Michael Psalidas – Emerging tendencies in the production, distribution and use of electrical power

It is particularly telling to look at the history behind the adoption of alternating instead of direct current, a choice that reflects the contemporary existence of the centralised model of energy use against the model of distributed generation. The predominance of Alternating Current (AC) over Direct Current (DC) was the result of an intense dispute and competition between two important personas of the economical and technological life in the USA, Thomas Alva Edison and the manufacturer George Westinghouse.

1. The future lies … in 1900

During the development of electricity, there was an initial dispute between AC and DC, around 1900. Those two basic technologies lead to two different materializations regarding the production and electricity consumption models:

The concentrative model, in which we have a few points where large amounts of electric energy are produced, and are transferred through networks of high voltage of transport and distribution to the consumption points – the consumers – that is households, companies, industries, transport media etc.
The allocated, in which we have many points of production, dispersed and near the consumption points. In this model, energy is produced in the place where it is consumed. This model is also known as dispersed or peer to peer production.

In the years that passed by since 1900, the centralized model based on the AC and its machines prevailed, and many technologies for the production, transport and distribution of electricity were developed. Similarly, devices for domestic and industrial use which operate on AC, were widely developed.

Dominant fuels for the production units, like in the rest of the industry, were the mineral fuels, such as oil and coal or the lignite.

2. Technological characteristics of electricity networks

2.1 Technological restrictions

Electric energy has certain peculiarities, some positive and some negative. One of its basic negative peculiarities is that it is not stored (at least at low cost in large quantities) and consequently, at any given moment the quantity produced must be consumed immediately. If not, phenomena of instability occur in the electric system, which among many other consequences can lead to its collapse.

A modern electric system is comprised of large production units, thermal, hydraulic, aeolian, solar etc., of networks of high voltage of transport (150 – 400 kV), of networks of medium voltage distribution (15 – 20 kV) as well as of networks of low voltage distribution (400 V).

Through the use of control systems via information and measure systems, the status of the electric system is monitored at any given moment. The Energy Control Centers are a necessary infrastructure for the Administrators of Transport Systems and they have, among others, the following capabilities:

The possibility to observe separately the status of each equipment – among the numerous that comprise the Production and Transport System-, as well as the realization of the necessary operations of the equipment. The operation of every Electricity producing Station and Transport Substation is monitored and the necessary operational controls or remote controls are realized in those spaces
All the necessary measures are taken, in order to secure unremitting supply of electricity and conservation of the frequency and the voltages at all the nodes of the system, within the context specified by the regulations
All the operational activities in the system are coordinated, in order to effect differentiations in the interconnections of the equipment in a secure and fast manner, following concrete, strict processes and Security Regulations
All the necessary actions are taken for immediate restoration of supply after emergencies or disorders in the system
All the necessary actions are taken early enough following a systematic prevision of the system load for commitment and charge of the production units, in order to satisfy any raise of demand
All necessary actions are taken on a constant basis, in order to effect the lowest possible cost of operation of the Electricity Production and Transport system

The safe, regular and economic production, transport and distribution of electricity is a complex technical and economic issue, that requires several calculations, complex mathematics and continuous adaptation, because the important parameters are changing all the time (namely the load, the capability to produce units, etc.).

Today, this system is built in a concentrative way. With the arrival of RES (Renewable Energy Sources) and the international tendency to exploit them, a hybrid model is beginning to emerge. Electric systems have no longer the concentrative structure of the past, but are now interconnected -in relation to the existing system- with low voltage RES units, mainly Aeolian and solar.

The problem that needs a solution is the one of the large penetration of dispersed production in the electricity networks. And this it is a political, technical, economic, but above all, a social problem.

2.2 The problem in Greece

The energy, environmental and economic conditions, which are formed on a domestic and international level, call for a very careful, long –standing, national planning for energy. As a report from ΤΕΕ1 (Technical Chamber of Greece) notes, Greece is in a turning point in view of the years 2013 and 2020, regarding not only electricity production but also the management of demand and energy saving.[1] The report concludes that there have been very few steps taken in relation to the latter issues, despite the constant interventions and proposals. In particular, until 2010 according to the Kyoto Protocol, and after 2013 with the expiry of the Protocol and the approval of the new Directive of the E.U. for the emissions of the greenhouse effect in the field of electric production, Greece is called upon to decide towards which direction will the framework move, for the development of the necessary new electricity production units.

