Economics and technology developments are changing the landscape of the power generation sector. Over the last 20 years, there has been a movement away from large centralised power stations towards decentralised generation close to the site of use.
The price of solar photovoltaic panels has dropped dramatically and is set to continue this trend. Combined heat and power technology, generating electricity and heat close to the site of use with gas engines is also now well-established cost effective technology.
The global weighted average levelised cost of electricity (LCOE) of utility-scale solar PV is forecast to drop by 40% by 2020, to $60/MWh, according to a new report from the International Renewable Energy Agency (IRENA). This follows a 73% drop in the LCOE of utility-scale solar PV between 2010 and 2017. For onshore wind price drops are also entrenched.
Battery storage technology costs are following a similar trend with projected cost reductions of 50-60% projected by IRENA to 2030.
These cost reductions are meaning decarbonisation of electricity supply is becoming much more practical and cost effective.
However, the intermittency of renewables such as solar and wind are a challenge, battery storage technology is only suitable for relatively short releases of electrical power. Embedded generation, particularly that within island mode microgrids is sensitive to supply and demand challenges along with frequency and loading rate changes.
This means hybrid power generation solutions are becoming more frequently deployed.
Microgrids typically consist of a number of different power generation technology types and draw upon the benefits of renewable energies, storage technologies and gas or diesel engines. The combination and synchronisation of different types of power generation technology can be referred to as ‘hybrid power generation’.
Microgrids typically form three distinct types – grid connected, island mode or grid connected microgrids that can be disconnected and operate in island mode.
There are also a number of distinct applications including microgrids linked to an unstable power generation network – such as that is common on the African continent, microgrids linked to a stable power grid that can be affected by natural disasters such as in the United States, or microgrids in remote areas such as in the Australian mining sector.
My company, Clarke Energy, (a Kohler company), and specialist in gas engine based power stations is seeing benefits to their customers in deploying application engineering skill sets for application in hybrid power generation scenarios.
One recent example is the OK Plast microgrid in Nigeria. Here the industrial captive power plant user had elected to use pipeline natural gas for power generation with 3 of GE’s J420 Jenbacher gas engines. Their manufacturing plant operates on island mode isolated from the unstable Nigerian power grid. The gas engines had back up with diesel gensets.
The customers facility was involved in the manufacture of plastic products with machinery that imposed frequent ‘relentless’ frequency swings of 20-200kW.
The solution proposed and delivered by Clarke’s engineering team was for the deployment of an ultra-capacitor system. This energy storage product is able to charge and deploy power rapidly to support the stable operation of the microgrid, reduce the need for the third gas engine and hence improve fuel efficiency and carbon emissions.
Remote areas of Australia are known for their prolific levels of sun. Many mines are located significant distances from electricity distribution networks. Whilst pipeline gas is a cost effective and low carbon emission solution for localised power, there are also benefits to combining gas engines with solar energy. Clarke Energy is now able to offer gas engines with solar photovoltaics and storage technology to meet the needs of customers in the field.
There is however no one-size fits all solution for microgrids. Each one is typically designed and procured with the specific requirements of the customer in mind and the local environmental resources. An understanding of the end users’ needs is essential therefore matching appropriate generation and storage technologies to provide an engineered solution.
 IRENA (2018) Renewable Power Generation Costs in 2017 https://irena.org/publications/2018/Jan/Renewable-power-generation-costs-in-2017
 IRENA (2017) Electricity storage and renewables: Costs and markets to 2030 https://irena.org/publications/2017/Oct/Electricity-storage-and-renewables-costs-and-markets
 Clarke Energy (2018) OK Plast Hybrid Power Plant Solution https://clarke-energy.com/2018/ok-plast-hybrid-power-plant-solution/