BETA
This is a BETA experience. You may opt-out by clicking here

More From Forbes

Edit Story

Who Says Nuclear Can't Smooth Out An Erratic Wind?

This article is more than 8 years old.

As renewables, especially wind, enter more and more of the energy market, the power grid has had to make some adjustments, particularly for the intermittency of the wind and the sun.

Intermittency is all the rage with folks who don’t like renewable energy. They point out that it takes so much natural gas, hydroelectric and even coal plants to back-up, or load-follow, wind and solar that it skews the benefits of the renewables and hides the actual carbon footprint.

But everyone just writes-off nuclear as being able to load-follow renewables because it’s just a waste not to be running a nuclear power plant when it could run, since it runs just about all the time anyway.

But not any more.

A new study by the Utah Associated Municipal Power Systems (UAMPS), together with NuScale Power and Energy Northwest, has shown that small modular reactors, a new design for nuclear power, can easily and economically back-up wind just fine. With none of the issues that older nuclear power plants conjure up in most people’s minds.

UAMPS is a consortium of forty-four utilities in Utah, Arizona, New Mexico, Idaho, California,
Nevada, Oregon and Wyoming. The consortium established
 a Carbon Free Power Project to encourage the deployment of clean baseload
 electrical power in response to the anticipated closure
 of coal plants over the next two decades.

UAMPS concluded 
that SMRs will be an important option and are working with NuScale Power to 
deploy the first full-scale NuScale SMR plant in Idaho. So the load-following of their wind farms is an ideal application that needed to be studied for its feasibility.

The study used the Horse Butte Wind Farm just south of Idaho Falls, operated by UAMPS. Commissioned in 2012, the Horse Butte Wind Farm consists of 32 V100 1.8 MWe Vestas turbines with a total nameplate capacity of 57.6 MWe, that covers 17,600 acres, or just under 30 square miles (see figure above).

The single NuScale nuclear power module is 76-feet tall and 15-feet in diameter and sits in a plant covering 32 acres or 0.03 square miles.

The study describes how the NuScale SMR is actually designed for load-following of wind, and meets all of the new guidelines and specifications relative to optimal load-following in the User Requirements Document from the Electric Power Research Institute.

The design and operating parameters allow reactor power changes down to 40% using only control rod movement removing the need to adjust boron concentrations in the primary coolant.

The condenser is designed to accommodate full steam bypass, thus allowing rapid changes to the system output while minimizing the impact to the reactor, which can continue to run at full power.

The multi-modular nature of the NuScale plant and the staggered refueling of individual modules means one module is always fairly new, with really high core reactivity, making it easier to perform power maneuvers with little xenon issues.

Therefore, the operator has the flexibility to use various modules in an optimal way for load-following. These designs allow the plant output to be varied in three ways spanning the full range of renewable’s intermittency time frames:

- taking one or more modules offline for extended periods of low grid demand or sustained wind output (Dispatchable Modules),

- adjusting reactor power for one or more modules during intermediate periods to compensate for hourly changes in wind generation (Power Maneuverability), or

- bypassing the module’s steam turbine for rapid responses to wind variations or demand changes in seconds to minutes (Turbine Bypass).

Varying between these three modes as the period of intermittency varies saves power, cost and wear. These operations really take advantage of the small size and scale of the SMR.

The study presented results from a recent analysis of nuclear-wind integration that utilized historical wind generation data from the Horse Butte Wind Farm in Idaho, design and test data from NuScale, and the experience of Energy Northwest in their implementation of limited load-following at the Columbia Generating Station, a traditional large, not-for-profit, nuclear power plant in Richland Washington.

There is a lot of good information in this study about wind, nuclear and grid dynamics, but the take-away for load-following is that the NuScale SMR can easily and economically compensate for wind output variations using a combination of power maneuvering and turbine bypass, or turbine bypass alone, even for the challenging dynamics of small-scale wind farms like Horse Butte.

The figure above from the study shows how a single NuScale module would load-follow the Horse Butte Wind Farm over the course of a typical day using these three methods, the day shown being the 11th of last November.

The same results apply to more realistic scenarios of larger markets with an increasingly high penetration of wind and reduced coal and gas generation as fuel prices and carbon penalties increase.

I found out about this study last week at theNuEx Conference in Corvallis, Oregon. The meeting was given by NuScale Power, the company that designed, and has been testing, the small modular nuclear reactor called out in this study.

The NuScale reactor takes advantage of being small - the reactor core is only 1/20th the size of traditional large cores with only 5% of the fuel of a large reactor. The NuScale’s reactor core, with its large surface area-to-volume ratio, sits below ground and allows natural processes to cool it indefinitely in the case of complete power blackout.

No humans needed to intervene. No AC or DC power needed. No pumps needed. And no additional water for cooling.

This makes the risk of a hypothetical meltdown for the NuScale reactor to be 1 in 100,000,000 or about ten thousand times lower than any Nuclear Regulatory Commission goal.

The NuScale small power modules are about 50 MWe each and 12 of them can be put together to make a power plant up to 600 MWe. The components can all be manufactured in a factory prior to shipping and assembly at the site, bringing the actual cost to produce electricity with this SMR to below that of any other source except hydroelectric.

But only one of these modules is needed to load follow a wind farm like Horse Butte. The others in a group of modules could be used for other purposes like providing process heat to industrial applications such as refining petroleum, desalinating seawater, producing hydrogen or just generating emission-free electricity in the remote areas where many wind farms and solar arrays are located.

This study supports the idea that our power needs could all be met with an integrated mix low-carbon sources like hydo, nuclear and renewables.

Just what the environmental doctor ordered.

Follow me on Twitter or LinkedIn