I see that Google has announced a new effort to make renewable energy as cheap as power from coal--a worthy goal, but one that I think reflects a misunderstanding of the barriers to the outcome they seek. If the cost of delivered electricity is being used as the catch-all for the competitive challenges faced by renewables such as wind and solar power, then it obscures fundamental issues that have less to do with the cost of generating power, and more to do with the infrastructure required to deliver clean energy reliably and consistently, around the clock.
There are plenty of people promoting renewable energy who understand the intermittent or cyclic nature of the highest-profile forms of "new" renewable energy, wind and solar power, and the difficulties involved in transmitting that energy from where the wind blows hardest and the sun shines strongest, and then leveling that output to match the diurnal and seasonal patterns of power demand. Coal wins in today's market not just because of cost--in fact its capacity cost is higher than that for natural gas turbines--but because of the combination of low-cost fuel, high reliability, and consistent output, plus the energy storage inherent in the coal itself.. That's why coal power plants, along with large-scale hydroelectric dams and nuclear plants, supply most of the baseload power dispatched in electric grids around the world.
Even if the cost of generating electricity from wind or sun fell to the same level as that from coal, those renewables could not substitute for coal in its baseload role today. I saw a good example of that yesterday afternoon, driving into the Los Angeles Basin from Phoenix. I-10 near Palm Springs is surrounded by hundreds of wind turbines, but more than half of them weren't spinning yesterday, including most of the smaller, older models. What is urgently needed for renewables to compete head to head with coal is not just lower capacity costs--since their fuel is free--but a low-cost way to store up their output and deliver it to the grid when it's needed.
The cost of generating power from wind, in particular, has fallen so much in recent years that it is only a penny or two higher than coal generation. That gap is being filled by the federal renewable generation credit and other state and federal incentives. But without cheap energy storage, wind will max out well before it reaches the scale of coal or natural gas-fired generation. Advanced grid technology can help, though we are many years away from a practical version of the "vehicle-to-grid" (VTG) scheme that would leverage the storage in electric cars to buffer the output of wind and solar power. If Google wants to make electricity from coal obsolete, they should focus their efforts not on bringing down the cost of solar panels or wind turbines, but in allowing large portions of their output to be stored at a cost below one cent per kilowatt-hour. That would truly change the world.