Back in mid-January, Stanford's TomKat Centre for Sustainable Energy hosted the Grid Integration of Renewables Workshop, bringing together a group to examine the issues relating to grid expansion and the integration of renewables into that grid. I came across a report on the workshop at the CleanTech blog that interested me but was unable to get much detail about the discussions.
Sometime in the past few weeks, the TomKat Centre posted most of the presentations given at the workshop. Collectively they provide an interesting picture of the issues at least these experts foresee as the proportion of intermittent renewables such as wind and solar that are connected to the grid becomes significant.
Keynote Speakers included U.S. Senator Jeff Bingaman (New Mexico) and Commissioner Jeffrey Byron of the California Energy Commission (CleanTech blog's report focuses on what the keynote speakers had to say in lots of detail so I won't try to add anything here).
- Gregor Czisch, Transnational Renewables, Germany - The Supergrid: 100% Renewable Electricity Supply for Europe and Its Neighborhood » (ppt)
- Mark Jacobson, Stanford - Grid Integration Challenges for 100% Conversion to Wind and Solar Power » (pdf)
- Hans Henrik Lindboe, Ea Energy Analyses, Denmark - Enabling Renewable Energy Integration in Denmark » (pdf)
- V. John White, Center for Energy Efficiency and Renewable Technologies - Pulling the Pieces Together: Thinking Regionally and Cooperatively » (pdf)
- Antonio Alvarez, PG & E - Efforts and Challenges to Manage California's Expected Intermittent Renewable Additions » (pdf)
- Debbie Lew, National Renewable Energy Laboratory - Finding Flexibility in the Existing System » (pdf)
- Nick Jenkins, Cardiff University, UK - Optimizing AC and DC Transmission Networks for High Penetration of Renewables » (pdf)
- Michael Wara, Stanford - Key Regulatory Challenges for Deep Penetration of Renewables (no links provided)
- Willett Kempton, University of Delaware - Low Cost Grid Integration via Met-Smart Interconnection and Storage Inherent in End-Use Devices » (pdf)
The clearest point of agreement running through the speakers' presentations was that increased reliance on non-hydro renewables would lead to greater uncertainty of supply, which would in turn demand greater flexibility within the management of the grid if supply and demand were to be successfully balanced. Suggested mechanisms for achieving the necessary flexibility generally fell into one of three categories, including:
Increase the Size of the Catchment
Speakers identified a range of approaches that relate to increasing the size of the area from which power can be drawn from to lessen the chance that power is available due to weather issues. Suggested mechanisms included imports, Balancing Area cooperation and development of "asynchronous" resources (i.e. resources that are expected to be couter-cyclical in the availability). The underlying assumption of efforts to increase the size of the catchment being that its always windy somewhere. Needless to say, just about any approaches relying on increased catchment size demand big investments in transmission infrastructure - perhaps one of the most significant challenges facing future grid development.
Better Manage Supply
While some of the suggestions appear to focus primarily on the need for standby conventional power sources, more creative approaches included development of asynchronous sources, as noted above, and the need for grid storage.
Better Manage Demand
Clearly an approach with a lot of future potential as Smart Grid technologies are developed, speakers focused on automatic demand response technologies, "dynamic pricing" (i.e. higher pricing during times of the day that electricity is in greater demand or less available) and curtailment or the ability to automatically cut off some customers or applications as demand increases/supply decreases.
When you say them fast, these all sound pretty simple. But they represent significant shifts in approach, huge infrastructure investments and potentially years of regulatory and public process to put in place.
Still an interesting collection of views on what seems the most likely future direction for electricity.