Is it possible to get all of our energy from renewable resources by 2050? A new report by the Solutions Project says the answer is yes.
Before we look at the report, let's back up a little. In 2000, renewables, including hydroelectric resources, accounted for 9% of the power supply, according to the Energy Information Administration (EIA). The renewable share of overall power supply jumped to 12% by 2012, and the EIA expects renewables to make up 16% of the power mix in 2040.
EIA estimates that the power supply in 2040 will include 35% natural gas-fired generation, 32% coal (down from 52% in 2000), and 16% nuclear.
The EIA forecast is not based on what's possible, like the Solutions Project report, but on what is likely. So is the all-renewable scenario even possible?
The 100% plan
The Solutions Project study presents a roadmap for all power eventually coming from wind, water and solar (WWS). The report breaks down the appropriate mix for each state. All new energy would come from WWS resources by 2020. About 85% of existing energy sources would be replaced by 2030, and they would all be replaced by 2050 under the plan.
Renewables plus “modest” efficiency measures would lower power demand by about 37%, according to the study. The switch to all renewables would stabilize energy prices because there are no fuel costs, producing annual per capita savings of $3,400, the study said. Adding health- and climate-related cost savings and the total per capita savings jumps to $6,500 a year.
“The greatest barriers to a conversion are neither technical nor economic,” the study said. “They are social and political. Thus, effective polices are needed to ensure a rapid transition.”
Switching to all renewables would slash greenhouse gas emissions, provide lots of new jobs and, according to the study, lower costs. It sounds great – so good that David Letterman had the report's main author on his show and managed to crack a few jokes while discussing solar and wind – but is this even possible?
PJM study finds 30% renewables doable
Let's look at a recent PJM report that found that a 30% renewable level is feasible, and would save customers money by lowering fossil-fueled generation. “In general, all the simulations of challenging days revealed successful operation of the PJM real-time market,” a summary of the report said.
The study found that PJM's large geographic footprint, spanning all or parts of 13 Mid-Atlantic and Midwest states, makes it easier to integrate intermittent renewable energy by lowering overall variability.
Further, last year, for an hour, wind produced more than 60% of the power on Xcel Energy's system in Colorado. Granted, it was for only an hour, but it's a sign that renewables can reach high penetration levels and the grid could keep operating without a hitch.
Utility-sponsored study: 50% 'green' power possible, but problems emerge
California, which is on track to getting 33% of its power from renewables in six years, could get 50% of its energy from renewables by 2030, according to a recent study sponsored by California's five largest utilities. However, adding that much renewable generation in California would present challenges to operating the grid, the study found.
“The study finds that renewable integration challenges, particularly overgeneration during daylight hours, are likely to be significant at 50% RPS,” the study said. “The study indicates that at high penetrations of renewable generation, some level of renewable resource curtailment is likely to be necessary to avoid overgeneration and to manage net load ramps.”
At the 50% renewable level, over-generation – producing more power than is needed – would occur all year long during some hours of the day because of solar, according to the study. There could be up to 25,000 MW of overproduction during extreme events, according to the study.
There are ways to deal with overproduction. For example, a diverse renewable portfolio produces less overgeneration than a portfolio tilted towards solar, according to the study. Increased regional coordination, demand response and energy storage would also reduce potential overgeneration, the study found.
The chart below shows that 5,000 MW of energy storage could roughly cut in half the amount of overproduction (shown in red in the chart below) on a typical April day.
A 50% RPS would increase rates by 9% to 23% depending on the renewable portfolio, according to the study. The least expensive option would be a diverse portfolio; the most expensive option includes a large amount of rooftop solar.
The big picture
While getting all of our power from renewable resources may be possible, the California study shows that getting even half of our power from renewables will require major changes to how the grid system runs. Emerging technologies like energy storage could help make this happen.
Adding renewables will be a process and all eyes will be on California, which has aggressive greenhouse gas reduction goals and will likely take the next step and shoot for getting half its power from renewables.