DL2 - Commercial Availability of Micro Gas Turbines

National R+D+i Programme Focused on Societal Challenges Programa Estatal de I+D+i Orientada a los Retos de la Sociedad

Project RTI2018-102196-B-I00, funded by: ERDF/Ministry of Science and Innovation – Spanish State Research Agency. Proyecto RTI2018-102196-B-I00, financiado por: FEDER/Ministerio de Ciencia e Innovación– Agencia Estatal de Investigación.

WP 1: Conceptual development of the SMGT concept

Task 1.1: Update of the status of related commercial products

Version 1. February 10, 2020 2

Technical References

Deliverable No. DL2 Dissemination level Public Work Package WP1 Task T1.1 Due date of deliverable January 30th 2020 Actual submission date February 6th 2020 3

History of Changes

Version Date Changes V.0 Original version created by Rafael González V.1 Revised by Antonio Muñoz Final February 10, 2020 Approved by David Sánchez 4

Executive Summary

The SOLMIDEFF project is aimed at accomplishing the following main objectives:

• Conceptual development of a Solar Micro Gas Turbine (SMGT) with optimised-design tailored to the needs of the bottoming desalination process, and potentially to other water treatment processes. • Experimental development of a bottoming desalination and water treatment system operating on electric and thermal energy produced by the micro gas turbine and enabling Zero Liquid Discharge (ZLD).

A graphical Abstract of the project is presented below, showing the flexibility of the SOLMIDEFF concept to be applied to different feed flows and services (from human consumption to agriculture).

Figure 1: SOLMIDEFF Main Objectives

The aim and scope of this document is to gather information about the commercial availability and of micro gas turbines, cornerstone of the SOLMIDEFF concept. As a result of this search, not only the availability but also the speciﬁcations of engines in the market place will be summarised and made available to interested readers.

The document is organised in three sections: i) introduction to micro gas turbines and to the current in- volvement of University of Seville with this technology; ii) review of currently available commercial engines; iii) speciﬁcation sheets of commercial engines, put together in the Annex section. Introduction 5

1 Introduction

1.1 Aim and scope The concept set forth in the SOLMIDEFF project is presented in Figure2. A parabolic dish collector is used to collect and concentrate solar energy into a focal plane where the Power Conversion Unit is installed. The PCU is comprised of a micro gas turbine engine and solar received. The compressor of the micro gas turbine drags atmospheric air which is compressed and fed into the solar receiver through the recuperative exchanger. The receiver is also a heat exchanger which transfers the concentrated solar energy received from the collector to the incoming stream of pressurised air, delivering air at high pressure and temperature. This air, typically at around 800oC, is then expanded across the turbine where power is produced to drive both the compressor and the electric generator. The gases exhausting from the turbine are discharged to the atmosphere but, before this, they ﬂow across a counter-current heat exchanger where they are used to preheat compressor delivery air before ﬂowing into the solar receiver. This layout was previously developed and demonstrated by the OMSoP project in Europe1.

The bottoming system of the SOLMIDEFF concept is comprised of two elements. An advanced desalination unit based on Reverse Osmosis technology is driven by the electric power produced by the micro gas turbine. This produces fresh water which can be used for a number of applications. Additionally, it produces a brine with high concentration of salts which is treated further in the second element of the bottoming system. This is a Zero Liquid Discharge unit driven by the waste heat available in the exhaust of the micro turbine (air at some 250-300oC). Both technologies, the advanced RO and ZLD units, will be demonstrated experimentally in SOLMIDEFF.

SOLMIDEFF is organised in theoretical and experimental activities. The solar micro gas turbine concept was recently demonstrated by a European Consortium participated by University of Seville. Therefore, SOLMIDEFF will now focus on the optimisation of this system, based on the lessons learnt in OMSoP, and on the operational strategies that ﬁt in best with the bottoming water treatment unit. The advanced Reverse Osmosis desalination concept and the innovative Zero Liquid Discharge unit will be developed and tested in SOLMIDEFF, in work packages incorporating theoretical and experimental tasks. Finally system integration will be analysed and the performance expected from the system (in terms of both power and water production) will be assessed.

Focusing on the micro gas turbine engine, regarded as the core component of the whole system upon which performance relies the performance of the entire polygeneration system, the assessment of the current state of the art is, at ﬁrst, a mandatory step. Accordingly, the scope of this report is to provide a quick review of the micro gas turbine units that are currently available in the market, with a multiple fold objective:

• To provide interested researchers in the topic with a quick guide to the Original Equipment Manufacturers that are active in the micro gas turbine space. • To review the speciﬁcations of commercial engines available, in order to assess which engine concept (layout, assembly, operating conditions) would ﬁt best in the SOLMIDEFF concept. • To highlight, if necessary, which technology gaps still need to be addressed by the industry.

As a ﬁnal comment, it is probably worth highlighting the active role currently played by University of Seville in the promotion of micro gas turbine technology in Europe. Indeed, the Department of Energy Engineering of this University is currently involved in the following ﬂagship activities contributing to the development of micro gas turbine engines:

1Further information can be found at https://cordis.europa.eu/project/id/308952/es 6 Introduction

Figure 2: Conceptual scheme of SOLMIDEFF.

• Prof. David S´anchez (Department of Energy Engineering, University of Seville, Spain) is along with Prof. Abdulnaser Sayma (Department of Mechanical Engineering and Aeronautics, City University London, United Kingdom) the co-founder of the European Micro Gas Turbine Forum (EMGTF). This is an initiative launched to foster the commercial deployment of micro gas turbines by setting the scenario where all stake holders have a platform to share knowledge and experience, collaborate and discuss a roadmap to move the technology forward.

• Partner of the NextMGT project. This is a Marie Sklodowska-Curie European Training Network that will run from 2020 to 2023 with the aim to move the technology forward thanks to the research carried out by ﬁfteen PhD students developing a coordinated research programme in the area of micro gas turbines.

• Partner in the OMSoP (Optimised Microturbine Solar Power generator) project, carried out between 2013 and 2017, where a solar micro gas turbine was designed and tested successfully. The economic and market assessment of the technology was, in this project, developed by USE.

• Active member of the Micro Gas Turbine working group of the European Turbine Network (ETN). ETN is a non-proﬁt membership association with 118 members, bringing together the entire value chain of turbomachinery technology worldwide.

