A Virtual Power Station (VPS) is a network of small, dispersed, interconnected generators which work together to provide a single, large, stable amount of electricity in the same way as a conventional power station. By using existing telecommunication networks, advanced energy management technology allows solar electricity systems across a large area to work together as one. In cooperating, the generators are able to manage their power production in order to maximise the benefit to the system owner as well as the wider electricity grid. In achieving this, the aim is to improve the economics, effectiveness and uptake of small renewable generators like solar photovoltaic (PV) and wind turbines.
The VPS Pilot is a technology trial partnership between CSIRO and Lake Macquarie City Council. The aim of the pilot is to trial the Virtual Power Station technology through a deployment on twenty distributed solar PV systems in the Lake Macquarie City Council area. These systems include Lake Macquarie households as well as Council facilities.
Readings are collected from each site and are transmitted to the central control system using mobile telecommunication networks. The control system uses this data to monitor the aggregate generation across the whole system, develops internal generation forecasts and controls the charging and discharging of batteries. This charge and discharge scheduling can be used to maximise benefit to the owner or the network – for example, storage can be used to reduce intermittency, or to shift power export to a period of maximum demand.
In this trial, due to the extra cost and complexity required, only one of the twenty deployment sites has battery storage installed.
Lake Macquarie City Council believes technology, like the VPS, will help encourage households to install solar electricity systems by improving the economics of solar systems and decreasing the payback period, which in turn reduces Lake Macquarie's carbon footprint. Embedded renewable generation, such as solar panels, helps make household energy independent and less affected by increasing energy prices. As the third-largest council in NSW, Lake Macquarie City Council has set its own target of greenhouse gas reduction for the City of 3% pa and increased renewable energy is one of the major strategies being uses to achieve this goal.
Solar Photovoltaic (PV) panels produce electricity from sunlight. Depending on the system configuration, the electricity produced can be used on-site, stored or sold directly to the electricity grid. More information on solar panels can be found at the Lake Macquarie City Council website.
Solar panels are a readily available, commercial technology which can be used by households to generate their own electricity. Because sunlight is the energy source, renewable electricity can be produced and greenhouse gas emissions are avoided.
The average Lake Macquarie household uses 24 kWh per day. To generate this much electricity, a household would need around a 5 kW photovoltaic system to receive a zero power bill. So, energy efficiency is a great place to start – whether or not you have solar!
The graphs on this website show the amount of electricity generated over the course of day for individual sites as well as the aggregate generation for the VPS as a whole. The calendar contains historical data so you can compare cloudy days to sunny days.
Individual graphs can also show interesting localised effects – say a cloud passing overhead or maybe the solar panel is shaded for part of the day.
Solar power generation can be affected by many things. This can include the angle of the panels to the sun, the movement of the sun over the course of a day, the seasonal variation in solar movement and weather effects.
On a sunny day, as the sun rises in the morning generation will begin and will increase as the sun continues to rise. In the afternoon as the sun begins to lower in the sky the solar generation will start to decrease. This results in a nice smooth curve over the course of the day – with the most power produced when the sun is right overhead.
Fluctuations can be short or long-term and can occur if clouds block the sunlight from reaching the panel. These look like sharp rises or falls on the graphs showing power output. Many fluctuations are caused by passing clouds which temporarily shade the panels and can cause a rapid drop in power generation.
One idea behind the VPS is that if there are enough sites connected – and these sites are suitably distributed – then the short-term effects at each site will not affect the VPS generation significantly and the combined system generation will be smoother.
The pilot will conclude toward the end of 2011 and the results will be evaluated by the project team. This trial will be used to improve the VPS and evaluate the market potential of this technology.