Bio-FlexGen will develop an optimised combination of biomass and green hydrogen for combined heat and power plants (CHP). It provides firm power and complements renewable sources such as wind and sun. Bio-FlexGen will also increase the efficiency and flexibility of renewable CHP plants, playing a major role in the energy system integration.
Due to a higher efficiency, three times more power can be generated from biomass for the same heat load. Starting and operating on 100% green hydrogen, the CHP-plant can quickly achieve full load. To meet fluctuations in seasonal energy demands and prices, there will be a variant of the plant. It adapts to long periods of low electricity prices or heat demand by producing climate-positive green hydrogen.
The Bio-FlexGen approach is highly energy efficient and it will bring down costs. Engineers will develop a power plant with a unique combination of gasification and gas turbine technology that allows the plant to use hydrogen for fast dispatch and biomass for low operating costs over time. Green hydrogen is an energy carrier to stabilise electricity grids. It is generated through solar or wind energy.
Unlike existing thermal power stations, the Bio-FlexGen power plant will generate electricity and heat from biomass much more efficiently than traditional methods. The Bio-FlexGen power plant will operate with up to 100% green hydrogen, thus enabling renewable energy sources to be better harnessed. Bio-FlexGen researchers will, among others, develop a novel combustion chamber. This will enable the gas turbine combustion system to adjust to changing compositions of bio-syngas and the hydrogen.
Bio-FlexGen: A novel CHP plant (system) with hourly, daily and seasonal flexibility for a modern grid based on:
- H2 production from biomass and the flexibility to switch from CHP mode in the winter season to H2 production mode when needed.
- Abundant O2 from electrolysis for the biomass gasification system with H2 production, achieving highly-efficient integration of solar and wind energy in the system.
The Bio-FlexGen challenges:
Renewable energies from solar and wind fluctuate with the weather. Thus, there are major challenges for combined heat and power plants from renewables:
Scalable CHP solutions are needed to provide:
1) Security of supply
2.) Cost-effective plants and affordable energy
3.) Flexible and robust energy for the total energy mix
The Bio-FlexGen solutions:
The Bio-FlexGen project will develop a flexible and highly efficient renewable energy CHP technology with 25 MW capacity. This plant, with on-demand digital optimisation, can flexibly generate four different products for the broader energy system or industrial applications: electricity, heat, hydrogen and/or CO2.
Biopower is provided with an extremely high efficiency (55%), plus a wide range (25%-100%) of loads. This is achieved by converting variable supplies of different low-cost biomass residues. Fast-dispatch peak power is provided off-season from renewable hydrogen. The plant can be designed to provide only CHP from biomass with fast-dispatch capability with hydrogen fuel. It can also be designed to provide all four products, depending on the particular application and its requirements.
The project will also look at how Bio-FlexGen can adapt to the energy system. This includes the economic viability of the CHP solution and the application of the technology for energy-extensive industry and the energy grid.
Combination of renewable energy sources
Bio-FlexGen will flexibly exploit the use of residual, non-food biomass. The gasification system is feedstock-flexible and scalable across various EU-applications. Moreover, it adjusts to biomass seasonal availability. Two types of biomass are targeted:
a) Forest residues – including pellets, wood chips and forest residues. These prevail in northern and central EU countries.
b) Wood waste – initial focus on low quality sorted wood waste. In the long run, Bio-FlexGen focuses on blends of agricultural residues. These are more abundant in southern Europe.
2. Renewable hydrogen
The plant will use renewable hydrogen for combustion in a gas turbine during fast-response, hydrogen-firing mode. The hydrogen will be generated through electrolysis, driven with electricity from wind or solar energy, or generated from the Bio-FlexGen plant itself”.
