Southern California Edison Thursday asked the California Public Utilities Commission for permission to conduct what it says is the first feasibility study for combining several "clean" coal technologies on a commercial scale. Methods So Cal Ed plans to use to clean up polluting coal have all been used before, but the utility's effort will be the first to combine them on a large scale, So Cal Ed said in a press statement.

So Cal Ed wants to build a 600-megawatt power plant using the "clean" coal methods. Combining the various methods to clean up coal is being called "clean hydrogen power generation" by the utility, which has about 4.7 million electricity customers. The utility wants Cal PUC approval to commit US$52 million from customer rates in a two-year period to the feasibility study.

"If  approved, this would represent less than a quarter of 1 percent of the current customers' rates," the utility said. So Cal Ed CEO John Bryson said this study is "part of a larger strategy we advocate for reducing US greenhouse gas emissions"  that include using more renewable energy, increasing energy efficiency, switching to cleaner transportation fuels and investing in new clean generation methods.

Coal is the by far the biggest source for electricity generation in the United States, making about half the country's power. But conventional coal-fired power plants are also the most polluting and a major contributor to climate-changing greenhouse gas emissions. California does not allow large-scale coal-fired power plants and last year banned new contracts for the import of electricity from coal power plants outside the state. Those plants contribute almost 20 percent of the electricity used in California.

Coal-fired plants have many advantages. They are cheaper to operate because coal is cheaper than natural gas, the source of more than half of the power used in California. Also, coal is a good source of "baseload" power. Baseload plants run about 80 percent of the time or more. The So Cal Ed effort is an attempt to allow California to use coal while also meeting the strict clean air requirements,  which are the most aggressive in the United States. California last year mandated that the state cut climate changing gases to 1990 levels by 2020, or by about 25 percent.

So Cal Ed is a subsidiary of Edison International based in Rosemead, just east of Los Angeles. The methods to be employed by "clean hydrogen power generation" include:

-- A chemical process that captures as much as 90 percent of the carbon in US-produced coal;

-- Production of a mainly hydrogen fuel that emits about 10 percent of the carbon released by an integrated gasification

combined-cycle (IGCC) plant that does not have carbon capture features;

-- Burning hydrogen in a combined-cycle generation system;

-- Sequestering carbon in a depleted oil formation to make enhanced oil recovery or in a deep saline formation.

(By Bernie Woodall, Planet Ark, 18/05/2007)