Preventing climate change is possible if we act now and adopt policies that reduce energy use by harnessing the energy efficiency potential of renewable resources. However, there is little chance of reaching this objective if our only measure of success is emissions reduction. Climate change is fundamentally a development issue, not a problem of contamination. As postulated in ‘Renewable Revolution: Low-Carbon Energy by 2030’ (Worldwatch Institute, 2009), what is really needed today is to transform the global energy system. The shift towards a sustainable energy system, based on efficiency and renewable energy, will require a complex and strongly embedded energy system to be replaced by one based on concepts such as microgrids.
Microgrids are systems that integrate power generation and energy storage and that can reduce transmission losses and improve efficiency in the use of electricity and heating. They are normally connected to a conventional centralized network. This single connection point can be switched off, allowing them to work autonomously. Furthermore, the management system and intelligent generation allow greenhouse gas emissions to be reduced. Thus, in large electricity consumers, implementing microgrids that include advanced electricity storage and management systems will contribute to resolving this environmental problem.
In this line, some of the main environmental benefits that will be obtained from a majority of users in environments of medium to high consumption using microgrids are:
- Encourages the use of renewable energy, reducing CO2 emissions.
- Reduces peak power consumption and provides ancillary services, increasing network reliability and reducing the need to generate reserve capacity in the electricity system.
- Reduce power consumption by setting manageable loads, reducing emissions of CO2.
- Reduces land use.
- Reduces losses in electricity transmission and distribution.
The use of electric transport is especially beneficial when the electricity used comes from sources with low emissions of CO2.
Moreover, as these “independent” power grid systems are deployed, and their results become more widely known, there will be greater awareness and knowledge of energy efficiency, in turn leading to:
- An increase in electricity generation from CO2-free sources, like solar photovoltaic and wind power. Thanks to the energy storage technologies, all the renewable energy generated will be consumed, even in areas with high availability of renewable energy.
- Greater stability in the grid, which will allow an increase of more than 40% in renewable energy generation by the year 2020. In addition, distributed storage will reduce the need for reserve generation capacity.
Microgrids are proposed as a solution for consumers committed to sustainable development and interested in having energy sources that are efficient, reliable and secure. Such facilities can be designed to suit the specific energy needs of each client and can work as stand-alone or connected to the main electricity grid. The incorporation of electric vehicles with bi-directional charge points provides additional electricity storage capacity, at the same time as it covers short and medium distance sustainable mobility needs. Optimized management of electricity storage reduces the number of short-duration outages. The high efficiency of electrochemical batteries, which can be fully discharged without damaging their condition, is fundamental. They cost less than other technologies and are environmentally favorable, and they allow the energy purchased at peak rate to be minimized and a lower maximum power level to be contracted. The new technologies controlling microgrids will allow companies to play an active part in managing energy, adjusting their demand to minimize costs and optimize resources.
Energy microgrids have great scope for their application, as they are a concept that can be customized to the needs and characteristics of each user or consumer. Companies with an interest in new technologies and sustainable development will soon be applying these systems, as they contribute to the efficiency of their infrastructure. Moreover, this new concept is suitable both in isolated locations and urban environments, and in low and medium power facilities. As a solution that allows sustainable energy to be used to meet power and transport needs, with guaranteed service and reduced operational costs, it is a concept that can be implemented not only in factories and commercial or operational centers, but also in hotel complexes, agricultural facilities, mining, quarrying, etc.
Projects are beginning to appear in Spain that seek to demonstrate the suitability and effectiveness of these solutions for electricity generation and distribution in small microgrid environments. One of these, called Factory Microgrid, will allow the viability of this concept in an industrial setting to be demonstrated, as it incorporates into the management of a fleet of electric vehicles a microgrid with the following components:
- A 120 kW wind turbine and a 40 kW roof-mounted solar photovoltaic installation.
- ZnBr flow batteries, storing up to 500 kWh of electricity.
- 6 bi-directional charge points (vehicle to grid, V2G) to be used by a fleet of 6 vehicles: 3 cars, 2 small trucks and 1 minibus.
- A rapid charge station for 50 kW electric vehicles.
This microgrid will allow a range of management strategies, depending on the application, to be tested and validated, generating 160,000 kWh/year free of greenhouse gas emissions, and avoiding emission of 96 metric tons of CO2, thanks to management of the electricity dispatched and the use of electric vehicles. Intelligent management will permit optimized renewable energy consumption both in transportation and in the factory’s daily work, reductions in peak energy consumption and in energy transmission and distribution losses, and will give the user a consistent electrical system, not requiring auxiliary systems that are dependent on fossil fuel.
Joaquín José Chacón Guadalix
Albufera Energy Storage