Caveats of green hydrogen for decarbonisation of heating in buildings

Hydrogen (H2) has rapidly become a topic of great attention when discussing routes to net-zero carbon emissions. About 14% of CO2 emissions globally are directly associated with domestic heating in buildings. Replacing natural gas (NG) with H2 for heating has been highlighted as a rapid alternative for mitigating these emissions. To realise this, not only the production challenges but also potential obstacles in the transmission/distribution and combustion of H2 must be technically identified and discussed. This review, in addition to delineating the challenges of H2 in NG grid pipelines and H2 combustion, also collates the results of the state-of-the-art technologies in H2-based heating systems. We conclude that the sustainability of water and renewable electricity resources strongly depends on sizing, siting, service life of electrolysis plants, and post-electrolysis water disposal plans. 100% H2 in pipelines requires major infrastructure upgrades including production, transmission, pressure-reduction stations, distribution, and boiler rooms. H2 leakage instigates more environmental risks than economic ones. With optimised boilers, burning H2 could reduce GHG emissions and obtain an appropriate heating efficiency; more data from boiler manufacturers must be provided. Overall, green H2 is not the only solution to decarbonise heating in buildings, and it should be pursued abreast of other heating technologies

The economics of heat pumps and the (un)intended consequences of government policy

In Europe, space and water heating account for approximately 80% of final energy use in the domestic sector. For many European countries the electrification of heat provision, via heat pumps (HPs), provides a promising decarbonisation pathway. The UK is no different, but recently concerns have been raised about the financial attractiveness of HPs given how, through various policy choices, taxes and levies are applied more heavily on electricity bills than gas bills. In this paper, we critically examine this argument by assessing the financial attractiveness of HPs across their lifetime for a typical UK household and within the current UK tax and regulatory regime. The results suggest taxes and levies do weaken the economic case for HPs: their current distribution having an unintended impact on the economics of HPs. Nonetheless, they are not the only reason for HPs comparative financial disadvantage. Upfront costs and HP performance, both influence the extent to which taxes and levies impact the economics of HPs. The results have implications for the future deployment of HPs in the UK and point towards policies to increase deployment (to drive down costs) and increase HP performance as being important

PV microgrid design for rural electrification

There are high numbers of remote villages that still need electrification in some countries. Extension of the central electrical power network to these villages is not viable owing to the high costs and power losses involved. Isolated power systems such as rural microgrids based on renewables could be a potential solution. Photovoltaics (PV) technology is particularly suited for countries like India due to factors such as the available solar resource, the modularity of the technology and low technology costs. It was identified that unlike larger isolated power systems, rural microgrids have a low energy demand as the loads are mainly residential and street lighting. Hence, these microgrids could be of a single-phase configuration. At present, the typical procedure followed by planners of rural networks does not consider the importance of PV source siting and optimisation of network structure. An improved design procedure is introduced in this work based on the use of centres of moments for central PV system sizing, simulated annealing for network structure optimisation and load flow based parametric analysis for confirming the PV microgrid structure before detailed software-based PV design. Case studies of two remote villages are used to inform and illustrate the design procedure

Potential for domestic thermal storage to absorb excess renewable energy in a low carbon future

Transition to low carbon electricity generation is key to meet the global emission targets. This requires a drastic shift from the current energy mix dominated by coal and gas to renewables especially wind and solar. Due to the intermittent nature of renewable generation, the probability of generation-demand mismatch is high. This mandates the need for storage of the excess generation in order to prevent curtailment. Utilisation of domestic hot water tanks to absorb this excess provides us with an economical option at a nominal incremental cost. This paper develops a method to quantify the capacity of hot water tanks required and the potential savings in a low carbon future. The results are explained with the UK as a case study. The results indicate that between one and ten Terra Watt hours of curtailment can be expected in the UK in the year 2040. Eighty percent of this energy can be captured if one-fifth of all houses in the UK are equipped with smart hot water tanks

Accelerating electric vehicle adoption : techno-economic assessment to modify existing fuel stations with fast charging infrastructure

With the increasing electric vehicle (EV) penetration, there arises an immediate need for charging infrastructure. In the future, the electrification of transportation will reduce the requirement of existing fuel stations, thereby rendering them obsolete. However, they are best suited to cater to the charging demand of EVs as the drivers are accustomed to the locations and the incremental cost of providing this service will be lower. In this paper, we propose a novel methodology to assess the techno-economic feasibility of retrofitting an existing fuel station with EV charging infrastructure also known as Electric Vehicle Supply Equipment (EVSE). To further enhance the value proposition, the potential of integrating Battery Energy Storage System (BESS) with EV charging infrastructure, which results in the reduction of grid connection costs, is studied. The sustainability of the proposed system is improved with additional onsite Photovoltaic (PV) generation. The proposed methodology is implemented for the UK as a case study. The configurations in this study are designed based on the technical considerations involved in retrofitting a typical fuel station as a fast charging facility for EVs. From the results, it is observed that the configurations with 4 EVSE, 1 BESS, and 8 h of operation and the configuration with 4 EVSE, 1 BESS, and 1 PV system for 8 h of operation are economically viable. The abovementioned configurations are the most economically feasible configurations in terms of the Net Present Value (NPV), Internal Rate of Return (IRR) and the Discounted Payback Period (DPP) amongst the other configurations considered in this study. The proposed methodology indicates that though the connection cost is the dominant factor affecting the feasibility, the use of BESS with or without PV can reduce the connection cost by almost 90% depending on the capacity of BESS. The methodology acts as a decision support tool to select a techno-economically feasible configuration of EVSE, BESS, and PV. Graphical abstract: [Figure not available: see fulltext.]

