Environmentalists and economists are beginning to consider options for replacing the state?s two nuclear power facilities if they are denied new investments. Currently, the California Public Utilities Commission is debating the value of investing about $1.5 billion in new steam generators for the Diablo Canyon and San Onofre Nuclear Generating Station plants in formal hearings. If Pacific Gas & Electric and Southern California Edison do not install new steam generators, they estimate that Diablo unit 2 will shut down in 2013, Diablo unit 1 in 2014, and SONGS units 2 and 3 in about 2009. Despite the looming deadline for nuke shutdown if new steam generators are not installed, policy development is just beginning. ?If we never look for alternatives, we?ll never have a choice,? said V. John White, Center for Energy Efficiency and Renewable Technologies (CEERT) executive director. Possible options include replacing power at the same site as nuclear and new generation?both fossil and renewable?coupled with new transmission. However, supply replacements are limited by cost, technology, and politics. ?If you shut down 4,000 MW, that?s over 10 percent of overall generation capacity going away and most likely going to be replaced with natural gas,? said Jim Detmers, California Independent System Operator vice president of operations. ?That could be committing 30 percent to 40 percent of generation to natural gas. Is that really what we want to do?? Both the CPUC and the California Energy Commission lean toward new, nonrenewable generation being supplied by liquefied natural gas to meet growing supply needs. However, LNG has ignited local opposition everywhere it?s been proposed. Calpine?s plans for Humboldt Bay are in retreat, and Bechtel?s plans for an LNG plant on Mare Island were shot down. Sound Energy Solutions? proposal for Long Beach is stuck between federal and state regulators feuding over jurisdiction. While renewables are being developed in general, they are not targeted for the geographic areas that would support the grid as effectively as the nuclear plants. On the ?negawatt? side, new renewable supplies get subsidies, but there?s no corresponding financial help for conservation to take the place of supplies that are shut down. Thus, conservation lags far behind renewables in ?replacement? power if the nukes are shuttered. In the five to ten years nuclear plants can still operate without new steam generation investment, the state?s renewables portfolio standard will have kicked in with something like 25,000 GWh of generation, according to the CEC. However, that power is not earmarked to replace nuclear plants. New geographically scattered supplies?renewables, fossil, or both?will not suffice as nuclear replacements because of the configuration of the grid unless transmission upgrades are included, according to grid operators. ?San Onofre is right on the load center. If you take it off, the impacts on the grid would be quite severe,? said Detmers. ?A decision to shut down San Onofre requires looking at other options.? A CAISO study released in 2000 investigated options in case San Onofre shuts down. At the time, it was assumed that replacement power would be coming not from new generation within the state, but from Arizona. It predicted blackouts if other Southern California power plants tripped off. It also predicted that if ?sufficient new generation is located near SONGS with sufficient transmission reinforcement,? major upgrades would not be required. Diablo would not present as much replacement difficulty to the grid, according to Detmers. ?There?s been an enormous amount of generation built in the Bakersfield area? that can tie into the same 500 kV circuits as Diablo does. However, taking Diablo off the grid would affect transfer capabilities on Path 15. Even after the third leg of Path 15 is complete, Detmers said, taking 2,200 MW off line would affect how much power Path 15 can import from the Pacific Northwest or, conversely, send south to north. Instead of freeing up the line to allow more transfers, the loss of Diablo?s baseload would actually reduce the amount of power the grid operator could allow to flow on Path 15. It is not so much the physical limits on the path, according to CAISO spokesperson Gregg Fishman, but because CAISO can?t put too many eggs in one basket for reliability reasons. ?Replacing that much lost local generation with imported power leaves too big a gap if the import line fails, or there?s some other problem.? At this point, the effect of loss of the nukes on the grid has not been modeled. The grid operator?s SONGS study no longer applies to the current generation situation, and the impact of the loss of Diablo has not been investigated. Despite the lack of investigation, it seems apparent that new generation built at the same interconnections as the nuclear power plants would not engender significant investments in new transmission. A few environmentalists have floated the idea of using offshore liquefied natural gas terminals at the nuclear plants? sites to fuel replacement plants. Wind generation on the coastal sites is also a possibility, but because of its intermittent nature, it does not provide the voltage support and congestion relief that baseload nuclear plants provide. Existing coastal plants such as Redondo Beach and Ventura could be repowered and provide much of the same support currently contributed by nuclear power, according to Detmers. If, instead, new replacement generation is built where it?s already planned instead of on the same sites as the nuclear plants?about 8,000 MW have been permitted or partially built, mostly in Southern California?the transmission system would have to be reconfigured to move away from its dependence on nuclear power. That means in order to ease the flow of electrons from where they?re produced to where they?re used, new local transmission would need to be sited or existing transmission upgraded. Recent successful opposition to San Diego Gas & Electric?s Valley-Rainbow transmission line, and less successful opposition to other transmission projects, such as Jefferson-Martin, show they are politically difficult as well as expensive. More than $28 billion has been invested in the Diablo plant alone. Replacing it, and San Onofre?s power, could take the same scale of financial commitment, say renewables proponents. ?The few thousand megawatts of conventional renewables we may be able to scrounge up are not going to make much of a dent? in replacement power, said CEERT research director Rich Ferguson. ?Ergo, the future is coal or LNG or solar.? Ferguson estimates that a massive solar investment would be needed to fill nuclear?s gap. However, no one has run financial numbers on such an investment. He expects that solar facilities on such a large scale would have to be in the desert to keep costs down. ?The problem of moving this energy to load centers is not trivial, but less of a problem, surely, than moving that much coal-fired power from New Mexico or Wyoming.?