The sharing economy is growing feverishly worldwide. Whether ride-sharing, tool-sharing or home-sharing, there are new value streams and new benefits to participants never before envisioned. Energy markets are no exception and are experiencing similar community-oriented revolutions.

Over a decade ago, the first community renewable energy (aka shared renewable energy) programs emerged, enabling multiple energy customers to participate in and share the economic benefits of a wind or solar energy system. Today, more than 14 states have enabled shared renewable energy programs, and hundreds of utilities offer some form of community or shared renewable energy program to their customers. More recently, “community choice aggregation” has sprung to life as a compelling alternative for communities looking to drive more renewable and clean energy development.

The latest community energy model to make waves: community storage. What is it? Where is it? To what extent is it, or could it be, “shared?” And, what can we expect from this new brand of community energy in the future? In this article, we explore the concept of community storage, provide an overview of projects and programs across the country, and offer some important insights on the challenges and opportunities for this novel concept.

What does community storage mean?

Community energy storage is currently a concept without a precise definition. It could be said that an energy storage system is community storage if it is (1) located within a community with defined boundaries, (2) serves such a community or (3) both of these things. This definition will tend to exclude bulk or utility-scale energy storage serving the utility and/or ratepayers as a whole, and singular, behind-the-meter (BTM) storage systems that primarily serve the building or home to which they are connected. In theory, anything between these two use cases could be community storage.

(Reuters) – U.S. deployments of energy storage systems will nearly triple this year thanks to sharply lower costs and state policies that support the case for installing batteries in homes, businesses and along the power grid.

That forecasted growth of 186 percent to 1,233 megawatt-hours of storage from 431 MWh compares with the 27 percent increase in 2017, according to a report by GTM Research and the Energy Storage Association trade group published on Tuesday.

That’s in part because some large projects that had been expected for 2017 were pushed into the early months of 2018, but also because the market for batteries in homes and businesses is finally taking off, according to GTM analyst Ravi Manghani, who said that part of the market logged growth of 79 percent last year.

The growth in the use of batteries for electricity storage has been a boon to manufacturers such as Tesla Inc (TSLA.O), LG Corp (003550.KS) and others.

Storage system costs have fallen by roughly two thirds in the last five years, Manghani said. In addition, more states are mandating utilities procure storage systems.

The market for energy storage is still small, generating just $300 million in value last year, the report said. But batteries have long held the promise of solving the intermittent nature of renewable energy sources such as wind and solar, so their development is closely watched by investors, regulators and power companies. The market is expected to exceed $1 billion in 2019, the report said.

Energy storage is finally becoming a legitimate option for utilities, commercial-building owners, and homeowners across the country. The biggest opportunity in 2018 may be in the commercial market, where the combination of solar and storage can create a cost-savings combo that gives building operators a lot of flexibility to control their energy costs.

Commercial solar projects alone have always struggled to be justifiable financially, because commercial customers’ bills typically include a payment for the energy they consume (consumption charge) and another portion based on their peak demand (demand charge). Traditional solar net metering may only reduce half of a customer’s bill, but combining solar with energy storage can reduce the cost of both components on utility bills and makes a valuable combo for the renewable-energy industry.

A leader emerges in commercial solar-plus-storage solutions

Most commercial energy-storage projects in the U.S. have used stand-alone systems like Stem to provide energy-storage solutions. Tesla‘s (NASDAQ:TSLA) Powerpack was another popular product, but it wasn’t paired with SolarCity’s commercial solar product in a turnkey solution.

SunPower (NASDAQ:SPWR) is trying its hand at providing a one-stop-shop solution for commercial solar and energy storage, and has a good shot at leading the market. It has long been a leader in commercial solar: It has installed about 1.7 gigawatts of commercial projects around the world and claims the No. 1 market-share position in the U.S.

The turnkey Helix commercial solar solution is now being combined with a product called Helix Storage to make a full solution for customers. SunPower will sell the system as a turnkey solution to installers, and develop some systems itself with large corporate customers. Then SunPower will use its own software and monitoring to control the energy-storage system to generate value.

When installed, Helix Storage will reduce demand charges for customers and even store cheap solar energy for consumption when electricity prices are highest. SunPower says it can leverage the data it’s gathered from monitoring 1.7 GW of commercial solar installations to maximize the benefits of solar plus storage in a way competitors will have a hard time matching.

Bringing the solution under one roof will also help with financing. Until now, most commercial solar projects had to be financed separately from energy storage, making both tricky for developers. Bringing them together should make financing and financial justification easier.

The U.S. energy storage market is no longer in its infancy. According to GTM Research and the Energy Storage Association’s newly released U.S. Energy Storage Monitor 2017 Year in Review, 100 megawatt-hours of grid-connected energy storage were deployed in the fourth quarter of the year, marking 1,080 cumulative megawatt-hours deployed between 2013 and 2017.

Even more impressive, GTM Research expects that the U.S. market will almost double this total in 2018 alone, with more than 1,000 megawatt-hours of energy storage forecast to be deployed this year.

