Europe has embraced offshore wind. Will the US?

Wind energy has made dramatic gains in Europe, rising from 2% of total power generation capacity in 2000 to 15% in 2015. In the past few years, much of this growth has come from new offshore wind farms. Thanks largely to falling costs, this trend is expected to continue.

The United States, on the other hand, has been slow to adopt the technology — the nation’s first offshore turbines came online late last year.

We asked Cameron Dunn, an energy expert in Arup’s Houston office, to weigh in on offshore wind’s American prospects.

How feasible or desirable is this form of energy in the US?

There is a key gap in the generation of electrons, specifically in the most populated areas in the United States. Major population centers tend to form around large bodies of water — for example, the northeastern US, around New York, and the coastal cities of California. Having this power demand next to the offshore source is, of course, the best-case scenario for offshore wind.

New York is one of the largest demand centers for electricity. People who want to buy electricity there happen to be sitting effectively in the water, on islands. They pay much more than the national average because of the difficulty of getting large amounts of electricity into that highly dense urban area.

Currently their grid is fed by all kinds of sources from around the northeastern United States: coal-fired plants, nuclear plants, gas plants, some hydro. But those plants are located quite far away from New York City, and electricity does not do well traveling over great distances. You lose energy for every mile of transmission.

Offshore wind, which would be located about 10 or 15 miles offshore — much, much closer than other large-scale new generation in the area — could generate tens if not hundreds of megawatts of electricity, with minimal loss due to transmission. So it’s very attractive.

If that’s the case, why haven’t we seen this take off?

Offshore wind is quite complicated, and certainly more challenging than onshore wind. There’s more risk involved; you have to consider waves, boats, fishermen, and marine habitats, for example. You need specialized equipment to reach the windmills, so they’re harder to service and harder still to install. Because of all this, offshore wind has always been more expensive than onshore alternatives.

Other parts of the world are showing that it is possible to do offshore cost-effectively. In Europe, offshore wind costs are dropping significantly. But their regulatory systems have been developed over time to suit offshore wind development, and in general the wholesale price of electricity is higher than it is here.

Offshore wind is much more complicated than onshore wind.

In the US, some people think we’d be much better off working to generate new capacity either with traditional methods or renewables like solar rather than developing offshore wind. From their perspective, it really comes down to cost.

Are onshore and offshore wind exactly the same, other than their location? Does either have any substantial advantages or disadvantages beyond this?

Scale is everything for energy generation. With onshore wind, the size of the turbine, and therefore how much energy you can produce, is limited. The blades get so big that we can’t transport them — they won’t fit on trucks or the roads.

That issue goes away when you’re offshore because there are no roads. You can make the blades and the tower and the nacelle as big as you want. Currently the larger offshore turbine can generate about 8.3 megawatts, twice what an onshore windmill can do. To produce the same amount of energy as an offshore wind farm, you would need at least double the number of onshore windmills, if not triple.

Offshore turbine manufacturers are continuing to increase the size. They plan on reaching 12-megawatt, even 15-megawatt turbines in the next five to seven years.

One proposed offshore farm in Nantucket Sound has been in limbo for about 15 years. What does this say about the public perception of offshore wind in the US?

In that case, the offshore wind development was actually within a bay, surrounded by land and residents. The plan was for about 100 windmills to be installed in the middle of the bay, in the residents’ line of sight and obstructing the navigable area of the bay. The locals said, “We don’t want that, thank you very much!”

It just really brought home the point that many people are particularly uncomfortable with this idea of something permanently in their space. They’ve gotten used to the idea of energy infrastructure being located somewhere else.

Are there examples where that’s been overcome?

Well, the Long Island Power Authority just made a deal for 90 megawatts of offshore wind power, set to be the second commercial development in the US. It’s intended to be online by 2020.

The key there is that the offshore site will be more than 13 miles from shore, and effectively not visible from the coast. This is becoming more common; most of the offshore developments being considered for the US are about 15 miles from shore to ensure that they don’t impact residents’ views. Reaching out this far has some cost and technical implications, but it’s become a well-established practice in the European offshore wind market.

Another interesting project that has gone ahead is visible from shore, though. It’s within a few miles from Block Island, Rhode Island. About a thousand people live there year-round, and there’s a tourist influx of about 20,000 in the summer.

The wind farm is visible from the island, but about 90% of the residents were in favor of it. The developers found a way to create a win–win scenario. Locals were paying huge amounts for energy, four to ten times the normal amount. The island was completely separate from the grid, so they were using big diesel generators, which don’t look great from a tourism perspective and are expensive.

So the developers committed to link the island to the grid and eliminate the need for diesel generation. They also promised residents that their energy bills would go down by about half. They found a situation where all these things lined up, and it worked.

Granted, there aren’t many situations exactly like that in the US.

You can point to Europe for examples of successful wind farms, but the situation there is very different. They tend to focus on climate change more than we do. They also tend to have more regulation, particularly around emissions. There are reasons for that beyond carbon. It’s more densely populated there, so it’s harder to find areas where you can locate fossil fuels or nuclear plants without seriously considering public health issues. You just won’t tolerate increased pollution in densely populated areas.

And they have different energy security issues than we do. Think of the United Kingdom. It’s an island. Its own national oil and gas resources have been in decline for the past decade or so. It’s increasingly reliant on other countries to supply its energy. From a security point of view, that’s a big negative.

How does offshore wind compare to other renewable energy sources in terms of ease and cost of implementation? Would it be more practical for the US to focus on solar, for instance?

Well, let’s go back to the New York example. New York sits a little bit north of the ideal for solar, but it still has a lot of potential. However, solar tends to need a lot of space, and you need large-scale solar farms to keep the cost down, to create economies of scale. So you could maybe take some big block of upper New York State and put in all these panels, but then you’d have to transmit that energy to the city, which is pretty inefficient. You could think about converting all the rooftops in New York City to solar, but that doesn’t seem likely to happen, and even then you’d be missing out on the economy-of-scale benefit.

There’s also hydro, but that’s not particularly advantageous for the New York area either — you need big rivers, varied topography, things that the geomorphology in that region doesn’t really lend itself to.

So the bottom line is that other renewables tend to drop out when you’re talking about New York, and you end up having a really good look at offshore wind.

Other renewables tend to drop out when you’re talking about New York, and you end up having a really good look at offshore wind.

Different renewables do make a lot of sense in other parts of the country, though. There are large, uninhabited areas relatively close to some high-demand centers. California, for example — they have both sun and land, so building a large solar farm there makes more sense.

And going back to onshore wind, look at Texas. Texas has a lot of land that has wind and very, very few people. This is one of the reasons why it’s the number one producer of wind-generated electrons in the United States.

The challenge in places like this, of course, is that they typically don’t have an urban center close by to buy the power they generate, so a lot of electrons are lost when it’s shipped somewhere else. Interestingly, when George W. Bush was the governor of Texas, he spent $1.5 billion to oversize the state’s main transmission lines. That really enabled onshore wind to take off there.

So we’ll see what the national and state governments do in the next few years around energy policy. That will really determine how these issues play out in the US.


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