Webinar’s solar-plus-battery secrets

One of the slides from the Ata Renewables presentation in last week's webinar. Pic: Ata Renewables.

One of the slides from the Ata Renewables presentation in last week’s webinar. Pic: Ata Renewables.

By Jason Deign

Combining battery storage with solar generation is already cheaper than using diesel in most microgrids, said experts at an Energy Storage Report webinar last week.

“As the key applications, we see islanded grids or microgrids, [where] PV and batteries are becoming cost-competitive with diesel,” confirmed Valts Grintals from Delta Energy & Environment in the event organised alongside Ata Insights.

A case in point is France, where interest in solar plus storage is highest in islands and “non-interconnected zones,” where around 60% of PV projects so far have been installed with batteries, Grintals said.

This interest is set to grow following the launch of a tender last year for almost 52MW more of island-based solar capacity, spread across 33 projects. “We expect to see more storage coming into these projects,” said Grintals.

“In France, PV and storage is a great solution to stabilise the grid [and] help enable microgrid use, and it is already cost competitive.”

Important applications for storage

Other important applications for storage with solar include grids where renewable energy integration is an issue, or places where a grid connection cannot handle new PV capacity, he said.

As well as France, Delta predicts solar plus storage is due to take off in Australia, Canada, South Africa, US and the UK. Australia is perhaps one of the biggest markets so far for large-scale PV with storage.

Grintals said 50% of PV projects were now being developed with storage, again with microgrids representing a significant portion.

Major microgrid developments to date include the 800kW, 2MWh Daly River Solar Project and the 2MW, 500kWh Garden Island Project.

Another speaker in the webinar, Burak Türker of Younicos, said microgrid designers were using batteries as a way of reducing the need for curtailment of both solar and wind energy.

Increasing self-consumption

At the same time, battery storage could help increase self-consumption, achieve higher renewable energy shares, improve ramp rates, comply with system operator requirements, and carry out demand shifting and arbitrage.

Younicos has put the microgrid solar-plus-storage theory into practice on Graciosa in the Azores.

There the company installed a 4MW, 3.2MWh lithium-ion battery system alongside solar and wind to cut down on diesel consumption.

Younicos has calculated the microgrid will have an 11% internal rate of return and a full system payback period of less than 15 years, saving almost 2.4m litres of diesel and cutting carbon emissions by 6,305 tons of CO2 a year.

While microgrids offer one of the best business cases for solar plus storage, the webinar speakers also noted growth in several other applications.

“We’ve noticed a huge interest”

For example, said Oscar Pereles, chief operating officer of Ata Renewables: “We’ve noticed a huge interest in our customers, in the last year or year and a half, in what could be potential solutions of utility-scale PV and batteries.”

Markets are moving from centralised to distributed generation, he said, but according to Navigant Research most energy storage will continue to be deployed on utility networks for the foreseeable future.

“The projects are in exponential growth,” he said. “We think storage will be a tsunami in the next five to 10 years.”

Technology-wise, all speakers agreed that lithium-ion was by far the market leader, although flow batteries were also mentioned as being of interest.

In terms of cost, flow and lithium-ion batteries are due to converge on pumped hydro by 2024, Navigant Research predicts.

Containerised lithium-ion storage

Pereles noted that Ata Renewables had been working on the potential for installing containerised lithium-ion storage in Puerto Rico since 2010, and had originally seen prices of around USD$1m for a 1MW, 420kWh system.

“That price has come down, as of today, to a half,” he said. “We’re talking prices for power batteries of around $1 a watt power and around half a dollar a watt-hour for energy applications.”

This fall in costs is driving solar-plus-storage take-up among utilities, for energy shifting, he said.

One example is Tesla’s Powerpack installation on the Hawaiian island of Kauai, where Tesla is providing the local utility with solar power at less than $0.14 per kilowatt-hour. That’s around 10% cheaper than what was available before.

Increasingly, adding batteries is to solar is no longer a prohibitively costly exercise, as Ata Renewables showed with an analysis of the impact of batteries on the cost of an 800MW PV plant in the United Arab Emirates.

A modest effect on the price of energy

It found the addition of current-market lithium-ion power batteries only had a modest effect on the price of energy, increasing it from $0.029 to $0.035 per kWh.

Moving to energy applications, the price rose to $0.0526 with one hour of storage, $0.0726 with two hours, $0.0889 with three hours and $0.0997 with four.

“With today’s technology, we can make an 800MW facility with a four-hour storage system, with shifting capabilities, below 10 cents,” Pereles said. “We might be able to compete with many other dispatchable energies today.”

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