The Hydrovolts Turbine

I've been spending a lot of time on posts about some of my passions--renewable energy, climate change, energy politics, and other things--I haven't spent nearly enough time on Hydrovolts technology. So, let's talk turbines.

First, some terminology:

• A turbine is the complete device, containing all parts that turn moving water into electricity, and especially the rotor, the generator, and the power electronics.
• A rotor is the part that spins in the current. For most turbines this looks like a propeller made of several blades, often similar to those used in modern wind turbines (but smaller and proportionally thicker.)
• The generator converts the mechanical energy (typically of a rotating shaft) into electricity through the use of magnets and wire windings.
• Power electronics take many forms but for turbines are necessary to both transform the electricity produced by the generator into the right form (e.g. AC or DC) and to condition the power by smoothing out voltage spikes, reducing line noise, etc.
• One important kind of power electronics is the inverter, which changes direct current (DC) into alternating current (AC). AC is used in the electrical grid, the wires in our homes and many large appliances. DC is used in cars, consumer electronics and most battery devices.
• A power cable brings generated and conditioned electricity to where it is used or to a point of transmission.
• Deployment hardware provides a way to position the turbine in service. This hardware varies widely with the size of the turbine, its type, and details of the site.

Hydrovolts is building small in-stream hydrokinetic turbines to create clean, renewable energy. The initial prototype is meeting all development objectives.

A key element of the Hydrovolts turbine is its unique rotor design. Most hydrokinetic turbines use a horizontal axis design where the axis of rotation, the shaft, is positioned parallel to the current flow. The moving current presses on two or more blades mounted radially from the shaft, causing it to rotate. Examples include the design from Marine Current Turbines:
Verdant Power has a 3-bladed design they have been testing in New York's East River (actually a tidal flow rather than a true river.) The mounting pylon is designed to rotate, allowing the turbine to capture power both on the incoming and outgoing tides:

The Clean Current turbine has several blades and differs from the previous two by placing the spinning blades in a cowling. This both allows a venturi effect to increase the speed of the water flow and somewhat shields marine life from the fast-moving blade tips:

These three designs all use horizontal axis rotors as part of their hydrokinetic turbine designs, but these companies are pursuing a different business from Hydrovolts. All primarily target utility scale power generation in tidal flows rather than small scale generation in freshwater flows. Hydrovolts business grew out of founder Burt Hamner's successful effort directing a study for Tacoma Power to assess the feasibility of tidal energy in the Tacoma Narrows. The study concluded and Tacoma Power agreed

that tidal generation will not be feasible in the Tacoma Narrows waterway for at least eight to 10 years and that other renewable resources, like wind power, are more economically feasible at this time.

Burt realized that, although feasible tidal power remained a distant prospect, the same kind of hydrokinetic technology could be shrunk down and deployed in many other places in a way that would have near-term feasibility.

Some other companies have had a similar idea.

Hydro Green Energy intends to place utility-scale devices using a horizontal axis design in permanent installations adjacent to existing hydroelectric dams. They installed their first 100kW unit in Hastings, MN a few months ago:

Free Flow Power has aggressively pursued Federal Regulatory Energy Commission (FERC) permits in the Mississippi River to place arrays of horizontal axis turbines, each with 7 blades:

Unlike these others, Canada's New Energy Corporation (EnCurrent) uses a vertical axis design. The rotating shaft extends from the rotor blades in the current flow up through a deploying raft to the generator and electronics above the surface:

The Hydrovolts rotor design is different from all of these, as it uses a cross-axis design where the rotating shaft is perpendicular to the water flow and parallel to the water surface. The design is similar to a paddlewheel or old-fashioned water wheel with one very significant difference: the Hydrovolts design is fully submerged. It is like a paddlewheel that can spin entirely under water:


The Hydrovolts cross-axis design has several significant advantages over competing designs:

• Simple: The flipwing blades are flat sheets rather than more complicated propeller blade designs. Flat blades can be made in many places and of many materials without expensive machinery or costly tooling.
• Robust: Because the blades are simple the turbine suffers little loss of efficiency if they are damaged, e.g. by denting or warping. Foil designs will be more severely impacted.
• Safe: The Flipwing turns at the speed of the current and has no tips or edges that could slice marine life, e.g. fish.
• Low fouling: Initial tests show that water-borne debris rolls over the top of the Flipwing, unlike with horizontal axis turbines which become easily entrained with material that wraps around the shaft.
• Adaptable: Almost all competing designs have a swept area (the working cross-section of the current) that is circular, so non-circular channel geometries cannot be efficiently harnessed. The Hydrovolts Flipwing is rectangular, and can be built to exactly match water flows of different dimensions, such as those that are wide and shallow.
• Scalable: The Hydrovolts Flipwing design can be manufactured to fit watercourses of almost any size both by scaling the individual device and by ganging together multiple turbines to maximize the swept area of an available channel.
• Easy Deployment: The Hydrovolts turbine is fully submersible and floats in the current. No watercourse modification (dams, penstocks, pilings, poured concrete) is needed. The turbine can literally be tossed in and held in place with deployment hardware as simple as two chains anchoring the turbine to each bank. (Other deployment hardware and options are available.)
• Low Cost: Simple rotor design, easy installation, and a compact design keep manufacturing and deployment costs low, resulting in much faster capital ROI for buyers.

