One of the main keys – and possibly THE main key - for a climate neutral Europe are technologies for the storage of renewable energies over longer time at an attractive cost and with an acceptable environmental impact. Renewable electricity and heat can be produced cheaply today and short-term storage solutions for evening out mismatches between production and demand are available at low cost. However, technologies for storing renewables for longer time-spans of months or seasons are scarce and costly and thus not widely used yet. Therefore, the REVEAL project develops a game-changing and unique solution to this challenge, using the conversion of aluminium oxide into aluminium metal (Power-to-Al) in an environmentally friendly way to store renewable energy and produce a "renewable fuel" in the form of aluminium. This ground-breaking technical solution will enable to store large amounts of energy with an unmatched energy storage density of over 15 MWh/m3 at an attractively low cost, without losses and with lower environmental impact than today's solutions. For example: cost for converting electricity into a seasonally storable form will be less than 7 ct/kWh, and the easy transportable energy vector can be used for heat and electricity or hydrogen production wherever and whenever needed, in scalable units from few kW to the MW range. Thus, this breakthrough high-density storage solution will enable to cover energy demands flexibly also in small units and off-grid situations, and – above all – in seasons where the demand is much higher than local renewable production could possibly cover. Therefore, with the emerging technology of carbon free reduction of aluminium oxide to aluminium in combination with the release of energy from an aluminium storage vector this project will provide one of the missing pieces of the puzzle for a climate neutral Europe.

Heat exchangers (HXs) are the most critical components of a geothermal power plant specially for organic Rankine cycle (ORC) based plant and the capital cost of heat exchanger accounts for a large proportion of ORC, and even reaches about 86% when air cooled condenser is used. Direct heat exchangers (e.g. geothermal brine to district heating) and ORC HXs such as superheater, preheater, evaporator are in direct contact with the geothermal brine, causing scaling and corrosion at different extent based on the thermophysical condition and chemical composition of the geofluid. To handle corrosion, expensive materials are recommended, but due to lower thermal conductivity and degraded performance over time compel to increases the size of the HXs. Hence, improvements in the antiscaling and anticorrosion properties as well as heat transfer performance of the HX material will lead to smaller, more efficient and less costly systems. GeoHex will rely on the use low cost carbon steel as base material for HX. Through modifying the surface with nano porous coating and controlling the surface chemistry (along with the surface structure), GeoHex will significantly improve the heat transfer performance of single phase and phase change heat transfer process respectively. To attribute the antiscaling and anticorrosion properties, the brine side of the surface will be Ni-P/Ni-P-PTFE duplex coated by electroless method. GeoHex will significantly reduce the cost of ORC plant while lowering the environmental impact. The technology concept can be exploited to build cost efficient HXs for solar thermal energy, heat pumps, absorption chiller, geothermal energy-based district heating cooling system. GeoHex enabled ORC plant, heat pumps and absorption chiller can be used for waste heat recovery application. Hence, GeoHex will significantly contribute to enhance the energy security, decarbonise the economy, establish the EU leadership on renewables.

The main objective of MEET is to capitalize on the exploitation of the widest range of fluid temperature in EGS (Enhanced geothermal systems) plants and abandoned oil wells. The aim is to demonstrate the lower cost of small-scale production of electricity and heat in wider areas with various geological environments, in order to support a large increase of geothermal-based production sites in Europe in a near future. In order to boost the market penetration of geothermal power in Europe, MEET project main goal is to demonstrate the viability and sustainability of EGS with electric and thermal power generation in all kinds of geological settings with four main types of rocks: granitic (igneous intrusive), volcanic, sedimentary and metamorphic with various degrees of tectonic overprint by faulting and folding. MEET brings together 16 European partners: Industrials, small and medium enterprises, research institutes and universities, but also several geothermal demonstration sites in Europe located in the various geological environments described above. The project aims at the optimization of the reservoir productivity and stimulation techniques, taking advantage of the existing infrastructures, the understanding of the various geological contexts, necessary to transfer the current known EGS technology to other typical basement rock situations in Europe, the demonstration and optimization of electric and thermal power generation in different geological settings. The assessment of the technical, economic and environmental feasibility of EGS is an integral part of the project, as well as the mapping of the main promising European sites where EGS can or should be implemented in a near future. Thus, MEET will provide a roadmap of next promising sites where demonstrated EGS solutions could be replicated in a near future for electricity and heat production with an evaluation of the technology and its economic feasibility and environmental positive impacts.

Future energy systems will face serious operational challenges with system reliability due to fluctuations caused by progressive integration of solar and wind power. Reliable and sustainable energy sources that can be utilized in large parts of Europe and that are able to balance these fluctuations are needed. Geothermal energy has the potential to become an excellent source for both base and flexible energy demands, providing much lower environmental footprint than both fossil and biomass fuels, as well as much less risks and societal resistance than nuclear power. There are however some techno-economic challenges which needs to be addressed to facilitate highly flexible operation of geothermal power plants. In GeoSmart, we propose to combine thermal energy storages with flexible ORC solutions to provide a highly flexible operational capability of a geothermal installation. During periods with low demand, energy will be stored in the storage to be released at a later stage when the demand is higher. As this approach does not influence the flow condition at the wellhead, critical infrastructures will be unaffected under variable energy generation. To improve efficiency, we also propose a hybrid cooling system for the ORC plant to prevent efficiency degradation due to seasonal variations. Efficiency will be further improved by larger power plant heat extraction enabled due to a scaling reduction system consisting of specially design retention tank, heat exchanger, and recombining with extracted gases. The scaling reduction system has the potential to almost double power production of many medium enthalpy geothermal plants. Overall, GeoSmart technologies will drastically reduce geothermal energy costs, making it cost competitive with its fossil fuel-based counterparts. To bring GeoSmart technology to TRL7/8, we will demonstrate it in a medium/high (Turkey) and low (Belgium) temperature fields to show its potential benefits and applicability in different settings.