The World's #1 Renewable Energy Network for News, Information, and Companies.
Untitled Document

Solar Intermittency: How Big is the Problem?

Intermittency is one of the major criticisms of solar — the majority of the energy is delivered when the sun is shining brightly, but virtually none is created at night or in substantial cloud cover.

How do solar developers view this issue — does it pose a huge stumbling block to current projects, or is it something that has been effectively managed? I spoke with two gentlemen, Martin Hermann, CEO of 8minutenergy Renewables and Paul Copleman, communications manager at Iberdrola Renewables, to find out more. 

Are there specific technologies used to deal with intermittency? Surprisingly, neither developer implements storage technologies on-site because there is no need to do so.

In fact, it seems that solar technology has already occupied a niche where it can thrive without a storage solution. 

Copleman explains, “[the] integration of significant amounts of intermittent generation is entirely feasible with the existing grid,” due to the “ability of the grid to respond to changes in generation levels in real time using the existing generation and transmission system.” Thus, on the supply side, the technology is feasible, and solar can fit into a niche market. “Solar PV’s production curve is aligned with the peak demand during the day and therefore helps to shave the peaks within a utility’s generation profile,” said Hermann.

In fact, even without storage technology, the PV intermittency seems to be effectively managed at current project scales. Mr. Copleman stresses the distinction between intermittency and predictability: “It’s important to understand that while solar is intermittent, it does not have a random generation pattern. Solar resource is very predictable, which makes grid integration less of an issue. Additionally, forecasting solar resource on a day-ahead and hour-ahead basis has a high accuracy factor.”

Besides having a predictable generation pattern, other measures are being used to tackle the problem. For example, Iberdrola is “evaluating its wind projects for where a co-located and co-interconnected solar project would increase capacity factor as well as decrease sub-hourly intermittency.” Also, project screening avoids locations where intermittency becomes a substantial issue for the system. 

While both gentlemen state that intermittent power is not a short-term problem, they agree that it would become an issue in the longer term. This would happen when solar finally moves from its current niche as a supplemental resource and transitions to become a firm, baseload resource. “Locating 1,000 MW of PV on one transmission line will clearly be more difficult to integrate than 1,000 MW of PV spread across multiple distribution and transmission lines and across a broader geographical area,” said Copleman.

Current researchers and developers of storage solutions should pay attention to two different milestones that would be game-changers in the way solar energy is utilized today. The first milestone, at three to five hours of storage, “will allow a precise overlap between the PV production curve and the demand peak of a particular utility,” said Hermann. “The second milestone, at 20 hours of storage, will enable PV to work as a base load resource.”  

Both solutions must be cost-effective though, as they will compete directly with traditional base load resources like LNG and coal. Once these milestones are reached, solar energy is set to transform the world in a much greater way.

Untitled Document

Get All the Renewable Energy World News Delivered to Your Inbox - FREE!

Subscribe to Renewable Energy World Magazine and our award-winning e-Newsletter to stay up to date on current news and industry trends.

 Subscribe Now



Evaluating the Case for Module-Level Shutdown

Hannes Knopf With 2014 NEC adoption in full swing, many are anticipating what the next version of the code will hold for the PV in...

A Case Study in Energy-Transition Momentum

Tim King South Australia is clearly at the forefront of the global energy transition as it establishes a fast-moving model oth...

Listen Up: Can I Get Solar if my Roof is Shaded?

The Energy Show on Renewable Energy World Rooftop solar panels only work when they are in direct sunlight. So if you have a partially shaded roof, the output o...

US Senate Democrats Unveil Energy Bill That Restores PTC and Extends ITC

Brian Eckhouse, Bloomberg Senate Democrats unveiled a bill that would provide more tax credits for renewable energy while killing some tax ince...

PRESS RELEASES Welcomes Jennifer Delony as Associate Editor

PennWell Corporation is pleased to announce that Jennifer Delony has joined the company...

Customized Energy Solutions Executes Agreement with the Massachusetts Clean Energy Center (“MassCEC”) and the Massachusetts Department of Energy Resources (“DOER”) for Important Energy Storage Study

Customized Energy Solutions (CES) has entered into agreements with Massachusetts Clean ...

CleanTX Releases New White Paper on the Future of Texas Solar in Texas

We love this new White Paper from our clean energy partners CleanTX

Sun Xtender® Launches New Website at

The newly designed website for Sun Xtender solar batteries is now live on the World Wid...


energy efficiency

Beyond the Trend: Maximizing the Impact of Your Energy Efficiency Solution

A revolution is happening in the energy sector. From the new regulations pushed out earlier this summer by the EPA’s ...

Northeast States Create Cap-and-Trade Program for Greenhouse Gas Emissions

Northeast states have worked together for several decades to address air quality issues and, more recently, climate c...

Why the Solar PV Industry Should Love Geothermal Heat Pumps Pt 2

It’s a marriage made in heaven: Solar PV and Geothermal Heat Pumps Part 2 of a 6-Part Series Prevailing Heati...

Park District Goes Solar, Saves Big While Preserving Open Space

Not only do community parks provide green space for recreation and leisure, they also increase property values, attra...


Siah Hong Tan is a research specialist in Singapore. He is currently performing research on material systems that might be able to convert sunlight directly into fuels like hydrogen or methanol, thus addressing the issue of enabling long term, lar...


Volume 18, Issue 4


To register for our free
e-Newsletters, subscribe today:


Tweet the Editors! @jennrunyon



Successfully Integrating Solar: A Proactive Approach

•      What does the increasing solar penetrati...

Solar Power Northeast

  From the team that produced Solar Power Southeast and the sol...

Solar Power Asset Management and Performance

SEIA and SEPA collaborated with industry leaders to present the first ev...


Fast facts: 4 things you need to know about the state of solar fina...

Fast facts: 4 things you need to know about the state of solar financing...

10 Questions You Should Be Asking

Tony Robbins is fond of saying that the quality of your life is directly...

Join us at the New Solar Power Northeast

From the team that produced Solar Power Southeast and the sold out P...


Renewable Energy: Subscribe Now

Solar Energy: Subscribe Now

Wind Energy: Subscribe Now

Geothermal Energy: Subscribe Now

Bioenergy: Subscribe Now