Out with the coal, in with the new

The critical role of buildings in the net zero transition of the grid and the solutions seeking to make it happen.

The last of the UK’s coal-fired power plants is now closing, representing an important milestone in the nation’s journey to net zero and a continuing shift away from fossil fuels in the electricity system’s fuel mix. In the wake of this milestone, we want to reflect on what this means for the grid, the critical role buildings have to play in enabling its transition, and the consequential innovation happening in this space. 

Our electricity system is moving away from centralised, dispatchable fossil fueled power plants towards a more distributed system with an increasing proportion of intermittent renewable energy, including energy generated on buildings. This has been shown to be the cheaper and cleaner option, but also presents challenges as it becomes harder to maintain supply and demand across the system and manage peak loads. Solutions exist to address this, including those to reduce energy use, decentralised and onsite energy storage as well as greater levels of flexibility at the demand side, and buildings can help with all of this. 

Buildings as prosumers of energy  

Increasingly, buildings are becoming so-called ‘prosumers’ of energy, meaning they both produce and consume electricity, making them active parts of the energy system. UKGBC’s Whole Life Carbon Roadmap for the Built Environment recommends 1 in 4 homes should have photovoltaics by 2050 if we are going to meet our net zero targets, which is also backed up by the National Grid Future Energy Scenario, so this increase is set to continue. 

Innovators are responding, with some platforms emerging to help homeowners understand the solar potential of the rooftop (see Solar Wizard and Fusion8) and others focusing on reducing upfront costs of solar via subscription models (see Sunsave). Some are focusing on the hardware itself, aiming to improve energy output, either through developing more efficient solar panels (see Oxford PV’s perovskite-on-silicon solar cell) or improving the yield of existing PVs (see Window Insulation’s solar enhancer). Others are looking at how to increase the ways in which buildings can generate electricity on site, including solar balconies and mechanical solar facades.  

It is important that the generation potential of the chosen solution and the embodied social, ecological or carbon impacts are properly considered. In addition, while some buildings will be able to be net exporters of energy, prioritisation should be given to onsite consumption to ensure energy is utilised as close to the point of generation as possible. In many cases it won’t be possible for buildings to produce all their own energy on site, let alone being net positive, in which cases renewable energy can be procured in line with UKGBC’s guidance. Where excess renewable energy is available on site there are digital platforms which can help you sell it or share with other buildings in your portfolio like UrbanChain and InRange.    

Buildings as energy stores

As well as using buildings to generate renewable energy, we also need to consider the intermittent output of solar and wind and therefore need for energy storage. Well insulated buildings themselves can also act as ‘thermal batteries’, which has the dual benefit of thermal comfort and enables the use of electricity when it is cleanest and cheapest through pre-heating or pre-cooling. This saves money and energy, while also smoothing off peak demand on the grid. This works best when buildings are thermally efficient, so retrofitting for energy performance also helps enhance flexibility.  

Innovation in battery storage for buildings includes integrated business model solutions like Field and Hybrid Greentech, thermal batteries like sand batteries, Rondo’s brick battery or phase change material thermal storage and smaller scale battery solutions like Powerwall, or the option to reuse electric vehicle batteries in homes. Vehicle-to-grid is another solution which avoids EV batteries being stationary and unused, and for homeowners, avoids the cost and impact of a dedicated home battery. Other innovative ideas in this space include turning skyscrapers into gravity batteries and using the foundations of homes as energy storage.  

  

Buildings as providers of demand side flexibility   

Due to the intermittency of renewables in the grid we need solutions that enable us to shift energy consumption to avoid peak times and therefore pressure on the grid. If you can control when energy is drawn from the grid, you can reduce the peak load and therefore the need for dispatchable power sources. UKGBC’s guidance informs how buildings should operate flexible to support the grid. 

Building-level flexibility can be achieved through using smart technologies and appliances that prioritise the use of onsite renewables and respond to the carbon intensity of the grid. For example, many home energy management solutions exist to help with demand side response (see Hive Home and gridX). Peak Power’s building energy management solutions help commercial buildings with peak shaving and various HVAC optimisation solutions (see BrainBox AI and Elyos Energy) can also time energy consumption to avoid peak times. 

 Bringing this all together

If the energy generation, storage and flexibility potential of buildings can be scaled up and aggregated it will have a significant impact at the grid level. It can also create a more decentralised and democratised energy system, where a greater variety of stakeholders can financially benefit.  

Different approaches are being explored, including virtual power plants, which are networks of distributed energy production and storage devices that can be optimised virtually to stablise the grid network, and microgrids that include generation and storage islanded from the main grid. Solutions supporting in this area include Piclo (a marketplace for local flexibility), Peak Power (offering energy storage optimisation and virtual power plants) and Axle Energy (connecting home energy assets with flexibility incentives and harnessing home batteries to balance the grid). 

 

So, as we wave goodbye to the last coal fired power plant, and with the Cumbia Coal Mine looking increasingly unlikely, it is time for buildings to come to the fore as key players in a more decentralised and sustainable energy system.  

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