This background provides the group at University of Seville in a privileged situation to contribute to the further development of micro gas turbines.

1.2 Micro gas turbines. Preliminary notes The current trend of the power industry anticipates two major changes of the global energy supply chain. On the one hand, energy policies worldwide head towards signiﬁcantly increasing the share of renewable energy sources in the mix (with the ultimate objective to enable all-renewable energy supply). On the other hand, a Introduction 7

paradigm shift from the current scheme based on centralised power generation and long-distance transport and distribution to decentralised, distributed power generation and consumption is progressively taking place. This sets out a need to develop eﬃcient small-scale, combined heat and power generation devices with fuel ﬂexibility capabilities and minimum to no emissions, able to not only operate on renewable energy sources but also on other fuels (for instance fossil) to secure energy supply under any circumstances. In this scenario, the particular features of micro gas turbines put this technology forward as an excellent candidate to enable the aforecited distributed generation scenario.

A standard micro turbine engine (MGT) includes the following components, shown in Figures3 and4: compressor, turbine/expander, combustor, recuperator, fuel supply system, bearings (and often lube oil system), electric generator, power conditioning and control unit, enclosure and balance-of-plant [1]. Some of these components might not exist in a particular MGT, and this may depend on the type of application and other requirements of the end-user.

Figure 3: Sectional drawing of a Capstone C65 engine.

Micro gas turbines are reliable (availability over 90%), compact engines able to achieve 30% electrical efficiency at full load and an overall energy utilisation of around 80% in CHP configuration. The engines can be considered clean in terms of NOx and CO (single digit emissions NOx emissions) and have installation costs starting from 800 e/kW [2]. Despite these features though, the performance targets of MGTs should be im- proved to better fit into the global energy scenario. Areas of performance improvement include fuel-to-electricity efficiencies of 40% or higher, capital costs lower than 500 e/kW and longer time between overhauls (ideally between 1 and 2 years).

Relative to other technologies for decentralised power generation at the smallest scale, micro gas turbines offer a number of advantages, including fewer moving parts, smaller footprint, lighter weight, much lower emissions, higher reliability, higher fuel flexibility and availability of clean, high grade heat in the exhaust. They have been commonly used in many engineering fields and have already been proven to be reliable and to work satisfactorily in a number of applications. 8 Introduction

Figure 4: Ansaldo Energia T100 MGT system for CHP applications.

From a market standpoint, the main competitor for the MGT is the internal combustion engine (ICE). Generally, it will have slightly higher electrical eﬃciency, approximately 30-34% compared to about 30% for a 100 kW MGT. However, as demonstrated in the OMES project [2], using MGTs brings about the following advantages:

• Lower maintenance costs. • Lower gaseous emissions (except CO2): NOx, CO and Unburnt Hydrocarbons (UHC). • Smaller footprint. • Lower vibrations. • Higher fuel ﬂexibility. • Higher availability.

Micro gas turbine manufacturers focus on a number of potential markets, for instance, commercial applications in tertiary buildings where there is a need for cost-effective electrical and thermal power, such as hotels, schools, hospitals, retail shops and office buildings. MGTs are also an attractive option for remote and reliable electrical power generation for telecommunication, mining, humanitarian missions or military applications. En- hanced recovery of oil and gas, wellheads, coal mines, and landfill operations using the by-product gases as fuel are a very important niche market for MGTs, which can also provide thermal oxidation of very low Btu fuels, such as landfill or waste gases, generating a useful electrical output.

Table1 provide estimates of the cost breakdown of MGTs for two diﬀerent power ranges. The source information to produce this table comes from data provided by the manufacturers during the aforementioned OMSoP project, vendor data and a survey recently carried out by the European Turbine Network. Introduction 9

Component <50 kWe 100-300 kWe Compressor and turbine 15% 25% Combustor 10% <10% Bearings 5% <2% Recuperator 20% 25% High speed generator 10% 5% Power conditioning and control unit 20% 25% Enclosure and BoP 20% 11%

Table 1: Cost breakdown of micro gas turbines (not that shares may not add 100% exactly) [3].

Based on these general principles of micro gas turbines, the following chapter provides a survey of the commercial products available today, ranked according to power output. 10 Market Review

2 Market Review

The preceding section reported the diﬀerent commercial applications targeted by micro gas turbine manufacturers. Nevertheless, despite the large number of applications and the transitional period through which the market is passing, with the associated instabilities and changing boundary conditions, the market share of Micro Gas Turbines in terms of industrial sectors is fairly steady. This is show in Figure5, where Oil and Gas is conﬁrmed to be the primary driver of market deployment, closely followed by commercial and industrial Combined Heat and Power. Far behind, units backing up renewable energy systems represent close to 10% of the total units installed.

Figure 5: Micro gas turbine market share of diﬀerent end-applications. Based on data from [3]

2.1 Acknowledgement The information about the state-of-the-art of micro gas turbines is scarce and, when available, it is scattered, often outdated and diﬃcult to compile. Therefore, in order to ensure that the information disclosed in this document is accurate and up to date, the authors have got in contact with the most relevant manufacturers of micro gas turbines, kindly requesting data of their respective product portfolio. The contribution of the following representatives of micro gas turbine Original Equipment Manufacturers is gratefully acknowledged:

• Mr. Radu Anghel, Director Sales Europe, Russia & CIS, Capstone Turbine Corporation. • Mr. Enrico Bianchi, Head of Microturbine Technology, Ansaldo Energia. • Mr. Tony Haynes, Commercial Director, Aurelia Turbines. • Mr. Jeffrey Armstrong, Principal Engineer, Flexenergy. • Mr. Willy Ahout, Chief Executive Officer, Micro Turbine Technology (MTT). • Mr. Johannes Mundstock, Office Manager, Euro-K. • Dr. Shaun Sullivan, Principal Engineer, Brayton Energy (system integrator). • Mr. Sean Fitzpatrick, Chief Executive Officer, Pure World Energy (system integrator).

Requests for Information (RFIs) have been sent to other OEMs and system integrators but, unfortunately, no replies have been obtained. For these, the information reported in technical documents and on the manufacturer’s website are reported in this chapter. Market Review 11

2.2 Micro Turbine Technology (MTT)

Micro Turbine Technology (MTT) is a Micro Gas Turbine manufacturer from The Netherlands. Their main product, which is commercial since April 2018, is called EnerTwin and it is a micro gas turbine for small-scale CHP applications. It provides 3.2 kWe and 15.6 kWt, with a combined eﬃciency of 94% (LHV)2.

