First European conference on polygeneration: community managed hyper-efficient renewable energy systems

The European Union has adopted an energy policy which doesn’t simply aim to boost competitiveness and secure energy supply but also aspires to increase energy efficiency, to save energy and promote climate-friendly energy sources. One way to combine these demands in a single system is by creating 'polygeneration' concepts.

The term means an energy supply system which delivers more than one form of energy to communities, in a very efficient way: electricity, heating and cooling can be delivered from a single plant with production fully integrated and coupled to prevent losses. Polygeneration can involve combined co-generation (power and heat) or tri-generation (power, heat and cold) plants often integratd with district heating, and all this powered by renewables (mostly biomass, sometimes in combination with solar or wind). Such polygeneration systems should be designed and controlled with a view to optimizing all relevant interactions between supply and demand. Their main benefit is in maximising the overall efficiency of the integrated system near the point of use.

Polygeneration combined with efficient district heating and cooling may provide added benefits to a larger community and involves smart interventions in the urban ecology. Secondary benefits may include improved reliability of the supply and distribution networks, arising from better interaction between producers and distributors.

Europe's first conference on the subject will take place in Tarragona, Spain, from October 16th to the 17th. The conference is organised in the frame of the CONCERTO project aimed at creating 'Energy networks in sustainable cities' - POLYCITY - to share the knowledge of the different CONCERTO projects on polygeneration updating on the latest development on the use of key technologies.

There are three POLYCITY projects under development: one in Germany's Scharnhauser Park in Ostfildern, a former military area where 10,000 people will be living in a hyper-efficient integrated community; one in Cerdanyola del Vallès, a development area planned for 50.000 inhabitants north of Barcelona, and the Arquata in Turin, a labour district which will be restored with regard to ecological criteria and hyper-efficient energy supplies. Each project is embedded in a network of regional partners and further 'observer communities'. This will guarantee a sustainable development of the projects and an effective adoption of the results by other communities.

A closer look at these projects reveals that polygeneration is more than a concept to boost the energy efficiency of renewable power systems: their decentralised, localized and distributed nature means that polygeneration involves local resource control and the active participation of communities, instead of individual consumers:
energy :: sustainability ::biomass :: bioenergy :: biofuels :: efficiency :: district heating :: district cooling :: cogeneneration :: trigeneration :: polygeneration ::

Scharnhauser Park
The most important measure in the Scharnhauser Park is the optimisation of a new biomass plant (combined heat and power). One of the targets is to use the residual heat to cool the office buildings in summer. Furthermore, all buildings will be equipped with optimal heat insulation to minimise heat loss in winter. It is planned to realise all measures between 2005 and 2010. This polygeneration system comes down to efficient trigeneration.

The whole project is designed as an exemplary ecological community development, where low energy building standards are prescribed for all plots and a wood fired ORC co-generation plant will deliver electricity and heating energy. Combining work places, residential areas and green park sections leads to an integrated living and transportation concept with high comfort and low energy consumption. The whole investment volume of the project with 480,700 m² built floor area is €1.5 million.

In the frame of the POLYCITY project a total of 178,000 m² of residential and commercial buildings will be constructed until 2009 and supplied by a 1 MWel and 6.3 MWth biomass co-generation unit, a 200 m² solar thermal plant and 70 kW of building integrated photovoltaics.

The first sections of the area have been developed in the last years and 2500 people are living on the site with about half of the work places already created (1200). €250 million have already been spent on public infrastructure (schools, kindergarden) and further €700 million Euros will be invested on the site. The complete site is owned and managed by the Town of Ostfildern (70%) and the Hofkammer Baden-Württemberg (30%), which have prescribed low energy building standards for all new constructions and obligatory connection to the heating network of the biomass co-generation plant.

The inclusion of cold production via the biomass heating network has been initiated through the POLYCITY proposal and signifies a major innovation.

Cerdanyola del Vallès
Eco-buildings for residential, industrial and service purposes will be established on a common basis of innovative sustainable construction.

Several innovative measures will be taken in the supply side. A high efficiency energy system is to be implemented in the new urban development called the Directional Centre, in order to produce electricity, heat and cold.