Initial in-water tests like that in the video above demonstrate that the device spins when entirely under water at a speed that matches the flow of the current. Subsequent testing using a custom-designed raft produced RPM, torque, and power numbers in line with theoretical predictions. The rotor was fixed in the water below the raft, and a chain drive was used to bring the rotational characteristics above the waterline to the monitoring and test equipment:

The raft was placed in the water and towed behind a research vessel at carefully calibrated speed, simulating the current flow of a stationary turbine in a flow of the same speed:

The Hydrovolts team used these and other results to improve the prototype design and to attach an initial generator design:

Company founder and Flipwing inventor Burt Hamner has continued to lead the Hydrovolts effort to produce a new generation of improved hydropower devices:

Further in-water tests using the boat-tow method continue to yield good results:

Recent lab test results validate the power output Hydrovolts expects its production units to make. Additional prototyping work is ongoing. While there are various design and optimization issues still to be finalized, we are pleased with the excellent results and the rapidity of our current progress. Based on the prototyping success, Hydrovolts is building the first of several demonstration units:

This unit will be placed in service within the next 3 months, with others to follow based on the needs of our development effort and based on feedback and interest from our customers.

Those interested in learning more or hosting a demonstration unit are invited to contact us.

Power from water^TM. The light bulb is on!

Awakening to Monsters

It's hard to think clearly when you're sleepy. It's harder still when listening to someone who is not talking sense.

In 2007 MIT Professor John Reilly co-authored a study [pdf] estimating costs of addressing climate change. John Boehner, Mitch McConnell and other blundering elephants in the GOP recently seized on the study, took some numbers out of context, used some facile math, and trumpeted their alarming news that addressing climate change would cost every American household a "tax" of more than $3,100 per year. Professor Reilly wrote them a letter [pdf]:

It has come to my attention that an analysis we conducted examining proposals to reduce greenhouse gas emissions, Report No., 146, Assessment of U.S. Cap-and-Trade Proposals, has been misrepresented in recent press releases distributed by the National Republican Congressional Committee. The press release claims our report estimates an average cost per family of a carbon cap and trade program that would meet targets now being discussed in Congress to be over $3,000, but that is nearly 10 times the correct estimate which is approximately $340. [...] Our Report 160 shows that the costs on lower and middle income households can be completely offset by returning allowance revenue to these households.

Despite his efforts to explain their error and get a correction, the GOP just likes the scary tax meme too much. Many have criticized the GOP for knowingly lying about this, and yesterday their motive was called out (via):

Few except special interests and politicians who do their bidding would argue that limiting emissions that put human health and the environment at risk puts a burdensome “tax” on American families and businesses.

OK, I know what you're thinking--this must be a rant from one of the usual suspects, but no--surprise! It's in a press release from the Republicans for Environmental Protection (REP). Who?

Turns out the REP has been around since 1995 and their web site features the sensible tag line: "Conservation is conservative." I couldn't say it better myself. A quick perusal of their web site shows an interesting mix of positions, predictably supporting John McCain in last year's election, but also nakedly heretical positions on such subjects as conservative scepticism on climate change, the need to stop mountain-top destruction for coal, hope for less party lockstep with the fossil industry, and even how drilling in ANWR won't lower fuel prices.

The REP states they are "not affiliated" with the national or any state GOP entity, and, unsurprisingly, they get no financial support from any GOP entity either. Yet how refreshing to find that there is a reality-based faction of the GOP (via):

Conservatives, of all people, should not ignore basic principles of economics. Such tactics, which are designed to score political points and gain headlines, are a disservice to American citizens, who urgently need Congress to debate the climate issue constructively. Voters are counting on their elected representatives to work together across party lines to develop balanced legislation to reduce greenhouse gas emissions, lower America’s dangerous dependence on oil, and help us move more quickly to a more diversified, robust energy economy.

A blog entry by REP's policy director Jim DiPeso details the errors pointed out by Reilly to Boehner's willful distortions:

Mistake No. 1: Boehner and company confused the revenue raised by selling emissions allowances with the cost of reducing emissions, which are different concepts.

Mistake No. 2: The price of emissions allowances reflects the marginal cost of avoiding the last ton of emissions, but there are ways to reduce emissions that cost less than cutting out that last ton.

Mistake No. 3: The average cost of emissions reductions per household would depend mightily on how allowance revenues would be used. Would they be spent on residential energy efficiency incentives? Workforce retraining in coal country? Rebates for low-income households? Dividend checks for every legal resident? Those are only a few of the ideas on the table. Each individual option and combination of options would yield a different cost outcome. And Congress isn’t close to settling on an answer.