This MGT can be used as a stand-alone system, in combination with a buﬀer tank, in a cascade of several MGTs or in combination with one or more conventional boilers. The main end-users targeted by EnerTwin are buildings with annual heating demands between 30 MWh and 120 MWh (around 4,000 to 15,000 m3 of natural gas). In addition to heat, the system also generates up to 25,000 kWh of electricity per year.

In applications with a higher heat-demand, the EnerTwin system could be arranged in a cascaded layout or combined with a previously existing heating system [4].

Figure 6: Core of the EnerTwin system (MTT)[4].

Regarding fuel flexibility, the EnerTwin unit runs on natural gas, biomethane, green gas and/or natural gas with up to 23% hydrogen content. Although not currently available, MTT is also working on a new combustion system able to run on LPG (Liquified Petroleum Gas) and “raw” biogas (free from H2S, but still with a high CO2 content). According to the company, this technology is expected to be available sometime in 2020. Finally, the emissions of the natural gas version of the EnerTwin system are below 27 ppm (15% O2) and below 50 ppm (15% O2) for NOx and CO. Noise is kept at 55 dB(A) at 1 metre from the engine [4]. These specifications are reported in Table2.

2112% according to the EcoDesign norms 12 Market Review

Electric output 3.2 kWe Thermal output 15.6 kWt Net electrical eﬃciency 16% Combined cycle eﬃciency >94% Rotor speed 240,000 rpm Maintenance interval 5,000 hours

NOx <27 ppm 15% O2

CO <50 ppm 15% O2 Noise 55 dB(A) at 1 m Dimensions (H x W x D) 995 x 600 x 1170 mm

Table 2: Speciﬁcations of the EnerTwin system [5]

2.3 Bladon

Bladon is a Micro Gas Turbine manufacturer from United Kingdom. Their main product is a micro gas turbine specifically designed for telecommunication applications, stemming as the world’s first manufacturer of micro turbine gensets specific for the telecoms market. The unit by Bladon MGT has a rated output of 12 kWe and the very interesting feature of enabling very long times between overhauls of up to 8,000 hours with low service costs due to its controlling and monitoring systems, according to the company’s website. An external view of the unit is shown in Figure7

Figure 7: Bladon Micro Gas Turbine [6] Market Review 13

Bladon is a fuel-flexible engine also since it can run on gaseous and liquid fuels. Available liquid fuels are diesel EN590:2009, kerosene K1 grade, diesel/kerosene mixtures, biodiesel and paraffin. Regarding gaseous fuels, the following can be used: natural gas, Liquefied Petroleum Gas (LPG), propane, butane and Compressed Natural Gas (CNG). The engine is reported to comply with the most stringent requirements in Class EU Reg- ulation 1628 Stage V 2016 and the noise level is below 65 dB(A) at 1 metre from the engine [6].

The company’s website does not have technical or economic information about the engine, hence no speciﬁca- tions are provided in this document, nor about its current commercial availability or market share. According to the information found, it seems that Bladon is still in the pre-commercial stage, but this has yet to be conﬁrmed.

2.4 Capstone

The American company Capstone is the largest manufacturer of micro gas turbines and they currently deploy most of the units installed worlwide. In contrast to the previous cases, Capstone has a wide portfolio of engines, whose commercial names refer to their net electric output: C30 (30 KWe), C65(65 KWe), C200S (200 KWe), C600S (600 KWe), C800S (800 KWe) and C1000S (1000 KWe); even if the last three systems are actually packages arranging multiple C200S in parallel. Furthermore, all of the engines can be paralleled in order to achieve much higher outputs of up to 30 MWe.

As most microturbines, Capstone’s engines make use of a recuperative layout in order to achieve higher eﬃciencies at moderate turbine inlet temperature. They are also known for a very tight integration, with the recuperator encapsulating the other components, and for the utilisation of air bearings in lieu of the more conventional oil bearings used in most engines. This solution arguably enables lower maintenance costs. Figure 8 shows the tight integration of the components, with the recuperator wrapping the core elements: compressor, expander and combustor. This, nevertheless, might bring about some issues related to accessibility when ser- vicing the engine.

Figure 8: Capstone Turbomachinery Technology [7]

Capstone micro gas turbines operate on a variety of fuels, including natural gas, biogas, Liquiﬁed Petroleum Gas (LPG)/propane, and liquid fuels (diesel, kerosene, and aviation fuel). In waste recovery applications, micro 14 Market Review

gas turbines burn waste gases (with low heating value, low-BTU) that would otherwise be ﬂared or released directly into the atmosphere. In addition, these micro gas turbines feature the lowest emissions of any non- catalysed gas-combustion engine, and digital power conversion to stand as the optimal power generation solution.

Thanks to the advantageous features common to all micro gas turbines and to the particular specifications of Capstone turbines, these systems can be employed in numerous applications such as: Oil & Gas, renewable energy, transportation, energy efficiency, critical power supply (back-up power), marine and others. The lineup of Capstone engines is comprised of six different systems, as follows: • C30 This is a compact system (see Figure9 delivering up to 30 kWe). The product line of C30 microturbines is arranged by the package, offering four different packagings: C30 High Humidity Offshore Package, C30 Industrial Package, C30 High Humidity Industrial Package and C30 Hazardous Location Package.

Figure 9: Capstone C30 Micro Gas Turbine [7].

• C65 The C65 engine delivers up to 65 kW of electric power while the UL-Certifed Combined Heat & Power version C65 ICHP provides 150 kWt of additional thermal power. The product line of C65 microturbines is also listed by the package, offering eight different packagings: C65 iCHP Industrial Package, C65 CARB Industrial Package, C65 iCHP SS HRM Industrial Package, C65 High Humidity Offshore Package, C65 Industrial Package, C65 Industrial Package With Low Emissions, C65 High Humidity Package and C65 Hazardous Location Package. An external view of the C65 cabinet is shown in Figure 10.

Figure 10: Capstone C65 Micro Gas Turbine [7].

