Storage may help utilities embrace distributed solar

Source: Umair Irfan, E&E reporter • Posted: Thursday, January 21, 2016

Storing electricity may be the sweetener utilities need to swallow distributed renewable energy.

Researchers and utility companies are looking at what would happen if they integrated energy storage with solar power as a unit in the hope of turning an energy liability into an asset.

“Storage is the missing piece of the puzzle,” said Rhone Resch, president and CEO of the Solar Energy Industries Association, during a conference call with reporters yesterday.

Combining batteries with photovoltaics resolves some of the problems power companies have had getting widespread intermittent renewable energy to play nice on the grid, an endeavor engineers are frantically chasing as solar panels spring up on rooftops and fields across the United States.

These zero-emissions power generators waver as clouds pass overhead and shut off when the sun sets, creating expensive load balancing problems for utilities that have to ramp up or power down other generators to fill in the gaps.

Rooftop solar is particularly challenging for utilities, since it turns energy end-users into producers for part of the day, forcing the grid to run in unintended ways and eating into power companies’ profits.

This is part of why many utilities have proffered lackadaisical support for distributed solar power, if not fought it outright, in places like Nevada, where utilities have successfully pushed back against solar power incentives like net metering and favorable power rates, leading solar developers to leave the state (ClimateWire, Jan. 11).

Searching for a business model

To help solve the problem, the Department of Energy yesterday announced $18 million in funding for combined solar and storage research projects (Greenwire, Jan. 19).

Dubbed SHINES for “Sustainable and Holistic Integration of Energy Storage and Solar PV,” it operates under the department’s SunShot Initiative,

“SHINES is a very apt and descriptive acronym,” said David Danielson, who leads the Office of Energy Efficiency and Renewable Energy at DOE. “One of the big opportunities around new distributed [energy] devices is that there are a number of valuable services they can provide to the grid.”

The proposals aim to study how solar plus storage will play on the grid and to find out if there is a business model that protects utilities, serves homeowners and cuts carbon emissions.

Private companies like Tesla Motors Inc. are already betting that a residential battery system may be the next home utility appliance, alongside furnaces and water heaters (EnergyWire, Nov. 16, 2015).

The question, then, is how to get homeowners who want to generate their own power, solar developers that want to coat every surface with photovoltaics, and utilities that want to protect their bottom lines all working toward the same goal.

The same question goes for the photovoltaic panels, batteries and transmission lines.

The Fraunhofer Center for Sustainable Energy Systems is one of the groups taking a stab at this. With about $3.5 million awarded by DOE, matched by more than $3.5 million of its own funds, the institute is developing a platform that makes solar panels, batteries and buildings all talk to each other.

‘Like a virtual power plant’

Kurt Roth, a co-primary investigator for this project and the director of Fraunhofer’s building energy technologies division, said the goal is to reduce the impact of wavering renewables on the grid and to match energy demand to supply.

The team will test the system with a utility-scale solar farm and battery system. “Part of the demonstration project is to understand how effective the system can be,” Roth said. “There will potentially be some trade-offs.”

Utility companies are chipping in, as well. “Big picture, we realized that distributed energy resources are here and here to stay,” said Karl Popham, the principal investigator for Austin Energy’s SHINES contribution. “We would rather be in a partnership with that and ahead of the curve than reactive to it.”

Austin Energy, the city-owned utility for Austin, Texas, is embarking on an initiative to combine solar power with storage to reach a levelized cost of energy of 14 cents per kilowatt-hour. DOE awarded the project $4.3 million, with matching funds from partners, the Texas state government and local officials.

Over three years, the utility will deploy two grid batteries and software that manages solar power at the grid, commercial and residential levels.

“It’s almost like a virtual power plant,” Popham said.

Aside from understanding the technical challenges, Popham said Austin Energy hopes to figure out how to reconcile the needs of people who want to generate their own electricity with the utilities that depend on selling it and provide the energy infrastructure. “One of the things we want to do, frankly, is understand the business model and see what works for the customer,” he said.

Tweaking the technology

The financial implications of distributed solar energy may still prove a bigger challenge than resolving intermittency.

In a 2013 report, the Edison Electric Institute, an electric utility association, described distributed solar power as an area “where the threats to the centralized utility business model have accelerated.”

Though a few solar panels on a house will be barely visible in the energy picture, panels on thousands of homes in a power market are a force to be reckoned with, especially as new deployment models and cheaper panels make it to market (ClimateWire, Dec. 18, 2015). There has been a thirtyfold increase in photovoltaic deployment since 2008.

“If you see the aggregate impact [of distributed solar panels], they have the impact of larger systems,” said Aminul Huque, a technical leader at the Electric Power Research Institute. “You have to treat them as a potential generation source.”

EPRI received $3.1 million from DOE, matched by another $3.2 million from other contributors, to study energy storage and solar power on the grid, working with five utilities to see how they can improve power systems from production to consumption.

The team is developing a two-tiered management system, with one tier maintaining stability across a wide area and another monitoring local electricity production from photovoltaics. By combining demand-side management, solar and load forecasting, smart inverters and energy storage, researchers hope to make solar power a bankable and reliable power source.

“Compared to [only using] photovoltaics, the integrated solution [with energy storage] is much more manageable,” Huque said.

Much of the technology to do this is already available, but it needs more tweaking to fill this role. “We are not starting from scratch, but we are improving them further,” he added. “All this will help you achieve the goal of making [solar] reliable and low-cost.”