Distributed generation on rural electricity networks - a lines company perspective : a thesis presented in partial fulfillment of the requirements for the degree of Master of Engineering in Energy Management at Massey University

CD held with Reference copyA number of electricity assets used in rural New Zealand yield a very low return on investment. According to the provisions of the Electricity Act 1992, after 01 April 2013, lines companies may terminate supply to any customer to whom they cannot provide electricity lines services profitably. This research was undertaken to assist the policy makers, lines companies, rural investors on the viability of distributed generation in a rural setting from the point of view of the lines company and the investor as well as to provide recommendations to the problem areas. A dynamic distributed generation model was developed to simulate critical distributed generation scenarios relevant to New Zealand, such as diverse metering arrangements, time dependent electricity prices, peak shaving by load control, peak lopping by dispatchable distributed generation and state subsides, which are not addressed in commercial software. Data required to run the model was collected from a small rural North Island sheep and beef farming community situated at the end of a 26km long radial distribution feeder. Additional operational data were also collected from the community on distributed resources such as solar hot water systems. A number of optimum distributed generation combinations involving a range of technologies under different metering arrangements and price signals were identified for the small and the medium investor. The effect of influencing factors, such as state initiatives and technological growth, on the investor and the lines companies were discussed. Recommendations for future implementation in order to integrate distributed generation on to rural networks were also given. Several key research areas were identified and discussed including low cost micro hydro, wind resource assessment, diversification of the use of the induction generators, voltage flicker and dynamic distributed generation techno-economic forecasting tools

Maximising revenue for non-firm distributed wind generation with energy storage in an active management scheme

The connection of high penetrations of renewable generation such as wind to distribution networks requires new active management techniques. Curtailing distributed generation during periods of network congestion allows for a higher penetration of distributed wind to connect, however, it reduces the potential revenue from these wind turbines. Energy storage can be used to alleviate this and the store can also be used to carry out other tasks such as trading on an electricity spot market, a mode of operation known as arbitrage. The combination of available revenue streams is crucial in the financial viability of energy storage. This study presents a heuristic algorithm for the optimisation of revenue generated by an energy storage unit working with two revenue streams: generation-curtailment reduction and arbitrage. The algorithm is used to demonstrate the ability of storage to generate revenue and to reduce generation curtailment for two case study networks. Studies carried out include a single wind farm and multiple wind farms connected under a 'last-in-first-out' principle of access. The results clearly show that storage using both operating modes increases revenue over either mode individually. Moreover, energy storage is shown to be effective at reducing curtailment while increasing the utilisation of circuits linking the distribution and transmission networks. Finally, renewable subsidies are considered as a potential third revenue stream. It is interesting to note that under current market agreements such subsidies have the potential to perversely encourage the installation of inefficient storage technologies, because of increased losses facilitating greater "utilisation" of renewable generation

[Report of] Specialist Committee V.4: ocean, wind and wave energy utilization

The committee's mandate was :Concern for structural design of ocean energy utilization devices, such as offshore wind turbines, support structures and fixed or floating wave and tidal energy converters. Attention shall be given to the interaction between the load and the structural response and shall include due consideration of the stochastic nature of the waves, current and wind

The Viability of Harvesting Corn Cobs and Stover for Biofuel Production in North Dakota

This study examines the impact of stochastic harvest field time, corn cob and stover harvest technologies, increases in farm size, and alternative tillage practices on profit maximizing potential of corn cob and stover collection in North Dakota. Using three mathematical programming models, we analyze farmers’ harvest activities under 1) corn grain only harvest option, 2) simultaneous corn grain and cob harvest(one-pass) option 3) separate corn grain and stover harvest (two-pass) option. Under the first corn grain only option, farmers are able to complete harvesting corn grain and achieve maximum net income in a fairly short amount of time with existing combine technology. However, under the simultaneous corn grain and cob one-pass harvest option, our findings indicate that farmers generate lower net income as compared to the net income of corn grain only harvest option. This is due to the slowdown in combine harvest capacity as a consequence of attaching cob harvester to the back of combine. Under the third option of a two-pass harvest system, time allocation is the main challenge and our evidence shows that with limited harvest field time available, farmers find it optimal to allocate most of their time harvesting grain, and then proceed to bale stover if time permits at the end of harvest season. As farm size increases, farmers are especially challenged in finding time to harvest both corn grain and cobs/stover. We show that a small decrease in corn yield due to changes in tillage practice can result in a large decline in the net profit of harvesting corn grain and cobs/stover.Cob, Stover, harvest field time, optimization, farm size, tillage, Crop Production/Industries, Production Economics,

The Potential for Wind Energy Meeting Electricity Needs on Vancouver Island

In this paper, an in-depth analysis of power supply and demand on Vancouver Island is used to provide information about the optimal allocation of power across ‘generating’ sources and to investigate the economics of wind generation and penetrability into the Island grid. The methodology developed can be extended to a region much larger than Vancouver Island. Results from the model indicate that Vancouver Island could experience blackouts in the near future unless greater name-plate capacity is developed. While wind-generated energy has the ability to contribute to the Island’s power needs, the problem with wind power is its intermittency. The results indicate that wind power may not be able to prevent shortfalls, regardless of the overall name-plate capacity of the wind turbines. Further, costs of reducing CO2 emissions using wind power are unacceptably large, perhaps more than $100 per t CO2, although this might be attributable to the mix of power sources making up the Island’s grid.Economics of wind power, grid system modeling, operations research