• C200S The C200S package delivers up to 200 kW of electric power and contains the worlds largest single-unit micro turbine using air bearings. As well as the smaller sister-engines, the C200S lineup is comprised of Market Review 15

eight diﬀerent packagings, including a C200S Industrial Package, C200S High Humidity Industrial Package and C200S Hazardous Location Package. Picture of the standard package is shown in Figure 11.

Figure 11: Capstone C200S Micro Gas Turbine [7].

• C600S / C800S / C1000S These large packages are arrays of several (three in the C600S to ﬁve in the C1000S) C200S in parallel, delivering from 600 to 1000 kW of electric power. In addition, the largest C1000S system can be arranged (in parallel again) to generate up to 30 MW of electrical power. In contrast to the preceding systems, the C600S/C800S/C1000S portfolio is listed by the controller, and not the packaging: Microturbine with PowerSync Lite (PSL) Controller, Microturbine with C1000 Controller, Microturbine with PowerSync Enhanced (PSE) Controller and Microturbine with PowerSync Master (PSM) Controller.

Figure 12: Capstone High Power packages comprised of multiple C200S engines [7]

Capstone has shipped over nine thousand these systems to more than seventy countries, which implies a cumulative installed capacity of almost a gigawatt, logging millions of operating hours. This is summarised in Figure 13 where the large disparity between the share of diﬀerent engines is shown. Indeed, the C65 and C30 engines represent 50% and 40% of the total units deployed, with the larger C600/C800/C1000 systems accounting for just 5.5% of the market volume. Nevertheless, the latter engines account for about 50% of the total installed capacity, with one third corresponding to the C65 engine.

The speciﬁcations of each micro gas turbine package oﬀered by Capstone are summarised in Table3. 16 Market Review

Figure 13: Total units shipped and cumulative installed capacity of Capstone engines worldwide [7].

C30 C65 C200 C600 C800 C1000 Electric output [kWe] 30 65 200 600 800 1000 Thermal output [MJ/h] NA NA 1420 NA NA NA Exhaust mass flow [kg/s] 0.31 0.49 1.3 4.0 5.3 6.7 Exhaust temperature [oC] 275 309 280 280 280 280 Net electrical efficiency [%] 26 29 33 33 33 33 CHP efficiency [%] <90 <90 <90 <90 <90 <90

NOx [ppm 15% O2] <9 <9 <9 <9 <9 <9

CO [ppm 15% O2] NA NA NA NA NA NA Noise at 10 m [dB(A)] 65 70 65 NA NA NA Dimensions (W/D/H) [m] 0.8/1.5/1.8 0.8/2.0/1.9 1.7/3.8/2.5 3.0/5.8/2.9 3.0/7.5/2.9 3.0/9.1/2.9

Table 3: Speciﬁcations of Capstone’s product line [8][9][10][11][12][13]

2.5 Euro-K

Euro-K is a Micro Gas Turbine manufacturer from Germany. Euro-K design and produces individual components and integrated systems according to the end user’s specifications, also in compliance with additional statutory requirements like the pressure vessel directive EG97/23/EG for immediate use. The company relies on additive manufacturing, thanks to which unprecedented configurations and weight and costs reductions are enabled. In terms of fuel flexibility, Euro-K engines run with diesel, natural gas, mixed gas, lean gas, oil gas etc. Market Review 17

The main micro gas turbine product by Euro-k is a Turbo Range Extender, TRE, intended for use in the auto mobile sector. The interest of these engines is brought about by the fact that the accumulators of electric cars have a very low energy density, what prevents the vehicle from covering the common driving missions (cycles) of more than 200km. Indeed, back-up engines running on reserve/emergency fossil-fuel tanks seem to be an excellent option to make these low-emission cars more attractive and flexible. A first product of this type by Euro-k is the MGT35 TRE, shown in Figure 15, which delivers 35 kWe with an efficiency of 28%. This system features gas foil bearings (lube-oil free bearings), thanks to which the life of the product is signifi- cantly extended, and enables an extended driving range of 1000-1500 km by continuously charging the batteries.

Figure 14: Turbo Range Sectional Drawing [14]

The MGT35 engine is the ﬂagship product of the company but other versions of the same concept are planned by Euro-K. These versions are still under development and will include diﬀerent layouts (for instance, without exhaust heat recovery) and power output (40, 60 kWe).

According to personal communications with Euro-K, six units have already been delivered to the customers and two additional units (without recuperator) are scheduled to be delivered by the end of 2019; for 2020, ten additional units will be assembled and delivered. The output of all these units is the same, which means that the total installed capacity using the MGT35 technology will be some 650 kWe by the end of 2020.

The core engine parameters of the MGT35 engine are shown in Figure 15.

Figure 15: Core Engine Parameters 18 Market Review

2.6 Professor Dr. Berg Kießling GmbH (B+K)

The German company Professor Dr. Berg Kießling GmbH (B+K) develops and produces decentralised CHP solutions to recover energy from solid waste. Their main commercial product is an externally-fired micro gas turbine called ClinX. ClinX is a decentralised combined heat and power system which converts heterogeneous, wooden residues from commercial and industrial users into heat and electricity. The special feature claimed by the company is that even very mixed wooden material streams such as industrial lumber, limb wood and waste timber are efficiently and profitably converted into energy from renewable resources.

A scheme of the ClinX unit is shown in Figure 16. In the combustion subsystem, wood residues burn at temperatures of up to 1200oC. Downstream of the combustor, a high-temperature heat exchanger transfers the heat of the combustion gases to the stream of high-pressure, low-temperature delivered by the compressor of the gas turbine. The resulting pressurised hot air is then fed to the turbine, causing this to spin and, ultimately, drive the compressor and generator. The exhaust air from the turbine is finally used as primary, hot combustion air in order to reduce the fuel flow required at the combustor. The power output of the system is in the range from 40-260 kWe and 150-1000 kWt, which means an efficiency of ≈26%.

With the development of ClinX, reportedly, B+K targets end-users willing to make eﬃcient use of low heating value fuels and to enable environmentally-neutral reuse of previously unused raw material sources. The modularity of the system facilitates erection and operation and the central combustion unit can arguably be extended to include energy conversion, water treatment, or refrigeration modules as needed [15].

Figure 16: Scheme of the ClinX system by B+K [15].

