Tamar Hallerman
GHG Monitor
04/20/12
Carbon capture and storage technology on coal and gas units will likely be a central option for baseload electricity generation in California under the state’s low carbon emissions plan, a new report says, emphasizing that improvements in cost, capture efficiency and storage characterization work are likely needed before the technology can be widely deployed in future years. The report, released late last week by the California Council on Science and Technology, is the result of two years of work from a group of energy experts tasked with informing state and local government officials of different pathways available to meet the state’s stringent climate change regime, which requires an 80 percent cut in greenhouse gas emissions below 1990 levels by 2050.
Last week’s report, a supplement to a larger summary study released in May 2011, focuses on the deployment potential for renewables and CCS on coal and natural gas facilities as options to generate low-carbon electricity in California. As part of their evaluations, researchers designed stress tests for each source of electricity to glean their maximum potential for fitting into the state’s emissions limits. Overall, the report says that fossil with CCS will likely be a significant component of the country’s energy future, particularly for baseload generation. “It is the only other currently scalable technology besides nuclear energy that can easily provide many tens of GW of baseload capacity in a future electric grid that would otherwise become increasingly dominated by variable wind and solar generation,” the report says. However, the document also acknowledges that there are several barriers to CCS deployment in the state.
More Capture Efficiency, Storage Characterization Needed
The report lists technology costs, capture efficiency rates and the need for storage capacity assessments as significant barriers to widespread use the technology will face in California. In particular, it says that a higher efficiency rate for CO2 capture beyond the current off-the-shelf rate of 90 percent will be needed before the technology can be deployed widely in the state due to the fact that the emissions cap is so stringent. The report says that emissions from the technology, although greatly reduced, add up quickly and will likely “contribute noticeably” to a stringent cap, leaving little room in the state’s greenhouse gas budget for the rest of the state’s economy to use. “As we move towards that 80 percent reduction goal, the emissions from everything is going to come into much sharper focus than it currently is because pretty much every megaton of carbon dioxide is going to count,” Jeffery Greenblatt, a staff scientist at Lawrence Berkeley National Lab who was one of the head authors of the report, told GHG in an interview.
The report’s authors also stress the need to further characterize the state’s saline reservoirs as eventual sites to store large quantities of captured CO2. In particular, they highlight the potential for CO2 storage in the state’s depleted oil and gas fields, which are largely well characterized, with estimates indicating that there is roughly 5,200 MtCO2 of storage capacity in the formations, or roughly enough capacity to bury emissions through 2050. But beyond that, the report says that more characterization work will need to be done in the state’s saline reservoirs, which have an estimated capacity of between 150,000 and 500,000 MtCO2 and are considered the only long-term option for long term storage policy. “There is non-zero technical and regulatory risk associated with saline aquifers that will need to be overcome, through more detailed characterization to eliminate those aquifer settings that do not meet the requirement for very low rates of leakage to shallower formations,” the report says. The study also lists environmental externalities and the need for CO2 transport infrastructure as barriers to CCS development in the state.
Large Role for Renewables
The report also estimates a large role for renewables as part of the state’s electricity generation mix through 2050. California has a renewable electricity standard in place that calls for 33 percent of the state’s electricity to be generated from the sources by 2020, and the study says that the role could be larger for non-baseload purposes. In addition to solar and wind, it particularly emphasizes geothermal energy as having large potential in the state. However, the report acknowledges that renewables’ inherent intermittence also guarantees a role for non-renewables like coal, natural gas and perhaps nuclear—which is currently banned under state law—in the future.
Ultimately, the report concludes that all sources of electricity will be needed to get California within reach of its goal. “One of the big takeaways for me from this report was the fact that no one set of technology solutions alone is going to be sufficient to get us to the long-term goal,” Bryan Hannegan, vice president for Environment and Renewables at Electric Power Research Institute and co-author of the report, told GHG. The report says that in addition to cost, one of the largest deciding factors for which technologies will be used will be how much baseload-capacity legislators seek to mandate. “Low-GHG electricity capacity can be provided in a number of ways, and California has many options to choose from. Perhaps the biggest choice the State needs to make is whether (or how much) to ensure it has baseload power generation,” the study says.
Main Report Published in 2011
The CCS and renewables report is a supplement to a summary study published in May 2011 that attempts to map out pathways to reach the state’s greenhouse gas emissions reductions goals through 2050. It concludes that ultimately an “aggressive,” near-complete overhaul of the state’s electricity and transport sectors—as well as an extensive energy efficiency effort for buildings—will need to be undertaken over the next few decades to reach the 2050 goal. “Essentially, in this time period, every existing building will either be retrofit to higher efficiency standards or replaced, 60 percent of light-duty vehicles will use electricity, so that the average fuel economy will be roughly 70 miles per gallon. Additionally, the electricity generating capacity of the state will be almost entirely replaced and then doubled, and all with near zero-emission technology,” the report says. “Meanwhile, infrastructure to produce biofuels—costing tens of billions of dollars—will have to be built, biofuel imports must become available and fossil fuel use will have to decline dramatically.”
Even with those efforts put into place, the summary report says that currently available technology—including those being demonstrated today—will only be able to account for a 60 percent reduction in greenhouse gas emissions state-wide. It concludes that pushing for the full 80 percent reduction will require “significant levels of research, development, invention and innovation” for technology that is not yet in existence. “Getting all the way down to 80 percent cuts will almost certainly require major advances in near-zero-emissions fuels. This is by far the biggest technology gap…California can’t just spend or deploy its way to an 80 percent reduction or beyond — and neither can anywhere else,” co-author of the report Jane Long, a principal associate director at large at Lawrence Livermore National Laboratory, wrote in a related column for the scientific journal Nature.
Despite the large-scale changes needed to meet the emissions reduction targets in the state, Greenblatt said that reaching California’s goal is still “possible.” “We’re not pretending that this will be a piece of cake. I think it’s going to be very difficult and it’s going to require a sustained commitment in the state to get there. But that’s why we’re starting to look at this now with a 40-year time horizon,” he said. “We’re getting on the right track with AB32…but we’re going to need a long-term investment in a number of infrastructure changes in order to get there.”
