China’s largest solar-plus-storage project has been connected to the grid. How big is it — 500 megawatts (MW)? 700 MW? 1,100 MW? Nope, we’re in 2020 — it’s 2,200 MW (2.2 GW).

Sungrow, the #1 suppliers of inverters for renewable energy projects, shared the news of the new record. Along with Huanghe Hydropower Development, Sungrow had a big hand in the project.

Alongside the massive 2.2 GW solar PV park, there’s a 202.86 MW/202.86 MWh energy storage plant. Getting all of that electricity out of the vicinity and onto the broader grid presents its own challenges, and that’s where a 800kV ultra-high voltage power line comes in.

“Sungrow offers its PV and energy storage portfolio coming with an embedded sub-array energy management function that can be used to control the output of solar and storage, allowing for improved accuracy of solar generation forecasts,” the company writes. “The flexibly-built microgrid system with Sungrow PV and energy storage system can supply electricity in the early construction period, making it one of the fastest completed renewable energy projects with a construction duration of over 4 months.”

Sungrow claims to be “the world’s most bankable inverter brand,” and it backs that claim up with a stunning 120+ GW worth of the tech installed worldwide. The company, founded by university professor Cao Renxian, says it has the “largest dedicated R&D team in the industry.” Furthermore, it offers more than solar PV inverters and related tech. It also sells energy storage systems of all sizes — for utility-scale, commercial, and residential use — and it helps build floating solar PV power plants. The company has been around since 1997, when I was still in high school! That’s the extreme early days for modern solar power.

That 120+ GW network of solar PV systems using Sungrow inverters spans more than 120 countries, and it gives the company a market share of more than 15% worldwide.

A multi-gigawatt co-location market looks set to take off within the next five years, however uncertainty over DC coupling, the need for costly symmetric grid connections and outdated regulatory frameworks risk stymying the market’s growth.

That was the conclusion from a discussion at this week’s Energy Storage Virtual Summit, featuring Solar & Storage Colocation, organised by PV Tech publisher Solar Media, which brought together a panel of industry experts in the fields of renewables and energy storage.

A survey of attendees at an earlier session hosted by BloombergNEF’s Jenny Chase found that 76% considered there would be a multi-gigawatt co-location market in less than five years, indicating industry confidence that co-located projects would be economically feasible in the short-term.

This was echoed by Ben Irons, co-founder of Habitat Energy, who said subsidies were no longer required for solar, storage or co-located solar-storage projects with prices as they are. Instead, these projects can be incentivised sufficiently through market design.

The US market, described as the epicentre of co-located projects by Chase, with a pipeline standing in excess of 8.9GW, also has a unique advantage in stimulating the development of solar-storage projects through the Investment Tax Credit. The ITC can be applied to both the solar and storage elements of projects as long as the battery charges from the connected solar array, providing tax refunds on equipment purchased.

This, Corentin Baschet, head of market analysis at Clean Horizon Consulting said, acted as a “big incentive” for co-located projects to come forward in the US as it posed a significant savings on project Capex costs.

Meanwhile, co-located projects were said to enjoy more or less subtle advantages in other markets. Baschet posed that, owing to the comparative lack of grid strength in areas of Africa, renewables assets featuring energy storage take on a “whole other dimension”, with large-scale solar farms effectively unable from connecting to regional grids without some form of grid-stabilising energy storage attached.

Governor Andrew M. Cuomo recently announced the completion of the first community solar paired with energy storage project in New York. The milestone project will reduce the energy costs for approximately 150 households in Westchester County and New York City as well as provide power to 12 Tesla electric vehicle (EV) supercharging stations.

The announcement supports Governor Cuomo’s goals to install 6000 MW of solar by 2025 and 3000 MW of energy storage by 2030, as called for in the Climate Leadership and Community Protection Act.

“New York remains unwavering in our commitment to developing renewable energy resources that will grow our clean energy economy and advance our nation-leading plan to fight climate change,” Governor Cuomo said. “This first-of-its-kind project in New York combines renewable energy and energy storage that together will deliver reliable, affordable, and sustainable energy creating a model for communities around the state.”

The New York State Energy Research and Development Authority (NYSERDA), through its NY-Sun and Retail Energy Storage programs, provided nearly US$800,000 in support of the community solar plus energy storage project, which is expected to provide participants with approximately 10% savings on their monthly electricity bills for 25 years as well as provide power to Tesla’s EV charging stations.

Installed by IPPsolar LLC, and owned and operated by Urstadt Biddle Properties Inc., the 557-kW rooftop solar project comprises nearly 1500 panels and is paired with 490-kW four-hour Tesla Powerpack lithium-ion (Li-ion) batteries.

Lieutenant Governor Kathy Hochul, who made the announcement in Yorktown Heights, Westchester County, said: “This announcement of the first completed community solar paired with energy storage project marks another major renewable energy milestone in New York. IPPsolar and Urstadt Biddle Properties had the vision and commitment to make this project a reality, and will serve as an example to other commercial properties that these projects can provide clean, affordable energy for years to come. We are proud in New York to lead the way with our commitment and efforts to combat climate change and build back better, cleaner, and greener for future generations.”