2.7 Ansaldo Energia The Italian company Ansaldo Energia is the current owner of The Turbec Microturbine company which, in turn, was originally a jointly-owned subsidiary of Volvo and ABB. The main commercial product of Ansaldo Microturbines, produced at its Genoa factory, is the AE-T100 Gas Microturbine suitable either for Power Only Market Review 19

(P) or for Combined Heat Power (CHP), Figure 17. This system is available in three diﬀerent versions: natural gas (AE-T100NG), biogas (AE-T100B) and external combustion (AE-T100E).

Figure 17: Ansaldo AE-T100 Micro Gas Turbine [16].

The AE-T100 engine produces 100 kWe electric power and about 200 kWt thermal power. Thanks to a recuperative layout and a turbine inlet temperature of approximately 950oC, the rated electric eﬃciency of the engine is 30% and, when used in combined heat and power conﬁguration, fuel usage can be as high as 90%. As it is the case for most micro gas turbines, modularity is another important feature of AE-T100 technology, allowing it to cover a broad power range by merely installing multiple units in the same location. According to the manufacturer, potential end-user applications can be found in both industrial and civil applications: food industry, drying processes (ovens, ceramic industry, painting plants, etc.), chemical and petrochemical plants, industrial laundries, wastewater treatment plants, retirement homes, hospitals, swimming pools, hotels, resorts, sports centers, luxury apartment buildings, etc.

The AE-T100 engine is assembled in a single-shaft conﬁguration, whereby the compressor and turbine wheels and the alternator spin on the same shaft at high speed; thus, the electrical generator is of the high-speed type. Also, akin to the previous gas turbine models, an exhaust gas recuperator is connected to the gas turbine in order to preheat the air delivered by the compressor and, therefore, increase the electrical eﬃciency. The scope of supply includes also an induced draft fan.

In addition to these elements, the AE-T100 Power and Heat version (AE-T100 PH) incorporates and exhaust gas heat exchanger for waste heat recovery. This rises the overall fuel usage of the engine and is useful to produce hot water for a downstream application.

According to the information provided by Ansaldo Energia, there are some 510 units in the field (including older Turbec engines). This implies a cumulative installed capacity of almost 50 Megawatts in three different applications as shown in Figure 18: Power Generation, Combined Heat and Power and Combined Cooling, Heating and Power. Amongst these, more than 75% correspond to units operating on natural gas (AE-T100NG) whilst externally fired units (AE-T100E) represent a mere 7% of the total units installed. 20 Market Review

Figure 18: Installed units by Ansaldo Energia according to industrial application.

AE-T100NG AE-T100B AE-T100E Electric output [kWe] 100 105 < 75 Net electrical eﬃciency [%] 30 30 Depending on heat source Fuel Natural Gas Biogas External heat source Exhaust Mass Flow [kg/s] 0.79 0.79 0.79 Exhaust temperature [oC] 270 270 Depending heat source Noise at 10 m [dB(A)] 72 72 72

Table 4: Speciﬁcations of the product line of Ansaldo Energia [16].

2.8 Flex Energy

Flex Energy is a micro gas turbine manufacturer relying on the technology originally developed by Ingersoll Rand in the 1990s. Their ﬂagship product is the Flex Turbine, adapted from the Dresser Rand KG2 developed by Ingersoll Rand in the early 2000’s. Now matured and deployed by Flex Energy Solutions, the performance has reportedly been proven over ﬁfteen years of operations on a wide range of gases and varied environmental conditions throughout the world.

Flex Turbines operate on primary fuel gas (such as landfill gas, digester gas, biogas, wellhead gas, flare gas, etc.) but they can also be operated on other available fuel gas (for instance, propane) if the primary energy source is not available. This dual-fuel capability is a distinctive feature of the engine, as it enables seamless operation when switching between different fuel supplies, along with the very low emission characteristics that are proprietary of micro gas turbines, Figure 19, and modularity.

Flex Turbines are robust, industrial-grade systems that burn cleaner than any gas turbines in their class. They transform associated ﬂare and natural gases from operations into a continuous source of clean electric power, no matter the working conditions. Its low NOx emissions on a wide range of associated and methane Market Review 21

Figure 19: Emission characteristics reported by Flex Energy [17]. gases meets air quality standards for expedited permitting.

A primary market targeted by Flex Energy is Oil & Gas, where the fuel tolerance of the Flex Turbines is claimed to provide the users with economic and operational advantages. As reported by the company, these engines feature a wide acceptable gas range (from ∼350 Btu/scf to ∼2500 Btu/scf), sour and acidic gas tolerance (6,500 ppmv H2S and 70% CO2 respectively) and low fuel supply pressure. In addition to this standard product line, an externally ﬁred version of the Flex Turbine (Flex Turbine EX) has recently been completed, where the combustor and fuel system are replaced by a high temperature heat exchanger. Also, given the modular assembly of the core engine components, the company reports to be able to engineer special layouts adapted to agreed-upon speciﬁcations with the end-users.

The Flex Turbine unit is presented in two different arrangements. The GT333S engine is a single unit package delivering 333 kWe at 33% net electrical efficiency (or 85% in Combined Heat & Power mode), Table 5. A larger package incorporating four engines running in parallel, increases the output to 1.3 MWe with the same efficiency and specifications (except for a slightly higher noise footprint). These packages are shown in Figures 20 and 21 and their main technical specifications are summarised in Table5.

Figure 20: Flex Energy GT333s Micro Gas Turbine [17].

Another solution oﬀered by Flex Energy, based on the Flex Turbine packages descried above, is the so-called FlexGrid technology shown in Figure 22. This solution is aimed at oﬀ-grid applications in remote locations and incorporates embedded controls. Embedded controls enable that each Flex Turbine automatically and actively 22 Market Review

Figure 21: Flex Energy GT1300s Micro Gas Turbine [17].

GT333S GT1300S Electric output [kWe] 333 1300 Net electrical eﬃciency [%] 33 (without gas booster) 33 Nominal Heat Rate [MJ/kWh] 11.1 (11.4 with gas booster) 11.1 Exhaust Mass Flow [kg/s] 2.3 9.2 Exhaust temperature [oC] 264 264

NOx [ppm 15% O2] <5 <5 Noise at 10 m [dB(A)] 62 69

Table 5: Speciﬁcations of the product line of Flex Energy. synchronises to other units in the FlexGrid so that multiple Flex Turbine units operate seamlessly together to run distributed loads, while sharing and shedding power, and maintaining stable grid conditions 24/7.

