A New Meaning For Smart Grids In Europe
BY FIONA RIDDOCH
Cogeneration can enhance smart grid operation by balancing the intermittent availability of renewable fuels
Editor’s Note: The following article was provided by Fiona Riddoch, managing director of COGEN Europe. COGEN Europe is the European trade association for the promotion of cogeneration, with the goal of working toward the wider use of cogeneration in Europe. Members include power companies, power authorities, national cogeneration associations and suppliers.
As pressure has mounted on the EU electricity transmission network to accommodate an increasing variety of new electricity sources, a loose concept of “smart grids” is increasingly referred to as a necessary development from the existing system.
The European Commission has gathered a wide group of stakeholders from across the electricity supply chain and created a “Task Force Smart Grids,” challenged with coming up with a definition and preliminary outline of exactly what Europe means by a “smart grid.” For the European Union to meet its 2020 energy and climate targets, the electricity supply system has to be able to manage a significant increase in periodic renewables and a wider range of electricity supply capacities and characteristics, while still maintaining supply to the customers.
Fundamentally, the new “smart grid” concept is a bundle of functionalities, services and standards, which together will allow new supply-side possibilities to interface smoothly with changing demand-side profiles. The customer as both supplier and consumer must be accommodated, and smart metering also falls under the remit of the Task Force Smart Grids.
An updated grid designed to deliver the 2020 Energy and Climate Goals must be smart, i.e., “smart grid.” While the concept is an enabler of the 2020 goals, it’s not an end in itself. This new, more diverse, more distributed world offers some upside for cogeneration. Cogenerators need to consider how best they can enhance grid operation in this new environment and what new business opportunities this represents.
One requirement will be rapid starting, stopping and efficiency over a wide load range. A gas plant has the advantage of being fast to start, adjust and stop. Around 40% of Europe’s cogeneration uses natural gas with an additional small percentage running on other gases.
Multiple small cogenerators combined with reasonable heat buffering may play a role in the new network. In the absence of sufficient capacity to meet peak demand or in the absence
of transmission capacity, high-efficiency cogeneration using gas can adjust the supply to meet rapidly changing demand.
In addition to exhibiting rapid response, gas engines (the main cogeneration technology in the MW ranges up to 15 MW) operate efficiently over a wide load variation. A distributed generation capacity also eases transmission issues and grid losses — meeting peaking needs more locally means more efficient supply.
The intermittency of renewables, and wind in particular, demands flexibility of response for operation from other suppliers on the grid. The successful combination of cogeneration and renewables is attracting increasing attention. Today in Denmark, when the wind speed drops by 1 m/s the country needs to find an additional 350 MW of electric power capacity. Gas cogeneration has the response time to be able to adjust to such fluctuation. To maintain the necessary high efficiency of primary energy use, the system must also meet heat demands associated with the electricity demand.
Traditional cogeneration users are beginning to find new ways (such as temporary heat storage or buffering) to meet this need for flexibility. There are already some gas-based cogeneration
systems that are responding to the market needs and exhibiting more flexibility in their operating approach.
Greenhouses in the Netherlands, for example, can respond to market demand by shifting their heat and electricity needs throughout the day. In Germany, micro combined heat and power (CHP) has been identified as the solution to balancing wind in the network. LichtBlick is the largest independent energy supplier in Germany and has announced its goal to place 100 000 micro CHP systems with an electric output of 20 kW each into homes and buildings in Germany. The property owner will be provided with the cogeneration unit and a heat storage
unit and be guaranteed that the home will be supplied with heat as required.
LichtBlick would maintain ultimate control over the cogeneration unit with remote capability to manage the unit. A large heat store decouples the production of heat from that of electricity
when necessary. The multiple small units give a sensitive and responsive network of immediate capacity to create a supply of up to 2 GW.
Denmark, the Netherlands and Finland all generate over 30% of their electricity in cogeneration plants and have experience in managing distributed generation and cogeneration in their networks. The Danish district heating companies (which use cogeneration) are increasingly providing the grid with balancing services, and the Danish model shows how a combination of a high wind-generating capacity and cogeneration can run together smoothly. The Task Force Smart Grids is planning to make its first report before mid-2010.
This year’s Joint Annual Conference of COGEN Europe and Euroheat & Power will be held June 2 in Brussels, Belgium. For more information, visit www.conference2010.eu.
Source: Diesel & Gas Turbine Worldwide