Date of Award

2016

Degree Type

Thesis

Degree Name

Master of Science in Ocean Engineering

Department

Ocean Engineering

First Advisor

M. Reza Hashemi

Abstract

Renewable energy can be a promising approach to supply energy for remote areas and islands, address price volatility of fuels, hedge against supply insecurities, and reduce CO2 emissions. Renewable energy has the power to create self-sufficiency in terms of electricity and the ability to be cost-effective and competitive in many areas. However, renewable energies are site specific. It is necessary to assess each case study separately to examine the available resources, environmental constraints, and socio-economic factors. Site assessments include resource characterization, technical practicability, economic feasibility, and market conditions.

The objective of this thesis is to assess the feasibility of renewable energy technologies in Cuttyhunk Island in Massachusetts, USA. Cuttyhunk Island is subjected to the constraints of islands’ electricity supply and it therefore can represent a good case study. Renewable resource assessments as well as technical, economic and market analyses have been performed to assess advantages and drawbacks of the site for the transition towards renewable energies.

Based on the analysis, which was carried out using available data and information from local residents, the feasibility of an integrated renewable energy system using wind, solar and wave power has been studied in order to supply electricity demand. The initial assessment showed that wave energy is not competitive compared to wind and solar in terms of cost and technology readiness. An integrated renewable energy system for the island was proposed, which includes a Photovoltaic-Wind-Diesel-Storage (PWDS) system. It was shown that the performance indicators for a renewable system combined with battery storage and diesel generators are the most competitive solution. The Levelized cost of electricity (LCOE) for the PWDS is estimated at $0.2587/kWh based on the available data and simplifications which were applied.

The wind turbine used in the system has a capacity of 100 kW and a portion of the electricity generated was 42.96 %. Total production of the wind turbines is 323,339 kWh/yr. The ground mounted solar arrays of the system have a portion of the electricity consumed of 42.9% with a capacity of 234.7 kW. The total energy production of the PV array is 322,867 kWh/yr. The 100 kW diesel generator accounts for 14.14 % of the electricity supplied. The battery storage system consists of lithium-ion batteries and has a capacity of 533 kWh. The storage can establish an autonomy time of 8.20 hours on average and stores 1,599,000 kWh before it has to be substituted at the end of its expected lifetime of 11.84 years. The storage ensures that the system has a renewable fraction of about 79 %.

This research shows that a self-sufficient renewable energy system is also possible for Cuttyhunk Island. The LCOE of a system with 100 % renewable energy fraction are $0.66/kWh. Subsidies for self-sufficiency however, can change these numbers, as they can contribute a proportion for the development of self-sufficient energy systems, even though a hybrid system has lower net present costs and provides electricity at lower costs.

The work in hand should be understood as a n initial feasibility study that needs to be continued with more detailed data. For instance, wind measurements should be performed on Cuttyhunk Island in order to better estimate the real wind speeds and its available power.

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