The feasibility of long range battery electric cars in New Zealand

New Zealand transport accounts for over 40% of the carbon emissions with private cars accounting for 25%. In the Ministry of Economic Development's recently released “New Zealand Energy Strategy to 2050”, it proposed the wide scale deployment of electric vehicles as a means of reducing carbon emissions from transport. However, New Zealand's lack of public transport infrastructure and its subsequent reliance on private car use for longer journeys could mean that many existing battery electric vehicles (BEVs) will not have the performance to replace conventionally fuelled cars. As such, this paper discusses the potential for BEVs in New Zealand, with particular reference to the development of the University of Waikato's long-range UltraCommuter BEV. It is shown that to achieve a long range at higher speeds, BEVs should be designed specifically rather than retrofitting existing vehicles to electric. Furthermore, the electrical energy supply for a mixed fleet of 2 million BEVs is discussed and conservatively calculated, along with the number of wind turbines to achieve this. The results show that approximately 1350 MW of wind turbines would be needed to supply the mixed fleet of 2 million BEVs, or 54% of the energy produced from NZ's planned and installed wind farms

Assessment of off-shore wind turbines for application in Saudi Arabia

This paper presents models and economic analysis of ten different wind turbines for the region of Yanbu, Saudi Arabia using the hybrid optimization models for energy resources (HOMER) software. This study serves as a guide for decision makers to choose the most suitable wind turbine for Yanbu to meet the target of 58.7GW of renewable energy as part of Saudi Vision 2030. The analysis was carried out based on the turbines initial capital cost, operating cost, net present cost (NPC) and the levelized cost of energy (LCOE). Additionally, the wind turbines were compared based on their electricity production, excess energy and the size of the storage devices required. The results show that Enercon E-126 EP4 wind turbine has the least LCOE (0.0885 $/kWh) and NPC ($23.8), while WES 30 has the highest LCOE (0.142 $/kWh) and NPC ($38.3) for a typical load profile of a village in Yanbu

Utility-scale Wind Power: Impacts of Increased Penetration

Intermittent renewable energy sources such as wind, solar, run-of-river hydro, tidal streams and wave fluxes present interesting challenges when exploited in the production of electricity, which is then integrated into existing and future grids. We focus on wind energy systems because they have an emerging presence, with new installed capacity approaching 8 GW annually. We survey many studies and compile estimates of regulation, load following and unit commitment impacts on utility generating assets with increasing wind penetration. Reliability (system reserve), observed capacity factors and the effective capacity (ability to displace existing generation assets) of wind energy systems are discussed. A simple energy balance model and some results from utility-scale simulations illustrate the existence of a law of diminishing returns with respect to increasing wind penetration when measured by wind’s effective capacity, fuel displacement or CO2 abatement. A role for energy storage is clearly identified. Finally, the scale of wind energy systems is shown to be large for significant energy production and preliminary evidence is reviewed showing that extraction of energy from the atmospheric boundary layer by such systems, when penetration levels are significant, may have potential environmental impacts.

Operations and maintenance planning for community-scale, off-grid wave energy devices

Conference paper from RENEW 2016: 2nd International Conference on Renewable Energies Offshore, 2016-10-24, 2016-10-26, Lisbon, Portugal. This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Marine Renewable Energy (MRE) has progressed towards commercialisation over the recent years but signifi-cant barriers still exist. This includes the currently high cost of energy, leaving MRE uncompetitive with re-spect to other more established renewable energy technologies. A significant proportion of this cost comes from Operation and Maintenance (O&M) activities. O&M activity can be reduced through the use of condi-tion-based maintenance scheduling. In offshore environments, the submerged location of most devices enables the use of underwater Acoustic Emission (AE), a new condition-monitoring technique. It combines acoustics (used for environmental monitoring of MRE influence on noise levels) with AE condition monitoring as used in air. This paper assesses the practicality of such an approach in complex ocean environments through detailed sound propagation modelling using the propagation model Bellhop in the Matlab toolbox AcTUP. Results show that acoustic propagation is very sensitive to variations in the shallow water environments considered. When concerning sensor placement, multiple-path interferences mean that the location of the measuring sen-sor(s) needs to be carefully considered, but might not cover all environmental variations over the several months necessary for accurate long-term monitoring. Associated to the shallow depths, these environmental variations also mean that some frequencies cannot be back-propagated easily, generally limiting access to the monitoring of Received Levels. The results presented here are the first steps toward optimizing AE sensor po-sitions and AE measuring strategies for arrays of devices.The lead author would like to thank the academic supervisors of this IDCORE project for their contributions, advice and support. Similar thanks must go to the engineers involved in developing the Squid devices at Albatern Ltd. The author would also like to thank Wave Energy Scotland, the IDCORE programme and their funding bodies, in particular the ETP (Energy Technology Partnership), for their support. IDCORE is funded by the Energy Technology Partnership and the RCUK Energy Programme; Grant number EP/J500847/1

Analysis of the optimal deployment location for tidal energy converters in the mesotidal Ria de Vigo (NW Spain)

The potential power output expected from the installation of a tidal farm near the mesotidal Ria de Vigo (NW Spain) is assessed using two different tidal stream energy converters (TEC). For this, the results of a previous resource assessment based on a 28-day long hydrodynamic simulation are used. From this data we identify the areas susceptible of hosting the farms, select the optimal location for them, and assess the total available and extractable energy for each turbine type. Finally, using a simple farm design based on standard inter-turbine separation, we estimate the expected power supplied by the farm. Irrespective of the site, the total available tidal power in the areas susceptible of hosting the farms is around 150 MW; at the optimal location, the hourly extractable power is about 22.5 MW, of which only between 10% and 15% can be harnessed by the designed farms, powering between 4411 and 6638 homes. A local analysis of the most energetic subregions within these sites increases this ratio up to 30%. Nevertheless, the power output is sufficient to fulfil the needs of between 1660 and 2213 households, depending on the chosen site and the selected TEC.Peer ReviewedPostprint (author's final draft