“We’re going to have to strike the word ‘nascent’ from our vocabularies when describing the U.S. energy storage market,” said Ravi Manghani, GTM Research’s director of energy storage. “Falling costs and favorable policies will be among the core drivers of the market’s breakout 2018. It’s not hard to imagine that every solar RFP by the end of the year will include storage.” ​

“The recent unanimous landmark decision issued by the Federal Energy Regulatory Commission is expected to lay the groundwork for the integration of energy storage technologies into the U.S. wholesale markets in a manner that compensates storage for the full range of value it is already capable of providing to the grid and end users,” said Kelly Speakes-Backman, CEO of ESA. “Policies and regulatory frameworks that level the playing field will further encourage energy storage deployment throughout 2018 and beyond as the industry builds toward a goal of realizing 35 GW by 2025.”

The U.S. energy storage market grew 27 percent in 2017, with 431 megawatt-hours deployed on the year. While the front-of-meter market made up the largest share of deployments, it was the behind-the-meter market that stole the show this year, growing 79 percent year-over-year with record deployments in both the residential and non-residential segments.

The Federal Energy Regulatory Commission’s Order 841 aims to reduce barriers to the deployment of energy storage in wholesale power markets.

It lays the foundation for the energy storage market to grow by as much as five fold to 50 GW over the next decade. But at least half of that potential growth would depend on the development of state, not federal, policies to support energy storage, according to a new report by The Brattle Group.

FERC’s order has been hailed as a landmark in the development of energy storage markets. It directs the operators of wholesale power markets — regional transmission organizations (RTOs) and independent system operators (ISOs) — to remove barriers that could keep storage resources from realizing their full value.

The Brattle report and the FERC order also coincide with the release of the 2017 U.S. Energy Storage Monitor by GTM Research and the Energy Storage Association, which found 100 MWh of grid connected storage deployed in fourth-quarter 2017. GTM expects the U.S. energy storage market will almost double in 2018 alone, with more than 1,000 MWh of storage deployed this year.

And the groundwork laid by FERC Order 841 “will further encourage energy storage deployment throughout 2018 and beyond as the industry builds toward a goal of realizing 35 GW by 2025,” Energy Storage Association CEO Kelly Speakes-Backman said in a statement.

According to the Brattle report, at least half of the 50 GW energy storage market it forecasts unfolding over the next decade could come from opening up the wholesale power markets to energy storage. But the greater part of the potential growth has to come from energy storage applications that serve the transmission and distribution sectors, which are largely beyond FERC’s jurisdiction.

The new hybrid energy storage device utilises aqueous electrolytes instead of flammable organic solvents making it environmentally friendly and safe. It can also be used with portable electronic devices as it facilitates a boosting charge with high energy density.

The device was developed by Professor Jeung Ku Kang and a team of scientists from KAIST’s Graduate School of Energy, Environment, Water, and Sustainability. The team assembled fibre-like polymer chain anodes and sub-nanoscale metal oxide cathodes on graphene to develop a hybrid energy storage with high energy and power densities. Conventional aqueous electrolyte-based energy storage devices have a limitation for boosting charges and high energy density due to low driving voltage and a shortage of anode materials. The research team came up with new structures and materials to facilitate rapid speed in energy exchange on the surfaces of the electrodes and minimise the energy loss between the two electrodes. Anodes were made with graphene-based polymer chain materials, graphene having a web-like structure that produces a high surface area, thereby allowing higher capacitance.

With regard to cathodes, the team used metal oxide in sub-nanoscale structures to elevate atom-by-ion redox reactions. This method realized higher energy density and faster energy exchange while minimizing energy loss.

The device can be charged within 20 to 30 seconds using a low-power charging system, such as a USB switching charger or a flexible photovoltaic cell. The developed aqueous hybrid energy device shows more than 100-fold higher power density compared to conventional aqueous batteries and can be rapidly recharged. Further, the device showed high stability with its capacity maintained at 100 percent at a high charge/discharge current.

MISO’s Energy Storage Task Force has been left wondering if it will help shape the RTO’s response to FERC’s sweeping storage participation order issued last month.

The task force has yet to learn its role in working with MISO staff to craft market rules to comply with Order 841, which directs RTOs and ISOs to remove barriers preventing storage from participating in energy, capacity and ancillary service markets. RTOs will be given 270 days from publication in the Federal Register to file revised tariff language with FERC outlining a participation model and another year to implement the changes.

“Frankly, we don’t know how this will affect the task force,” task force Chair John Fernandes said during a March 1 meeting. He added that MISO’s Steering Committee would have to issue a directive for the task force to begin specifically considering Order 841 compliance. Until then, the group will continue to examine what MISO rules might need to be revised or added to enable storage to participate in markets. (See MISO Staff, Stakeholders Envision Expanded Storage Participation.) Wisconsin Public Service’s Chris Plante pointed out that MISO doesn’t necessarily run compliance filings by stakeholders before they are filed with FERC.

The RTO says it will use stakeholder input on the compliance filing, although it’s not yet clear how extensively stakeholders or the task force will guide the process.

“MISO is actively working on the Order 841 compliance filing though it has not yet appeared in the Federal Register,” spokesman Mark Brown said. “While the compliance obligation lies with MISO, MISO intends to leverage its stakeholder groups to get input from stakeholders as it works through the issues as identified in the filing. This includes the Energy Storage Task Force and other stakeholder subcommittees.”

Fernandes said FERC’s order defines storage as resources that can inject into the grid, making them eligible for make-whole payments and qualification as capacity resources.

“FERC was clear that they don’t want to change market rules to accommodate storage, but they want it to be able to participate,” Fernandes said. “The idea of this order is to allow storage to participate in markets considering their operating characteristics.”