Congratulations to 2OE Class of 2009!

This year the MIT 2OE class consisted of 4 members. We asked each senior to fill out a short questionaire about their time at MIT and here are their responses:



Mike Smith-Bronstein

Plans: Nuclear Officer on a navy submarine

Favorite MIT Class: 2.005 (Thermal Fluids Engineering I) or Music of Africa

Favorite OE Memory: Watching the robotic kayak actually work in 2.017

Advice to Freshmen: Office Hours.

Kaitlyn McCartney

Plans:

Working for a small environmental and marine engineering consulting firm out of Falmouth MA and then going back to school for a Master's or PhD.. haven't decided yet! But the company will pay for it :-)

Favorite MIT Class:
Intro to Naval Arch. or Robotics

Favorite OE Memory:
Sinking our autonomous kayak in 2.017. Sad but funny.

Advice to Freshmen: Enjoy college, don't stress too much or work too hard. Its over before you know it.

Brooks Reed

Plans:

I'm entering the MIT/WHOI joint program next year, and plan to be co-advised by Franz Hover at MIT and Dana Yoerger at WHOI. I'm not sure which project I will be working on yet, but probably something related to navigation and control of AUVs. Eventually I think I'd like to be a research engineer somewhere, possibly at an oceanographic institution.

Favorite MIT Class:

Probably 2.005 or Popular Musics of the World (21M.294)

Favorite OE Memory:

I had a lot of fun with our 2.017 ROV project. Also, taking part in the first pool test of the Sea Grant Odyssey IV AUV.

Advice to Freshmen:

In terms of OE, classes aren't everything. Try to take opportunities to learn about the field from a broader perspective. It will help you stay interested, apply what you learn in class, and have good background knowledge for jobs and internships. Other than that, have fun.

Elizabeth Palmer

Plans: Working in the LNG Ships group at ExxonMobil.

Favorite MIT Class: 2.005

Favorite OE Memory: Testing the 2.011 ROV in Prof. Techet's class freshman year

Advice to Freshman: Don't take MIT too seriously.

Current Status of Tidal Power Generation Part V: Economic Analysis

Current Status of Tidal Power Generation

This is the fifth part of the first portion of a multi-part series featuring papers on OE-related topics by students from the 2.65 class. The series is intended to raise interest and awareness of ocean energy research at MIT and in the world. This portion is on Tidal Power generation and is written by James Modisette, a graduate student in course 16. His sources and the full-text with citations are available upon request.

Economic Analysis

The economics of tidal power generation are very complicated. The barrage style tidal power plants have gone through extensive testing and La Rance has demonstrated that it is an economically viable way of generating power. However, barrage style tidal power plants require massive initial capital and extensive construction time. Due to these limitations, there has been no significant interest in barrage tidal power since the early 1980s and it seems that nothing will disturb this trend.

On the other hand, tidal stream generators have the attraction of being small devices that can be installed on a piecemeal basis, thereby reducing their initial costs. This allowed for the creation of the first major tidal generation project in the U.S., Verdant Power. It also generated interest in tidal power throughout the north east and west of the U.S., as well as the U.K.. As studies of various designs, notably in the U.S., U.K., Canada, Japan, etc., are concluded, the long-term economic potential of stream turbines will become clearer. At this point, the cost of tidal stream power generation is a great unknown. Depending on which advocate is speaking, a very different conclusion can be drawn. For instance, a proposed 35 megawatts tidal stream facility beneath the Golden Gate Bridge in San Fransisco has user energy costs ranging from 6.6–7.6 cents per kilowatt hour from Electric Power Research Institute’s (EPRI’s) feasibility study [21] to 0.85–1.40 dollars per kilowatt hour from a feasibility study prepared by URS for the San Fransisco Public Utilities Commission.

One thing certainly undermines the value of the EPRI’s feasibility study, tidal power generation will be more expensive in the future than either wind or solar power, currently priced at 7 and 10–40 cents per kilowatt hour respectively. Tidal power is behind in development and a great deal of money and time needs to be spent on engineering and assuaging concerns about the environmental impact. Verdant Power claims it will spend more than five years and $2 million on environmental research, monitoring the impact of its turbines on fish and migratory birds before it will get to the final stages of obtaining the necessary permits to install more turbines and be capable of producingelectricity on a larger scale of ten megawatts. Wind and solar advocates have already spent much time on these issues, giving them a leg-up on development.

An attempt to compare the initial capital investments is presented in table 2. The numbers for tidal power are estimates, as only one “commercial” facility has been constructed and projecting unknown numbers into the megawatt scale is difficult. Table 2 indicates that with tidal power’s advantage of predictability over other renewable energy sources, it is not far from being an economically viable way to produce energy. Although, if a tax is not levied on carbon-dioxide and equivalents emissions, coal and natural gas will continue to be the only economic options.

