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ICON Energy Windfarm Proposal - An iconic solution to a windfarm design problem

Location Selection

The methodology utilised by ICON Energy to select the location of the wind farm site will be detailed in this section. The team wanted to select the location in a logical and methodical manner whilst considering all the factors that would comprise an ideal wind farm site. Firstly, a table with each factor that the team considered important and it’s corresponding weighting was created. Each factor was then given a score out of ten, and then considering the weighting, was given a total score out of ten. The table can be seen below.

table showing all factors

Secondly, the team felt it was important to consider the initial opinions of the residents that were supplied with each location in the brief. These opinions were summarised and collated into a table as seen below.

Options

Finally, the team wanted to look at each location from an environmental perspective, so a table was collated to summarise these factors to allow for an efficient evaluation of these factors. This table can be seen below.

Environmental Perspective

When considering all three tables, it was deemed that location 4 was the best site to build on. It scored highest in the weighted average table, and the only real drawbacks in the other two tables were that the windfarm could affect tourism and provide no benefit to the community, both factors the team felt they could mitigate, as well as the coastal location however this could be mitigated through efficient design

Social Impacts

ICON Energy team is dedicated to a harmonious intergrowth between community and the wind farm project. On one hand, efforts will be made to maintain interactive communication between the community and developers. On the other hand, specific community engagement plans come up to mitigate the negative effects brought by the project and achieve sustainable development.

Realization of Interactive Communication

Freephone numbers and freepost email addresses will be set up to provide basic interaction channels. Also, to make the residents fully aware of their accessible channels and the rights to voice for themselves, door-knocking and drop-in sessions shall be held regularly to strengthen the bond with community.

Community liaison group will be maintained to improve consultation efficiency, which help collect, sort and express community’s demand. Meanwhile, the group is expected to have some of the power over the use of community benefit fund, which will achieve effective community self-management if the empowerment is properly monitored.

Financial support

Direct financial compensation will be allocated considering the disturbance brought to the community, especially during the construction stage. It could also be used to mediate unexpected dispute.

Community benefit fund will be approved to provide solutions to various demand from the community, whose purpose and use strategy should be flexible. For example, considerable amount of this fund should be used to develop local tourism for it caters for community’s prominent attitudes. Similarly, education resources could be proposed to upgrade as long as there is demand for that.

Engagement Plan

Guarantee of community’s quality of life will be given priority to along all stages. The layout of turbines is designed carefully to create exclusion zone of noise and shadow flicker, along with which the impact will be further mitigated through specific technical methods. Also, community-friendly commuting plans will be made to ease traffic congestion based on investigation into local daily schedule.

Tourism industry will be highly supported through hiring consulting firms and local practitioners to derive constructive guidance to achieve a prospecting development.

Additionally, efforts will be made to equip the wind farm with educational facilities. Exhibitions and open days can be held to convince people of a renewable future. At the same time, developers will seek for cooperation with local schools.

A local employment rate will be guaranteed within the construction, operation and maintaining process of the project. Contracts could be signed to confirm that.

Definitely, there are other community concerns the developer dismiss at this stage. Early-stage surveys and continuous interaction will hopefully make community’s voice responded to.

Environmental Impacts

Minimising Impact on surroundings

The two main ways of mitigating impacts is to avoid through design and reduce the impact.

To mitigate the impact of noise on the surrounding areas, wind turbines are positioned a sufficient distance away from places that could be affected by the noise such as houses, or animal habitats. To reduce the noise from the wind turbines, serrated trailing edge blades can be used to improve airflow over the blade, resulting in better aerodynamics, less turbulence, and therefore reduced noise. The turbines can also operate at reduced power to vary the speed of rotation and the pitch angle can be increased.

To mitigate the impact of shadow flicker wind turbines are positioned a sufficient distance away from places that could be affected by the noise such as houses. To reduce the impact of shadow flicker, technology can be used to stop the wind turbines from operating in certain light conditions.

To mitigate the impact on bird and bat populations, wind turbines should be positioned a sufficient distance away from protected bird and bat habitats, and to reduce the impact, wind turbines can be turned off during key periods such as when birds are migrating and things.

Location

There is no peat where the wind turbines are to be constructed which is beneficial. There are no ancient woodlands or RSPB reserves. However, there are some disadvantages of the location such as nearby bats and great crested newts. The soil is mostly clay and silt which could be problematic for building on, but with the right foundation, it will be fine.

The location is mostly grade 1 and some grade 2 agricultural land, which means the land is of excellent quality for agriculture. This could mean the land is more expensive and that some of it cannot be used to grow crops

Materials

The materials were chosen to reduce the impact of wind turbine construction on the environment, the concrete used in the foundations can be made using 'waste' materials such as fly ash, blast furnace slag and recycled aggregate. Steel reinforcement can also be used to reduce the volume of concrete required.

There are several ways to recycle the materials used in wind turbines after use, some of these include using the concrete from the foundations as concrete aggregate on other building sites.

