**4. Conclusions**

purely on merits and benefits. Should VES prove technically efficient and cost-effective in mitigating the problems of VRES, policy makers will face significant challenges to design adequate regulatory instruments to incentivise the improvement of the building stock for VES proliferation. The pricing methods and, therefore, the remuneration of DSOs in the presence of demand flexibility is currently a hotly contested topic in the current regulatory debate, but its financial benefits for building owners are expected to be too small to mobilise capital investments. Converting power to gas, on the other hand, effectively shifts the massive decentralised energy generation paradigm from the electricity grid to the gas grid, where it is currently very limited. Policy makers should revisit existing instruments, such as feed-in tariffs for electricity, in light of this shift and investigate whether they should incentivise green electricity generation, carbon-free gas generation or both. Another market/policy side effect of conversion technologies is that they close the loop between the electricity and the natural gas grids and markets. Gas to electricity conversion has long been available, gas-fired plants

The emerging ability to purchase electricity and transform it to gas to be sold on the market enables two-way transactions. The relative price of energy carriers (and their volatilities), the conversion efficiency and potential supply security issues are critical factors on how conversion outputs can be used in the energy markets; the structure of the respective markets needs to be examined to verify that they can enforce prevailing regulations given this new capability. Securing funding for policy implementation is another major aspect. There is a stark contrast between the investment structure for grid expansion and storage/conversion system deployment in the grid. The former are financed using funds (indirectly through electricity bills) mostly defined by regulatory bodies since electricity grids provide public utility service. The latter would likely be deployed by private companies through market mechanisms and therefore for profit. Deferred investments on public money cannot directly fund private ven-

To overcome such issues, PLANET will investigate alternative market models/structures as well as regulatory policies for maximising social welfare. It will design and propose a coherent reform recommendation package touching upon both the energy market structure and the necessary regulatory policy instruments to achieve a decarbonised energy system by 2050. The objective of this package will focus on the market integration of VRES generation and storage/conversion technology under fair terms with the ultimate goal to support achievement of the Energy Union targets. This activity will be complemented by an investigation of extensions to market roles and business models that will be required to facilitate the com-

The project is at a beginning state, and this means that the consortium is actually working on the elaboration of the potential business cases for the deployment of energy conversion/storage technologies in the European grids, on the investigation of necessary business roles for the successful proliferation of technologies and in identification of PLANET system require-

tures without skewing competition and violating EU legislation.

mercial exploitation of the conversion/technology.

ments as an initial step for implementation.

**3. Results and outlook**

are widespread.

140 Smart Microgrids

During the project, PLANET will be also in charge to move the application of the decision support system from a specific network topology towards a more generic network topology. Flexibility in the instantiation of network topologies, selection of conversion and storage options as well as other available infrastructure will ensure the applicability of the tool to very diverse environments and situations that reflect the particularities of grids across Europe. In terms of socio-economics, the ultimate aim of the DSS deployment in real-life scenarios brings opportunities for the further integration of RES-E generation on the electricity grid as well as feeding the gas and heat networks from their oversupply. Long-term side effects of this may include the cost reduction of energy (regardless of carrier), increased security of supply since all generation will be local as well as a significant improvement of social welfare as a direct consequence of these.

Renewable energy sources hold the promise to decarbonise the entire system, including the electricity, heating, gas and transport systems with the use of appropriate conversion and storage technologies. Optimal use of the latter becomes critical in order to achieve the ambitious EU policy objectives of the Energy Union. The PLANET solution will comprise a valuable tool in the arsenal of policy makers and network planners for the coordinated design of networks and compatible policy instruments for the stimulation of the most appropriate technology deployments that can achieve the aforementioned objectives.

Since the annual expected curtailment of solar and onshore wind sources is expected to grow significantly from 29 TWh of electricity in 2030 to 217 TWh curtailed in 2050, the distribution grid should be modified to operate with a higher degree of flexibility. Flexibility sources are required not only for balancing demand and supply, but also for enhancing stability and reliability through voltage/frequency regulation and other ancillary services. Key requirements to achieve proper grid operation include smarter energy grids and enhanced flexibility provided by a wide range of technologies and solutions, such as energy storage, energy conversion and network interconnection, along with demand response.

**References**

Union. 2012. DOI: 10.2833/10759

Düsseldorf, Germany; 2016

Document.pdf [Accessed: April 25, 2018]

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[3] Weiss R et al. Optimal scheduling of a P2G plant in dynamic power, regulation and gas markets. In: 10th International Renewable Energy Storage Conference (IRES 2016);

[4] CEN-CENELEC-ETSI Smart Grid Coordination Group (SG-CG). CEN-CENELEC-ETSI Smart Grid Coordination Group—Framework Document. November 2012. Available from: ftp://ftp.cen.eu/EN/EuropeanStandardization/HotTopics/SmartGrids/Framework%20

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Conference (ENERGYCON); Leuven, Belgium; 2016

These solutions will permit a lower use of curtailments, increasing the benefits of RES on the environment. The impact of PLANET outcomes of market transformation will be multifold: initially, the deployment of conversion and storage solutions can reduce the impact of RES generation unpredictability of existing wholesale markets and can relax the necessity for real-time markets giving time to policy makers and the energy system to respond to the new grid challenges. Furthermore, PLANET will provide solutions to encourage and stimulate self-consumption of locally produced electricity in order to isolate intermittency before it becomes a grid problem through a novel human-centric virtual energy storage system that transforms conventional heating/cooling systems into flexible energy resources that respond to local generation or market/grid conditions. The same solution can also become an enabler for the active participation of buildings in energy markets through energy cost optimization or even service provision for grid or energy balancing.

Finally, PLANET facilitates the absorption of electricity exceeding demand from intermittent RES through conversion to alternative energy carriers, such as natural gas or heat/cold, and injection in the respective distribution networks for short-term or even seasonal storage. The PLANET tools enable market actors and regulators to optimally plan, install, commission and dispatch energy conversion units along the electricity distribution grid in order to ensure maximum absorption of excess RES generation and immediate consumption or conversion into alternative carriers.
