Solar on Route 66 is great. Storage would make it revolutionary.

by Anna Gretz
July 21, 2016

Without energy storage, the new roadway panels will lose some of their potential value.

Historic Route 66 in Conway Missouri is going to receive star treatment with the nation’s first solar roadway panels, MoDot announced last month. This is just another step in the accelerating use of solar and other renewable energy resources in both the public and private sector, and yeah, it’s awesome. But in all the excited conversations about the new roadway panels, there’s one key piece that’s missing: energy storage. Without energy storage, the new roadway panels lose a chunk of their potential value. We’ll tell you why.

But first, let’s talk about the panels themselves.

The roadway panels that will be used were developed by the Idaho-based startup Solar Roadways, founded by Scott and Julie Brusaw. If these names ring a bell, it might be because of their viral video, “Solar FREAKIN’ roadways” released on 2014, which has more than 21 million views. The concept is brilliant: so many roads and parking lots bake in the sun all day, every day. There’s a huge energy resource that hasn’t yet been tapped. Why not create a solar panel that’s durable enough to withstand traffic so we can harness all of the solar energy beating down on our roads? Scott and Julie Brusaw asked this question, and came back with a visually-appealing, hexagonal answer: Solar Roadways. The startup’s crowdfunding campaign more than doubled their goal of $1 million with a total of $2.2 million in funds, along with three funding contracts from the U.S. Department of Transportation. Now, they’re ready to hit the pavement.

The Brusaws, along with the Missouri Department of Transportation, loved the idea of using the historic, iconic Route 66 as the site of the project--the roadway is a part of our country’s history, and will now take part in creating a new, cleaner future. The first installation won’t be on the road itself, however, but at a rest stop alongside Route 66. MoDot reports that this is the first phase, and that they hope to move to a parking lot, then a travel area soon.

The project itself has undeniable appeal. Not only will the panels help generate power for the rest stop, but they have heating elements that will prevent snow and ice accumulation as well. Treating roads and sidewalks during winter storms is not only costly, but puts chemicals into the water system. Solar roadways prevent the use of chemicals, generating clean energy at the same time. They are hoping to have the panels in place before the snow starts falling at the end of the year.

Though the Route 66 Solar Roadways project is the first of its kind in the United States, it’s not the international debut of a solar road. November of 2014 brought the unveiling of the Netherlands’ SolaRoad, which has exceeded expectations. Within six months, SolaRoad (which is actually a bike path) generated over 3,000 kWh of power. That’s about a year’s worth of electricity for a single-person household. The electricity from SolaRoad is fed directly into the grid, and used mostly for street lighting and traffic systems.

This is likely what will happen to the energy generated by the roadway panels installed off of, and soon on, Route 66; the energy will be fed back into the grid, to be used to meet the electrical needs of the area. This seems fine until you consider the strain this puts upon an already taxed electricity grid.

Here’s how grid-connected solar works:

Grid-connected, or on-grid, solar systems generate direct current (DC) electricity from solar panels, and feed it into a DC/AC inverter to to create an alternating current (AC) used for powering electrical equipment. If the solar panels are generating more electricity than the equipment needs, it is fed back into the utility grid. Since there is almost always a mismatch in electricity demand between electrical equipment and the power generated by solar systems, the grid has to do some work, regulating power by either receiving surplus, or providing additional electricity.

Here’s how grid-connected solar can go wrong:

Since solar is an intermittent energy source, it presents challenges to utility grids. For example, if the Route 66 Roadway of the Future is churning out a certain amount of generated power from solar panels, and then a cloud drifts over a large stretch of road, it will suddenly slash the roadway’s power output by a huge percentage--possibly up to 70 or 80 percent in just minutes. If the roadway panels are supplying a high quantity of power to the grid, a rapid loss of energy like this can cause the grid’s electrical current to drop dangerously low, damaging electrical equipment, or even causing a blackout. This is what happened in Kauai, Hawaii, one of the country’s leading regions in solar power penetration. How is Kauai dealing with the problem? Energy storage.

With batteries, energy can be stored up and released in the case of a frequency drop, preventing damaged equipment and widespread outages. But frequency drops aren’t the only problem. Kauai is set to encounter another issue, one that could become a problem for Missouri’s grid if the Solar Roadway project continued to expand: Excess solar power generation.

When we’re dealing with the utility grid, there really is such a thing as too much solar power. If solar panels were installed on roadways and parking lots across the country, it would be awesome. But not if it was connected to the grid. A deep and wide system of solar panels could result in more solar generation than what a particular power grid can carry. This would either overwhelm the grid and cause damages and blackouts, or result in having to throw the surplus power away, defeating the purpose of generating it in the first place.

But there’s another option: energy storage. Storing surplus power not only prevents grid overload, but creates a power reserve that can be tapped after the sun goes down. This is why Solar Roadway projects should include energy storage in their plans every single time. Without it, the mismatch of the power demand could tax the grid at least, or result in damages and unused power at most.

If Solar Roadways are in our future, then batteries need to be right alongside them.