Financial Feasibility

To find out if this project would be financially feasible the initial costs, annual costs and annual revenue were considered. The initial cost was calculated by adding the ‘balance of plant cost’, the ‘grid connection cost’, the ‘social impact cost’, the ‘environmental impact cost’ and the ‘total cost of turbines’. The total initial cost totalled over 49.6 million pounds, in order to even begin building the windfarm therefore we would need to apply for a loan. An application for 50 million pounds was submitted to the bank and we quickly got an approval for the requested loan amount at 1% interest. The annual costs for the project would be annual maintenance costs, location rent and the repayments of the loan (paid back over 10 years). The location rent has a set cost of £6,000 plus 6% of the year’s revenue for the first 13 years. After 13 years the rent set cost increases to £8,000 with 8% of our annual revenue going to the location rent. The projected annual revenue could then be calculated. First the total number of watts our farm would produce was found by using the knowledge of the turbine rating, the total number of turbines, P50 energy value etc. With the total number of MWh calculated per year we multiplied that value by the price we could sell each MWh for, this gave a us a projected annual revenue of over 43 million pounds. The total annual revenue was then simply calculated by subtracting the total annual cost, depending on what year our project was in this value was between £34,800,000 and £40,400,000. This is shown below.

Costs
Then simply by plotting the total revenue vs the total cost it could be seen that out break-even point would happen just before the end of the second year.

Graph showing Revenue vs Cost

Technical Design

The first stage of the technical design process was to select a turbine from the three options given in the project brief. The three turbine options can be seen below.

Turbine selection

Turbine 2 was deemed to be the ideal selection based on the group’s location. Moreover, Turbine 2 provided an excellent balance of power rating (MW) and cost per turbine (£). Furthermore, the hub height (m) and rotor diameter (m) were deemed to be suitable for the chosen location.

Looking at the power curve (seen below) and associated information for the 3.6 MW WTG, it was observed that the maximum average wind speed was 10 m/s which was suitable for our location which has a mean wind speed of 8.31 m/s; the selection of this WTG would also allow the turbines to function as normal with an increase in wind speed of up to 1.69 m/s without any significant losses.

Wind turbine power curve

The next stage of the technical design process was to select the number of wind turbines to be utilised within the wind farm as well as determine an optimal arrangement.

A decision was made to connect to a nearby substation with an operating voltage of 132 kV. This meant the team was limited to a wind farm with a power rating of 60 MW. To maximise the allowed power rating, 16 turbines were selected to give a power rating of 57.6 MW.

WAsP software was utilised to determine the optimal arrangement of the turbines. The turbines were placed in an area of the chosen location that would limit the impact on local residents. Moreover, the turbines were placed in a location with a consistent wind speed to allow for a consistent amount of generation for each turbine which would help reliability and efficacy.

The 16 turbines were arranged in 3 rows, with a distance of roughly 1000m (around 9 rotor diameters between them). This arrangement was done to limit significant wake losses.

Furthermore, the turbines were oriented at an angle of 35 degrees to allow the turbines to face the direction of the wind. The arrangement of the turbines with an overlay of a data grid indicating the wind speed can be seen below.

image showing turbine position overlaid by wind speed

An image of the turbine site, with the wind direction and substation being utlised both highlighted in yellow can be seen below.

turbine site

Finally, a table was constructed with all the relevant figures and calculations to demonstrate the energy feasibility of the proposed wind farm arrangement.

feasibility table

Decommissioning

Currently around 85% of a wind turbine can be recycled, including steel, cement, copper wire, electronics and gearing. Most of the metal components of the wind turbine, e.g. yaw gears, brake calipers, can be recycled once they have been decommissioned. Although this can introduce impurities into the metal however not enough that it would significantly impact the mechanical properties of the material. Other options could include selling on components after their design lifetime to be refurbished and sold on in the secondhand market, through companies such as Renewable Parts Ltd. This would be more environmentally friendly as it would require less energy than recycling the component.

The real issue with decommissioned wind turbines is the blades. This is partly due to their sheer size but mostly because they are made from non-recyclable materials, including fiberglass/resin. In Germany, a company called Zagons Logistik have identified a way to use old wind turbine blades as cement filler. This is currently the only feasible large-scale way for repurposing the blades and by 2028 it will reach capacity of the waste expected to be produced, which is far before the expected time of decommission of the proposed wind farm. Decommissioned turbine blades are mostly buried in landfill sites in the UK. Siemens have recently developed a blade that can be separated into multiple parts due to developing a novel recyclable epoxy resin so the whole blade can be recycled, and it would be great if this was incorporated into the wind turbine design. The turbine blades would also be manufactured at its Alexandra Dock factory and thus reducing transportation costs and energy.

Feasibility

Overall, the design of the wind farm had to take into consideration many factors, including physical constrains, planning constraints and the grid capacity. This lead to design we have avoiding residential areas, watercourses and MOD low flying areas. The location is also close to a suitable grid connection to harness the energy produced by the wind farm.

Risk Assessment of Construction and Maintenance

Here is a short risk assessment of some of the key hazards and risks throughout the wind turbine's lifetime.

Risk assesment

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