There is nothing wrong with encouraging clean, renewable, domestically produced energy. But California’s proposition 7 “would, if approved, require California utilities to procure half of their power from renewable resources by 2025″ (ref. Ballotpedia). Currently California’s public utilities are mandated to generate 25% of their electricity by 2025, and this is an ambitious goal. Just getting to 25% renewable electricity by 2025 would require more than doubling renewable power generation in California. Getting to 50% by that time would require renewable power generation in California to nearly quintuple.
To understand why accomplishing such an ambitious goal is not necessarily practical, you don’t have to be an economist or a renewable power expert. You simply need to take a look at the current cost for renewable power technology. While you’re at it, write off hydropower, which constitutes most of the renewable energy in California. The chances any significant new hydropower generation ever gets built in California are slim and none – despite whatever sentiments you may hold for or against hydro. This leaves geothermal, solar and wind.
While geothermal holds exceptional long term potential, ala enhanced geothermal drilling, today there isn’t a single operating example of a power station employing enhanced geothermal technology. And most of California’s conventional geothermal power resources have already been developed. So now you are down to wind and solar energy. And since Californians by 2025 are going to be consuming about 1,000 gigawatt-hours per day, if proposition 7 is enacted, 500 gWh per day will have to come from wind and solar power.
Solar power, installed – not including transmission or storage infrastructure – costs about $7.0 million per megawatt of output; this equates to $7.0 billion per gigawatt. If this sounds expensive, it is, but to get a truly accurate price you have to also take into account yield. Even in sunny California, solar energy (in terms of full-sun-equivalent hours), can only be harvested on average for 4.5 hours per day, which means to get 500 gWh of solar generated electricity each day in California, you would need to install 111 gigawatts of solar arrays (500/4.5), which would cost $777 billion dollars.
Wind power, installed – is a better deal currently than solar – insofar as you can probably get costs down to around $2.5 million per megawatt of output, or $2.5 billion per gigawatt. But the yield figures are also not promising. In California there is widespread disagreement on the yield for wind power – credible estimates range from 10% (2.4 hours per day) to 25% (6.0 hours per day). Given the magnitude of what is being proposed, it would be prudent to project wind yields in California somewhere in the middle of this range, say 17.5%, or 4.2 hours per day. This means to get 500 gWh of wind generated electricity in California you would need to install 119 gigawatts of solar arrays (55/4.2), which would cost $297 billion dollars.
It is tempting, and not entirely implausible, to expect prices for solar power to drop significantly over the next several years. But given the cost of balance of plant and installation labor, it is unlikely solar electricity is going to get measurably cheaper than wind power no matter how inexpensive the actual collector materials become. Moreover, the costs for new transmission lines and grid upgrades, the costs for massive energy storage units (since the sun and wind are only producing power during small portions of the day), and the costs for land aquisition, permitting and fighting environmentalist lawsuits will be substantial. For these reasons, estimating the total cost for California to deliver 50% renewable electricity at $300 billion is probably the very best case, if not fantastically optimistic. This is $20 billion per year for the next 15 years. Readers are encouraged to critique these projections.
California has already mandated utilities to accomplish a 25% RPS (renewable portfolio standard) by 2025. It would make sense to see how this already ambitious process unfolds, giving solar and wind technology – along with future technologies such as enhanced geothermal – time to mature, before leaping to a 50% RPS mandate.