by Adam James and Bracken Hendricks
Americans have always prided themselves on thinking big. When it comes to energy, the National Renewable Energy Lab (NREL) has given big-thinkers everywhere a shot in the arm with a new study that concludes:
“Renewable energy sources, accessed with commercially available technologies, could adequately supply 80% of total U.S. electricity generation in 2050 while balancing supply and demand at the hourly level.”
This is a very big finding from one of the world’s most credible experts on advanced energy technologies. This detailed analysis makes clear that renewable energy is here, it is ready, and it can provide a very large share of the energy we need to run an advanced, prosperous and growing economy. The remaining question is whether we are ready to take the leadership to seize this opportunity.
Before we go into the high-level findings and some of the more impressive details, there are a few observations.
The first is on what the NREL study says about what we don’t need to hit 80 percent renewables.
We don’t need some crazy cool new technology or some groundbreaking invention. We aren’t waiting on the scientific community to make some breakthrough. Would revolutions in storage and batteries help us reach 100% renewable energy? Sure. But this 80 percent by 2050 target is possible with commercially available technology. That’s a big deal.
The second is about what this study shows we do need to make this renewable energy future a reality.
We need to transform our thinking about modernizing our electricity system — on everything from system planning and flexibility, to new business models and market rules. America needs to take the same approach it took with every other strategic infrastructure upgrade that unlocked economic growth in our past. From building railroads and highways to rural electrification, we focused our policies on capturing the scope and potential payoff of a major national project. That included providing the incentives to businesses and consumers through smart policy to lift all boats and increase economic productivity.
So before the dirty details: kudos to NREL for taking a look at what is possible and for laying out something visionary. The national debate on building a renewable energy future desperately needs to be re-focused and this report is a great step in that direction — making it clear that bold ambition is readily achievable.
Later this month, the Center for American Progress will also release a report on the convergence of renewable electricity, energy efficiency and smart grid technology, and how these technologies together represent a state change in our national energy infrastructure. Our piece on the Information and Communications Technology (ICT) revolution builds on NREL’s findings to lay out a framework for this national energy transformation.
The executive summary of the NREL report highlights a few key findings:
- We Can Deploy Lots and Lots of Renewables Nationwide: 80 percent of U.S. electricity could be generated from renewable sources by 2050. Every region in the U.S. would contribute substantially to the RE base, in a way that is consistent with local resources.
- Multiple Technology Pathways Exist to Get Us There: Any existing constraints on transmission capacity, flexibility, and resource availability can be compensated with other resources, technologies, and approaches that balance loads and improve reliability.
- The Lights Will Stay On: Electricity supply and demand can be balanced hourly in the 80 percent renewables scenario, event with 50 percent coming from variable generation. Ironically, the challenges are not from renewables failing to produce, but rather mainly involve managing low-demand periods and curtailment of excess generation.
- Technology Advances and New Ideas Wanted: Increasing the system flexibility is crucial. This will require new technology advances, new operating procedures, new business models, and new market rules which are conducive to increased flexibility.
- More Transmission Infrastructure Needed: It is absolutely necessary to build new transmission if this renewable future is going to be a reality.
All these points indicate that the electricity system is not struggling with a lack of technology; it is suffering from a classic failure of imagination and foresight in implementation. Aside from new transmission and some technological advances, the the current roadblocks are due to entrenched business models and market rules that are not designed to reward efficiency, integration, or new entrants into the generation market. It hasn’t always been this way. At its best, America has been a leader in the development of forward thinking national infrastructures. In this report, NREL points the way toward continued leadership.
What could the 2050 electricity mix look like?
The NREL study went through several different renewable penetration scenarios evaluated against a baseline. The baseline scenario was the business-as-usual path where we continue phase out support for renewables and the energy mix is mostly dominated by fossil fuels. The other scenarios show a variety of levels of renewable penetration, starting with 30 percent RE and continuing up in 10 percent increments to 90 percent RE.
Here’s a breakdown the possible renewable generation mixes for 2050:
Three of the more interesting conclusions from this graph are:
- Wind and Solar are Big Winners: Wind stands to gain the most in terms of absolute KWh from NRELs scenarios- largely at the expense of coal and natural gas. Solar, however, has the largest percentage increase across the board.
- Nuclear Remains Pretty Stable in All Cases: Nuclear power will remain a relatively consistent proportion of the energy mix under all scenarios; however, it won’t see any new growth in base load power plant construction.
