Many countries around the world face an uncertain future over the next few decades as they move to greater electricity use and at the same time look to more intermittent low-carbon generation. India, which suffered numerous serious blackouts recently is already operating near the limits of its generation and network capacity and so provides an ideal case study for testing innovative solutions that can make power networks more resilient. The research outputs from this project will provide foresights into the development of low-carbon smart grids in India and the UK.

Local Direct Current (DC) grids, supported by local storage and local renewables in residential and commercial buildings, are identified by RCUK and DST as the key enablers for demand reduction and demand flexibility (demand response). Compared with local AC grids, they have highly desirable features to provide a game-changing solution to meeting the UK and India's rising demand in a sustainable way. This is because at least 30% of our demand (mobile phones, computers, consumer electronics) is fundamentally DC consumptions [1], local DC grids can achieve 40% demand reduction by removing lossy DC to AC conversion and directly feed these demand with local renewables and local storage [2]. This electrical conversion saving is set to rise substantially when the use of electrical vehicles (EVs) -vehicle charging and discharging are inherently DC- and efficient DC lighting becomes widespread. Lighting is currently responsible for 19% of our domestic consumption [1], the EV use will increase our traditional consumption by more than 40% by year 2050 [3]. Secondly, when backed up by local energy storage and renewables, local DC grids can substantially increase demand flexibility, thus enabling users and grid operators to take greater advantage of intermittent renewables. Finally, when main grid supply experiences supply interruptions, local DC grids have less technical issues to be disconnected from the main grid and re-connected back to the grid, thus ideal for provide support to security of supply.

There are a number of smart grid demonstration projects around the world to test the viability, efficiency and economics of a local DC grid. This includes the UK's first DC network at the University of Bath, which has led to a subsequent larger DC grids demonstration project across 10 schools, 1 office and 30 homes. These demonstration projects are primarily focused on balancing energy supply and demand and energy security at the local community level. Such demonstrators are supported by expensive energy storage solutions such as batteries, which make for a weak business case that limits the scale and speed of their uptake. In response to the RCUK-DST June 2012 workshop this proposal will address the research challenge of DC Networks in smart energy grids in the UK and India. We will look at how they can be used in residential and commercial buildings in practical and economically viable ways to make better use of local community renewable energy supplies especially when central generation is over-stretched or broken.

This consortium of Indian and UK experts in Energy Networks will take the timely step of investigating how DC networks, can increase the efficiency of renewable energy-storage systems deployed at a community level to benefit the resilience of the National Grid. The research outcomes will deliver cheaper and securer solutions to complement the traditional risk-prevention techniques used by grid operators, which will have difficulties coping with the added risks of introducing low-carbon, low-inertia, low-availability generation technologies.

References:
1. DECC, "Digest of United Kingdom Energy Statistics (DUKES)".
2. "Direct-Current Voltage (DC) in Households", Peter Vaessen, KEMA, 2005.
3. DECC, "Demand Side Response: Conflict Between Supply and Network Driven Optimisation", Poyry/Bath, August 2011 .

Potential Impact:
The HEAPD project will provide a strategic direction for the future of smart electricity grids and smart consumers in the 2030-2050 timeframe and deliver tools and technologies of alternative Direct Current (DC) transition pathways to a low carbon future. The potential beneficiaries, initially in the UK and India will be utility companies, energy suppliers, manufacturers (of control systems and hardware for smartgrids), academia (power electronics, energy networks, ICT,) policy makers (governments and energy supply regulators and planners) and society.
By understanding the benefits of local DC grids and storage requirements on the national supply infrastructure, this bi-lateral project will produce results relevant to India and the UK. The immediate outcome of this project will be to provide theoretical support to existing demonstration DC projects and provide guidance for the design of future systems with the challenges of decarbonisation and security of supply. In the longer term, the project aims to have a significant impact on the flexibility of the electricity network and its consumers, who through the new design, management and economic models will be able to play a vital role in ensuring local renewable energy and storage solutions benefit both the local and national systems. Our ambition is to place the UK and India in an internationally leading position in this important field and provide a secure platform for future joint projects.
More specifically, the research outcomes will inform:
1) The design, management, control and protection of local DC grids that can address large energy deficits introduced by low carbon developments, providing a robust regional defence system to large-scale supply interruptions.
2) The magnitude of benefits from introducing local DC grids and the impact on the development of smart transmission and distribution system, consumer energy usage habits (demand reduction and demand response) and the local DC grids' business case.
3) The required innovation in tariff structure (smart tariffs and smart contracts) and social interventions such that consumers can be pursued to defer their energy use to times of higher availability and lower demand when the system is under severe stress.
Society and policy
The above technical outcomes will contribute towards us having an energy infrastructure that is fit for purpose for the UK's and India's low carbon future and therefore society. As both countries increasingly rely on low carbon energy generation which have less resilience to peak loads and weather variations, solutions such as the one proposed will benefit society by helping to ensure the lights stay on.
This research will inform regulators, policy makers and government about the paradigm shift required in the design, operation, control, management and protection of local grids and their implications to our future low carbon systems. But also inform the tariff and cost structures which will enable these technical changes to be economically viable.
This work enables communities in India and the UK to utilise their renewables generation to a greater advantage, benefit the local consumers as well as wider systems especially when the central generation and infrastructure system is over-stretched or broken. This work could also help the UK and Indian understand how DC networks present cheaper and secure alternative to meeting rising demand in a sustainable way.