Renewable Energy – challenges and solutions.
Critics of renewable energy often cite the fact that technologies like wind and solar only produce energy when the wind is blowing or the sun is shining. They argue that we can’t effectively utilize renewable energy until appropriate energy storage technology is developed. While the fact that wind and solar don’t produce energy around the clock is certainly a major disadvantage, we find that the problems associated with the intermittent nature of many renewables are often exaggerated, and rarely discussed from a practical perspective.
The Challenges of Renewable Energy
The difficulty associated with integrating variable sources of electricity stems from the fact that the power grid was designed around the concept of large, controllable electric generators. Today, the grid operator uses a three-phase planning process to ensure power plants produce the right amount of electricity at the right time to consistently and reliably meet electric demand. Because the grid has very little storage capacity, the balance between electricity supply and demand must be maintained at all times to avoid a blackout or other cascading problem.
Intermittent renewables are challenging because they disrupt the conventional methods for planning the daily operation of the electric grid. Their power fluctuates over multiple time horizons, forcing the grid operator to adjust its day-ahead, hour-ahead, and real-time operating procedures.
Take the example of solar panels. Solar energy is inherently only available during daylight hours, so the grid operator must adjust the day-ahead plan to include generators that can quickly adjust their power output to compensate for the rise and fall in solar generation. Furthermore, power plants that typically produce electricity all day every day might instead be asked to turn off during the middle of the day so that the energy produced from solar can be used in lieu of fossil electricity.
Incentivizing Energy Production at the Right Time and Place
While it’s possible to manage second-to-second and hour-to-hour fluctuations in renewable energy output through aggregation and prediction, predicting how much renewable energy will be available a day ahead of time is significantly more difficult.
Integrating a large share of intermittent renewable energy into our daily electricity operations will require a mix of sources that complement each other to roughly equal our total energy demand over the day. This is technically possible because continental wind energy tends to peak at night, coastal wind energy tends to peak during the day, and solar can peak at various times over the day, depending on which way it is oriented.
Accomplishing this mix will require an efficient and effective electricity market that incentivizes electricity generation at the right time and place. Existing competitive electricity markets already have prices that vary over the day and over a region depending on the local level of electricity supply and demand. Exposing renewable energy to these prices can help encourage a mix of renewable sources that produces just the right amount of energy when we need it, and reduces the need for costly energy storage.
A Sustainable Electric Grid of the Future
While the challenges posed by the intermittent nature of many renewable energy sources certainly increase the complexity of effectively operating the grid, they are far from insurmountable. In many ways, they pale in comparison to the enormous challenges that were overcome to initially string all the wires, build all the power plants, and implement all of the controls that make up the present grid. Minimizing the costs associated with renewable variability will be a major challenge of the coming years and decades. We don’t doubt that the solutions that emerge will surprise us in more ways than one.