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4 October 2019

California floating wind plans, need transmission rethink

When we talk to people about something as simple as forecasting a technology like floating wind, they list deals which are in development. When you look at California, it is well understood that Humboldt County has some of the strongest winds and is on course to emerge as a large floating wind farm or two at some point.

But this week seems to be the first time that anyone has realized that the job includes getting the energy not just to the shore, but to somewhere that can use it and given that it is a five hour drive to San Francisco, that means either a massive transmission upgrade or a huge undersea cable.

If the designated areas offshore at Humboldt ends up being is fully developed, it should lead to around 2.1 GW of capacity, and that is far too tempting to use for powering the homes of 8 million people in the Bay Area. So how does it get there?

What has emerged as a fresh idea this week is that it can be delivered on a big undersea cable, because the nearby transmission infrastructure has not been designed to export power. This is the same problem that you usually get when you locate a new power station anywhere for the first time.

The plan now appears to be building an undersea cable to run along the coastline, simply because the entire reason for choosing floating wind in this region is because if wand farms are floating, they can be far enough offshore that they disappear over the horizon and local people and visitors won’t be able to see, and therefore moan about, them. This will preserve the natural beauty of the area, so building a 250 mile row of transmission towers, each over 1,000 feet tall, would defeat the object of protecting that natural beauty – hence the idea of an undersea cable. When we say natural beauty, think 2,000 year old Redwood and Sequoia trees, 250 feet tall – you would not want to suggest knocking down a few of those to build a transmission line.

Of course an undersea cable was always going to be needed to bring the wind farm’s energy ashore, but this is now adding considerable cost to the development and it may end up being the straw that broke the camel’s back, in the sense that profitability and therefore bankability details may suddenly change, or the local operators will have to pay for it, and charge their consumers.

You have to ask why no-one thought of this before? And of course they did, but there is so much to do when you go through the process of planning, approving and building a piece of infrastructure of this size and everyone puts their trousers on one leg at a time. Transmission guidance is now falling to the Schatz Energy Research Center at Humboldt State University. A team there is in the middle of multiple assessments in how to use the offshore wind from Humboldt Bay and just a week or so ago, received the contract for assessing the next stage – transmission.

The University release said that transmitting energy south to San Francisco would involve either (a) an expansion of the current onshore transmission system, or (b) development of a subsea transmission cable and adds that it will partner with ecological consultants at H.T. Harvey, to conduct a preliminary evaluation of environmental effects associated with subsea cable.

Given that this research needs to evaluate impacts to marine organisms and ecosystems and identify areas for future in-depth review, the route for an undersea cable still seems years away. The results of this work won’t be with us prior to March 2020 which begs the question of when does that mean offshore power is likely to begin flowing?

When we first asked about this issue, we felt that a few hundred MW would be available by around 2024, with some 50 MW usable trials before this date, say in 2021. That date is still not out of the question for 50 MW of power, but once we start looking at 500 MW in around the 2028 time frame, whatever solution opted for needs to have been funded, built, tested and approved. In June, BOEM said it hopes to have a California offshore wind lease sale during 2020. It will have to have the answers by then. It turns out that the two existing transmission options can only carry 70 MW or 150 MW of electricity.

The director of Schatz Center director is reported as saying “Anything beyond a small, pilot-scale deployment would require some sort of upgrade to the transmission infrastructure or for a fairly significant amount of local storage.”

Its final report will be on three scenarios, a 50 MW pilot, a 150 MW pilot and a 2.1 GW full build-out of the entire area.

The Bureau of Ocean Energy Management (BOEM) was asked for a lease in 2018 for Humboldt County for up to 150 MW of floating offshore wind in over 20 miles from the coast of Eureka. Partners in this included Principle Power, EDPR Offshore North America and Aker Solutions.