This polygeneration system will comprise natural gas cogeneration plants with an electrical output of about 46 MWe, with thermal cooling facilities (absortion and adsorption chillers) and a district heating and cooling network within the Science and Technology Park, which represents the core of the Directional Centre and has a thermal demand of 74.000 MWh for heating and 152.000 MWh for cooling.

To promote the use of renewable energies in Spain, the system will also include RES represented by a gasification biomass plant of 1 MWe, mainly fuelled by wood waste from the furniture industry or by subproducts from agricultural processes, and a solar thermal plant of 2000 m2 of collectors that will produce hot water for cooling purposes.

A Communal Energy Management System (CEMS) that integrates supply and demand will be implemented to optimise the system exploitation. This polygeneration system will be implemented in several stages, according to the pace of development within the Directional Centre. The results of the first stage will determine the suitability of implementing greater RES in subsequent stages.

This project will make sure that the residential and the industry buildings as well as the scientific park are supplied efficiently with innovative energy. The exceptional approach in this project is that the whole energy is produced with power-heat-cold-coupling. The innovative character consists of different integrated systems for the advanced production of electricity, i.e. of warmth and cold in one net.

In this heat cooling net an innovative management system adjusts the raw energy consumption to the inquired quantity consumed. Consumption centres are meant to supply industry and service buildings efficiently with energy. Only residential buildings are excepted, since these are to be supplied by private investors.

Arquata
The Italian project Arquata, coordinated by the Fiat Research Centre, is part of a larger initative aimed at promoting integrated energy systems based on distributed generation (co-generation and renewable energies). The initiative involves the relevant stakeholders in the region, such as public administrations, utilities, research centres and users.

The overall Arquata District Contract is a detailed programme including several measures of urban and social requalification such as the refurbishment of the council buildings, the realisation of green areas, the creation of common spaces dedicated to social activities, social and occupational development of the district, the improvement of mobility, the creation of small commercial spaces.

The different measures on the supply side aim at achieving energy efficiency through system integration. To supply district heating and electricity demand in the most efficient way, gas fired co-generation will cover the bulk of the energy demand. The co-generation unit is heat demand driven, so that additional solar thermal energy would reduce the co-generation unit operating hours and thus reduce economic operation. However, to have a share of renewable energy, the high rise office building will integrate multifunctional photovoltaic panels as sun-shading devices.
The energy efficient energy supply system will contain:

• A natural gas modular co-generation plant (0.9 MWel, 1.1 MWth) to be installed at the ATC commercial building.
• An absorption chiller, thermally coupled to the co-generation plant, placed in the ATC commercial building that will provide cold for the climatisation of the ATC building itself.
• Modification of the district heating distribution grid to provide heat storage for peak management.
• Photovoltaic modules to be integrated in the facade of the ATC commercial building as Sun-shading devices with a total peak power of 50 kW.
• Additional photovoltaic modules to be installed on the roofs of the council buildings with a total peak power of 100 kW.

The excess electricity produced by the co-generation plant will be provided to the distribution grid. ATC will install telematic electricity meters for each of the customers/exchange points with the distribution grids in order to monitor all the electricity flows in the Arquata area.

Observer Communities
Within each project region and outside of them, a network of associated communities is set up to disseminate the project experience and to replicate the project results. More advanced communities speed up the learning curve for communities just starting the process, and a living network of European communities is formed. Communities outside the regional circles will be attracted to participate in the process.

The associated communities will transfer the project results into other regions and to the key players in administration and industry. 19 Eastern and Western European and several Canadian communities have already registered. The number of associated communities will be enlarged during the project phase.


POLYCITY is part of the CONCERTO initiative, launched by the European Commission. CONCERTO is addressing the challenges of creating a more sustainable future for Europe’s energy needs by applying an integrated approach towards Energy Efficiency measures combined with the increased use of Renewable Energy Sources on a local level. Currently, nine projects and their communities are carrying out demonstration activities.

References:
The POLYCITY project website.

The CONCERTO program's website.

1st European Conference on Polygeneration website.