“Solar-charged batteries” can help solve California’s energy shortage, with energy storage already playing a small but active role in mitigating the struggle to meet peak energy demand, according to the leadership of two trade associations based in the US state.

“Some headlines and quotes from experts erroneously lay blame for the blackouts on solar energy,” Bernadette Del Chiaro, executive director of the California Solar & Storage Association told Energy-Storage.news.

Instead, Del Chiaro said, solar energy did “exactly what solar energy can be relied upon to do: generate tons of electricity on hot sunny days to meet California’s growing need for energy. If not for all the solar power on the grid, the weekend’s outages would have been far longer and more widespread.”

“Moving beyond blame, what is needed is MORE solar energy combined with solar-charged batteries, not more fossil fuel power plants, to cover evening peak loads! The state is not doing enough on this front. That’s the problem.”

It has been widely reported that California has experienced problems meeting demand for electricity over the past few days, with grid operator CAISO issuing a proclamation of a State of Emergency on 14 August 2020.

The state was experiencing an Extreme Heat Event (defined as “widespread temperatures well in excess of 100 degrees throughout the state”), and CAISO said “significant demand and strain” had been put on California’s grid, while limiting energy imports from surrounding states.

Mexican energy regulator the Comisión Reguladora de Energía (CRE) has issued two new deliberations which forbid the establishment of solar energy communities and block solar-plus-storage deployment.

The new measures cancel previous provisions which enabled PV system owners to sell excess power to nearby consumers and deploy energy storage, and come on top of rules recently introduced by the government to further hinder the rising share of renewables in the country’s energy mix. The authorities have taken an anti-renewables stance with the aim of consolidating the position of state-owned utility the Comisión Federal de Electricidad (CFE). Previous measures included the suspension of renewables auctions and a stop on grid connections for new solar and wind projects.

Mexican trade body the Asociación Mexicana de Energía Solar said the energy community provision canceled by the regulator had offered the opportunity for solar electricity to be used in remote communities and by the small and medium-sized businesses which supply around 80% of the nation’s jobs. “The new decision affects a vulnerable social stratum that lives in remote communities and lacks an electricity grid, by denying them access to clean energy,” stated the solar organization.

The association also criticized the energy storage move, stating: “It is worth mentioning that today in Mexico there are already two power plants in operation that include storage systems and at least three more power plants under construction that will include this type of technology.”

The trade body added: “The two new resolutions of the CRE generate uncertainty and confusion in the solar energy sector. These actions are contrary to the official discourse of the federal government and the commission itself, which have made public their intention to increase the reliability of the electricity system and benefit communities and Mexicans in vulnerable situations.”

The drop in battery prices is enabling battery integration with renewable systems in two contexts. In one, the battery serves as a short-term power reservoir to smooth over short-term fluctuations in the output of renewable power. In the other, the battery holds the power for when renewable power production stops, as solar power does at night. This works great for off-grid use, but it adds some complications in the form of additional hardware to convert voltages and current.

But there’s actually an additional option, one that merges photovoltaic and battery hardware in a single, unified device that can have extensive storage capacity. The main drawback? The devices have either been unstable or have terrible efficiency. But an international team of researchers has put together a device that’s both stable and has efficiencies competitive with those of silicon panels.

Solar flow batteries
How do you integrate photovoltaic cells and batteries? At its simplest, you make one of the electrodes that pulls power out of the photovoltaic system into the electrode of a battery. Which sounds like a major “well, duh!” But integration is nowhere near that simple. Battery electrodes, after all, have to be compatible with the chemistry of the battery—for lithium-ion batteries, for example, the electrodes end up storing the ions themselves and so have to have a structure that allows that.

So, the researchers used a completely different sort of chemistry. Flow batteries use solutions of two chemicals that can undergo charge-exchange reactions, shifting them between two chemical states. The battery basically borrows those charges in order to produce current when discharging, or it pumps charges back in to shift the chemicals to their alternate state, thus charging the battery. Flow batteries have the advantage that their total storage capacity is simply dependent upon the total volume of solution you use.

While there are many chemistries capable of working in a flow battery, the researchers started with their photovoltaic system and used that to choose the battery’s chemistry.

Even here, they didn’t exactly use off-the-shelf hardware. There was silicon involved, but it was part of a two-layer solar cell. In this setup, one photovoltaic material absorbs a set of wavelengths that aren’t absorbed by a second; the first layer, by contrast, is transparent to those wavelengths absorbed by the second. This allows a single cell to absorb a much broader range of wavelengths than would be possible otherwise, upping its overall efficiency.

For their device, the bottom layer was silicon. On top of that is a layer of perovskite photovoltaic material. Perovskites are a potential next-generation solar material, useful because they’re made from cheap ingredients and can be created simply by evaporating a solution of the perovskite. Unfortunately, these chemicals also have a propensity to decay, which has made for short lifetimes in many experimental setups. The researchers here don’t try to solve all of these problems; they simply use a perovskite-on-silicon photovoltaic setup and don’t try to run it for long enough that chemical decay is an issue.