Figure 22: FlexGrid [17].

In the FlexGrid, each Flex Turbine unit is packaged with a generator braking resistor (GBR) for deploying reserve power and absorbing excess power. Thus, if a higher power output is incidentally demanded, additional Flex Turbines come online and their respective control systems maintain the optimum load on each unit, resulting in steady voltage and frequency. Market Review 23

2.9 Aurelia

Aurelia is a micro gas turbine manufacturer based in Finland and producing the A400 engine, with a power output of 400 kWe and a rated eﬃciency of slightly over 40%, both ﬁgures at the upper end of the respective ranges for this type of devices. Figure 23 shows an artist view of the A400 package, showing the distribution of components inside the container.

Figure 23: Aurelia A400 Micro Gas Turbine [18].

In comparison with the foregoing engines, Aurelia’s technology introduces certain particular features which are partly enabled by the larger size of the engine. These are essentially:

• A more complex power cycle layout, shown in Figure 24. Even if still based on the Brayton cycle like all gas turbines, the configuration of the A400 engine incorporates not only heat recuperation downstream of the turbine but also intercoooled compression. Thus, the compression process is split in two centrifugal stages, in between of which a heat exchanger cools the air stream down, therefore reducing the overall compression work for a given pressure ratio. • As a result of this cycle configuration, the engine is arranged in two shafts. Each shaft is comprised of compressor, turbine and generator, which sets this engine apart from the usual two-shaft configuration with a free high-pressure shaft and the generator spinning in the low-pressure shaft at a lower speed.

According to the company, the cycle conﬁguration implemented in the A400 engine enables very high rated eﬃciency (over 40%) and, more importantly, exceptional part-load characteristics as compared to gas engines and micro gas turbine packages incorporating multiple units; this is shown in Figure 25.

A detailed analysis of a prototype A400 engine was presented by Aurelia and Lappenranta University of Technology ASME Turbo Expo in 2016 [20], conﬁrming the values later reported by the company’s website. According to this reference, the overall pressure ratio of the engine would be in the order of 5:1, with a 60/40 pressure ratio split between the low and high pressure compressors. Turbine inlet temperature at the high- pressure turbine would on the other hand be around 1075oC, implying the utilisation of special materials. 24 Market Review

Figure 24: IGR-2 cycle conﬁguration of the A400 engine [19].

Figure 25: Rated and part-load eﬃciency comparison as reported by Aurelia [19].

Finally, engine exhaust temperature would be lower than 200oC, thanks to the low delivery temperature of the high-pressure compressor enabled by the intercooler. Whether or not these process data correspond to the actual commercial engine is unknown to the authors of this report; nevertheless, the overall speciﬁcations declared by the company are very similar if not the same, as shown in Table6. Accordingly, the data released in [20] provides (presumably) a good picture of how the real engine would look like.

A400 Electric output [kWe] 400 Net electrical eﬃciency [%] 40.23 Nominal Heat Rate [MJ/kWh] 8.955 Exhaust Mass Flow [kg/s] 2.2 Exhaust temperature [oC] 185

NOx [ppm 15% O2] <15

CO [ppm 15% O2] <15 Noise at 10 m [dB(A)] <75

Table 6: Speciﬁcations of the A400 engine by Aurelia [21]. Market Review 25

Personal communications with the company conﬁrm that they have not shipped any commercial unit yet. However, an A400 engine was built in 2016 and there are two units currently in production, which will be shipped in February 2020 and April 2020 to Russia and Mexico. Additionally, three more units are expected to be shipped in 2020 (all to Germany).

The main markets/applications targeted by the company are Combined Heat and Power (hot water) and greenhouse gases where clean CO2 at moderate temperature is much appreciated. Syngas and hydrogen-rich fuels are also identified as niche markets [18]. 26 Market Review 9 15 < < 5 9 < < 5 9 < < 9 75 333 1300 400 < < 9 15 Depending 918 Depending 3690 14,385 3582 < < > 9 15 918 < < > Table 7: Technical specifications summary. 27 N/A < MTT Bladon Capstone Euro-k B+K Ansaldo Energia Flex Energy Aurelia MGT35 ClinX AE-T100NG AE-T100B AE-T100E GT333S GT1300S A400 EnerTwin Bladon MGT C30 C65 C200S C600S C800S C1000S C] 230 Up to 400 270 270 Depending 264 264 185 C] N/A N/A 275 309 280 280 280 280 o o [ [ [kW] 3.2 12 30[kW] 65 35 200 600 40-260 800 100 1000 105 − − [m] 0.6x1.17x0.995 N/A N/A 13.8 12.4 10.9 10.9 10.9 [m] 0.6/1.1/0.9 0.6/1.1/0.9 0.6/1.1/0.9 0.6/1.1/0.9 0.6/1.1/0.9 0.6/1.1/0.9 0.6/1.1/0.9 0.6/1.1/0.9 − − − − [MJ/kWh] N/A N/A 13.8 12.4[MJ/kWh] 10.9 N/A 10.9 N/A 10.9 N/A 10.9 N/A N/A 12.2 11.1 8.955 [%] 16/94 N/A 26[%] 29 33 28 33 26 33 30 33 30 Depending 33 33 40.2 [kg/s] N/A N/A 0.79 0.79 0.79 2.3 9.2 2.2 [kg/s] N/A N/A 0.31 0.49 1.3 4.0 5.3 6.7 − − − − − − [ppmvd] N/A N/A [ppmvd] [MJ/hr] N/A N/A 457[MJ/hr] 888 2,400 N/A 7,200 N/A 9,600 12,000 − − − − [ton] N/A N/A 2.25 2.25 2.25 6.577 21.818 25 [ton] 0.205 0.7 0.4 0.76 6 11.25 14.1 21.2 [dBA] N/A 65 72 72 72 N/A N/A N/A [dBA] 55 65 65 70 N/A N/A N/A N/A − − − − Technical specifications summary: Weight Dimmensions (W/L/H) Noise NOx Emissions Exhaust Mass Flow Exhaust Gas Temperature NOx Emissions Weight Dimmensions (W/L/H) Net Heat Rate LHV Fuel Flow HHv Exhaust Mass Flow Net Heat Rate LHV Fuel Flow HHv Electrical Power Output Electrical Efficiency Exhaust Gas Temperature Noise Electrical Power Output Electrical Efficiency Integration of Micro Gas Turbines into CSP systems 27

3 Integration of Micro Gas Turbines into CSP systems

Dish-Stirling systems have been investigated as a very eﬃcient and ﬂexible solar power generator at the small-scale during decades. Some very detailed review reports are available in the open domain, for instance [22, 23], providing an overview of the historical development of this technology and giving detailed information about system performance, capital costs, operation and maintenance.