Technology companies / Associations
Bio-FlexGen has two major goals – and novel approaches:
1. Utmost flexibility of CHP plants:
Our engineers aim at developing a combined heat and power plant (CHP) system with hourly, daily and seasonal flexibility. Hydrogen production from biomass will be the key element here. This includes the flexibility to switch from CHP mode in winter to hydrogen production when needed. This will be achieved by increasing the flexibility of the biomass-fired TopCycle (BTC) technology. Accordingly, the plant will be called CHP BTC.
2.Highly efficient integration of renewable energies:
The system will efficiently integrate solar and wind energy as abundant oxygen from electrolysis will be fed into the biomass gasification system that produces the hydrogen.
Plant and system optimisation and Digital&Market optimisation
The operation mode and set points of the plant will be designed to hourly/daily/seasonal load, biomass and renewable hydrogen availability as well as plant operation status. This will make the plant agile on market demand and prices. This digital optimisation will involve collecting the following data:
- Type of end users energy system (power grid, district heating or other H2 or C02 networks) and industry
- Market data: online/and or estimated/statistical data of the existing market prices (fuel, electricity, heat, H2, CO2)
- Demand fluctuation: data on hourly/daily seasonal load variation
- Plant status: operation data displaying the status of the different components of the “CHP plant”.
The Bio-FlexGen engineers aim at increasing Digital&Market optimisation from current TRL 5 to TRL 8.
To optimise and validate the flexible operation modes of Bio-FlexGen, there will be three use cases:
Use case 1: SWEDEN: District Heating – Tekniska Verken
The business use case in Sweden investigates the application of the new CHP technology in the production portfolio of district heating companies (DHC) from both technical and economical perspectives. This use case will specifically answer four questions:
- Which electricity markets and grid service markets are relevant for DHC with CHP BTC plants?
- How can DHC with CHP BTC plants schedule and operate their existing production and heat storage units to participate in these markets?
- How do CHP BTC plants affect the income of the DHC by participating in different markets?
- Will it be profitable for DHC to invest in CHP BTC plants instead of investing in heat-only units or conventional CHPs?
Use case 2: SPAIN – Cement Industry – CEMEX
Due to its high thermal and electric energy intensity, cement production is a perfect fit for CHP applications. Heat from CHPs could be used to preheat the raw material feed before entering the kiln.
Actual status quo:
State-of-the art kilns have up to six pre-heater stages. They use the off-heat from the main kiln to preheat the raw material feed. Additional pre-heater stages are considered to be one of the most effective ways to reduce the thermal energy intensity of cement production in the future. However, an optimised use of the off-heat stream complicates the process and is very costly.
The Bio-FlexGen approach:
CHP could generate the electricity required for operating crushing, grinding and conveyor belt installations. At the same time, obtained heat streams of around 300 °C can be used to heat the raw material feed. Thus, much less fuel will be used.
Use case 3: Spain – Mining & chemical industry – SULQUISA
Sulquisa is one of the leaders in the production of anhydrous sodium sulphate of natural origin. It obtains this by exploiting deposits of sodium salts from mining in Madrid.
SULQUISA has three identical lines of sodium sulphate production. Since the production process is intensive in both thermal and electrical energy, it has three cogeneration lines. These are formed by a gas turbine and a recovery boiler. With the current demand for steam from the three plants, two of the three available turbines are in operation, one of them with an afterburner. The turbine not in production is left as a back-up or replacement situation to cover incidents and maintenance of the other two. The Biopower BTC could potentially replace one of the existing CHP units.
1 : Flexible oxygen/air-blown hybrid fluidised bed (HFB) gasifier.
Current TRL level: 2
The hybrid fluidised bed gasifier is a novel concept to manage the challenge of biomass gasification at very high pressures. The technology concept and design have been created for full-scale plants based on the experience of Bio-FlexGen engineers from atmospheric and pressurised gasifiers. These include a 70kW, 40 bar and bubbling fluidised bed (BFB) rig at KTH and a 500 kW plasma waste gasifier in China. And the 18 MW 18 bar circulating fluidised bed (CFB) gasifier at Värnamo. The EUCANwin project (provides RTD input) will develop and operate a 40 bar HFB gasifier in air-blown mode, with a thermal power at relevant scale (TRL 5, i.e. over 500 kW).
