How SCADA RTUs Support Low Carbon Economies
25 May 2021
The UK’s electricity supply grid is facing a period of rapid transformation as the country transitions to a low carbon economy. Rising demand for electricity, caused by a shift in technologies will see a greater number of battery-enabled products connected to the National Grid.
Electric vehicles (EVs) usage is forecast to dramatically increase in the next 10 years, leading to increased demand for charging points on the LV (low voltage) side of the electricity distribution network.
Electric vehicles can be split into two types: BEV (battery electric vehicles) and PHEV (plug-in hybrid electric vehicles). In the UK, by the end of April 2021 there were over 515,000 plug-in vehicles registered (245,000 BEVs and 270,000 PHEVs) and the curve continues to grow, steeply.
To charge, these vehicles need a plug-in connection, whether at home, at work or at a third-party charging point such as a motorway services, car park or retail outlet. The transition to battery powered vehicles will therefore mean more connections being made to the LV side of the UK’s electricity network.
The UK Electricity Network
Since the 1990s, the UK has been moving away from a traditional centralised power generation model, reliant on a small number of power plants to one that is more widely dispersed. Today, coal, gas and nuclear power stations play less of a part in the UK’s energy mix, as renewable power generation becomes more widely adopted.
On some days in the UK, over 30% of the electricity available is generated from some form of renewable power installation. Whilst the majority will be derived from off-shore wind farms and solar photo-voltaic (PV) installations, pumped hydro and tidal can also play a part in the supply mix.
The UK has over 1,500 wind farms and over 430 large scale solar PV installations with the biggest being in Shotton, Deeside. These installations along with thousands of small domestic PV installations, provide power to the National Grid 365 days a year; when conditions allow.
Renewable power installations also present the electricity suppliers (District Network Operators – DNOs / utilities) with the increasingly complex task of managing multiple connection points to the grid and the balancing of supply and demand.
UK Plc typically uses over 300TWh of electricity per year. Whilst the demand fell 2.2% in 2020 due to the impact of COVID on business and industry in general, the need for electricity did not. As with most advanced nations, the UK continues to become ever more reliant on the internet to deliver immediate data connection, storage and content delivery. Without electricity the internet and many connected systems do not run.
Low Voltage (LV) Distribution
LV is the distribution side of the grid that we connect into in our homes, at work and during our daily lives. Most utilities, are investing in their electricity supply networks as countries like the UK transition into low carbon economies and adopt electricity for transportation as well as domestic heating. The rapid reduction in reliance on traditional fossil fuels (petrol, diesel, oil, coal and natural gas) is highly beneficial to the environment, in terms of the greenhouse gas reduction. However the change places increased demand onto the electricity supply network and one that can only be managed through the use of improved automation & energy storage solutions, and potentially the use of artificial intelligence (AI) based algorithms to remove network downtime.
Couple this with a rapid shift towards electric transportation and electricity-based heating and it is not hard to see why the utility companies are focused on increasing their automation and control investments. Without this, the LV distribution network could increasingly see power interruptions and equipment failures.
Battery Energy Storage (BES)
Renewable power is an instance source of electricity when the ‘right’ conditions for generation are present. What makes renewable power plants more useful in terms of meeting supply and demand, is connection to battery energy storage (BES) systems.
Often referred to as grid energy storage systems, a BES uses lithium-ion or lead acid type batteries to store generated electricity. This can be used to supplement more traditional electricity generation methods, to meet peak demands and/or equipment failures. Failures can occur in substations and distribution transformers. Power generation plants can suddenly going off-line as happened in the UK in August 2019 when two power plants (one traditional and one an off-shore wind farm) disconnected from the grid ‘near simultaneously’.
Whilst grid-scale energy storage provides one solution, in time there will be millions of electric vehicles on UK roads that will have to connect to a charging point at some time. Those vehicles installed with bi-directional chargers provide an additional resource to supplement the energy from BES type systems. Of course, the EV owners will have to have some control over when and how much stored energy they supply to the grid but this will provide them with a revenue generation opportunity and way to fund their vehicles. EVs are still more expensive than fossil-fuelled vehicles but the difference in price should reduced as scale economies take effect and incentives for vehicle to grid (V2G) become more widely used.
Remote Terminal Units (RTUs)
Substation automation revolves around the installation of the type of advanced remote terminal units (RTUs) manufactured by companies like Remsdaq. A Remdaq Callisto RTU, for example, can collect data on a local substation’s environment including meteorological data (e.g. AC & DC power, temperature, humidity, gas pressure, transformer oil temperature and local wind speeds) and supply this to the master station software in use by the utility operator. Thousands of readings may be supplied for substations across an electricity supply network to help the utility maintain uptime and prevent power outages. For reference utility related key performance indicators and measures include: Customer Interruptions (CI) and Customer Minutes Lost (CML).
The renewables revolution led to a shift in the UK’s electricity supply mix and changed the landscape in terms of wind farms and solar PV installations. The move towards electric vehicles could be as visible in terms of the number of physical charging points required. The UK has over 32million cars on the road, all of which could be powered from electricity (or hydrogen) in the future.
More fundamentally, EVs are a form of transportable energy that can be connected to the grid and used to help meet power demands when required. Not only could this help to fund their purchase but it could also help to reduce further the reliance on fossil-fuelled and nuclear-powered generating stations. The UK could become even greener in both its generation and usage of electricity, as could other countries, and this in turn could help to limit the forecast rise in global temperatures.