The advantages of dish-microturbine systems, as compared to systems based on Stirling engines, is that dish-Brayton systems have a potential for longer engine lifetime and also less maintenance. They also facilitate hybrid operation (fuel backup) and run smoothly and quietly thanks to the absence of reciprocating parts. It must be acknowledged that the performance of dish-Stirling systems is superior but this is at the cost of some inherent engineering challenges like hydrogen sealing and recharging, which reduce the reliability of these systems. Table8 lists the advantages and disadvantages of dish-microturbine systems as compared against dish-Stirling and photovoltaic technology.

Photovoltaic Dish - Stirling Dish - mGT Footprint High Low Low Capital cost Low High High Electricity cost Low Medium High Technological development High Medium Low Commercial deployment High Low Low Maintenance requirements Low High Medium Maintenance cost Low High Medium Reliability High Low Medium Noise No Yes Yes

Table 8: Comparison of solar technologies [24].

A very good review of dish-Brayton technology is provided by Gavagnin in [24]. In this reference, the history of dish-Brayton systems since the first developments by Ericsson in the late XIX century is tracked in detail. It is confirmed that a large number of conceptual and experimental developments have been carried out, either for space or (mostly) ground applications and, in some case, also incorporating fossil fuel backup. None of these have reached the commercial stage though, mostly due to the lack of reliability of the solar subsystem and to the low performance of turbomachines adapted from other applications, rather than specifically developed for the project at hand.

Three projects in the last decade are worth noting. The ﬁrst one was developed by Capstone Inc. in collab- oration with Heliofocus, as presented by Dickey in [25]. The system was based on a Capstone C65 engine and, even if it was intended for dish application, it was tested at the solar tower of the Weizmann Institute in Israel. Due to some issues related to system integration, the performance of the engine was well below expectations. Another dish-Brayton system was conceptually developed by Brayton Energy under contract of the Department of Energy [26]. This system made use of two dishes with an integrated open loop of air previously compressed and stored in a cavern for Compressed Air Energy Storage (CAES). The power conversion unit is based on a 28 Integration of Micro Gas Turbines into CSP systems

recuperative cycle with reheat where the air taken from an underground compressed air storage system is first sent to the recuperator, then to a first solar receiver and across two expansion stages and, finally, to another reheat receiver followed by the final expansion down to ambient pressure. The unit incorporated the capacity to burn fossil fuel in series with the solar receiver.

The Optimised Microturbine Solar Power Generator (OMSoP) is the last noteworthy experimental project carried out worldwide. It was funded by the 7th Framework Programme of the European Commission under Grant Agreement No. 308952, and developed by a Consortium including academia and industry in Europe (University of Seville included). OMSoP designed and constructed a 5 kWe prototype based on a recuperated micro gas turbine and this system was eventually tested at the premises of ENEA in Rome, Italy. The project also looked into the economics of the technology, conﬁrming that the system could become competitive against photovoltaics in favourable locations (high direct normal irradiance) [24].

Figure 26: Demonstrator of the Solar Micro Gas Turbine developed in the OMSoP project, located in ENEA (Rome) [24]. Conclusions 29

4 Conclusions

In this report, the current commercial availability of micro gas turbine systems has been explored. This review has limited to systems which can, reportedly, be purchased and installed. Systems under development or in the pre-commercial stage have been excluded for the sake of clarity and in order to avoid conveying misleading ideas about the maturity of the technology.

Based on the information provided in the report, the following general conclusions can be drawn:

• Micro gas turbine technology is already mature from a technological standpoint. The fleet currently in operation has credited a large number of operating hours in different environments and using a variety of fuels. • The market is seeing new manufacturers coming in and delivering micro gas turbines (or packages) of different size (a few kilowatts to over a megawatt) which aim to fill a gap in terms of both output and potential end-application. • Except for very specific engine models, most OEMs rely on the same engine concept making use of radial turbomachinery and a simple recuperative Brayton engine. This implies that the rated efficiency of most engines in the marketplace is very similar for all manufacturers.

• Solar micro gas turbines have already been tested successfully in the last decade, even if further development is still needed to raise performance and increase reliability. Fortunately, it looks like some of the latest developments of conventional engines running on fossil fuels can be incorporated into their solar counterparts (air bearings, more eﬃcient turbomachinery, high-speed generators, additive manufacturing), thus accelerating the maturation process of the technology.

As it is always the case, a large effort is still needed to develop business cases where micro gas turbine yield clear competitive advantages over other small-scale power generation technologies. This is not because there are not many of these but because of the fierce competition between different power generation technologies and the short-term focus of many investors. Micro gas turbines are reliable, flexible, quiet and require moderate maintenance. But most importantly, they produce virtually no NOx and particle matters and a moderate amount of Carbon Dioxide, which is a pressing concern in urban areas. The shift towards decentralised power generation and, with it, the growing number of prosumers producing (and selling) their own power at home will expectedly help create the conditions for the mass deployment of micro gas turbine engines. 30 Annex

Annex 1 - MTT Technology

Combined Heat and Power (CHP)

The objective of Combined Heat Power (CHP) is to generate electric power at locations where also a heat demand is present for either domestic or industrial heating. This way, CHP saves energy as the heat and transportation losses by large electric power stations are avoided.

Heat Exhaust Recuperator

EnerTwin micro-CHP system Generator

Fuel An efficient high-speed permanent magnet generator converts the mechanical power from the micro turbine into electric power. Combustor The generator is fully integrated in the micro turbine rotor system,

Air avoiding costs and losses of additional bearings and couplings.