- Ending Reliance on Fossil Fuels is Possible: Even with the shale gas boom in the United States, these models show natural gas could play a smaller role in the total energy mix than some analysts are predicting. Also, technological stability can be maintained across the overall system with declining coal generation.
Regionally Specific Solutions: Doing What You Do Best
Another great breakdown from the NREL report is how every region will contribute its own blend of renewables to the national mix. Obviously, different areas have different strengths and this graph does an excellent job of showing precisely what those are:
Here you can see concentrated solar power (CSP) in the Southwest, wind in the Central region, and biomass in the Southeast playing dominant roles. Every area plays to its strengths, and is woven together to create a more diverse, reliable and flexible energy system nationwide.
There Is Massive Potential for Reducing CO2 Emissions (Without Losing Reliability)
It makes sense that higher percentages of renewables would decrease emissions. The NREL study, however, does a great job of mapping out the precise implications for carbon in the charts below:
As you can see, under the baseline scenario (BAU) we are in big trouble, with CO2 emissions rising. However, the higher the penetration of renewables in the electricity mix, the more dramatic the implications for lowering carbon. Here’s another way to put that data:
The big takeaway here is that under the 80 percent renewables scenario, natural gas-fired and coal-based electricity generation also declined by about 80 percent by 2050. Consequently, so did emissions.
Overcoming Obstacles: Grid Flexibility and New Transmission
The study evaluates renewable energy penetration scenarios with several variables; including constraints on transmission, flexibility, and resources. Each of these constraint scenarios had implications for how exactly renewables were utilized.
For instance, a constrained transmission scenario favored resources that don’t require transmission like rooftop PV. Constrained flexibility meant more reliance on non-variable renewables, like CSP, and less on utility-scale PV and wind. Under the constrained resources scenario, biopower, geothermal, and hydro (which you can’t find everywhere) were limited; whereas CSP and onshore wind reached high levels of penetration.
What does this have to do with obstacles? Well, system planners, operators, and Public Utility Commissions that want to hit high renewable targets will have to harness different technologies based on their constraints. We can’t do much about the resource constraints issue, but we can do something about flexibility and transmission nationwide. Here’s a little more background on why that’s necessary and what it would entail.
Grid flexibility, or the ability of the grid to meet demand in a variety of changing circumstances, is a crucial component of an efficient and useful power system. As higher percentages of renewables are incorporated, however, some have expressed concerns that the grid will not be flexible enough to meet demand. This is largely because supply and demand must be balanced in real time.
The NREL study acknowledges this concern and explains how 80 percent renewables still allow for a flexible grid.
First, the 80 percent renewable scenario must provide adequate generation capacity to meet demand. The NREL study showed that the 80 percent renewable scenario provided more than enough capacity to meet demand — even under times of system stress. Storage technology and transmission infrastructure would also chip in massively. In other words, the lights would still stay on.
In addition to being able to meet generation capacity requirements, the system must have a certain amount of energy on standby, also known as an “operating reserve.” The NREL study found that the 80 percent scenario was more than sufficient to meet these requirements. In their words: “integrating high levels of variable generation is not an insurmountable task even under relatively conservative assumptions for transmission and institutional flexibility.”
“the supply- and demand-mix, planning and operating reserves, and transmission system predicted by ReEDS under the scenarios analyzed were sufficient to meet load on an hourly basis, and that hourly mismatches between supply and demand on a regional basis were therefore not anticipated.”
Share the Wealth- Building New Transmission
Getting to 80 percent renewables efficiently suggests the need for construction of 110-190 million miles of new transmission and 47-80,000 miles of new intertie capacity across the three interconnections. This would cost anywhere from $6.4 to $8.4 billion annually. However, this is in line with recent annual investments of $2 billion to $9 billion annually from 1995-2008. So, the new infrastructure demands are well in line with our national trajectory.
An interesting implication for transmission, though, is that NREL found its use would increase by 8 percent (from 32 to 40 percent) with the 80 percent scenario. This is what enables every region to significantly contribute to renewable energy supply. For more on the transmission issue, you can see the fourth volume of the NREL study here.
The report offers a great blueprint for thinking about our energy future. It once again shows that a renewables-dominant energy system is not a technical challenge, but an engineering and creativity challenge.
Adam James is a Special Assistant at the Center for American Progress; Bracken Hendricks is a Senior Fellow at the Center for American Progress.