The basic criteria in this planning should be the safety of supply, the total production cost per kwh, including the cost for the restoration of the environment, the environmental implications regarding pollution, the management of water resources and the production of greenhouse gases and the obligations of the country that arise from the European and international commitments.

In the current state of affairs, we detect the following tendencies:

The rise of oil prices which sweeps along natural gas prices and the conservation of intense stock exchange attributes in the future.
The rise of coal prices (there has already been a rise noted in the past few years from 60 to 130 dollars per tone) because of increased demand and the inability to augment production significantly for a long time in the future.
The obligatory compliance for the reduction of greenhouse gases not only on a local but on a regional level as well because of the increased financial impacts of pollution (among others the trading of pollutants).

The combination of the above mentioned factors calls for a very careful, long – standing energy planning, which after the first unsuccessful plan is reformed once again. The targets imposed by E.U. legislation, regarding the increase and diffusion of RES but mainly the penalization of the production of greenhouse gases, in case of failure of the plan, will render the energy supply of the country not only problematic but possibly disastrous for its development.

Given the problem of production and exploitation of lignite, and the gradual shutting down of the four oil units that are still in use (Lavrio, Aliveri), all the proclamations about new production should be studied extremely carefully in the framework of strategic planning. What also should be researched and examined is the installation of electricity production units that are directed towards RES production and that utilise the new emerging technologies.

3. Dispersed production in the electrical energy system

3.1 Microgrids

Electric Energy Systems (EES) are being restructured mainly due to environmental reasons and the installation of units of production nearer to the consumers is continuously growing. Strategies and algorithms of operation of distribution networks with high penetration of dispersed and mostly renewable production, including provisions for storage of a few hours time are developed, aided by the appropriate tools of analysis techniques. An important study is the development of methodology for the estimation and valuation of the avoiding pollutants from escaping into the environment by the network, due to the installation of Dispersed Production (DP) units.

This particular methodology must be based on the observation that the operation of DP affects the function of polluting units that are integrated in the network. Issues to be investigated are also the structure of the microgrid, which is a network of law or medium voltage distribution with connected DP units, controlled loads and storage units in order for it to appear in the network as an entity.

The method of calculation of the structure, the control, as well as the operation of the microgrid must take into account the offers of the DP units, the demands of the consumers and the limitations of supply sufficiency in cases of error in the network, in order to optimize the operation of the microgrid according to the proposed operation policies.

The calculation must be applied for various values of the market, with realistic offers of the producers and the loads providing the possibility for the limitation of supply sufficiency of the microgrid to be included or not, either only in the critical loads or for the total demand. In addition, the potential of participation of the microgrid in the pollutants trade must be examined, in order to further raise its income. The valuation of avoided pollutants from this operation shows the important decrease of avoided pollutants but also the satisfactory increase of income for producers and consumers of the microgrid alike. Finally, a methodology for the appreciation of the uncertainty of the load to be allocated in thermal units of an autonomous EES with high penetration of wind energy production should be elaborated.

3.2 Energy independent buildings

In the framework of modern tendencies, solutions that are integral scientifically, methodologically documented, technologically reliable and economically sustainable must be studied, for the creation or transformation of energy independent buildings, constituting thus a solid reference basis, for those who want in practice to apply the idea of withdrawal from conventional, polluting and costly energy sources in buildings, proving at the same time that a partial or a total empowerment of the buildings consists a realistic perspective.

Technology makes a key intervention in the field of energy optimization of buildings, by integrating soft energy applications such as solar panels, geothermal pumps, energy storage equipment and automations, in order to produce heat, refrigeration and hot water use.

In addition, with the installation of fuel cell in combination with the solar panels, the creation of a second power network with DC is feasible, which can easily feed consumers of DC that are already used in the buildings, like the high efficiency lamps, electronic devices, entertainment devices, etc. Let us not forget that the TV set, the telephone, to fax, the high efficiency lamps, the computer etc., they all operate practically with DC, which is produced by power supplies from the current network DC.

