Interview by Rikki Stancich

Last September, Chieti, Italy-based solar technology firm, Innova Technology Solutions officially launched its novel Trinum dish / Stirling solution. The co-generation solution, which generates electricity (1kWe) and thermal energy (3 kWt), is designed for industrial and residential applications.

A 10 m² parabolic dish tracks the sun and reflects the rays onto the head of a Stirling engine. Dutch firm  Microgen Engine Corporation produced the Stirling engine, which was adapted by Innova for solar applications, and for which Innova has the exclusive rights.

CSP Today speaks to Innova's CEO, Francesco Guidetti, to learn more about the solution and about why dish-Stirling technology has the potential to be more cost effective and efficient than PV technology.

CSP Today:  Innova has developed a modular version of dish / stirling technology, where a 10m² dish reflector area can be adjusted according to the season/requirement. What is the advantage of this approach, compared to existing methods for adjusting the solar field?

Francesco Guidetti: The basic advantage is, depending on latitude you can use eleven, ten or nine slices of the solar dish. This immediately generates a cost saving. And when you install the machine, it’s easier to lift slices, [rather than an entire dish]. You slide the slices into the support and the mirrors are self-adjusting. The structure is made of metal and the mirrors slide in on a rail. The entire structure weighs roughly 190 kilograms (418 pounds).

CSP Today: Innova describes its dish as 'dust resistant', given that the dish can close up during the night. To what extent does this reduce the frequency of mirror washing? Is it possible that the O&M costs linked to the moving parts on the self-closing mechanism might cancel out any savings on mirror washing costs?

Francesco Guidetti: It depends on the location. Regardless of the fact that it ‘sleeps’ at night, if it is in an industrial place or in a desert it still needs to be cleaned. However, the ‘sleeping’ mode would reduce the cleaning frequency by 50 percent. You would probably need to clean them once per month in urban areas, but it depends on the weather conditions.

The closing mechanism was designed more for safety than to reduce the cleaning and O&M costs. These are cogeneration machines are designed to work in residential areas. In the event of strong winds it is entirely safe. It safely operates in winds of up to 50km/hour and resists in 160km/hour winds if closed.

CSP Today:  Innova is a technology developer, yet out sources the manufacturing process in order to focus on technology design and product marketing/business development. Why have you opted for this business model? What are the advantages of such an approach? Is this a medium-term strategy - would you consider bringing production in-house at any stage?

Francesco Guidetti: We cannot focus on everything and do everything. Developing a solar powered engine is complex, so we outsourced the manufacturing to people who are more specialised than us.

We may reconsider this approach in the future. Currently, it is a company-efficient approach; we need to focus on our core business, which is R&D in developing the smallest stirling engine powered by the sun.

CSP Today: There has been some debate recently about whether CSP can compete with PV, yet Innova says that its dish technology performs better than its PV equivalent in terms of output, space requirement, environmental impact and the fact that it is plug and play technology. Can you provide greater detail on how it achieves this?

Francesco Guidetti: It is a very different technology to PV. The PV system makes electricity; our system co-generates, no inverter is needed and it is 100% recyclable. Strangely enough, traveling around the various conferences and events, the environmental advantages of CSP doesn’t seem to be a hot topic…Yet we are in renewables for environmental reasons. PV has a whole host of disadvantages when it comes to lifecycle analysis.

Our whole effort is to further develop and refine existing technology, to ensure it is efficient and fully recyclable, and to make it available and accessible to a vast number of people in industrial and non-industrial areas. 

There isn’t the same level of experience or understanding of dish / Stirling as there is for PV and we don’t enjoy the same subsidies / incentives, despite the fact that we co-generate hot water at 60°C-65°C and electricity in a small space with one machine – which the client likes.

CSP Today: The CSP sector is finally gaining a foothold in the international energy markets, however, we have yet to see large-scale deployment of dish/Stirling technology. Why are developers continuing to shy away from this technology and when are we likely to see dish / Stirling projects go into the ground?

Francesco Guidetti: There are several reasons: Firstly, producing a reliable Stirling engine requires industrial scale and quantities that are just about to appear on the market. Secondly, for some reason the technology is currently not eligible for subsidies.

There is a need to produce the engine on an industrial scale. To make a parabolic trough, you need to bend the glass in only one direction; in a dish, it must be bent in two directions and the tracking must be more precise. Collateral technologies need to catch up.

CSP Today: Which markets is Innova focusing on at present?

Francesco Guidetti: We are still targeting the residential market and small-to-medium enterprises that need heat and electricity.

The majority of our market is currently in the south of Italy, where we will deliver the first machines in May. It has taken three years to develop and now we are confident in what we have. We have roughly 74 customers in southern Italy.

We have also been approached in South America – in Chile and Argentina. We are also considering North Africa (Tunisia and Libya), and the UAE. We are also in discussion with India for the supply of off grid versions.

The unique selling point is that a co-generating system that takes up half the space of existing solutions. It is suited to industrializing areas. In terms    of price, we are still somewhat more expensive, mainly because we are in the first years of deployment. That said, we are already comparable, but it should be remembered that we are still just at the beginning of our cost curve.

The machine occupies 2m² of terrain. The operational surface is 15m² and these units are designed for installation on the ground, rather than on rooftops. But they could be adapted for rooftop installation.

Image credit: Innova's Trinium dish/Stirling solution

To respond to this article, please write to the editor:

Rikki Stancich: rstancich@csptoday.com