Target TRL level: 5
Within the Bio-FlexGen project, the EUCANwin gasifier will be developed, adapted and operated as an oxygen-blown HFB gasifier. It will be used to validate the technology in a relevant environment (TRL5). This means 10-25 bar pressure, velocities, temperatures, representative geometry and interfaces. Furthermore, the ability to operate both on air-blown and oxygen-blown gasifiers with the same equipment will be validated. The same goes for the use of high ash woody feedstocks, including blends of forest residues and sorted wood waste.
2 : Flexible gas turbine combustion system for 100% H2 and 100% syngas firing
Current TRL-level: 3
Before Bio-FlexGen started in September 2021, the project partner PHOENIX had performed successful tests: The current syngas and natural gas burner in the PHOENIX combustion system was tested in atmospheric conditions with hydrogen. Very low emissions, stable operation and flashback safety were observed.
Target TRL-level: 4
The targeted TRL level will be above TRL 4 for hydrogen combustion and will be very close to TRL 5. The burner will be developed and tested in a full scale, modular combustion type. The pressure will be up to 10 bar with industrially relevant fuels, flows and temperature. The main gap to “relevant environment” is the validation pressure of around 10 bar compared to full engine pressure of around 40 bar. This affects heat transfer, energy densitiy and thermal acoustics. From a flashback and reactivity perspective, hydrogen at 1-7 bar is probably more challenging than 7-40 bar.
There is yet another innovation within the Bio-FlexGen project: The catalytic steam reforming.
The Bio-FlexGen engineers will convert tar and lighter hydrocarbons in the dusty syngas to H2 and CO – and this will be brought from TRL2 to TRL 3!
The Bio-FlexGen solution: Combination of renewable energy sources and cutting-edge technology
Bioenergy is currently the largest source of renewable energy in the world. But wind, solar and geothermal are fast-growing alternatives. The role of wind and solar in electricity production will increase more rapidly than other renewable sources. However, bioenergy will continue to be a primary source for heating and transport fuels for decades to come. It has a significant, sustainable potential without competing for food production.
According to Bioenergy Europe, a conservative estimate of the technical, cost-efficient and sustainable potential of biomass in the EU from agriculture, forestry and the waste sector totals 17 EJ by 2050. This includes up to 60 % from agricultural residues. Today, 6 EJ per year is used, with 70% woody biomass, 20 % agricultural and 11 % from waste, including waste wood.
Green hydrogen, produced from low-cost wind and solar electricity, is seen by many as a key enabler for grid stability and the decarbonisation of difficult sectors. Oxygen is co-produced with the hydrogen and is also a useful product for industry or power plants. As hydrogen can be stored and transported, this allows for a greater output from variable renewables to be integrated in the energy system. Consumers of hydrogen are those sectors which are hard to de-carbonise such as long-distance transport, steel/cement production, and the production of peak power without CO2 emissions.
The solution: Flexible CHP technology
Bio-FlexGen will use green hydrogen and biomass and develop a novel, flexible CHP technology. This will meet the demand for a higher fuel, product and load flexibility. What is more, it will feature a significantly higher electrical efficiency and power output – with a strong reliability and robustness.
Bio-FlexGen engineers will achieve this through a unique combination of gasification and gas turbine technology. It allows the CHP plant to use hydrogen for fast dispatch and biomass for low operating costs. Due to this high efficiency, three times more power can be generated from biomass for the same heat load. The plant quickly achieves full load by starting and operating on 100% hydrogen. It will also be able to mitigate fluctuations in seasonal demand and prices: A variant of the plant can provide climate-positive hydrogen production during long periods of low electricity prices or heat demand.
