Paths to successful renewable integration


Renewable energy sources are quickly gaining market share in the U.S. grid. Credit: S&C Electric Company.

Renewable energy sources are quickly gaining market share in the U.S., driven by a combination of renewable portfolio standards, changes in customer behavior, and environmental policies discouraging fossil fuel generation.  

But integration of these variable resources still poses a problem to the reliable flow of power. Steady technology advances are, however, making these challenges easier to overcome.

Embracing renewable efficiencies

"The fusion of information and communications with power can increase the accuracy -- ultimately in real time -- with which variable resources are addressed within the grid market," said Lisa Dobrianksy, Director of the Global Energy Network, during last month's RETECH conference.

This includes the implementation of sophisticated controls that can help align generation and load in order to ensure efficient use of renewable energy. 

It also involves setting policies that consider long-term economic welfare and environmental attributes of all available generation resources. The potential outcome -- one that won't come without significant tweaking -- is a cleaner, more efficient grid.

Managing intermittency is well-understood to be one of the biggest challenges of renewable resources, and creates much more uncertainty than coal or nuclear generation.

Still, "It's better to have as much flexibility in the system as possible," said Matt Futch, Global Policy Director for IBM's Energy & Utilities Industry practice.

But intermittency is a deep problem that goes beyond surviving momentary cloud cover or periods of little or no wind. It also has the potential to be a long-term problem.

"When grid operators think about renewable operation, they're actually thinking across the spectrum on different timeframes," said Judy Chang a principal at Brattle Group, during RETECH.

Intermittency is a deep problem that goes beyond surviving momentary cloud cover or periods of little or no wind. It also has the potential to be a long-term problem.  ___________________________

Solar, for example, experiences both short-term variability, affecting immediate power quality, and seasonal variability -- both of which pose distinct problems.

But nearly every part of the country gets some amount of sunshine, and this geographic diversity allows solar to mitigate a good deal of these intermittency issues, according to James Torpey, Director of Market Development at SunPower.

Power of prediction

Advances in forecasting technology platforms are further closing this gap, leading to better generation models and lower prices.

"The more instability you have in your forecasting and the more you don't know what's actually going to happen, it's going to cost you more," Torpey said, noting that forecasting now has the capability of reducing prediction errors down to 4 or 5 percent.

Another popular method for avoiding renewable integration issues is load shifting and demand-side management programs.

"The more you can move the load around so that you can deal with issues around variability, the better you will be able to manage your grid," Torpey said.

New technologies emerge

Storage is another possible solution, and many see it as the Holy Grail of renewable integration, but it's a technology that has yet to become cost effective and is still a long way from commercial adoption. Aside from that, the energy industry is also working feverishly to roll out more game-changing technologies to tackle renewable integration.

The Electric Power Research Institute is working to smooth out voltage variability that can occur with renewable energy, with a focus on wind power. EPRI is creating a better way to inspect and asses wind turbine health while they are in operation in order to avoid blade failures and power disturbances caused by sudden shutdowns, according to Bryan Hannegan, Vice President of Environment and Renewables at EPRI.

Utilities and customers must both realize, however, that increased supply of renewable and variable resources will not necessarily lead to cheaper electricity rates. But with future energy demand likely to grow rapidly, few would argue that renewable energy resources will play a major role going forward.

"We have to get away from thinking that the cheapest [source of energy] is best," Torpey said.