Making sense of trends and data

The Storage Bottleneck in Renewables

Published 1.11.2017
Solar power generation is intermittent, there is not way around the fact. Each day the sun irradiates the earth with enough energy to power everything humans use, if only humans could collect that energy and store it. Cloudy days happen, as does nightfall.

Current power generation schemes that incorporate renewable energy tend to force utilities to take the renewable energy when it's generated, whether there's demand for the energy or not. In addition, power companies need to meet the power needs of customers when they happen— and demand for power is not constant through out a 24 hour period. Demand surges happen, and those must be accounted for as well.

If renewable power could be effectively stored— and effective storage is by definition low cost and low loss— then renewable power advocates would have a stronger argument to make to communities. With adequate storage technology, renewable power sources would provide power as fossil fuel source do now: on demand and without interruption, and at lower cost.

The purpose of this piece is to consider recent efforts and progress in renewable energy storage. Japan is leading the way. Renewable energy sources are important for a country with no oil or other fossil fuels. Japan is looking to wean itself from nuclear.

As part of a project in Kofu City, the prefecture has built a 1-MW solar power station that’s being made available to developers of storage devices who want to run tests under closed conditions, according to Masaki Sakamoto, an official in charge of the project.

This is a large scale solar power station to be used for pilot programs. And therein is part of the problem. Storage is still very much research, and utilities want no part of something that might not work. So they create small projects, that don’t necessarily scale to the real size needed.

Projects like the one in Yamanashi underline how Japan is racing to dominate a new age of energy technologies using a model similar to the one used by the nation to develop its automobile and semiconductor industries.

This model doesn’t work in the US because it’s centralized. The US market is decentralized, at least it has been in the past.

The device at the Yamanashi facility, set up by the Railway Technical Research Institute, uses a superconducting magnetic bearing that allows the wheel to spin with a minimum of friction. The superconducting technology is an offshoot of work the institute developed for trains that operate using magnetic levitation. A maglev train is being run through its paces on a test track in Yamanashi.

Superconductivity is a technology that waned as a topic of interest in the US, less so in Japan.

In November, the site added a system based on a modified nickel metal hydride battery developed by a startup called Exergy Power Systems Inc. The system has enhanced durability compared with typical nickel metal hydride batteries widely used in hybrid vehicles, according to a statement by the prefecture.

With storage, rooftop solar makes sense. Without it, it’s a pain in the neck for utilities and is dependent on subsidies and tax credits.

Japan is leading the global market in residential fuel cells after the first such devices hit the commercial market in 2009. With hydrogen still not readily available, home fuel cells in Japan use city gas delivered through existing pipes to extract hydrogen.

In the US, individual states are leading the way in storage, as was the case for wind and solar power development. Massachusetts in the latest.

Over the past three years, the Commonwealth has committed tens of millions of dollars toward energy storage deployment, produced a landmark study documenting the benefits of energy storage on the state’s electric grid, integrated storage into a myriad of state policies and programs, and is now considering implementation of a utility procurement mandate for energy storage.

If Massachusetts goes for the mandate, it will be the third state to do so. California and Oregon have done so too. Massachusetts wants 1.7 GW of storage, ultimately.

Massachusetts also now lets utilities own storage assets— and here is the reason that more existing storage assets aren’t used for renewable energy, Utilities use their market advantages to control the market and don’t let third parties enter the market. One answer is to cap the amount of storage a utility can control. Another would be to get utilities on board with renewables— though that hasn’t worked all these years.

A third answer is to build new storage assets for renewables. In New York, an old abandoned iron mine may see new life as a pumped-storage hydroelectric project. The mines are flooded, so the engineers want to circulate some of that ground water to an array of turbines a half mile underground.

While logistically complex, the plan is at the same time incredibly simple: Engineers for the proposed Mineville project would drain roughly half of the water from the mine shafts and pump the remainder into an upper chamber/reservoir. The water would then be released into a lower chamber/reservoir, powering turbines and creating electricity. The turbines would be reversed to pump the water back to the upper reservoir repeat the process.

The power to pump the water up is from solar and wind generation. If gets the approvals and gets built (in three years time) it’s the first of its kind.

The idea was first floated in 1990 as they looked for ways to generate revenue from the defunct mine. Gov Cuomo wants 50% of NY’s power to come from renewables by 2030, which is why there’s money for the project. Old mines are preferred because there are less environmental issues, given the damage has already been done.

The large-scale pumped-storage projects, which have been used for decades to meet peak demand for electricity produced by fossil fuel and nuclear plants, represent 97 percent of the nation's energy storage today.

Most of which is controlled by utility companies producing power using fossil fuels.


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