Geospatial analysis to identify promising car parks for installing electric vehicle charge points : an Oxford case study

Historically in the UK, uptake of electric vehicles (EVs) has been dominated by those with off-street parking. In fact, a recent report by Deloitte found that nearly 90% of EV drivers currently charge privately. However, if we wish to meet the UK Government's targets of net zero by 2050 and no further sales of fully internal combustion engine vehicles after 2030, EV charging will need to be made accessible to those without driveways. Local Authorities and the companies they work with have a significant role to play in infrastructure planning to get ahead of the curve of accelerating EV uptake. This Visualising Transport Geography article investigates whether it is possible to identify locations for public EV chargers which may be more valuable to residents

Impact of public and residential smart EV charging on distribution power grid equipped with storage

The large-scale penetration of electric vehicles (EV) in road transport brings a challenging task to ensure the balance between supply and demand from urban districts. EVs, being shiftable loads can provide system flexibility. This work investigates the potential role of smart charging of EVs in mitigating the impact of the integration of a mix of residential and public EV charging infrastructure on power networks. Furthermore, the impact of integrating solar photo-voltaic (PV) and battery energy storage systems (BESS) has been explored where BESS improves PV self-consumption and helps in peak shaving during peak load hours. Annual losses, transformer congestion, and cost of electricity import assessment are detailed by considering the power network of Stockholm as a case study. Smart charging with loss-optimal and cost-optimal charging strategies are compared to uncoordinated charging. The cost-optimal charging strategy is more favorable as compared to the loss-optimal charging strategy as it provides more incentives to the DSOs. The loss-optimal charging strategy reduces 35.5 % of losses in the network can be reduced while the cost-optimal solution provides a 4.3 % reduction in the electricity cost. The combined implementation of smart charging, PV, and BESS considerably improves energy and economic performance and is more effective than EV smart charging alone

Second-life battery systems for affordable energy access in Kenyan primary schools

As the world transitions to net zero, energy storage is becoming increasingly important for applications such as electric vehicles, mini-grids, and utility-scale grid stability. The growing demand for storage will constrain raw battery materials, reduce the availability of new batteries, and increase the rate of battery retirement. As retired batteries are difficult to recycle into components, to avoid huge amounts of battery waste, reuse and repurposing options are needed. In this research, we explore the feasibility of using second-life batteries (which have been retired from their first intended life) and solar photovoltaics to provide affordable energy access to primary schools in Kenya. Based on interviews with 12 East African schools, realistic system sizes were determined with varying solar photovoltaic sizes (5–10 kW in 2.5 kW increments) and lithium-ion battery capacities (5–20 kWh in 5 kWh increments). Each combination was simulated under four scenarios as a sensitivity analysis of battery transportation costs (i.e., whether they are sourced locally or imported). A techno-economic analysis is undertaken to compare new and second-life batteries in the resulting 48 system scenarios in terms of cost and performance. We find that second-life batteries decrease the levelized cost of electricity by 5.6–35.3% in 97.2% of scenarios compared to similar systems with new batteries, and by 41.9–64.5% compared to the cost of the same energy service provided by the utility grid. The systems with the smallest levelized cost of electricity (i.e., 0.11 USD/kWh) use either 7.5 kW or 10 kW of solar with 20 kWh of storage. Across all cases, the payback period is decreased by 8.2–42.9% using second-life batteries compared to new batteries; the system with the smallest payback period (i.e., 2.9 years) uses 5 kW solar and 5 kWh storage. These results show second-life batteries to be viable and cost-competitive compared to new batteries for school electrification in Kenya, providing the same benefits while reducing waste

Demonstration of a whole energy systems accelerator

This paper presents a novel testing and demonstration platform, named the Whole Energy System Accelerator (WESA), developed by PNDC and Energy Systems Catapult (ESC). This platform enables real households to interact in real time with network hardware in a closed feedback loop. At the distribution level, rapid decarbonisation of heating and transport and the growing penetration of distributed energy resources can result in new patterns of generation and demand. Consumers on a local network will collectively influence the network state, however the prevailing market arrangements and consumer preferences will determine individual reactions to this state. The WESA testing and demonstration platform enables a holistic exploration of interaction between networks and domestic consumers, i.e. impact of domestic loads on a network under different scenarios and the level of demand side flexibility achieved by different market structures. This paper presents the architecture of the WESA platform. A test scenario where a physical EV charger is integrated and controlled within the core WESA data flow and the results of the first real life demonstration of the feedback loop are also presented. The WESA platform can be used to simulate future scenarios with consumers switching to LCTs and the impact on the network assets, and to test and demonstrate different possible management/incentive approaches including market options for achieving demand flexibility

Impact of charging rates on electric vehicle battery life

This article synthesizes the sparse empirical literature on the impact of different charging rates on electric vehicle battery life with a focus on popular electric car models. The findings show that rapid and ultra-rapid charging cause more degradation of the most common electric vehicle batteries than fast charging, although this degradation is limited to an extent by battery management systems. The information in this article can aid in planning the expansion of different types of charging infrastructure and be used to inform drivers who are switching to battery electric vehicles