-ion batteries would drop to between $145-480/kWh, flow batteries to $108-576/kWh, sodium sulphur to $$120-330/kWh, and sodium nickel chloride to $130-200/kWh.

All of those projections are already within our $150-200/kWh range, which means our renewable energy goals are much more attainable than they first appeared.

Plus, new solar + storage technologies are always being developed, making storage solutions cheaper and more efficient over time. They may soon even be able to directly compete with fossil fuel plants in cost.

In short: it’s definitely possible to get storage costs low enough to handle our renewable energy needs.

Take that, solar skeptics!

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