In most developed cities the systems that deliver and consume energy, such as electricity networks or gas grids, were built up over centuries. With so much change in technology over the past few decades, the design principles on which these systems were built are often out-of-date and hidden in layers of precedent.
Today, drivers such as speed, flexibility, proximity and self-sufficiency outstrip traditional factors such as certainty and lowest capital cost. This enables engineers, striving for ultimate energy efficiency, to cross the supply/demand boundary and use innovations from the digital revolution and changes in energy technology to release us from precedent and enable us to build on the principles of holistic and systemic integration.
Against the backdrop of climate change, this creates a number of exciting opportunities to create efficiencies that were unimaginable just a decade ago.
Embed flexibility as a key part of the project brief
We spend much time debating the ‘right’ solutions to drive down carbon emissions of urban energy systems. So in the UK, for example, this centres on whether the government should promote electrically-driven heat pumps or combined heat and power (CHP) led district heating. CHP can be the lower carbon solution when the gas supply has a lower carbon footprint than electricity from the grid – but as we decarbonise our electricity supply, heat pumps begin to compete in carbon terms. The problem is that nobody knows exactly how successful countries will be in decarbonising their electricity grids – so solutions should plan for various scenarios that take into account all likely developments in the national energy sector. It should also be noted that aspects such as air quality implications, space availability, security of supply, and restrictions on refrigerant should also feature in determining the optimal solution.
Looking at problems as uncertainties to be tested rather than fixed assumptions, the answer is to embed flexibility in outcomes, certainly for the longer term but even on a daily or hourly basis. And modern systems allow us to do just that. Power-to-gas technology enables us to convert renewably generated electricity into more easily stored gas at times of low demand, interseasonal thermal storage allows us to store wasted summertime heat in the ground for use in winter, and improvements in battery technology mean electric vehicles can store energy and feed this back into the grid at times of low capacity.
The art is to know when to redirect surplus/waste energy for immediate use elsewhere, and when to store it to plug future capacity gaps. The answer lies in more accurate forecasting of near-time supply and demand conditions and an improved understanding of the energy cascade (the energy lost in conversion between one form of energy and another). For an emerging community with little connection to outside utilities and the restrictions of ‘spinning reserve’, it is easier to envisage developing a ‘plug and play’ power system, where flexibility and measurement of ultimate efficiency is as crucial to the brief as cost effectiveness and revenue certainty.
Community energy and the rise of the prosumer
Thanks to the growth of small-scale renewable energy projects, clean energy no longer flows just from utility providers to consumers, but also in the opposite direction such that residents can contribute to the energy resilience of their communities. Taking advantage of this change doesn’t just require more agile system architecture but also transactional ability.
And it doesn’t just stop with buying and selling energy; emerging transactional revolutions such as Blockchain mean we can imagine a future where surplus electricity from one occupant’s roof-top PV panels could be exchanged for an evening’s baby-sitting or any other service.
Use peak power limitations to drive energy reduction and demand management
Emerging or expanding ‘off-grid’ settlements have more opportunity to embrace new approaches to energy supply than is possible in well-established urban centres already reliant on ubiquitous utility-connected systems. Furthermore, battery storage is becoming a real contender for resilience in the context of solar generation, with some speculating on future communities with decentralised PV/battery storage and no need for an electricity grid except in very dense areas of cities.
However, peak capacity concerns can be mitigated if connections across the supply and demand divide can be made, such that businesses and citizens benefit from responsible energy behaviour and are penalised for unnecessary waste. For example, we worked with the Abu Dhabi government to trial switching off air conditioning in selected public buildings. We discovered that, due to the natural thermal inertia of the buildings, air conditioning could be turned off for up to four hours a day before any noticeable effect on occupants. This study highlighted a value in a building’s thermal inertia – which developers could conceivably sell to utility suppliers as a mitigation measure for peak capacity issues.
In short, innovative technologies and an appreciation for the new ways that customers interact with utility suppliers can all help to streamline energy systems, driving down costs and reducing pressure on the environment. However, this requires us to approach energy projects with an open mind – eschewing old assumptions in favour of new thinking.