Table 2: Estimated initial capital cost in dollars per peak kilowatts installed.










When considering renewable energy sources like tidal, solar, or wind, further economic consideration must be made. A variable power source affects the grid as a whole. There is an inherent inability for thermal energy sources to adjust their power output instantaneously when renewable energy becomes available or disappears. Either inefficiencies from the start-up costs of thermal energy sources will need to be accounted for in the grid or some form of storage will need to be added. Both of these options come with costs and consequences. Eventually someone will pay have to for this and it certainly won’t be the utility company. No plant built recently, all outside the U.S., has been built for less than $2, 000 per kilowatt of generating capacity.

An additional economic variable that must be addressed for any renewable energy is what form of subsidy is available to that energy source. Unfortunately, there are currently no U.S. federal subsidies available for tidal power, although it is a renewable energy source and one would hope that the government will begin to see it as a viable alternative. There are some states, MA, CA, RI, HI, etc., that have provided support for tidal power, either through low interest funding or subsidies and, therefore, they are the areas where development of tidal power plants is occurring. On the other side of the Atlantic, tidal power generation is receiving more significant support. SeaGen, for instance, is benefiting from U.K. support where it is receiving three times the subsidies or Renewable Obligation Certificates per megawatt hour than onshore wind farms. The extra incentives in the U.K. are helping tidal power catch up to the existing renewable energy developments.

Be sure to keep following this series, the next portion of this paper will focus on the future of tidal energy generation.

Current Status of Tidal Power Generation Part IV: Issues Surrounding Tidal Power Generation

Current Status of Tidal Power Generation

This is the fourth part of the first portion of a multi-part series featuring papers on OE-related topics by students from the 2.65 class. The series is intended to raise interest and awareness of ocean energy research at MIT and in the world. This portion is on Tidal Power generation and is written by James Modisette, a graduate student in course 16. His sources and the full-text with citations are available upon request.

Issues


Tidal-power generation, like all renewable energies, has its own set of limiting characteristics. Like wind and solar, tidal power cannot provide the constant power generation of a coal-fired power plant. A double-effect barrage or a tidal stream turbine will only produce peak power over four periods of several hours each day. There is also a variation, due to lunar and solar cycles, in the amplitude and period of the tides. However, these variations are predictable whereas wind and solar resources are at the whim of the weather. Scientists already know all the future variations in the tidal cycle. So a tidal power plant may add complexity to managing the power grid but it will not cause unexpected loss or creation of power.

Another limitation of tidal power plants is that along with the long construction times and massive amounts of capital necessary for installation of tidal barrages, they also require specific geographic coastal configurations. This leads to potentially large impacts on ports and shipping lanes and ends up with a case of NIMBY that may never be resolvable. Imagine if Jim Gordon had attempted to take over Nantucket Harbor for Cape Tidal as opposed to putting 130 turbines over thirteen miles away from Nantucket for Cape Wind. Even if they make environmental and economic sense, tidal barrages demand such a significant amount of coastal real estate that it is nearly impossible to conceive of having them in the U.S.

Tidal stream generators address this problem directly by being smaller, local units that can be placed underwater so that they are not visible and do not affect boat traffic. Tidal power generation has an environmental impact much like any other source of energy. There is no way that the construction of a tidal barrage will not alter the ecosystem of a living tidal basin, as demonstrated by La Rance. With the barrage tidal system there is a loss of seawater exchange. This loss leads to a change in the salinity of the water which can cause wholesale changes in ecosystems. The original ecosystem of the estuary where La Rance was installed was almost completely destroyed. It took the restocking of the estuary and ten to fifteen years before a new biological equilibrium
was reached.

Another environmental impact that both tidal barrages and tidal stream generators present, is a danger to fish. Tidal barrages benefit from existing hydro-power plants which also face this challenge and are being forced to develop new turbines that can operate without hurting fish. One possible solution for tidal barrages is to wait and allow standard hydro-power to solve the fish problem. Stream turbines, on the other hand, do not have that luxury. Verdant Power has already been delayed five years in the permitting process and has spent more than $2 million on environmental research.

Another limiting characteristic is that tides aren’t always close to urban populations where there is a high demand for power. For instance, there are large tides in Newfoundland but the population density is negligible. Transferring tidal power generated in Newfoundland to the urban regions of southern Canada or the Northeastern U.S. is infeasible. The capital to create the power lines to transfer the power is outrageous and by the time the power reached the cities a significant amount of energy will have been wasted in transit canceling out any benefits of generating the renewable energy.

Be sure to keep following this series, the next portion of this paper will focus on an economic analysis of tidal power generation..