Fast Demand Response as an Enabling Technology for High Renewable Energy Penetration in Isolated Power Systems

摘要

Electricity consumers living in remote areas or on islands often cannot be supplied from conventional interconnected power systems. These consumers are usually serviced by a local electricity generation and distribution system which we will refer to as an 'isolated power system' (IPS). Electricity in IPSs is traditionally generated using diesel fuel. Due to remoteness and consequent high cost of diesel fuel supply, the cost of electric energy in IPSs is high compared to conventional interconnected systems. In some locations the price exceeds US $1/kWh, which is an obvious incentive for introducing renewable energy (RE) generation. Unfortunately, RE from the two most abundant energy sources - wind and solar - incurs significant stability and reliability issues due to the intermittency of those sources. This issue has been widely discussed in the research and industry literature. Many existing conventional and isolated power systems have already integrated RE. Because a small investment can have a relatively large impact, the RE penetration in some IPSs is high (i.e. greater than 10%). Consequently, IPSs are at the forefront of high RE power systems research. One of the key lessons this research has provided is that RE sources need complementary, or enabling, technologies to deal with the attendant issues of highly variable power output, low inertia, etc. Examples of complementary technologies include: energy storage (e.g. battery, hydrogen, flywheels), new types of conventional generators (e.g. bio diesel, low load diesel engines) and, demand control (e.g. smart grid services). Most researchers see battery or hydrogen storage as the appropriate complementary technology for high renewable penetration in IPSs. However, these technologies are complex and costly. They also have integration challenges and low inertial response. Some biodiesel fuels still rely on mineral diesel to some extent (e.g. B5, B20), and while they often reduce the ecological footprint, they do not necessarily reduce operating costs. Low load diesel engines have proven that they can support high levels of RE in some applications, however this technology is still young and all impacts on operational and maintenance costs have not yet been fully assessed. This paper presents fast (i.e. sub-second) demand response (DR) as an RE enabling technology in IPSs.