There are multiple direct and indirect results for the environment, the economy and the users:

Effective abolition of oil, natural gas and other polluting and costly forms of energy use.
Annihilation of direct pollutants such as CO2 and SO2 and their release in the environment.
Extra energy saving and reduction of air pollution.
Increase of competitiveness of the products used.
Reinforcement of entrepreneurship of the Greek sector of solar energy.
Increase of the involvement of solar energy in the energy balance of the country.
Motives for the improvement of planning and implementation of passive and active systems of energy saving.

3.3 In Greece

The hybrid systems and the microgrids aim at the big penetration of RES into the electrical networks. Especially in our country, the application of those systems presents a particular interest for the non connected islands, where electricity is obtained by means of mineral fuels combustion, oil in particular. The development of the high potential of wind and solar energy in our country’s islands constitutes a great challenge and a high priority in accordance with the European and National policy for the energy and the environment. The ultimate goal is the development of RES in order to cover the needs of the islands in energy and water by applying advanced technologies friendly to the environment.

The situation in Greece today

In 2008 there was a total of 210,9 MW of installation of renewable sources, raising the total power up to 1198,33 MW. Among 8.200 requests for the installation of 3,5 GW photovoltaic, in 2008 only 9 MW were installed.

In 2007, 125 MW wind farms were installed in our country. Until the end of 2008, 4.397 requests were submitted for the production of 47.336 MW. Among those, only 1.038 MW possess a license to operate and they correspond to a scarce percentage of 13,9%. In addition, 225 MW have a license to operate in the non connected insular system (source from the Regulatory Authority for Energy)

The case of Kythnos

Kythnos is a point of reference internationally regarding the development of technologies of utilization of wind and solar power. In 2001, CRES (Center for Renewable Energy Sources) in collaboration with the Municipality of Kythnos and German manufacturers installed and operates an autonomous microgrid in Gaidouromantra location, which provides with electricity 12 houses with dispersed photovoltaic systems and batteries via bidirectional power converters, covering thus all their needs in lighting, refrigerator operation, TV and other little electrical appliances.

Today a new phase of installation of the most up to date technology in the microgrid of Gaidouromantra is in progress. Through the installation of intelligent load controllers, which manage non critical loads, like irrigation pumps or water heaters, an optimal management of the available electricity is succeeded without central control. This technology carries a special importance for the application of advanced management techniques for the demand and saving of energy (intelligent networks), not only for the Greek islands but for the future energy systems as well, which are anticipated to include a great penetration of dispersed production.

Kythnos acquired international fame for the development of wind and solar energy and it can become a new starting point for the broader development of RES in the insular area towards the direction of sustainable development and ecological tourism that is a great challenge for the future.

Hybrid park in Icaria

A hybrid system that will operate with wind and solar energy is expected to ensure autonomy for Icaria from 2010 and after. The mayor of Raches is preparing in this island of the Eastern Aegean a model hybrid park that will combine wind and hydroelectrical energy. The project was inaugurated recently is expected to be completed in 2010. The total investment reaches 23 million Euros. The park is expected to produce annually energy equal to 11 GWh. Apart from the autonomy energy wise, Icaria will also have a significant reduction in emissions, whereas new jobs will be created.

As we already mentioned, the first hybrid park was created in Kythnos in 1983 with a combination of wind and solar energy and it made up a model autonomous system worldwide. The leadership of Kythnos has started in 1982 when the first wind park of Europe was created there.

4. The consumer becomes a producer and has a p2p involvement in the network

A last but interesting issue that deserves to be briefly mentioned is the political and social dimension of dispersed production. In the DP model, the consumer is also a producer; he consumes and lives production, since the process takes place in his own ecosystem, in the town, the village, his home.

Today, the consumer has no idea about production, the microclimate conditions of Megalopolis or Ptolemaida for example, the pollutants, the mines, and the destruction of natural wealth. He imports energy from a black box and uses it uncontrollably, blatantly and without the least environmental conscience.

Today, the production of electrical energy is usually the concern of someone else, whereas it should become a concern for every one of us.

Αναφορές

[1]- “Στροφή προς τις ΑΠΕ για τις μονάδες ηλεκτροπαραγωγής προτείνει το ΤΕΕ [TEE supports the transition to renewable sources of energy]“, Ενημερωτικό Δελτίο του ΤΕΕ [TEE newsletter], 31/3/2008

Special issue: p2p energy
Tags: energy, Greece, Michael Psallidas, p2p