Despite the usual political headwinds, the US Department of Energy seems determined to sail the ship of US energy independence into the sparkling green future of renewables. The latest development involves a new round of funding for something called high temperature concentrating solar power. This “Gen 3” solar tech partly revolves around the use of new alloys, and that’s where the age of nickel comes in.
As if concentrating solar power isn’t complicated enough already, now they have to go and add more bells and whistles? Glad you asked! CleanTechnica has been contacting some of the funded projects to get the insider perspective on the Energy Department’s high temperature strategy. In this installment, researchers John Shingledecker and Cara Libby of EPRI, the Electric Power Research Institute graciously took some time for a phone interview.
High Temperature Concentrating Solar Power: Group Hug For US Taxpayers!
In a nutshell, the Department of Energy is upping the ante on CSP research because CSP has an energy storage element that will help leverage more wind and solar power into the grid. I know, right?
The new round of funding for pursuing the high temperature angle was announced last month, in the form of a $72 million pie divided among three teams.
In the current round, the teams have two years to design facilities that will test three different pathways for raising the temperature on concentrating solar power. In the end, one team will be selected to receive additional funds for building and operating their facility.
The three pathways under consideration are using superheated falling particles (yes, literally falling particles), tweaking current molten salt technology to accommodate higher temperatures, or using a high-temperature gas for heat transfer.
So, Why High Temperature CSP?
EPRI comes into the picture as a resource for all three teams. For those of you familiar with the organization’s role in fossil fuel development, that may seem out of character. But, as Mr. Shingledecker explains, when the focus is on electricity, innovation is source-agnostic.
Shingledecker, who is EPRI’s Principle Investigator for the project, points out that the current generation of CSP technology has roots in conventional power generation (interview lightly edited for clarity and flow):
A lot of the developments are being taken from fossil power plant steam cycles or coal boilers, but they only go up to 620 degrees C.
Seven hundred degrees and beyond has been the subject of much study — for example advanced supercritical technology, involving supercritical CO2 power cycles based on CO2 as a working fluid.
There are also some unique attributes for third-generation concentrating solar, for example using very thin-walled tubes in solar receivers.
So, we’re taking our experience and combining it with unique aspects of the generation three concept.
EPRI has been involved with CSP for many years, and what we’re trying to provide is options.
The Age Of Nickel
If you caught that thing about thin walled receivers, you’re on to something.
Shingledecker notes that it’s commonplace to measure early human history by the availability and use of materials: stone, iron and bronze. There are of course limitations with this formulation, but Shingledecker points out one important similarity with next-generation solar power.
“Materials are always the enabling technology. They define what you can do,” he said.
In that regard, the new era of renewable energy could become known as the Age of Nickel. Here’s Shingledecker again:
EPRI’s role is centered around the materials potentially to be used. The basic premise to gaining higher efficiency is to go to higher temperatures, which reduces costs.
When you go to higher temperatures, that challenges the materials of construction.
At EPRI we have a lot of expertise in high temperature materials, and based on our experience we’ll be examining nickel-based alloys.
Today’s central CSP plants have some nickel-based alloys, but [for this project] we’re using higher strengths and optimizing materials selection.
For more details, here’s the Energy Department’s rundown on the Gen 3 CSP award to EPRI:
…this team will investigate manufacturing methods for alloys that had previously been designed for high-temperature power service in advanced ultra-supercritical steam. They will examine the cost and performance advantages of manufacturing pipes and tubes from flat sheets after further processing, which can lower capital costs. If these alternate manufacturing routes of alloys can produce pipes that are able to maintain operating lifetimes similar to piping produced from other nickel-based alloys, they have the potential to reduce the cost of these components by about thirty percent.
What About Batteries?
Cara Libby is EPRI’s Senior Technical Leader for Renewable Energy. During our phone call she had a concise answer for those of you wondering why the US doesn’t simply focus on improving proven energy storage technology, namely lithium-ion batteries:
PV, wind and batteries are all inverter based, but they are not able to provide grid services…inertial reserves, spinning reserves, regulation services and black starts are some of the services that CSP could provide.
If you are a lithium-ion battery fan and have something to say about that, drop us a note in the comment thread. Before you do, note that Libby’s list of services is not quite the same as the services described in a recent US Energy Information Agency report.
Libby spearheaded a 2014 EPRI white paper on molten salt CSP titled, “Concentrating Solar Power: Molten Salt for Heat Transfer & Thermal Energy Storage” that takes a deeper dive (breaks added for readability):
CSP plants with storage also deliver value to the grid. Relative to PV, CSP systems have sufficient thermal inertia to avoid major ramps in power generation during cloud passage; TES can further buffer output fluctuations and dampen effects on voltage and other grid parameters.
…CSP plants with TES also are much more dependable, in terms of supplying power during the highest-price periods of the year…In addition, they can mitigate the impacts created by PV and wind projects and allow higher penetration of these variable-output resources by being dispatched to afford voltage regulation and frequency control, provide ramping and spinning reserves, and reduce renewable curtailment.
Have at it! But, before you do also consider the renewable hydrogen angle that the Energy Department is pursuing for concentrating solar power.
Whither US Energy Policy?
If you are keeping up with current events, you may have noticed that the announcement of new funding for high temperature CSP R&D comes just as the Trump Administration is making another attempt at saving uneconomical coal and nuclear power plants.
Talk about tilting at windmills! If the Administration’s last such attempt at preserving the electricity generation model of the 20th century is any indication, this latest plan will go nowhere fast.
Realistically speaking, it’s likely that some parts of the nation’s remaining coal and nuclear fleet will be in operation for the foreseeable future. They will just play a (much) smaller role, that’s all.
Follow me on Twitter.
Photo (screenshot) via EPRI.