Mistake No. 4: This is the truly embarrassing one. An economics major who made a boneheaded slip-up like this would get a red “F” on his term paper. I’ll let Reilly explain the error: “The costs are borne over time and it is wrong to produce a simple average of such costs as that does not take into account the time value of money.”

This manifestly mendacious manipulation of the truth by GOP leaders was so egregious that the St. Petersburg Times gave them it a "Pants on Fire" rating on the PolitiFacts Truth-o-Meter saying:

If Boehner and McConnell had simply misstated the results of the MIT study, the Truth-O-Meter would have been content giving this one a False. But for them to keep repeating the claim after the author of the study told them it was wrong means we have to set the meter ablaze. Pants on Fire.

So, we have the Congressional GOP leadership misrepresenting a scholarly study to support a willfully ignorant and scientifically bankrupt position, using sophomoric economic analysis to frighten people, and refusing to back down in the face of proof of their falsehoods, even when exposed by conservative Republicans. All of this rather begs the question: What does it mean to be a conservative? Some political blogs have been remarking for a while that there is a growing divergence between "Republicans" and "conservatives" and some better-known conservatives who were not part of the GOP leadership stood on the sidelines in the last election following the clearly unconservative reign of George Bush. Bush and Dick "Deficits don't matter" Cheney have completed a 30-year long Republican co-opting of conservatives into a deeply radical agenda of (among other things) faith-based policy-making. The unifying intellectual framework of these Republicans has been a hostility to science that encourages violence to the truth. At long last conservatives awake from their sleep of reason to behold the monsters.

Time for a new pragmatism:

The American public is interested in leaders who recognize and operate in reality. The American public is interested and desires leaders. The American public is tired of outright deceit from politicians. And, as long as the Republican Party leadership is intent on rejecting reality, intent on pandering truthiness, and in obstructing, rather than leading, it won’t have an electoral future.

Wrote TulipFarmer in the comments:

There was a time when conservatives believed in good science and engineering - they called it "Yankee ingenuity". It was Yankee ingenuity that built bridges, sky scrapers, and won world wars. It grew food, and gave Americans the longest life span in the world. Climate change is like gravity, it is not something to debate, it is something to measure. And, it has been measured. We should measure it again, but debating it is not going to change those measurements. (We should also keep going out and getting better measurements of gravity.) What is worth debating is what to do about global warming. We need to be very smart about what we [do] with respect to global warming. There is no left and right, no Republican and Democrat, there is no "them and us", there is only smart and dumb.

Like in the old adage about cutting the Easter ham in half, conservatives have been allied with the Republicans for so long they hardly seem to remember the original reason why. An honest and lucid reappraisal would be timely if only to freshen conservative ideas and separate them from their use as shallow slogans to dress meaningless rituals to further the Republican quest of power for its own sake. If conservatives can truly awake and throw of the torpor of their suicide pact with the Republican party they may find political relevance for themselves and their ideas. Such an awakening would be good and welcome, and perhaps even lead, shall we say, to morning in America.

Focus The Nation

From the Focus The Nation web site:

On Jan. 31, 2008, Focus the Nation's inaugural Civic Engagment campaign organized the largest teach-in in US history—educating nearly 1 million people on climate change at 1900 institutions—landing significant press in all major outlets including TIME, New York Times, Newsweek, MSNBC, CNN.com, NPR and major dailies in each state. Youth organizers were rock stars. They created partnerships with academic and business leaders who helped them grab the reins of their future and connect their campus with more than 64 members of Congress and hundreds of state and city officials.

In addition to forging thousands of intergenerational partnerships in congressional districts across the country on the issue of climate change, we heard loud and clear from our key organizers in every state that they were ready to build the clean energy future. The clean energy economy is here. And Focus the Nation can help you join it. This year's Civic Engagement campaign is the Nationwide Town Hall on America's Clean Energy Future, occuring in Congressional Districts across the country on April 18th, 2009.

Get involved. Congress is starting to turn the long-overdue idea of addressing carbon emissions with a first draft of an actual plan using a cap-and-trade system. Educating as many people as possible about the reality of climate change, the role humans play in it, and the damage we are doing are critical to building support for addressing it. And address it we must. As the mechanic in the old oil filter ad said, "you can pay me now or you can pay me later." Paying now would be very affordable according to a thorough McKinsey study:

The macroeconomic costs of this carbon revolution are likely to be manageable, being in the order of 0.6–1.4 percent of global GDP by 2030. To put this figure in perspective, if one were to view this spending as a form of insurance against potential damage due to climate change, it might be relevant to compare it to global spending on insurance, which was 3.3 percent of GDP in 2005. Borrowing could potentially finance many of the costs, thereby effectively limiting the impact on near-term GDP growth. In fact, depending on how new low-carbon infrastructure is financed, the transition to a low-carbon economy may increase annual GDP growth in many countries.

Paying later? Not such a good deal, either in money, or in lives.