Factors influencing the uptake of heat pump technology by the UK domestic sector

Enhancement of energy efficiency and introduction of newer and more efficient space and water heating technologies in the UK domestic sector are essential if the UK is to achieve its ambitious target for 2050 of reducing greenhouse gas (GHG) emissions to less than 80% of 1990 levels. The UK domestic sector currently relies heavily on conventional boilers for space and water heating even though electric or gas engine driven vapour compression heat pumps can provide heating and cooling with more than double the efficiency of conventional boilers. UK government has recently introduced laws and policies that are designed to accelerate the uptake of renewable heating technologies by domestic consumers rather than relying solely on market forces. To date despite their excellent performance heat pumps are not the primary choice of the general UK domestic consumer. Factors that may influence this behaviour have been analysed and are discussed here.     

Grate-firing of biomass for heat and power production

As a renewable and environmentally friendly energy source, biomass (i.e., any organic non-fossil fuel) and its utilization are gaining an increasingly important role worldwide. Grate-firing is one of the main competing technologies in biomass combustion for heat and power production, because it can fire a wide range of fuels of varying moisture content, and requires less fuel preparation and handling. The basic objective of this paper is to review the state-of-the-art knowledge on grate-fired boilers burning biomass: the key elements in the firing system and the development, the important combustion mechanism, the recent breakthrough in the technology, the most pressing issues, the current research and development activities, and the critical future problems to be resolved. The grate assembly (the most characteristic element in grate-fired boilers), the key combustion mechanism in the fuel bed on the grate, and the advanced secondary air supply (a real breakthrough in this technology) are highlighted for grate-firing systems. Amongst all the issues or problems associated with grate-fired boilers burning biomass, primary pollutant formation and control, deposition formation and corrosion, modelling and computational fluid dynamics (CFD) simulations are discussed in detail. The literature survey and discussions are primarily pertaining to grate-fired boilers burning biomass, though these issues are more or less general. Other technologies (e.g., fluidized bed combustion or suspension combustion) are also mentioned or discussed, to some extent, mainly for comparison and to better illustrate the special characteristics of grate-firing of biomass. Based on these, some critical problems, which may not be sufficiently resolved by the existing efforts and have to be addressed by future research and development, are outlined.     

Sustainable rural bioenergy production for developing countries

Bioenergy is a renewable energy source made from biomass, which are organic materials such as plants and animals. Until enough biomass resources to ensure energy demand in the world is available, the bioenergy obtained from biomass, there may be used for heat, electrical and transport. Main biomass thermo-chemical conversion technologies are pyrolysis, gasification, and liquefaction. Biomass can be burned to produce heat and electricity, changed to gas-like fuels such as methane, hydrogen, and carbon monoxide, or changed to a liquid fuel. Modern biomass can be used for the generation of electricity and heat using modern conversion technologies. Technological advances have made modern biomass cogeneration plants cleaner, more efficient, and, under certain conditions, cost-effective as compared to public utility grids and fossil-fuel boilers or generators. Biomass can be converted to liquid biofuels: bioethanol and biodiesel. Two biofuels are becoming more and more attractive and competitive as complementary to or substitutions for petroleum basic products, due to their economic and environmental benefits.     

生物质再燃降低燃煤锅炉NOx排放研究综述

我国能源结构以化石燃料为主,不可再生且污染严重,开发和推广应用可再生能源,逐步调整与优化能源结构,意义重大.生物质能是一种清洁可再生能源,也是当前世界能源研究热点之一.重点介绍了生物质再燃利用技术的原理和应用现状,生物质再燃技术包括直接再燃、气化再燃以及高级再燃,使用生物质用于燃煤锅炉再燃,既可以合理利用生物质,又能有效降低燃煤锅炉的NOx排放,NOx减排率可达50%～90%,具有广阔的推广和应用前景.     

Role of hydrogen in future North European power system in 2060

The Balmorel model has been used to calculate the economic optimal energy system configuration for the Scandinavian countries and Germany in 2060 assuming a nearly 100% coverage of the energy demands in the power, heat and transport sector with renewable energy sources. Different assumptions about the future success of fuel cell technologies have been investigated as well as different electricity and heat demand assumptions. The variability of wind power production was handled by varying the hydropower production and the production on CHP plants using biomass, by power transmission, by varying the heat production in heat pumps and electric heat boilers, and by varying the production of hydrogen in electrolysis plants in combination with hydrogen storage. Investment in hydrogen storage capacity corresponded to 1.2% of annual wind power production in the scenarios without a hydrogen demand from the transport sector, and approximately 4% in the scenarios with a hydrogen demand from the transport sector. Even the scenarios without a demand for hydrogen from the transport sector saw investments in hydrogen storage due to the need for flexibility provided by the ability to store hydrogen. The storage capacities of the electricity storages provided by plug-in hybrid electric vehicles were too small to make hydrogen storage superfluous.     