Heat exchanger

Compressor High speed Turbine The efficient heat exchanger transfers heat from the micro turbine generator exhaust to the micro-CHP heating system circuits. Recuperated micro turbine in a CHP configuration Operation profile Micro gas turbines The EnerTwin has a rapid (< 2mins) start-up capability. Moreover, The EnerTwin CHP system generates electric power using a 4 kW power can be modulated down to about 30% without significant micro turbine. Gas turbines are known for their high power to weight loss of efficiency. ratio and low maintenance costs. Using off-the-shelf turbocharger technology leads to low production costs. The turbomachinery Monitoring and control components are optimized for the turbogenerator application. The EnerTwin micro-CHP system has an on-line control and monitor- Driving a high-speed generator at 240,000 rpm, the EnerTwin micro ing capability for remote operation, Virtual Power Plant and smart CHP system has a net electric efficiency of >16% (20% shaft power grid applications. This offers excellent installation and operation efficiency on the turbogenerator). The limited turbo-machinery cost flexibility in cascade and other configurations. and their very low maintenance requirements offer great potential for cost effective micro-CHP systems. The generator is coupled to Noise the micro turbine by a unique in-house developed compact rotor concept. Due to the recuperator, part load efficiency can be kept Micro turbines emit only high frequency noise that can effectively close to the design point maximum. be damped. Compared to alternative concepts, the EnerTwin has very low noise emissions. Recuperator Benefits for the environment The recuperator is an advanced heat exchanger recovering exhaust heat into the gas turbine working cycle, saving almost 50% of fuel The EnerTwin micro-CHP system offers a substantial contribution compared to a system without a recuperator and providing a sub- to CO2 emission reduction. With MTT’s clean low-NOx combustor, stantial increase in efficiency. other exhaust gas emissions levels are minimal.

More information: www.enertwin.com Specifications

Max. Min.

Performance at ISA * Net electric power 3.2 1.0 kW Net thermal power 15,6 ** 6.0 kW

Power to heat ratio at max power 20 %

Net grid output efficiency (electrical) 16 %

Total efficiency > 94 ** %

iaw EcoDesign (EU 813/2013) > 110 %

Rotor speed 240,000 180,000 rpm

Fuel flow (H gas, 38.5 MJ/nm3) 1.87 0.84 nm3/h

Fuel Natural gas H, E and L

Operating conditions Ambient air pressure 0.8 .. 1.1 bar Inlet air temperature -20 .. 40 0C

System room temperature 5 .. 40 0C

Heating system Water flow rate 3 .. 21 l/min Water return temperature 5 .. 60 0C

Water out/buffer vessel temperature 5 .. 80 0C

Water pressure 0,7 .. 4 bar

Maintenance Service interval > 5000 hours

Emissions NOx < 27 ppm @ 15% O2

CO < 50 ppm @ 15% O2

CO2 savings 3 – 6 *** tons/year Noise 55 dB(A) 1m

Control OpenTherm heating control interface RS-485 Modbus remote control interface

0-10V building management system interface

MTT proprietary cascade operation control interface

Installation Dimensions (h x w x d) 995 x 600 x 1170 mm Weight (empty/with water/oil) 205 / 215 kg

Natural gas connector ¾”

Water connector ¾”

Inlet air and flue gas pipes DN 100 (parallel)

Grid connection 230 / 50 VAC / Hz

* ISA conditions are 15 0C and 1.01325 bar dry air. ** Depending on heating system operating conditions such as water return temperature. *** Depending on operating profile.

MTT Micro Turbine Technology

Eindhoven T +31 (0)88 688 0010 E-mail: [email protected]

The Netherlands F +31 (0)88 688 0050 Internet: www.mtt-eu.com

www.enertwin.com Annex 31

Annex 2 - Capstone C30 Microturbine High-pressure Natural Gas

Achieve ultra-low emissions and reliable electrical generation from natural gas.

Ultra-low emissions One moving part – minimal maintenance and downtime Patented air bearings – no lubricating oil or coolant Integrated utility synchronization – no external switchgear(1) Compact modular design allows for easy, low-cost installation Multiple units easily combined – act as single generating source Remote monitoring and diagnostic capabilities Proven technology with tens of millions of operating hours Various Factory Protection Plans available C30 Microturbine

Electrical Performance(2)

Electrical Power Output 30 kW Voltage 400/480 VAC Electrical Service 3-Phase, 4 Wire Wye Frequency 50/60 Hz Electrical Efficiency LHV 26%

Fuel/Engine Characteristics(2)

Natural Gas HHV 30.7– 47.5 MJ/m3 (825 –1,275 BTU/scf) Inlet Pressure 379– 413 kPa gauge (55– 60 psig) Fuel Flow HHV 457 MJ/hr (433,000 BTU/hr) Net Heat Rate LHV 13.8 MJ/kWh (13,100 BTU/kWh)

Exhaust Characteristics(2)

3 NOx Emissions @ 15% O2 < 9 ppmvd (18 mg/m ) Exhaust Mass Flow 0.31 kg/s (0.69 lbm/s) Exhaust Gas Temperature 275°C (530°F) Dimensions & Weight(3)

Width x Depth x Height(4) 0.76 x 1.52 x 1.79 m (30 x 60 x 71 in) Weight - Grid Connect Model 405 kg (891 lb) Weight - Dual Mode Model 578 kg (1,271 lb)

Reliable power when and where you need it. Clean and simple. Minimum Clearance Requirements(5)

Horizontal Clearance Left & Right 0.76 m (30 in) Front 0.93 m (37 in) Rear 0.90 m (35 in)

Acoustic Emissions

Nominal at Full Power at 10 m (33 ft) 65 dBA

Certifications

• UL 2200 Listed • CE Certified

C30 Engine Components

Exhaust Outlet Recuperator

Compressor Generator Fuel Injector

Combustion Chamber Air Bearings

Turbine Recuperator Housing

(1) Some utilities may require additional equipment for grid interconnectivity (2) Nominal full power performance at ISO conditions: 15˚C (59˚F), 14.696 psia, 60% RH (3) Approximate dimensions and weights (4) Height dimensions are to the roofline. Exhaust stack extends approximately 170 mm (7 in) above the roofline (5) Clearance requirements may increase due to local code considerations Specifications are not warranted and are subject to change without notice.

©2019 Capstone Turbine Corporation. P0819 C30 HP Natural Gas Data Sheet CAP135 | Capstone P/N 331140A Call us (toll free) 1.866.422.7786 | Tel: 1.818.734.5300 | www.capstoneturbine.com www.capstoneturbine.com C65 Microturbine High-pressure Natural Gas

Achieve ultra-low emissions and reliable electrical generation from natural gas.