| 1. |
- James, P. A. B., et al.
(författare)
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Implications of the UK field trial of building mounted horizontal axis micro-wind turbines
- 2010
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 38:10, s. 6130-6144
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Tidskriftsartikel (refereegranskat)abstract
- Building mounted micro-wind turbines and photovoltaics have the potential to provide widely applicable carbon free electricity generation at the building level. Photovoltaic systems are well understood and it is easy to predict performance using software tools or widely accepted yield estimates. Micro-wind, however, is far more complex and in comparison poorly understood. This paper presents the key findings of the building mounted (<2 kWp) turbine component of the UK micro-wind trial undertaken by the Energy Saving Trust in 2008/09. The monitored performance of 39 horizontal axis turbines in urban, suburban and rural locations is discussed alongside the accuracy of predictive wind speed tools for the sites. The performance of urban and suburban micro-wind sites in the trial was poor with annual generation of less than 75 kWh/m2 swept area, the majority of which were less than 25 kWh/m2. Good rural sites had an annual generation of between 100 and 280 kWh/m2, far less than the nominal 360 kWh/m2 (10% load factor for a typical turbine) that is often assumed. In the light of these findings, the potential impact of the UK’s latest policy instrument, the 2010 micro-generation tariffs, is considered for both micro-wind and photovoltaics.
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| 2. |
- Sissons, M. F., et al.
(författare)
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Pole-mounted horizontal axis micro-wind turbines : UK field trial findings and market size assessment
- 2011
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215 .- 1873-6777. ; 39:6, s. 3822-3831
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Tidskriftsartikel (refereegranskat)abstract
- This paper discusses the key findings of the pole-mounted turbine (2.5–6 kWp) component of the UK micro-wind trial. The real world performance of horizontal axis turbines is compared with yield estimates based on site wind speed prediction. The distribution of UK agricultural farms is overlaid with wind resource mapping to estimate the number of potential agricultural farm sites for micro-wind. The yield performance of turbines during the monitoring period was observed to be very close to that predicted by NOABL–MCS wind speed estimates. Based on an installation criterion of a maximum 12 year payback time, with a 6% discount rate and micro-generation feed in tariffs available, there are ∼87,000 farm sites for micro-wind in the UK. If 10% of these farms were to install micro-wind turbines (to a capacity of 48 kWp per farm) this would correspond to a capacity of 418 MWp, with an annual generation yield of 1025 GWh, comparable to that of a large, on shore wind farm in the UK. It should be noted that the feed in tariff considered in this paper is that available in the UK in 2011, which, at 26.7 p/kWh (∼30 Euro cents/kWh) represents a significant subsidy.
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| 3. |
- Blunden, L. S., et al.
(författare)
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Tidal current power for Indonesia? An initial resource estimation for the Alas Strait
- 2013
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Ingår i: Renewable energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 49:0, s. 137-142
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Tidskriftsartikel (refereegranskat)abstract
- Indonesia – with its many narrow straits and significant tidal range – might be expected to have considerable potential for tidal current power generation. A particularly promising site is the Alas Strait, with shallow depth, high tidal current velocity and location far from major shipping lanes. In this study, a hydrodynamic numerical model of the Alas Strait was run and validated against some tidal current velocity measurements. The results of the model were then used to estimate the practically exploitable energy resources in the strait, using a development of a method used in previous resource estimations. In this method, the incident velocity on each row of an array was extracted from the model and then attenuated based on the direction of the flow and the number of rows deep into the array. In this way, the effects of practical array shape can be simulated without the need to include computationally expensive parameterization of turbines in the model. Two scenarios were considered, with and without a maximum depth limitation of 40 m. The first scenario gave an estimate of the practically exploitable annual energy yield from the Alas Strait of 330 GW h with the second scenario nearly double at 640 GW h.
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| 4. |
- Dimitriou, T., et al.
(författare)
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Impact of current occupant behaviour on potential carbon savings in a council owned tower block undergoing retrofit
- 2014
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Ingår i: Proceedings of CIBSE ASHRAE Technical Symposium 2014.
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the impact of current user behaviour on the carbon savings from retrofit measures including Mechanical Ventilation with Heat Recovery (MVHR) in a council owned 107-flat tower block. Prior to the retrofit, temperature and relative humidity monitoring was undertaken in 18 flats for 35 days. The measurements were then used to develop occupant behaviour profiles and their relation to the heating system. Dynamic thermal simulation of the flats pre- and post-retrofit was performed using TRNSYS, with the identified user behaviour profiles as the key parameter. The results highlight that for these fuel poverty constrained flats the estimated carbon savings of retrofit will be typically half those predicted using standard rules for temperature in living spaces.
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| 5. |
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| 6. |
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| 7. |
- Bourikas, Leonidas, et al.
(författare)
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Addressing the challenge of interpreting microclimatic weather data collected from urban sites
- 2013
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Ingår i: Journal of Energy and Power Engineering. - : Scientific Research Publishing, Inc.. - 1934-8975 .- 1934-8983. ; 1:5, s. 7-15
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents some installation and data analysis issues from an ongoing urban air temperature and humidity measurement campaign in Hangzhou and Ningbo, China. The location of the measurement sites, the positioning of the sensors and the harsh conditions in an urban environment can result in missing values and observations that are unre-presentative of the local urban microclimate. Missing data and erroneous values in micro-scale weather time series can produce bias in the data analysis, false correlations and wrong conclusions when deriving the specific local weather patterns. A methodology is presented for the identification of values that could be false and for determining whether these are “noise”. Seven statistical methods were evaluated in their performance for replacing missing and erroneous values in urban weather time series. The two methods that proposed replacement with the mean values from sensors in locations with a Sky View Factor similar to that of the target sensor and the sensors closest to the target’s location per-formed well for all Day-Night and Cold-Warm days scenarios. However, during night time in warm weather the re-placement with the mean values for air temperature of the nearest locations outperformed all other methods. The results give some initial evidence of the distinctive urban microclimate development in time and space under different regional weather forcings.
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| 10. |
- Papafragkou, Anastasios, et al.
(författare)
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The impact of the GB Feed-in Tariffs and Renewable Heat Incentive to the economics of various microgeneration technologies at the street level
- 2011
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Konferensbidrag (refereegranskat)abstract
- England, Scotland and Wales planning regulations require zero carbon homes by 2016. This can be expected to accelerate the uptake of microgeneration technologies. To incentivise small low-carbon generators the UK Department of Energy and Climate Change (DECC) proposed two new systems: the Feed-in Tariffs (FIT) and the Renewable Heat Incentive (RHI). This paper investigates the impact of these two systems on the carbon performance and the economics of various microgeneration technologies under two scenarios: (a) at the single dwelling level and (b) a local microgrid at the street level. The economic implications of combining a number of houses to form a local microgrid are assessed and expressed in terms of percentage of capital investment outstanding. The paper concludes that the current structure of the FIT and RHI does not incentivise microgeneration technologies according to their carbon performance and does not favour street-level schemes such as the one investigated in this paper. However it is sufficient to drive the market forward.
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