Valuing the attributes of renewable energy investments

Increasing the proportion of power derived from renewable energy sources is becoming an increasingly important part of many countries's strategies to achieve reductions in greenhouse gas emissions. However, renewable energy investments can often have external costs and benefits, which need to be taken into account if socially optimal investments are to be made. This paper attempts to estimate the magnitude of these external costs and benefits for the case of renewable technologies in Scotland, a country which has set particularly ambitious targets for expanding renewable energy. The external effects we consider are those on landscape quality, wildlife and air quality. We also consider the welfare implications of different investment strategies for employment and electricity prices. The methodology used to do this is the choice experiment technique. Renewable technologies considered include hydro, on-shore and off-shore wind power and biomass. Welfare changes for different combinations of impacts associated with different investment strategies are estimated. We also test for differences in preferences towards these impacts between urban and rural communities, and between high- and low-income households.     

Life cycle impacts of waste wood biomass heating systems: A case study of three UK based systems

With increasing renewable energy targets and the use of biomass for energy production, questions arise about the sustainability of differing types of bioenergy. Much has been made about the renewable transport fuel obligations and the impact the production of biofuel can have on the environment, but there has been less consideration of more small scale biomass heating systems. This work examines the life cycle impacts of the production and use of three such systems using waste wood in the South West of England. Burning of wood in the UK was reduced after the introduction of legislation to reduce smog in the 1950s, and so the impact of the emissions from the boilers has been examined. Whilst the boilers studied complied with UK emissions legislation, the emissions were the most significant impact found. However, there were differences in the emission levels depending on the loading of the boiler. In all cases the energy payback of the systems was under one year, ranging from approximately four to ten months.     

Raising the temperature of the UK heat pump market: Learning lessons from Finland

Heat pumps play a central role in decarbonising the UK's buildings sector as part of the Committee on Climate Change's (CCC) updated abatement scenario for meeting the UK's fourth carbon budget. However, the UK has one of the least developed heat pump markets in Europe and renewable heat output from heat pumps will need to increase by a factor of 50 over the next 15 years to be in line with the scenario. Therefore, this paper explores what lessons the UK might learn from Finland to achieve this aim considering that its current level of heat pump penetration is comparable with that outlined in the CCC scenario for 2030. Despite the two countries’ characteristic differences we argue they share sufficient similarities for the UK to usefully draw some policy-based lessons from Finland including: stimulating new-build construction and renovation of existing stock; incorporating renewable heat solutions in building energy performance standards; and bringing the cost of heat pumps in-line with gas fired heating via a combination of subsidies, taxes and energy RD&D. Finally, preliminary efforts to grow the heat pump market could usefully focus on properties unconnected to the gas-grid, considering these are typically heated by relatively expensive oil or electric heating technologies.     

Renewable energy resources and technologies applicable to Ireland

The energy consumed in Ireland is primarily achieved by the combustion of fossil fuels. Ireland's only indigenous fossil fuel is peat; all other fossil fuels are imported. As fossil fuels continually become more expensive, their use as an energy source also has a negative impact on the environment. Ireland's energy consumption can be separated into three divisions: transportation, electricity generation and heat energy. Ireland however has a vast range of high quality renewable energy resources. Ireland has set a target that 33% of its electricity will be generated from renewable sources by 2020 [I. Government. Delivering a Sustainable Energy Future for Ireland; 2007.]. The use of biomass, wind and ocean energy technologies is expected to play a major part in meeting this target. The use of renewable energy technologies will assist sustainable development as well as being a solution to several energy related environmental problems. This paper presents the current state of renewable energy technologies and potential resources available in Ireland. Considering Ireland's present energy state, a future energy mix is proposed.     

Bioenergy for heat and electricity in the UK: A research atlas and roadmap

The UK has a significant biomass resource, estimated at an annual 20 million tonnes, but only a fraction of this is captured effectively for energy, contributing approximately 4.1% of the UK's heat and electricity production (Department for Environment, Food and Rural Affairs, 2007a. UK Biomass Strategy: http://www.defra.gov.uk/Environment/climatechange/uk/energy/renewablefuel/pdf/ukbiomassstrategy-0507.pdf (accessed 24 May 2008)). Much biomass combustion technology may be considered as mature, although bottlenecks in the quality and quantity of feedstock are apparent, and further fundamental research is required to increase crop yield in a sustainable manner, with low-chemical inputs to ensure efficient energy balance. In the short term, it could be useful for the UK to focus on developing a limited number of bioenergy chains, linked to combined heat and power microgeneration and the use of bioenergy for community and public sector projects. This should be linked to a joined-up policy and regulatory framework. A clear strategy for land management is also required, since many competing uses for land will emerge in the coming decades, including food production, nature conservation, carbon sequestration, urbanisation and other forms of renewable energy use. This finite resource must be managed effectively. In the long-term future, considerable excitement exists about the possibility of new bioscience technologies harnessed to improve photosynthetic gains for bioenergy, including the use of synthetic biology. It may be possible to produce the designer energy plant whose outputs would include high-quality chemical and liquid biofuels. Gasification of biomass also requires further technology development.     

