Massive Grid Changes Needed to Solve VRE Problems

Amber Plante for Zondits, September 2, 2015. Image credit: Argonne National Laboratory

Variable renewable energy (VRE) is running into skeptics in the U.S. who state that by its very nature it is not compatible with the current electrical grid. While standard electrical generation and some forms of hydroelectricity, biomass, and geothermal power can offer a steady state of electrical output, VRE, in forms such as solar and wind energy, ebbs and flows with changes in conditions. If the wind isn’t blowing, for instance, a minimal amount of energy is being produced. When it is very windy, however, this excess can overwhelm the current grid system and destabilize it.

Navigating the electrical grid when dealing with variable energy sources can be a tricky. One problem that the grids in the U.S. face revolves around the forecasting that grid operators use to predict which power source will be more advantageous to use: Will the wind be blowing? Will it be a cloudy day? The power generated by these sources need to keep up with the demand, which can also vary based on time of year – or even time of day. If excess VRE is created, storage then becomes a huge problem: How can leftover energy be used when conditions are unfavorable? Electricity is expensive to store.

Studies have shown, however, that large electrical grids can handle the varied output of VRE sources. Utility providers in Spain and Denmark have successfully integrated VRE into their grids, and even the International Energy Agency has stated that too much attention is being paid to the variability of VRE while other factors, such as market penetration of renewables and demand-side flexibility, are more important.

Grid operators can better prepare themselves for the use of VREs by employing diversity to their sources of renewable energy – that is, using weather to their advantage by switching between power sources. Weather conditions that are bad for one type of energy can be advantageous for another type. The following article explains how the electrical grid works, and why if we want renewable energy in the form of VRE, the structure and manageability of the grids must change.

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