By Alison Ebbage

The two are to use NEST’s prototype Thermal Energy Storage (TES) system along with Masdar’s experimental ‘beam-down’ CSP installation at Masdar City, with work set to commence in the second quarter of 2014. The aim is to demonstrate and prove cost-effective, flexible and scalable TES solutions for the global renewable energy sector.

At the same time, NEST energy storage project will serve as a research platform for Masdar Institute, and is expected to become the first pilot to prove the feasibility of the new TES system in the MENA region.

Exploiting benefits of beam down

Plans are to couple the TES technology with the beam down solar concentrator at Masdar City, which essentially is a 100 kWth concentrated solar power (CSP) pilot plant comprising of 33 heliostats, 280 m2 of mirrors, and a 20 metre-high central reflector.

The beam-down concentrator places the chemical reactor or solar thermal receiver at the base of the tower on the ground and allows researchers to investigate alternatives to employ solar energy in a more accessible way, as opposed to working at the top of a tower.

Dr Nicolas Calvet, Assistant Professor who is in charge of Masdar’s TES research facility, explains: “Beam down technology is essentially a concentrator made up of 33 heliostats - each of which sends light up to the top of a high tower where mirrors then beam down the light. It’s a two way reflection which means that towers could be removed and people don’t have to work at a height of 140m on top of the tower”.

“The beam down facility was initially born to validate the beam down technology but now that it has been proven, attention moves to how else it can be used to help develop CSP with storage,” says Calvet.

Scalable to an unlimited degree

The NEST pilot scheme, meanwhile, is set to run for two years. As a modular, scalable system for high-temperature thermal energy storage, it will also serve as a platform for TES research at Masdar Institute with the objective of developing new combined solar receiver/TES systems with higher temperatures and higher levels of efficiency.

NEST technology is a patented concrete storage system which has already been subjected to testing within a laboratory environment. The storage concept is scalable to almost an unlimited degree and can be mass-fabricated on the basis of standardised modules composed of inexpensive and readily available materials.

Storing energy in the form of heat, the system can be effectively incorporated into thermal power plant configurations enabling greater operational flexibility, energy reliability and security.

The system can also be adapted in terms of thermal regime and storage capacity to fit almost any type of thermal power generation system, such as CSP, biomass, coal and waste incineration, amongst others.

Specifically, the geometry of the system and composition of the concrete are unique, allowing for superior thermal capacity and conductivity and with minimal heat loss. The integration of the heat exchanger within the concrete module is also key.

“The whole design is to have heat going in and out, but with an investment cost of 30% less than with molten salts. We think the running costs will be much less as well,” says Olvind Resch, CEO at NEST.

Now the system needs to be tested, documented and proven within a live environment before it is made available commercially. And although the test site is on a scale of 1MW/hr, its modularity means that it can be scaled up quite easily for commercial use in both large and small energy plants.

Resch continues: “We think this will be commercialised as soon as it is absolutely proven to work. We anticipate that it will be installed in plants in 2016 subject to ongoing negotiations – we hope we’ll be formalising contracts within the next 12 months.”

Masdar’s wider work

The NEST agreement is just part of Masdar’s broad scope of research work. To date, the institute has published over 400 papers in peer-reviewed journals, 280 conference proceedings, 19 book chapters, and two full books.

On a practical level, it is constantly on the lookout for promising collaborations with leading companies, in a bid to bring energy storage technology to the forefront of the renewable industry.

So far, three US patents have been approved, 39 patent applications have been filed and over 60 invention disclosures received since the Institute’s inception. In addition, more than 40 companies and government agencies are currently involved with Masdar Institute in some form of partnership, research program or collaboration.

One of particular interest to the CSP community is the CSP on Demand (CSPonD) project with the Massachusetts Institute of Technology Energy Initiative (MITEI). Due to start in July this year, its scope is to test molten salt composition with a view to gaining efficiencies within the energy production process.

As Dr. Fred Moavenzadeh, President of Masdar Institute, recently said: “With the support of the UAE’s leadership, we continue to seek partnerships with pioneering companies across the world that have expertise in energy storage technologies”.

To comment on this article, please contact the author, Alison Ebbage.