Biomass today: A new beginning for an old resource?

Biomass, the oldest ‘new and renewable’ source of energy currently provides about 12% of the world's total energy supply. This is predominantly in the form of combustion for use in domestic cooking or heating. There are strong economic, environmental and social drivers to move away from traditional biomass combustion to advanced thermochemical biomass conversion technologies. Peter Fardy, First Renewables UK Ltd provides an overview of the latest developments in this emerging area.     

The future of the Feed-in Tariff (FiT) scheme in Europe: The case of photovoltaics

The key objective of this study is the examination of the regulatory and policy framework of the feed-in-tariff (FiT) scheme, specifically its effect on both the electricity pricing as well as the local and European renewable energy sources (RES) market, and accordingly the definition of its feasibility as a scheme for the further development and promotion of renewable energy technologies (RETs). This work discusses the FiT scheme implementation for photovoltaics (PVs) in four case study countries - Denmark, Germany, Cyprus, and Spain. A model describing the conditions under which a FiT scheme is led to collapse is also introduced and a parametric analysis towards revealing the sensitivity of the different parameters affecting it, is delivered. The study concludes with significant policy implications that should be considered for future implementation of the scheme. For the prevention of the collapse of the scheme, the tariff's value ought to be determined by each country's government based on a set of influencing factors including the operational, capital and investment costs of each RET, the standard cost of renewable energy (RE) generation and the avoidance cost, which would be regularly reviewed depending on the excess of the annual capacity.     

Feasibility assessment of introducing distributed energy resources in urban areas of China

In this study, based on the consideration of achieving a low-carbon city, a distributed energy system is promoted by integrating combined heat and power (CHP) plant, biomass energy and photovoltaic technology, for the urban areas in China. An analytical model has been developed for estimating an economically efficient installation and operation pattern for the distributed energy system. As an illustrative example, a numerical study is conducted of feasible distributed energy system for a model area in Shanghai, while considering five scenarios with different technology combinations. According to the simulation results, although enjoying reasonable environmental merits, it is hard to diffuse the distributed generation technologies, especially some renewable ones, in the model area from the economic point of view. Currently, the most feasible technology is the natural gas CHP system, which has a cost reduction ratio of only 0.7%. In addition, the sensitivity analyses illustrate that the introduction of electricity buy-back and the reduction of biogas price can promote the adoption of some renewable technologies to some extent.     

Exergy analysis and multiobjective optimization of a biomass gasification based multigeneration system

Biomass gasification is a process of converting biomass to a combustible gas suitable for use in boilers, engines and turbines to produce combined cooling, heat and power. This paper presents a detailed model of a biomass gasification system and designs a multigeneration energy system which uses the biomass gasification process for generating combined cooling, heat and electricity. Energy and exergy analyses are first applied to evaluate the performance of the designed system. Next, minimizing total cost rate and maximizing exergy efficiency of the system are considered as two objective functions and a multiobjective optimization approach based on differential evolution algorithm and local unimodal sampling technique is developed to calculate the optimal values of the multigeneration system parameters. A parametric study is then carried out and Pareto front curve is used to determine the trend of objective functions and assess the performance of the system. Furthermore, a sensitivity analysis is employed to evaluate effects of design parameters on the objective functions. Simulation results are compared with two other multiobjective optimization algorithms and effectiveness of the proposed method is verified using various performance indicators.     

Strategic optimization of forest residues to bioenergy and biofuel supply chain

Forest residues are renewable materials for bioenergy conversion that have the potential to replace fossil fuels beyond electricity and heat generation. A challenge hindering the intensified use of forest residues for energy production is the high cost of their supply chain. Previous studies on optimal design of forest residue supply chains focused on biofuel or bioenergy production separately, mostly with a single time period approach. We present a multi‐period mixed integer linear programming model that optimizes the supply chain of forest residues for the production of bioenergy and biofuels simultaneously. The model determines (i) the location, type and size of the technologies to install and the period to install them, (ii) the mix of biofuel and bioenergy products to generate, (iii) the type and amount of forest residues to acquire and the sourcing points, (iv) the amount of forest residues to transport from sources to facilities and (v) the amount of product to transport from facilities to markets. The objective of the model is to maximize the net present value of the supply chain over a 20‐year planning horizon with yearly time steps. We applied the model to a case study in British Columbia, Canada, to investigate the production of heat, electricity, pellets and pyrolysis bio‐oil from available forest harvesting residues and sawmill wastes. Based on current energy generation costs in the region and the predicted operating costs of new conversion plants, the results of our model recommended the installation of small biomass boilers coupled with steam turbines for electricity production (0.5 and 5 MW) and pyrolysis plants with a capacity of 200 and 400 odmt day^?1. We performed a sensitivity analysis to evaluate the sensitivity of the optimal result to changes in the demand and price of products, as well as the availability and cost of forest residues. Copyright © 2014 John Wiley & Sons, Ltd.     

