Archive for the ‘Intermittent Resources’ Tag

Renewable “Intermittent” Sources and the Grid

We all know the wind doesn’t always blow and the sun doesn’t always shine at any given location as forecasted. Over the last year, there’s been increasing dialogue about the challenges of bringing renewable energy sources, such as solar photovoltaics (PV) and wind energy onto the utility grid.  These source of energy have variable and uncertain “intermittent” characteristics and that creates problem for ensuring the grid is stable and reliable. A new generation of tools like ramp forecasting tools and short-term event predictor would permit operators to anticipate major events in California is in the forefront of advancing these long-term goals, which includes bringing 20 percent renewable energy sources onto the California utility grid by 2010 and 33 percent by 2020. Add to the complexity that 80 percent of the area’s renewable energy resources are in the southern half of California. There is no doubt these goals are important and highly desired over the next few years.

To achieve that 33 percent goal, the California ISO’s preliminary studies have revealed that California will need more than 800 miles of new 500-kV transmission capacity, “planned, approved, sited and constructed by 2020.”

ECCO International is working on market integration issues with clients in various regional markets. Some of these challenges are cropping up with the newly proposed ancillary services and products being designed for scheduling purposes. Another important part of this challenge is to examine the economics of a variety of potentially competing technologies including demand response, transmission, flexible generation, and improved operational practices. 

There’s no shortage of challenges ahead in terms of integrating these sources into the grid, especially when the sources of renewable energy reach more than 20 percent of the overall energy mix of the grid.  For starters, there are no utility scale storage systems (batteries) to store electricity when the production of energy exceeds the demand. Cal ISO does have project plans for 200 MW of storage capacity will be operational in its footprint by 2012, with as much as 1,000 MW by 2020.  There are also important policy questions that figure into the longer-term renewable energy trend to bring these sources onto the grid.  Often, the question comes down to two key issues: reliability and cost. What cost and what level of reliability are California residents, commercial and industry energy consumers ready and willing to participate? What are the market incentives that need to be in place to make the changes happen?

Let’s also not forget that some renewable energy sources also have some inherent operating characteristics unique to them, which can adversely impact the overall reliability of the utility grid. What happens, for example, when the wind forces are less than originally forecasted for the day or there are more clouds in the sky, thus impacting the overall generation of solar power? How does that impact the market participants and stakeholders?  We are only at the beginning of this shift to renewable energy sources. But in order to achieve these ambitious objectives, there has to be alignment of policies and regulations with all market participants, including business and consumers.