MICROGRIDS PROVIDE SOLUTIONS TO TODAY’S ENERGY CHALLENGES

A port city on Kodiak Island in Alaska. A remote town in Australia. A Red Cross centre in Kenya. A research station in Antarctica. What all these places have in common is a high level of energy self-sufficiency achieved by means of renewable energy and microgrids supplied by ABB. The company is a bellwether and the market leader in microgrid technology with well over 70 references around the world.

Microgrids are small-scale power networks – or self-contained, local electrical systems that can operate equally well whether or not connected to a central grid. Microgrids often incorporate on-site renewable energy sources like wind and solar, as well as customised battery storage systems.

Solar and wind power were previously seen as marginal and expensive forms of energy generation. They have now become competitive in windy and sunny places. Their growing popularity is down to the associated technologies having become more sophisticated and cheaper.

“Renewable energy can now be generated, decentralised and brought to where there is demand, which is why its use is growing extremely rapidly all over the world. There are several reasons for this. The Western world wants to cut carbon dioxide emissions, and developing countries want to use it to cater for their rapidly growing energy consumption. Often the use of renewable energy is an economical way to generate electricity”, says Matti Vaattovaara, Vice President, Sales, at ABB.

The move from large, centralised power generation units to increasingly decentralised systems is a true energy revolution. Renewable, locally generated energy capacity is expected to more than double, and wind and solar power are expected to account for 50 per cent of all renewable energy by 2040.

CHALLENGES POSED BY UNRELIABILITY AND INFLEXIBILITY

Renewable energy has its own challenges: even the windiest places are not always windy, and no sunny spot gets the sun 24 hours a day. It is easy for a large central grid consisting of multiple power plants to adjust its output in real time, but wind farms and solar parks are too small to do so. The solution lies in microgrids, which are capable of alternating between decentralised resources, energy stores and traditional power sources, such as diesel generators.

“Microgrids make it possible to flexibly integrate the generation and consumption of renewable energy either independently or with the help of a central grid”, Vaattovaara explains.

Self-contained microgrids balance supply and demand locally. This can be achieved with the help of local diesel generators or a gas-fired power plant and often also battery storage systems where electricity can be stored and released from as necessary. Battery storage systems and flexible loads are key to maximising the use of renewable energy. The output of microgrids that are connected to a central grid can also be adjusted with the help of the central grid.

“The central grids in many countries are not as powerful as the one we have in Finland, and power cuts are therefore common. The sources of back-up power are not always sufficient, and a fault can cause a whole building or an entire district to lose power. Microgrids can be used to supply renewable energy locally while there is a fault in the central grid. This way, even microgrids that were not intended to be self-contained end up operating self-sufficiently due to problems in the central grid.”

SAVINGS AND LOWER EMISSIONS

Microgrids can help communities to reduce or eliminate the use of diesel generators or other fossil-fuel sources. Vaattovaara gives an example: a remote town in Australia that was previously powered by diesel generators. The fuel had to be brought to the town from thousands of kilometres away. A microgrid solution has allowed the town to considerably increase the use of solar power, which has cut the consumption of diesel by more than 400,000 litres and carbon dioxide emissions by 1,100 tonnes per year.

“Microgrids are an excellent solution for remote locations with not much infrastructure. They help to support the central grid and improve the quality of electricity. They can also be used to optimise power generation costs by supplying electricity from battery storage systems instead of using diesel generators. Microgrids are key to maximising local renewable energy generation”, he adds.

Because microgrids are typically located at or near the place where energy is used, they are inherently efficient. And because the components of a microgrid – including the automation technology, batteries, power converter and control systems – can easily be transported by container, they can be standardised, pre-tested and quickly installed.