生物质热解气化技术的现状、应用和前景

生物质能的利用正在日益引起人们的关注。现在，生物质热解气化被用作生产燃料气的普遍技术路线，生产的燃料气被广泛应用于锅炉、发动机、气轮机或燃料电池。本文概述了目前国内外生物质热解和气化技术的现状，特别介绍了国内外几种比较新颖的技术，并且简要地阐述了这些技术的机理、应用以及优点，同时部分地给出了这些技术的流程图和示意图。     

The implications of an increasingly decentralised energy system

The UK government has signalled that the increasing use of decentralised energy forms part of its plan to achieve the UK's contribution to the EU's sustainable energy targets. Much of the technology for decentralised energy already exists, although it is not widely used in the UK. There will be need for new developments in onsite energy production, and in the delivery, integration and regulatory infrastructure to support it. Other State of Science reviews for this project describe particular energy technologies, but this paper highlights selected developments in thermal technologies and in biological processes which offer the potential for breakthroughs in converting biomass to energy. The effectiveness and deployment of decentralised energy can be enhanced by systems and infrastructure technology, not just for electricity but also in heat and biogas networks. Such systems are expected to be a focus of rapid development over the next two decades. Opportunities exist particularly in active networks, smart metering and intelligent tariff-interactive load management.     

Review of technology in small-scale biomass combustion systems in the European market

This work studied the importance of wood pellets, chips and wood logs for small- and medium-scale heat production. Pellet use can contribute substantially to reaching the renewable heat and electricity goals set by the European Union (EU) Renewable Energy Directive. Consequently, to integrate into European energy markets, pellet use must be a key piece of the EU energy policy.This study provides a wide perspective on the state-of-the-art small-scale biomass combustion units, particularly those that use pellets for fuel. Small-scale combustion units include stoves and boilers with capacities less than 200 kW. A wide market review has been conducted, including a review of the literature and information from manufacturers and test institutes. A database has been created, which includes 186 companies and offers 995 different models, providing an extensive view of the European market. The large number of new companies shows that the solid-fuel boiler market is continuously increasing across Europe. The technologies that are currently the most widely used are described and compared.     

Multi-objective,multi-period optimization of biomass conversion technologies using evolutionary algorithms and mixed integer linear programming (MILP)

The design and operation of energy systems are key issues for matching energy supply and demand. A systematic procedure, including process design and energy integration techniques for sizing and operation optimization of poly-generation technologies is presented in this paper. The integration of biomass resources as well as a simultaneous multi-objective and multi-period optimization, are the novelty of this work. Considering all these concepts in an optimization model makes it difficult to solve. The decomposition approach is used to deal with this complexity.Several options for integrating biomass in the energy system, namely back pressure steam turbines, biomass rankine cycles (BRC), biomass integrated gasification gas engines (BIGGE), biomass integrated gasification gas turbines, production of synthetic natural gas (SNG) and biomass integrated gasification combined cycles (BIGCC), are considered in this paper. The goal is to simultaneously minimize costs and CO₂ emission using multi-objective evolutionary algorithms (EMOO) and Mixed Integer Linear Programming (MILP).Finally the proposed model is demonstrated by means of a case study. The results show that the simultaneous production of electricity and heat with biomass and natural gas are reliable upon the established assumptions. Furthermore, higher primary energy savings and CO₂ emission reduction, 40%, are obtained through the gradual increase of renewable energy sources as opposed to natural gas usage. However, higher economic profitability, 52%, is achieved with natural gas-based technologies.     

Preference heterogeneity for renewable energy technology

This study explores heterogeneity in individual willingness to pay (WTP) for a public good using several different variants of the multinomial logit (MNL) model for stated choice data. These include a simple MNL model with interaction terms between respondent characteristics and attribute levels, a latent class model, a random parameter (mixed) logit model, and a hybrid random parameter-latent class model. The public good valued was an increase in renewable electricity generation. The models consistently show that preferences over renewable technologies are heterogeneous among respondents, but that the degree of heterogeneity differs for different renewable technologies. Specifically, preferences over solar power appear to be more heterogeneous across respondents than preferences for other renewable technologies. Comparing across models, the random parameter logit model and the hybrid random parameter-latent class model fit the choice data best and did the best job capturing preference heterogeneity.