Systems Engineering

Energy Systems Catapult collaborated with UK Power Networks (UKPN) under Network Innovation Allowance funding to investigate the behaviour of domestic electricity consumers and the distribution network supplying them under a Cold Start scenario in 2030.

With electrification of heating and transport expected to be at far higher level in the next decade, an extended power outage under severe weather conditions would lead to a sudden demand surge to levels far higher than normal peak levels as electrical devices are reactivated.

Using an innovative Dynamic Energy Systems Simulation tool, our Systems Engineering team created dynamic models using a portion of real electricity network to understand the physical impacts of fault conditions on energy assets and appliances within the network under different outage scenarios. A range of metrics were produced, including power flows, voltages, loading and balancing.

The results will allow UKPN to identify:

• Network areas with high risk of adverse effects from power restoration after Cold Start.
• Mitigation measures such as operational policies, network controls, demand-side flexibility and conventional reinforcement.
• Explore novel mitigation methods based on in-home appliance flexibility.

The Cost Reflective Pricing project investigated whether or not the fixed costs on energy bills – for network, environmental and social costs – are efficiently distributed between the standing charge and unit (per kWh) price of electricity and gas tariffs.

With these fixed costs currently recovered from the unit price, this means consumers that use more energy will pay more for the same fixed costs.

The study found that overall consumers are:

• Under-charged for the fixed costs of making energy supply available and over-charged for the units of energy they consume;
• Consumers with household generation technologies (such as solar PV) will buy fewer units of energy from the grid, so under-paid their fair share of fixed costs. Which must then be recovered in the bills of other consumers, including those in fuel poverty, increasing others energy bills.
• Consumers with household demand technologies (such as heat pumps) will buy more units of energy from the grid, so over-paid their fair share of fixed costs recovered in the unit price.

The Cost Reflective Pricing study found that rebalancing fixed and volumetric charges into the standing and unit prices respectively and moving environmental and social costs to general taxation, would more recover fixed costs more efficiently. As a result, the marginal cost of operating a heat pump would be lower than a gas boiler.

Following this study, Ofgem made some initial changes to charging consistent with the argument that network charges should have a larger fixed component and a smaller per kWh charge.

The ReFLEX Orkney project is aiming to integrate electricity, transport and heat networks in the Scottish Islands, using advanced software to balance supply and demand.

Energy Systems Catapult has supported the project with systems integration support by applying the Aspects of Integration framework to help develop their Basis of Design.

• The Basis of Design document is a record of the major thought processes and assumptions supporting design decisions made to meet the project’s requirements, together with reference to constraints such as national and international Codes and Standards.

Using the AoI framework to explore the solution architecture it was recognised that a separate design team needed to be established to take ownership of the integrated energy system design.

The design team consisted of members from each of the eight project partners with a variety of skill sets and levels of experience on the project. Therefore developing a common language to discuss a complex project was vital.

The team went on to develop an initial project Basis of Design, drawing upon Catapult systems thinking and facilitation, training in Model Based Systems Engineering and an introduction to the Enterprise Architecture software.  In the three months following its inception, the design team was able to develop a basic system model using systems engineering software and use the results to inform the Basis of Design, which was accepted by the funder UKRI as a project deliverable.