The 100% Renewables Approach: What will it take?

chat Posted Jul 14, 2015 by Rezwan | Category : Energy Supply Solar Wind
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Good news! There is a 100% Renewables plan for your state via the Solutions Project.  Here’s the plan for New Jersey. It’ looks great!  If we follow the plan, we’ll be at 100% Wind, Water and Solar for all purposes by 2050. What’s the hold up?

The hold up is that most people don’t know what this actually means, or looks like on the ground. Without this information, action is impossible.

With this information, many will still balk, because it is an intense solution. Here’s what it would take for the US to run on 100% Renewable Energy.

One of the big challenges here is that wind and solar power plants have a much lower “capacity factor” than plants that run on fuel. A fuel-based plant can run around the clock (with breaks for maintenance), while wind and solar plants produce energy only when the wind is blowing or sun is shining. Although a nuclear plant and a wind farm might have the same “nameplate capacity” of 1 gigawatt, you’d actually need three or four wind farms that size to produce the same number of MWh as the nuclear plant. (EIA info on US capacity factors here; nuclear is highest, producing around 90 percent of the time, while solar PV is lowest, at around 20 percent.)

The upshot of this is that to meet most energy demand with wind and solar, you have to radically overbuild electrical generation capacity. To wit: the authors estimate that total US energy demand in 2050 will average 2.6 terawatts. To produce that much energy, they propose building power plants with a total of 6.5 TW of capacity. By way of comparison, the US currently has about 1.2 TW of installed electric generation capacity, so this plan would involve expanding generation capacity fivefold in 35 years.

Here’s what that would require:

  ... 328,000 new onshore 5 MW wind turbines (providing 30.9% of U.S. energy for all purposes), 156,200 off-shore 5 MW wind turbines (19.1%), 46,480 50 MW new utility-scale solar-PV power plants (30.7%), 2,273 100 MW utility-scale CSP power plants (7.3%), 75.2 million 5 kW residential rooftop PV systems (3.98%), 2.75 million 100 kW commercial/government rooftop systems (3.2%), 208 100 MW geothermal plants (1.23%), 36,050 0.75 MW wave devices (0.37%), 8,800 1 MW tidal turbines (0.14%), and 3 new hydroelectric power plants (all in Alaska).

That will meet average demand. Then you need 1,364 additional new CSP plants and 9,380 50 MW solar-thermal collection systems (“for heat storage in soil”) “to produce peaking power, to account for additional loads due to losses in and out of storage, and to ensure reliability of the grid.”

“This,” the authors note, “is just one possible mix of generators.” But no matter what mix you pick, if you’re confining yourself to WWS, you’re going to be building a huge amount of generation capacity.

There’s no need to confine yourself to one solution. But there IS a need to get familiar with the solutions and choose something NOW, before you run out of options.

Notes & Related:

In Favor of 100% Renewables

Critical of 100%

Mother Jones: Why We Need Nuclear Power

Good Climate News Headlines Bury the Bad News Lead
Two Birds With One Stone: Nuclear Weapons into Nuclear Energy

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