To develop and validate a reliable, cost-efficient, secure and flexible CHP system. This will be based on the combination of highly efficient use of local biomass with renewable hydrogen production. The CHP system is adaptive and scalable to variations in energy demand and energy supply.
Bio-FlexGen has therefore set the following objectives which will be reached at the end of the project in August 2024:
- To achieve up to 55% electrical efficiency from biomass and increased flexibility, Bio-FlexGen will develop and validate (TRL5) a hybrid fluidised bed (HFB) gasification system. This is a novel reactor concept. It allows for both air and oxygen firing in the same reactor with various biomass streams. This enables the Bio-FlexGen plant to be seasonally flexible. Furthermore, it can choose between electricity and hydrogen production from biomass. It will also be able to adapt to variations of biomass availability as feedstock.
- To develop and validate (TRL4) a prototype combustion system that can use 100% renewable fuels, including 100% hydrogen, up to full load, along with switch from hydrogen-firing to bio-syngas firing. This will be compliant with emission reduction targets and with high stability. Therefore, the gas turbine will dispatch CO2-free power quickly when the plant is not providing heat and power from biomass. This allows for optimised economic performance, i.e. capture price peaks with high quality fuels.
- To address the integration and adaptability of Bio-FlexGen to the energy system as well as the economic viability for three user cases. Therefore, the economic feasibility will be quantified for different boundary conditions and future scenarios. A system-wide impact assessment will be performed to consider the benefit for the overall electricity system and heat networks.
- To address sustainability studies of the full supply chain for implementing the technologies developed in Bio-FlexGen. This includes their respective environmental and social impact: The assessment of the project technology. And, most importantly: Bio-FlexGen will measure and assess the social impact of the project in local communities. Making the Green Deal real – and responsibly so!
Policy makers / regulators
Flexible, green, and cost-efficient CHP plants – with due respect for society!
Security of primary energy and electricity is crucial for a well-functioning society. Solar and wind power strengthen security of supply because they decrease the dependency on fossil fuels. Yet, the integration of these intermittent sources is a major challenge for the stable operation of the electricity grid. More flexible, renewable energy from combined heat and power plants (CHP) will help integrate a higher degree of variable renewable energy (VRE). This will improve grid stability. Flexible CHP operation will balance intermittent power in some cases, and a high electrical output from CHP provides grid inertia in other cases.
Bioenergy from sustainable biomass sources, waste streams for example, is a renewable and local fuel that also decreases reliance on imports and increases security of supply.
However, it is challenged by varying availability. There are two ways to address this:
1. Bio CHP plants of the future need to be fuel-flexible.
2. CHP plants need to be highly efficient to increase the amount of biopower per unit when biomass is scarce.
Conventional bio-CHPs are not currently cost-effective when they don’t supply heat. Their electrical efficiency stands between 25-35% depending on scale and fuel. This leads to low system impact when providing renewable energy, say, at off-season periods for district heat applications. In addition, such plants are not designed for fast-start capability compared to, say, gas turbines. Nor are they constructed for fast load changes or for efficient market operations during shorter periods of high electricity prices. The challenge therefore is to make bio-CHP systems more electrically efficient, to be able to meet changes in demand and to do all this in a cost-efficient manner.
Bio-FlexGen will draw on variable renewable sources and biomass. It will bring about greater flexibility in fuel, products and loads. It will also deliver significantly higher electrical efficiency and output along with high reliability and robustness. This will be achieved by combining gasification and gas turbine technology, which will allow the plant to use hydrogen for fast dispatch and biomas for low operating costs over time. Due to the high efficiency, three times more power can be generated from biomass for the same heat load, and the plant can quickly achieve full load by starting and operating on 100% hydrogen. To meet fluctuations in seasonal demand and prices, a variant of the plant can provide climate-positive hydrogen production during long periods of low electricity prices or heat demand.
With due respect for society
And, most importantly: Bio-FlexGen will measure and assess the social impact of the project in local communities . Making the Green Deal real – and very responsibly so!